/* The map is the structure. An opened board grows on the canvas. */
.canvas-export-wrap { position: relative; flex: none; }
.topbar .canvas-export-icon { position: relative; display: grid; place-items: center; width: 32px; padding: 0; }
.topbar .canvas-export-icon svg { width: 18px; height: 18px; }
.topbar .canvas-export-icon[hidden] { display: none; }
.canvas-export-icon::after { content: attr(data-tooltip); position: absolute; z-index: 91; right: 0; top: calc(100% + 8px); width: max-content; padding: 5px 8px; border-radius: 6px; background: var(--shell-ink); color: var(--shell-surface); font: 12px/1.5 var(--ce-font-sans); pointer-events: none; opacity: 0; visibility: hidden; }
.canvas-export-icon:is(:hover, :focus-visible):not(:disabled):not([aria-expanded="true"])::after { opacity: 1; visibility: visible; }
.canvas-export-menu { position: absolute; z-index: 90; right: 0; top: calc(100% + 8px); display: grid; width: min(252px, calc(100vw - 24px)); padding: 5px; border: 1px solid var(--shell-line); border-radius: 12px; background: var(--shell-surface); box-shadow: 0 10px 30px #25344224; }
.canvas-export-menu[hidden] { display: none; }
.canvas-export-menu button { display: grid; gap: 4px; width: 100%; padding: 11px 12px; border: 0; border-radius: 8px; background: transparent; text-align: left; font: inherit; color: var(--shell-ink); cursor: pointer; }
.canvas-export-menu button:is(:hover, :focus-visible) { background: var(--shell-hover); }
.canvas-export-menu button:focus-visible { outline: 2px solid var(--board-blue); outline-offset: -2px; }
.canvas-export-menu button strong { font-size: 13px; font-weight: 500; }
.canvas-export-menu button span { font-size: 12px; line-height: 1.5; color: var(--shell-ink-2); }
.canvas-export-menu button:disabled { opacity: .45; cursor: default; }
/* Learning pauses are separate from knowledge prose and its highlight offsets. */
.tutor-anchor { margin: 16px 0; padding: 10px 0; border-top: 1px dashed #b9cfd5; border-bottom: 1px dashed #b9cfd5; font-family: var(--ce-font-sans); }
.tutor-return { margin: 8px 0; padding: 0; border: 0; }
.tutor-anchor button, .knowledge-tutor-status button { border: 0; border-radius: 6px; padding: 5px 0; background: transparent; color: var(--board-blue); font: inherit; font-size: 11px; cursor: pointer; }
.tutor-history { margin: 0; }
.tutor-history > summary { display: block; position: relative; padding-right: 26px; cursor: pointer; list-style: none; color: var(--board-blue); font-size: 13px; line-height: 1.65; }
.tutor-history > summary::-webkit-details-marker { display: none; }
.tutor-history-heading { display: flex; align-items: baseline; gap: 14px; }
.tutor-history-heading > span { color: var(--board-ink); font: 500 19px/1.5 var(--board-hand); }
.tutor-history-heading small { color: #536b77; font-size: 12px; }
.tutor-history-takeaway { display: -webkit-box; -webkit-line-clamp: 1; -webkit-box-orient: vertical; overflow: hidden; margin-top: 4px; color: #536b77; font-size: 12px; }
.tutor-history-chevron { position: absolute; top: 0; right: 2px; font-size: 23px; }
.tutor-history[open] .tutor-history-chevron { transform: rotate(90deg); }
.tutor-record { padding-top: 12px; margin-top: 12px; border-top: 1px dashed #d4e1e5; }
.tutor-record + .tutor-record { margin-top: 12px; }
.tutor-record dl { display: grid; grid-template-columns: 64px minmax(0, 1fr); gap: 8px 14px; margin: 0; }
.tutor-record dt { padding-top: 1px; color: #536b77; font: 12px/1.7 var(--ce-font-sans); }
.tutor-record dd { min-width: 0; margin: 0; font: 13px/1.7 var(--ce-font-sans); color: var(--board-ink); }
.tutor-record-text { white-space: pre-wrap; overflow-wrap: anywhere; }
.tutor-record-text.md { white-space: normal; }
.tutor-record-text.md > :first-child { margin-top: 0; }
.tutor-record-text.md > :last-child { margin-bottom: 0; }
.tutor-record-text.md p { margin: 0 0 6px; }
.tutor-record-full > summary { list-style: none; cursor: pointer; }
.tutor-record-full > summary::-webkit-details-marker { display: none; }
.tutor-record-preview { display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.tutor-record-more { display: inline-block; padding-top: 3px; color: var(--board-blue); font-size: 12px; }
.tutor-record-full[open] .tutor-record-preview { display: none; }
.tutor-record-full[open] .tutor-record-more { font-size: 0; }
.tutor-record-full[open] .tutor-record-more::after { content: '收起完整内容'; font-size: 12px; }
.tutor-record-full[open] > .tutor-record-text { padding-top: 6px; }
.tutor-record-mode { color: #536b77; }
.tutor-record-label { margin: 8px 0 2px; font-size: 11px; color: var(--board-muted); }
.tutor-record-label:first-child { margin-top: 0; }
.tutor-record p, .tutor-feedback { margin: 0 0 6px; font-size: 13px; line-height: 1.7; }
.tutor-feedback > :first-child { margin-top: 0; }
.tutor-feedback > :last-child { margin-bottom: 0; }
.tutor-record > p { white-space: pre-wrap; overflow-wrap: anywhere; }
.tutor-note-saved { display: block; margin: 6px 0 0 78px; font-size: 12px; color: #536b77; }
.tutor-study-note { margin-top: 22px; padding: 14px 0 0; border-top: 1px solid var(--board-line); font-size: 14px; line-height: 1.9; }
.tutor-study-note h3 { font-family: var(--board-hand); font-size: 19px; font-weight: 500; }
.knowledge-tutor-status { padding: 0 22px 16px; }
/* 导师提问：从输入条上方弹出的卡片，可折叠成一条队列态 */
.composer-tutor-question {
  position: absolute; left: 0; right: 0; bottom: calc(100% + 8px);
  display: flex; flex-direction: column; box-sizing: border-box;
  max-height: min(520px, calc(100dvh - var(--tutor-input-height, 62px) - 110px));
  margin: 0; padding: 10px 12px 8px;
  border: 1px solid var(--shell-line); border-radius: 12px;
  background: var(--shell-surface); box-shadow: 0 12px 32px #2534421f;
  transform-origin: bottom center; animation: tutor-rise .18s ease-out;
}
.canvas-composer.is-tutor-reading .composer-tutor-question { position: relative; bottom: auto; }
@keyframes tutor-rise { from { opacity: 0; transform: translateY(8px) scale(.99); } to { opacity: 1; transform: none; } }
.tutor-question-head { display: flex; flex: none; align-items: center; gap: 3px; }
.tutor-question-label { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 12px; color: var(--shell-ink-2); }
.tutor-question-label b { font-weight: 600; color: var(--shell-ink); }
.tutor-question-count { margin-right: 5px; font: 12px var(--ce-font-sans); font-variant-numeric: tabular-nums; color: var(--shell-ink-2); }
.tutor-icon-button {
  position: relative; display: inline-grid; place-items: center; flex: none; width: 28px; height: 28px; padding: 0;
  border: 0; border-radius: 7px; background: transparent; color: var(--shell-ink-2); cursor: pointer;
}
.tutor-icon-button:hover { background: var(--shell-hover); color: var(--shell-ink); }
.tutor-icon-button:disabled { opacity: .35; cursor: default; }
.tutor-icon-button svg { width: 17px; height: 17px; }
.tutor-icon-button::after { content: attr(data-tooltip); position: absolute; z-index: 2; right: 0; bottom: calc(100% + 7px); width: max-content; max-width: min(230px, calc(100vw - 48px)); padding: 5px 8px; border-radius: 6px; background: var(--shell-ink); color: var(--shell-surface); font: 12px/1.5 var(--ce-font-sans); white-space: normal; pointer-events: none; opacity: 0; visibility: hidden; }
.tutor-icon-button:is(:hover, :focus-visible)::after { opacity: 1; visibility: visible; }
.tutor-question-toggle svg { transition: transform .16s; }
.composer-tutor-question.is-collapsed .tutor-question-toggle svg { transform: rotate(180deg); }
.tutor-question-body { min-height: 0; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; }
.tutor-question-text { margin: 7px 0 8px; font-size: 14px; line-height: 1.7; color: var(--shell-ink); overflow-wrap: anywhere; }
.composer-tutor-question.is-collapsed { padding-bottom: 8px; }
.composer-tutor-question.is-collapsed .tutor-question-body { overflow: hidden; }
.composer-tutor-question.is-collapsed .tutor-question-text {
  margin: 2px 0 0; display: -webkit-box; -webkit-line-clamp: 1; -webkit-box-orient: vertical; overflow: hidden;
  color: var(--shell-ink-3); font-size: 12px;
}
.composer-tutor-question.is-collapsed :is(.tutor-hint, .tutor-error, .tutor-question-actions, .tutor-panel-answer, .tutor-panel-feedback, .tutor-panel-status) { display: none; }
.tutor-question-actions { display: flex; flex: none; justify-content: flex-end; gap: 4px; margin-top: 2px; }
.tutor-question-actions .tutor-icon-button[data-tutor-action="continue"] { color: var(--board-blue); background: var(--shell-hover); }
.tutor-hint { margin: 12px 0; padding-left: 11px; border-left: 2px solid #b8cdd7; font-size: 12px; line-height: 1.8; }
.tutor-hint strong { color: var(--board-blue); font-size: 12px; font-weight: 500; }
.tutor-hint p { margin: 4px 0 0; white-space: pre-wrap; overflow-wrap: anywhere; }
.tutor-panel-answer, .tutor-panel-feedback { margin: 12px 0 8px; font-size: 13px; line-height: 1.75; overflow-wrap: anywhere; color: var(--shell-ink); }
.tutor-panel-answer > strong, .tutor-panel-feedback > strong { display: block; margin-bottom: 4px; color: var(--shell-ink-2); font-size: 11px; font-weight: 500; }
.tutor-panel-answer p { margin: 0; white-space: pre-wrap; color: var(--shell-ink-2); }
.tutor-panel-feedback .md > :first-child { margin-top: 0; }
.tutor-panel-feedback .md > :last-child { margin-bottom: 0; }
.tutor-panel-status { margin: 10px 0 6px; font-size: 12px; color: var(--shell-ink-2); }
.tutor-panel-status::before { content: ''; display: inline-block; width: 6px; height: 6px; margin-right: 7px; border-radius: 50%; background: var(--board-blue); animation: tutor-thinking 1.2s ease-in-out infinite alternate; }
@keyframes tutor-thinking { to { opacity: .3; } }
.tutor-error { color: var(--state-error); font-size: 11px; line-height: 1.7; }
.composer-panel { max-height: calc(100dvh - 50px); overflow-y: auto; overscroll-behavior: contain; }
.tutor-anchor button:focus-visible, .tutor-history summary:focus-visible { outline: 2px solid var(--board-blue); outline-offset: 4px; }
@media (max-width: 600px) { .tutor-icon-button { width: 32px; height: 32px; } }
@media (prefers-reduced-motion: reduce) { .composer-tutor-question { animation: none; } .tutor-panel-status::before { animation: none; } }
/* Mentor selection: a small faculty directory, with a shared teaching sample. */
.mentor-sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.mentor-presence {
  /* 左下角：与右下角的提问按钮分居画布两侧，不再占据顶栏位置。 */
  position: absolute; z-index: 44; left: 20px; bottom: 18px; top: auto;
  display: flex; align-items: flex-end; gap: 8px;
  --mentor-accent: #276885;
}
.mentor-presence[hidden] { display: none; }
.mentor-character {
  position: relative; display: block; width: 88px; height: 88px; flex: none;
  border: 0; padding: 0; border-radius: 24px; background: transparent; cursor: pointer;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.mentor-character::after { content: '切换导师'; position: absolute; left: 12px; bottom: -3px; font-size: 9px; color: var(--ce-muted-foreground); opacity: 0; transform: translateY(-2px); transition: opacity .2s, transform .2s; pointer-events: none; }
.mentor-character:hover::after, .mentor-character:focus-visible::after { opacity: 1; transform: none; }
.mentor-character-line { position: absolute; left: 0; top: auto; bottom: 100%; width: max-content; max-width: min(240px, calc(100vw - 145px)); margin: 0 0 10px; padding: 9px 12px; border: 1px solid color-mix(in srgb, var(--mentor-accent) 22%, var(--ce-border)); border-radius: 3px 12px 12px; background: var(--ce-card); color: var(--ce-foreground); font-size: 11px; line-height: 1.65; box-shadow: 0 4px 16px #25344208; pointer-events: none; }
.mentor-character-line:empty { display: none; }
.mentor-picker {
  width: min(820px, calc(100vw - 32px)); max-height: calc(100dvh - 32px); margin: auto; padding: 26px 30px 22px;
  border: 1px solid var(--ce-border); border-radius: 24px; background: var(--ce-card); color: var(--ce-foreground);
  box-shadow: 0 24px 90px #142c3c26; overflow: auto; overscroll-behavior: contain;
}
.mentor-picker::backdrop { background: #172e3f63; backdrop-filter: blur(5px); }
.mentor-picker[open] { animation: mentor-enter .2s ease-out; }
.mentor-picker-kicker { margin: 0 0 7px; font-size: 11px; color: var(--ce-muted-foreground); letter-spacing: .08em; }
.mentor-picker h1 { margin: 0; font-family: var(--board-hand); font-size: 29px; line-height: 1.45; font-weight: 600; letter-spacing: -.02em; }
.mentor-picker-heading > p:last-child { margin: 8px 0 20px; font-size: 12px; line-height: 1.7; color: var(--ce-muted-foreground); }
.mentor-picker-cards { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; min-width: 0; margin: 0; padding: 0; border: 0; }
.mentor-card { display: block; position: relative; cursor: pointer; min-width: 0; }
.mentor-card > input { position: absolute; width: 1px; height: 1px; opacity: 0; }
.mentor-card-content { display: flex; flex-direction: column; height: 100%; padding: 15px 17px 13px; border: 1px solid var(--ce-border); border-radius: 15px; background: var(--ce-card); transition: border-color .15s, background .15s, box-shadow .15s; }
.mentor-card:hover .mentor-card-content { border-color: var(--mentor-accent); }
.mentor-card > input:checked + .mentor-card-content { border-color: var(--mentor-accent); background: color-mix(in srgb, var(--mentor-paper) 45%, var(--ce-card)); box-shadow: inset 0 0 0 1px var(--mentor-accent); }
.mentor-card > input:focus-visible + .mentor-card-content { outline: 2px solid var(--mentor-accent); outline-offset: 3px; }
.mentor-card-top { display: flex; align-items: center; gap: 13px; }
.mentor-card-portrait { display: block; width: 76px; height: 76px; flex: none; }
.mentor-card-identity { display: flex; flex-direction: column; gap: 5px; min-width: 0; }
.mentor-card-role { font-size: 10px; color: var(--mentor-accent); font-weight: 600; }
.mentor-card-name { display: flex; align-items: center; gap: 10px; font-family: var(--board-hand); font-size: 21px; font-weight: 600; line-height: 1.1; }
.mentor-card-gender { font-family: var(--ce-font-sans); font-size: 10px; color: var(--ce-muted-foreground); font-weight: 400; }
.mentor-card-tone { font-size: 10px; color: var(--ce-muted-foreground); line-height: 1.5; }
.mentor-card-check { display: grid; place-items: center; width: 20px; height: 20px; border: 1px solid var(--ce-border); border-radius: 50%; color: transparent; margin-left: auto; align-self: flex-start; font-size: 12px; flex: none; }
.mentor-card > input:checked + .mentor-card-content .mentor-card-check { background: var(--mentor-accent); border-color: var(--mentor-accent); color: white; }
.mentor-card-promise { display: block; margin: 12px 0 5px; font-size: 14px; font-weight: 600; letter-spacing: -.01em; }
.mentor-card-description { display: block; font-size: 11.5px; color: var(--ce-muted-foreground); line-height: 1.7; }
.mentor-card-method { display: block; margin-top: 10px; font-size: 10px; color: var(--mentor-accent); opacity: .85; }
.mentor-picker-preview { margin-top: 16px; padding: 12px 16px; border-left: 3px solid var(--mentor-accent); border-radius: 0 10px 10px 0; background: var(--ce-muted); min-height: 82px; }
.mentor-preview-label { display: block; font-size: 10px; color: var(--mentor-accent); }
.mentor-picker-preview p { margin: 6px 0 0; font-family: var(--board-hand); font-size: 16px; line-height: 1.65; }
.mentor-picker-error { margin: 8px 0 0; font-size: 12px; color: var(--state-error); }
.mentor-picker-error:empty { display: none; }
.mentor-picker-footer { display: flex; align-items: center; justify-content: flex-end; gap: 16px; margin-top: 18px; }
.mentor-picker-footer > span { font-size: 10px; line-height: 1.6; color: var(--ce-muted-foreground); }
.mentor-picker-actions { display: flex; align-items: center; gap: 8px; flex: none; }
.mentor-picker-actions button { border: 1px solid transparent; border-radius: 10px; padding: 11px 16px; font: inherit; font-size: 12px; font-weight: 500; cursor: pointer; }
.mentor-picker-cancel { background: transparent; color: var(--ce-muted-foreground); }
.mentor-picker-cancel:hover { background: var(--ce-muted); }
.mentor-picker-confirm { background: var(--ce-primary-700); color: var(--shell-accent-ink); min-width: 150px; }
.mentor-picker-confirm:hover:enabled { background: var(--ce-primary-600); }
.mentor-picker-confirm:disabled { background: var(--ce-muted); color: var(--ce-muted-foreground); cursor: default; }
.mentor-character:focus-visible, .mentor-picker-actions button:focus-visible { outline: 2px solid var(--ce-ring); outline-offset: 3px; }
@keyframes mentor-enter { from { opacity: .3; transform: translateY(8px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { .mentor-picker[open] { animation: none; } .mentor-card-content { transition: none; } }
@media (max-width: 600px) {
  .mentor-picker { width: calc(100vw - 20px); max-height: calc(100dvh - 20px); padding: 22px 18px 18px; border-radius: 19px; }
  .mentor-picker h1 { font-size: 25px; }
  .mentor-picker-cards { grid-template-columns: 1fr; gap: 10px; }
  .mentor-card-content { padding: 14px 16px; }
  .mentor-card-portrait { width: 68px; height: 68px; }
  .mentor-card-promise { margin-top: 10px; }
  .mentor-card-method { margin-top: 7px; }
  .mentor-picker-footer { align-items: stretch; flex-direction: column; gap: 10px; }
  .mentor-picker-actions { justify-content: flex-end; }
  .mentor-picker-confirm { flex: 1; }
  .mentor-presence { left: 12px; bottom: 12px; top: auto; gap: 6px; }
  /* 手机上画布很窄：只留导师卡，隐藏大幅立绘 */
  .mentor-character { display: none; }
  .mentor-character::after { left: 4px; bottom: -8px; }
  .mentor-character-line { left: 0; max-width: min(220px, calc(100vw - 115px)); }
}
/* 手绘头像直接铺满人物按钮 */
.mentor-character > svg { display: block; width: 100%; height: 100%; border-radius: 24px; }
.mentor-card-portrait svg { display: block; width: 100%; height: 100%; }
.mentor-card-portrait { height: 88px; }
.mentor-card:hover .mentor-paper-wash { opacity: .65; }
@media (prefers-reduced-motion: reduce) {
  .mentor-presence, .mentor-character::after { transition: none; }
}
:root {
  --board-paper: #fffdf7;
  --board-ink: #253442;
  --board-line: #e6ddcd;
  --board-blue: #1689bd;
  --board-marker: #fff0b4;
  --board-muted: #5e6b74;
  /* 自托管霞鹜文楷保证各端字形一致；系统楷体只作为加载前的回退。 */
  --board-hand: "LXGW WenKai", "Kaiti SC", "STKaiti", "KaiTi", "Noto Serif SC", serif;
}
.node.chat.knowledge-node {
  border: 1px solid var(--board-line);
  border-radius: 16px;
  background: var(--board-paper);
  box-shadow: 0 3px 14px #25344207;
}
.node.chat.knowledge-node.selected { border-color: var(--ce-primary-400); box-shadow: 0 0 0 3px var(--ce-primary-50), 0 6px 24px #25344209; }
.node.chat.knowledge-node.knowledge-morphing { overflow: hidden; border-color: var(--board-line); box-shadow: 0 3px 14px #25344207; will-change: width, height, transform; }
.node.chat.knowledge-expanded { background: var(--board-paper); }
.knowledge-head.chat-head { padding: 18px 20px 12px; border: 0; align-items: flex-start; }
.knowledge-heading { flex: 1; min-width: 0; }
.knowledge-head .chat-title { margin: 0; font-size: 17px; line-height: 1.5; white-space: normal; color: var(--board-ink); letter-spacing: -.025em; overflow-wrap: anywhere; }
.knowledge-compact .chat-title { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; }
.knowledge-expanded .chat-title { font-family: var(--board-hand); font-size: 25px; font-weight: 600; line-height: 1.4; }
.knowledge-node .node-tools { display: flex; gap: 4px; padding-top: 1px; flex: none; }
.node.chat.knowledge-node .node-tool { width: 25px; height: 25px; background: transparent; color: var(--board-muted); }
.knowledge-node .card-notes-toggle { position: relative; }
.knowledge-node .card-notes-toggle::after { content: attr(data-tooltip); position: absolute; z-index: 7; right: 0; bottom: calc(100% + 7px); width: max-content; padding: 5px 8px; border-radius: 6px; background: var(--shell-ink); color: var(--shell-surface); font: 12px/1.5 var(--ce-font-sans); white-space: nowrap; pointer-events: none; opacity: 0; visibility: hidden; }
.knowledge-node .card-notes-toggle:is(:hover, :focus-visible):not(:disabled)::after { opacity: 1; visibility: visible; }
.node.chat.knowledge-node .node-tool:not(.del) { color: var(--shell-accent); }
.node.chat.knowledge-node .node-tool:not(.del):hover { background: var(--shell-accent); color: var(--shell-accent-ink); }
.node.chat.knowledge-node .node-tool.del:hover { background: var(--state-error); color: #fff; }
.node.chat.knowledge-node .node-tool:disabled { opacity: .4; cursor: default; }
.node.chat.knowledge-node:focus-within .node-tools { opacity: 1; }
.knowledge-source { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; margin: 0 24px 4px; color: var(--board-muted); font-size: 11px; overflow-wrap: anywhere; }
.knowledge-node .chat-answer { padding: 5px 20px 14px; font-size: 14px; line-height: 1.85; color: var(--board-ink); overscroll-behavior: contain; }
.knowledge-compact .chat-answer { max-height: none; }
.knowledge-summary { margin: 0; font-size: 12.5px; line-height: 1.8; color: #61717b; overflow-wrap: anywhere; }
.knowledge-expanded .chat-answer { padding: 8px 30px 22px; }
.knowledge-preparing { margin-left: 10px; font-size: 12px; color: var(--board-muted); }
.knowledge-node .chat-answer-text { white-space: normal; }
.knowledge-node .chat-answer-text.md p { margin: 7px 0; }
.knowledge-node .chat-answer-text.md strong { font-weight: 650; background: linear-gradient(transparent 57%, var(--board-marker) 57%, var(--board-marker) 93%, transparent 93%); }
.knowledge-node .chat-answer-text.md pre { white-space: pre-wrap; }
.knowledge-node .chat-answer-text.md h3.board-section-title {
  display: table; margin: 0 0 9px; color: var(--board-ink); font-family: var(--board-hand); font-size: 20px; font-weight: 600; line-height: 1.5;
}
.board-section { position: relative; margin: 19px 0 0; padding-left: 0; }
.board-writing { position: relative; }
.board-ink-layer { position: absolute; inset: 0; width: 100%; height: 100%; overflow: visible; pointer-events: none; }
.board-ink-layer ellipse { fill: none; stroke: var(--board-blue); stroke-width: 1.5; opacity: .8; }
.board-section[hidden] { display: none !important; }
.board-section:first-child { margin-top: 0; }
.board-intro { padding-bottom: 15px; border-bottom: 1px solid #e8eae5; }
.knowledge-expanded .chat-answer-text { position: relative; }
.board-text-cursor { position: absolute; width: 2px; height: 14px; background: var(--board-blue); transform: rotate(18deg); pointer-events: none; }
.board-pen-tip { fill: var(--board-blue); stroke: none; }
.board-section-title::after { content: ""; display: block; width: 44px; margin-top: 3px; border-bottom: 2px solid var(--board-blue); transform: rotate(-2deg); opacity: .65; }
@keyframes board-write-in { from { opacity: .35; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.board-visual { margin: 22px 0 4px; }
.board-visual figcaption { margin-bottom: 12px; font-family: var(--board-hand); font-size: 18px; color: var(--board-blue); }
.board-visual-items { display: flex; align-items: stretch; gap: 19px; }
.board-visual-item { flex: 0 0 calc((100% - (var(--visual-count, 3) - 1) * 19px) / var(--visual-count, 3)); box-sizing: border-box; min-width: 0; min-height: 96px; position: relative; padding: 16px 12px; text-align: center; }
.board-outline { position: absolute; inset: 0; width: 100%; height: 100%; overflow: visible; pointer-events: none; }
.board-outline path, .board-connector path { fill: none; stroke: var(--board-blue); stroke-width: 1.4; stroke-linecap: round; stroke-linejoin: round; vector-effect: non-scaling-stroke; }
.board-connector { position: absolute; right: calc(100% + 1px); top: 23px; width: 18px; height: 24px; overflow: visible; pointer-events: none; }
.knowledge-node .chat-answer-text.md .board-visual-item strong { display: block; font-family: var(--board-hand); font-size: 16px; font-weight: 600; background: none; overflow-wrap: anywhere; }
.board-visual-item span { display: block; margin-top: 5px; font-size: 11px; line-height: 1.65; color: #6d7e86; overflow-wrap: anywhere; }
.board-compare .board-visual-item { text-align: left; }
.board-compare .board-visual-item:nth-child(even) .board-outline path { stroke: #bd9b39; }
.knowledge-actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 0 20px 14px; }
.knowledge-part-retries { display: flex; gap: 8px; flex-wrap: wrap; padding: 10px 20px 14px; }
.knowledge-part-retries button { border: 1px solid var(--shell-accent-line); background: var(--shell-accent-soft); color: var(--shell-accent); border-radius: 7px; padding: 6px 9px; font: inherit; font-size: 11px; cursor: pointer; }
.knowledge-part-retries button:disabled { opacity: .5; cursor: wait; }
.knowledge-actions button, .knowledge-parent button { display: inline-flex; align-items: center; gap: 5px; padding: 0; border: 0; background: transparent; font: inherit; font-size: 11.5px; cursor: pointer; }
.knowledge-play { color: var(--board-blue); }
.knowledge-play svg { width: 15px; height: 15px; }
.knowledge-meta { font-size: 10px; color: var(--board-muted); }
.knowledge-node .chat-branches { flex-direction: column; align-items: flex-start; gap: 6px; padding: 13px 20px; border-top: 1px solid #edf0ef; }
.knowledge-node .chat-branch { max-width: 100%; padding: 5px 9px; background: var(--shell-accent-soft); color: var(--shell-accent); border: 1px solid var(--shell-accent-line); border-radius: 7px; font-size: 11px; line-height: 1.6; white-space: normal; text-align: left; }
.knowledge-node .chat-branch::before { content: "↗ "; }
.knowledge-node .chat-branch:hover { background: var(--ce-primary-50); border-color: var(--ce-primary-200); }
.knowledge-node .chat-ask { padding: 12px 20px; background: #f4f7f480; border-color: #edf0ef; }
.knowledge-node .chat-ask .ask-input { width: 100%; border: 0; border-radius: 0; padding: 1px 0; background: transparent; font-size: 12px; box-shadow: none; }
.knowledge-parent { padding: 10px 20px 12px; border-top: 1px solid #edf0ef; }
.knowledge-parent button { display: block; max-width: 100%; color: var(--board-muted); text-overflow: ellipsis; overflow: hidden; white-space: nowrap; text-align: left; }
.knowledge-node button:focus-visible { outline: 2px solid var(--ce-primary-400); outline-offset: 4px; }
.knowledge-node .chat-illus { margin-top: 18px; }
.knowledge-node .chat-illus-img { max-height: 220px; }
.knowledge-narrow .knowledge-head { padding: 16px 16px 10px; }
.knowledge-narrow .chat-answer { padding-left: 18px; padding-right: 18px; }
.knowledge-narrow .board-visual-items { flex-direction: column; gap: 18px; }
.knowledge-narrow .board-visual-item { flex-basis: auto; }
.knowledge-narrow .board-connector { right: auto; top: -22px; left: calc(50% - 9px); transform: rotate(90deg); }
#edges path.knowledge-edge { stroke: var(--ce-primary-400); stroke-width: 2.5; stroke-dasharray: 6 5; animation: dash-flow 1s linear infinite; }
#edges path.knowledge-edge.active { stroke: var(--ce-primary-500); stroke-width: 3; }
#edges path.knowledge-edge-reveal { stroke: white; stroke-width: 12; stroke-linecap: round; animation: none; }
#edges [data-flow-ready="false"] > .knowledge-edge { animation-play-state: paused; }
/* 常驻输入条：贴在画布区域底部居中（相对 stage-wrap 定位，左右栏变化都自动跟随） */
.canvas-composer {
  position: absolute; left: 50%; right: auto; bottom: max(18px, env(safe-area-inset-bottom));
  z-index: 56; width: min(620px, calc(100% - 48px));
  transform: translateX(-50%);
}

.canvas-composer [hidden] { display: none !important; }
.composer-panel { position: relative; width: 100%; box-sizing: border-box; padding: 5px 6px 5px 16px; border: 1px solid var(--shell-line); border-radius: 16px; background: var(--shell-surface); color: var(--shell-ink); box-shadow: 0 10px 30px #2534421f; transition: opacity 160ms ease; }
/* 常驻态是一条胶囊；首屏的引导态仍是方一点的卡片 */
.canvas-composer:not(.is-centered) .composer-panel { border-radius: 999px; }
.canvas-composer.is-tutoring:not(.is-centered) .composer-panel { padding: 8px 10px 8px 16px; border-radius: 16px; }
.canvas-composer.is-tutoring .composer-row { align-items: flex-end; }
.composer-row { display: flex; align-items: center; gap: 10px; }
.composer-row > #composer-input { flex: 1; min-width: 0; }
.canvas-composer.is-dimmed .composer-panel { opacity: .5; }
.composer-panel-head { display: flex; align-items: center; gap: 10px; margin: 0 0 6px 2px; }
.composer-context { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 11px; color: var(--board-muted); }
.composer-text-action { border: 0; padding: 3px 0; background: transparent; color: var(--board-blue); font: inherit; font-size: 11px; cursor: pointer; white-space: nowrap; }
.composer-icon-action { display: inline-grid; place-items: center; flex: none; width: 34px; height: 34px; padding: 4px; border: 1px solid var(--shell-line); border-radius: 10px; background: var(--shell-surface); color: var(--shell-ink-2); cursor: pointer; transition: border-color 140ms, background 140ms, color 140ms, transform 140ms, box-shadow 140ms; }
.composer-icon-action:hover { border-color: #a9cbd5; background: #f5fafb; color: var(--board-blue); box-shadow: 0 3px 9px #2534420b; transform: translateY(-1px); }
.composer-icon-action:active { transform: scale(.96); }
.composer-icon-action:disabled { cursor: default; opacity: .48; box-shadow: none; transform: none; }
.composer-icon-action svg { width: 18px; height: 18px; }
.composer-icon-action img { display: block; width: 24px; height: 24px; object-fit: contain; filter: contrast(1.12) saturate(1.12); }
.composer-icon-action:focus-visible, .composer-send:focus-visible { outline: 2px solid var(--shell-ink); outline-offset: 2px; }

#composer-input { display: block; width: 100%; min-height: 32px; max-height: min(180px, 30vh); margin: 0; padding: 6px 0; border: 0; outline: 0; box-sizing: border-box; resize: none; background: transparent; color: var(--shell-ink); font: inherit; font-size: 12.5px; line-height: 1.6; overflow-y: auto; }
#composer-input::placeholder { color: var(--shell-ink-3); }
.composer-panel:focus-within { border-color: #82b8cb; }
.composer-panel-foot { display: flex; gap: 6px; align-items: center; flex: none; }
/* 输入条形态不显示快捷键提示；首屏的引导态再显示 */
.composer-key-hint { display: none; margin: 0; }
.is-centered .composer-key-hint { display: block; margin: 6px 0 0; padding: 0; color: var(--shell-ink-3); font: 10px/1.5 var(--ce-font-sans); text-align: right; }
.composer-add {
  display: grid; place-items: center; flex: none; width: 32px; height: 32px; padding: 0;
  border: 1px solid var(--shell-line); border-radius: 999px; background: var(--shell-hover);
  color: var(--shell-ink-2); cursor: pointer; transition: background .14s, border-color .14s, color .14s;
}
.composer-add:hover { background: var(--shell-surface); border-color: var(--shell-edge); color: var(--shell-ink); }
.composer-add svg { width: 18px; height: 18px; }
.composer-topic-tools { display: flex; align-items: center; gap: 6px; }
.canvas-composer .composer-send {
  display: inline-flex; align-items: center; justify-content: center; gap: 5px; flex: none;
  height: 32px; min-width: 74px; padding: 0 12px 0 14px; white-space: nowrap; border: 1px solid var(--shell-accent); border-radius: 999px;
  background: var(--shell-accent); color: var(--shell-accent-ink); font: inherit; font-size: 12.5px; font-weight: 500;
  cursor: pointer; box-shadow: 0 3px 9px #25344218;
  transition: background 140ms, border-color 140ms, transform 140ms, box-shadow 140ms;
}
.canvas-composer .composer-send:hover:not(:disabled) { filter: brightness(1.08); box-shadow: 0 5px 12px color-mix(in srgb, var(--shell-accent) 18%, transparent); transform: translateY(-1px); }
.canvas-composer .composer-send:active:not(:disabled) { transform: scale(.96); }
.canvas-composer .composer-send svg { width: 15px; height: 15px; opacity: .75; }
.canvas-composer .composer-send:disabled { opacity: .7; cursor: default; box-shadow: none; }
.canvas-composer .composer-attachments { padding: 7px 0; }
.composer-status { margin: 6px 0; color: var(--board-muted); font-size: 11px; line-height: 1.65; }
.composer-learning-loading { display: flex; min-height: 182px; flex-direction: column; align-items: center; justify-content: center; gap: 9px; padding: 20px 14px; text-align: center; }
.composer-learning-loading[hidden] { display: none !important; }
.composer-learning-spinner { width: 34px; height: 34px; flex: none; border: 3px solid #dce9ed; border-top-color: var(--board-blue); border-right-color: var(--board-blue); border-radius: 50%; animation: learning-route-spin .9s linear infinite; }
.composer-learning-kicker { color: var(--board-blue); font-size: 10px; letter-spacing: .06em; }
.composer-learning-loading strong { color: var(--board-ink); font: 500 16px/1.6 var(--ce-font-sans); }
.composer-learning-topic { max-width: 100%; overflow: hidden; color: var(--board-muted); font-size: 12px; text-overflow: ellipsis; white-space: nowrap; }
.composer-learning-topic:empty { display: none; }
.composer-learning-loading small { color: #8d9ba3; font-size: 10px; }
@keyframes learning-route-spin { to { transform: rotate(360deg); } }
.canvas-composer button:focus-visible { outline: 2px solid var(--board-blue); outline-offset: 3px; }
.pending-composer-summary { padding: 18px; color: var(--board-muted); font-size: 12px; }
.pending-composer-summary p { margin: 0 0 12px; white-space: pre-wrap; overflow-wrap: anywhere; }
.pending-composer-summary button { border: 0; padding: 0; background: transparent; color: var(--board-blue); font: inherit; font-size: 11px; cursor: pointer; }
.pending-composer-summary small { display: block; margin-bottom: 8px; }
@media (max-width: 700px) {
  /* 输入条常驻后，导师卡上移让位，两者不重叠 */
  .stage-wrap .mentor-presence { bottom: calc(var(--composer-panel-height, 64px) + 22px); }
  .canvas-composer { bottom: max(12px, env(safe-area-inset-bottom)); width: calc(100% - 24px); }
  .composer-panel { padding: 8px 9px 8px 16px; border-radius: 18px; }
  .composer-learning-loading { min-height: 158px; padding: 14px 8px; }
  .composer-learning-loading strong { font-size: 14px; }
  .composer-panel-foot { gap: 6px; }
}
@media (prefers-reduced-motion: reduce) { .composer-panel { transition: none; } }

/* The same question sheet starts in the middle, then folds to its corner. */
.canvas-composer.is-centered {
  left: var(--entry-x, 50%); top: var(--entry-y, 50%); right: auto; bottom: auto;
  width: var(--entry-width, min(640px, calc(100vw - 120px)));
  max-height: var(--entry-height, calc(100dvh - 160px));
  transform: translate(-50%, -50%);
}
.composer-welcome { margin: 0 0 24px; color: var(--board-ink); }
.composer-welcome-kicker { margin: 0 0 10px; font-size: 11px; letter-spacing: .12em; color: var(--board-blue); }
.composer-welcome h1 { display: table; position: relative; margin: 0 0 12px; font-family: var(--board-hand); font-size: clamp(30px, 3vw, 42px); line-height: 1.4; font-weight: 600; letter-spacing: -.04em; }
.composer-welcome h1::after { content: ''; position: absolute; left: 1px; bottom: -2px; width: 54%; height: 5px; border-top: 2px solid #1689bd75; border-radius: 50%; transform: rotate(-1.5deg); }
.composer-welcome h1 span { color: var(--board-blue); }
#composer-welcome-copy { margin: 0; color: var(--board-muted); font-size: 12px; line-height: 1.8; }
.is-centered .composer-panel { width: 100%; max-height: none; padding: 20px 22px 16px; border-color: transparent; border-radius: 20px; box-shadow: 0 8px 30px #2534420a; transform-origin: center; }
.is-centered .composer-row { flex-direction: column; align-items: stretch; }
.is-centered .composer-row > #composer-input { flex: none; width: 100%; }
.is-centered .composer-panel-foot { width: 100%; justify-content: flex-end; }
.is-centered #composer-input { min-height: 78px; font-size: 16px; line-height: 1.85; }
.is-centered .composer-send { width: auto; height: 38px; }
.is-centered .composer-send svg { width: 21px; height: 21px; }
.is-centered .composer-topic-tools .composer-icon-action { width: 34px; height: 34px; }
.composer-suggestions { margin-top: 23px; }
.composer-suggestions-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 10px; gap: 12px; font-size: 11px; color: var(--board-muted); }
#composer-shuffle-topics { display: inline-flex; align-items: center; gap: 5px; padding: 4px 0 4px 6px; border: 0; background: transparent; font: inherit; color: var(--board-blue); cursor: pointer; }
#composer-shuffle-topics svg { width: 13px; height: 13px; }
.composer-topics { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 9px; }
.composer-topic { position: relative; min-width: 0; padding: 12px 28px 12px 14px; text-align: left; border: 1px solid var(--shell-line); border-radius: 11px; background: color-mix(in srgb, var(--shell-surface) 92%, transparent); color: var(--board-ink); cursor: pointer; transition: border-color 140ms, background 140ms; }
.composer-topic > span { display: block; margin-bottom: 5px; font: 10px/1.4 var(--ce-font-sans); color: var(--board-muted); }
.composer-topic > strong { display: block; font: 400 13px/1.65 var(--ce-font-sans); overflow-wrap: anywhere; }
.composer-topic > svg { position: absolute; right: 10px; top: calc(50% - 7px); width: 14px; height: 14px; color: #9eafb7; }
.composer-topic:hover { border-color: #8ebdce; background: var(--board-paper); }
.composer-topic:hover > svg { color: var(--board-blue); }
.composer-topic:disabled, #composer-shuffle-topics:disabled { cursor: default; }
.learning-entry .help-tip, .learning-entry .empty-hint { visibility: hidden; pointer-events: none; }
.learning-entry #stage { cursor: default; }
.is-departing { pointer-events: none; }
.is-departing .composer-welcome, .is-departing .composer-suggestions { opacity: 0; transform: translateY(-8px); transition: opacity 160ms, transform 200ms; }
.is-departing .composer-panel > * { opacity: 0; transition: opacity 140ms; }
@media (max-width: 700px) {
  .composer-welcome { margin-bottom: 20px; }
  .composer-welcome h1 { font-size: 29px; }
  .is-centered .composer-panel { padding: 15px 16px 12px; border-radius: 16px; }
  .is-centered #composer-input { min-height: 85px; font-size: 14px; }
  .is-centered .composer-key-hint { font-size: 9px; }
  .composer-topics { grid-template-columns: minmax(0, 1fr); gap: 7px; }
  .composer-topic { padding: 9px 27px 9px 12px; }
  .composer-topic > span { display: inline; margin: 0 7px 0 0; font-size: 9px; }
  .composer-topic > strong { display: inline; font-size: 12px; }
  .composer-suggestions { margin-top: 18px; }
}
@media (max-height: 600px) {
  .is-centered .composer-welcome { margin-bottom: 14px; }
  .is-centered #composer-welcome-copy { font-size: 12px; }
  .is-centered .composer-welcome h1 { font-size: 28px; margin-bottom: 0; }
  .is-centered .composer-suggestions { display: none; }
  .is-centered #composer-input { min-height: 64px; }
}
@media (prefers-reduced-motion: reduce) {
  .composer-learning-spinner { animation: none; }
  .composer-panel, .composer-icon-action, .composer-send { transition: none; }
  .composer-icon-action:hover, .composer-send:hover:not(:disabled) { transform: none; }
  .composer-topic, .is-departing .composer-welcome, .is-departing .composer-suggestions, .is-departing .composer-panel > * { transition: none; }
}

/* 游客也保留左栏（精简入口），不再整条隐藏，避免画布左侧空一块。 */
@media (max-width: 700px) {
  .is-centered .composer-key-hint { font-size: 10px; }
  .is-centered .composer-welcome { margin-bottom: 14px; }
}
/* 极窄屏：输入条仍保持一行，只缩小两个按钮 */
@media (max-width: 420px) {
  .composer-add { width: 36px; height: 36px; border-radius: 999px; }
  .canvas-composer .composer-send { height: 36px; min-width: 0; padding: 0 12px; font-size: 12px; border-radius: 999px; }
  .canvas-composer .composer-send svg { display: none; }
  .composer-panel { padding: 7px 7px 7px 16px; }
}
@media (max-width: 360px) {
  .is-centered .composer-key-hint { font-size: 9px; }
}

/* Reading mode turns the current map into a quiet, printable learning note. */
body.notes-mode { overflow: auto; }
body.notes-mode .app, body.notes-mode #canvas-composer,
body.notes-mode #learning-course { display: none !important; }
.canvas-notes-loading > button { min-height: 38px; padding: 0 14px; border: 1px solid #d8e5e9; border-radius: 9px; background: #fff; color: var(--board-blue); font: 12px var(--ce-font-sans); cursor: pointer; }
.canvas-notes-view[hidden] { display: none !important; }
.canvas-notes-view { position: fixed; inset: 0; z-index: 170; overflow-y: auto; overscroll-behavior: contain; background: var(--ce-background); color: var(--board-ink); }
.canvas-notes-toolbar { position: sticky; top: 0; z-index: 2; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 16px; min-height: 66px; padding: 0 clamp(16px, 4vw, 48px); border-bottom: 1px solid #dce5e8; background: #f8fafcf2; backdrop-filter: blur(12px); }
.canvas-notes-toolbar button { display: inline-flex; align-items: center; gap: 8px; width: max-content; min-height: 38px; padding: 0 12px; border: 1px solid transparent; border-radius: 10px; background: transparent; color: var(--board-muted); font: 12px var(--ce-font-sans); cursor: pointer; }
.canvas-notes-toolbar button:hover { border-color: #d8e5e9; background: #fff; color: var(--board-blue); }
.canvas-notes-toolbar button:focus-visible { outline: 2px solid var(--board-blue); outline-offset: 3px; }
.canvas-notes-toolbar button svg { width: 17px; height: 17px; flex: none; }
.notes-toolbar-title { display: flex; align-items: center; gap: 10px; white-space: nowrap; }
.notes-toolbar-title strong { color: var(--board-ink); font-size: 13px; font-weight: 650; }
.notes-toolbar-title span { color: var(--board-muted); font-size: 11px; }
.notes-download-actions { display: flex; align-items: center; justify-self: end; gap: 9px; }
.notes-export-hint { color: var(--board-muted); font-size: 10px; white-space: nowrap; }
.notes-export-menu-wrap { position: relative; }
.canvas-notes-toolbar .notes-download-trigger { display: grid; place-items: center; width: 38px; min-height: 38px; padding: 0; border-color: #b9d9e2; background: #fff; color: var(--board-blue); }
.canvas-notes-toolbar .notes-download-trigger:hover { border-color: #a7ccd7; background: #f7fbfc; }
.canvas-notes-toolbar .notes-download-trigger:disabled { cursor: wait; opacity: .48; }
.canvas-notes-toolbar .notes-download-trigger svg { width: 18px; height: 18px; }
.notes-export-menu { position: absolute; top: calc(100% + 7px); right: 0; z-index: 4; display: grid; min-width: 132px; padding: 5px; border: 1px solid #dce5e8; border-radius: 11px; background: #fff; box-shadow: 0 10px 26px #2637471a; }
.notes-export-menu[hidden] { display: none; }
.canvas-notes-toolbar .notes-export-menu button { width: 100%; min-height: 36px; padding: 0 10px; border: 0; border-radius: 7px; color: var(--board-ink); font-size: 11px; text-align: left; }
.canvas-notes-toolbar .notes-export-menu button:hover { border-color: transparent; background: #f2f8f9; color: var(--board-blue); }
.canvas-notes-toolbar .notes-export-menu button:disabled { cursor: wait; opacity: .48; }
.canvas-notes-page { width: min(820px, calc(100% - 40px)); min-height: calc(100dvh - 110px); box-sizing: border-box; margin: 28px auto 64px; padding: clamp(28px, 6vw, 68px) clamp(22px, 7vw, 78px); border: 1px solid #e1e8e8; border-radius: 18px; background: var(--board-paper); box-shadow: 0 10px 32px #26374708; }
.canvas-notes-loading { display: grid; justify-items: center; align-content: center; min-height: 48vh; gap: 13px; text-align: center; }
.canvas-notes-spinner { width: 34px; height: 34px; border: 3px solid #dce9ed; border-top-color: var(--board-blue); border-right-color: var(--board-blue); border-radius: 50%; animation: learning-route-spin .9s linear infinite; }
.canvas-notes-loading strong { color: var(--board-ink); font-size: 17px; font-weight: 550; }
.canvas-notes-loading p { max-width: 480px; margin: 0; color: var(--board-muted); font-size: 12px; line-height: 1.8; }
.notes-meta { display: flex; flex-wrap: wrap; gap: 7px; margin: 0 0 26px; }
.notes-meta span { padding: 5px 9px; border: 1px solid #e1e8e8; border-radius: 999px; color: var(--board-muted); font-size: 10px; }
.notes-kicker { color: var(--board-blue); font-size: 11px; letter-spacing: .08em; }
.canvas-notes-article h1 { margin: 10px 0 13px; color: var(--board-ink); font: 500 clamp(30px, 5vw, 42px)/1.45 var(--board-hand); letter-spacing: -.02em; overflow-wrap: anywhere; }
.notes-lede { margin: 0 0 35px; color: var(--board-muted); font-size: 15px; line-height: 1.9; }
.notes-overview { margin: 0 0 36px; padding: 20px 23px; border: 1px solid #d9e7ea; border-left: 3px solid var(--board-blue); border-radius: 12px; background: #f6fbfc; }
.notes-overview-label { color: var(--board-blue); font-size: 10px; letter-spacing: .06em; }
.notes-overview .md { margin-top: 10px; color: var(--board-ink); font-size: 14px; line-height: 1.9; }
.notes-overview .md > :first-child { margin-top: 0; }
.notes-overview .md > :last-child { margin-bottom: 0; }
.notes-chapter { position: relative; margin: 35px 0 0; padding: 27px 0 0; border-top: 1px solid #e3e9e8; }
.notes-chapter[data-depth="1"] { margin-left: clamp(0px, 3vw, 28px); }
.notes-chapter[data-depth="2"] { margin-left: clamp(0px, 5vw, 52px); }
.notes-chapter h2, .notes-chapter h3 { margin: 0 0 12px; color: var(--board-ink); font-size: 21px; font-weight: 620; line-height: 1.55; overflow-wrap: anywhere; }
.notes-chapter h3 { font-size: 18px; }
.notes-question { margin: 0 0 15px; color: var(--board-muted); font-size: 12px; line-height: 1.8; }
.notes-core { margin: 15px 0 20px; padding: 14px 17px; border-radius: 10px; background: #f5f7f3; color: var(--board-ink); }
.notes-core-label { display: block; margin-bottom: 5px; color: #607c61; font-size: 10px; }
.notes-core .md, .notes-body .md, .notes-subsection .md { font-size: 14px; line-height: 1.95; overflow-wrap: anywhere; }
.notes-core .md > :first-child, .notes-body .md > :first-child, .notes-subsection .md > :first-child { margin-top: 0; }
.notes-core .md > :last-child, .notes-body .md > :last-child, .notes-subsection .md > :last-child { margin-bottom: 0; }
.notes-subsection { margin: 23px 0; }
.notes-subsection h3, .notes-subsection h4 { margin: 0 0 8px; color: var(--board-ink); font-size: 15px; font-weight: 620; }
.notes-aside, .notes-saved-note { margin: 14px 0; padding: 13px 16px; border-left: 2px solid #9bbfca; background: #f7faf9; color: var(--board-muted); font-size: 12px; line-height: 1.85; }
.notes-aside strong, .notes-saved-note strong { display: block; margin-bottom: 4px; color: var(--board-blue); font-size: 10px; font-weight: 600; }
.notes-highlights { display: grid; gap: 8px; margin: 20px 0; }
.notes-highlights-label { color: var(--board-muted); font-size: 10px; }
.notes-highlight { padding: 10px 13px; border-left: 3px solid #e3c75d; border-radius: 0 8px 8px 0; background: #fff8d9; color: #534927; font-size: 13px; line-height: 1.8; }
.notes-highlight[data-color="green"] { border-color: #73ae83; background: #edf8ed; color: #355741; }
.notes-media-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(220px, 100%), 1fr)); gap: 12px; margin: 20px 0; }
.notes-figure { min-width: 0; margin: 0; padding: 8px; border: 1px solid #e3e9e8; border-radius: 11px; background: #fff; }
.notes-figure img { display: block; width: 100%; max-height: 360px; object-fit: contain; border-radius: 7px; background: #f6f8f8; }
.notes-figure figcaption { padding: 8px 4px 2px; color: var(--board-muted); font-size: 10px; line-height: 1.6; }
.notes-media-pending { padding: 13px; border: 1px dashed #cbdcde; border-radius: 9px; color: var(--board-muted); font-size: 11px; line-height: 1.7; }
.notes-generated-status { margin: 0 0 20px; padding: 10px 13px; border-radius: 9px; background: #fff8e8; color: #79613c; font-size: 11px; line-height: 1.7; }
.canvas-notes-error { display: grid; justify-items: center; align-content: center; min-height: 48vh; gap: 12px; text-align: center; }
.canvas-notes-error strong { color: var(--board-ink); font-size: 17px; }
.canvas-notes-error p { margin: 0; color: var(--board-muted); font-size: 12px; }
.canvas-notes-error button { min-height: 38px; padding: 0 16px; border: 0; border-radius: 9px; background: var(--board-blue); color: var(--shell-accent-ink); cursor: pointer; }
@media (max-width: 600px) {
  .canvas-notes-toolbar { grid-template-columns: 1fr auto; gap: 6px; min-height: 58px; padding: 0 12px; }
  .notes-toolbar-title { display: none; }
  .canvas-notes-toolbar button { min-height: 36px; padding: 0 8px; }
  .notes-download-actions { gap: 6px; }
  .notes-export-hint { font-size: 9px; }
  .canvas-notes-page { width: calc(100% - 20px); min-height: calc(100dvh - 74px); margin: 10px auto 28px; padding: 27px 20px 40px; border-radius: 14px; }
  .notes-lede { font-size: 14px; }
  .notes-overview { padding: 16px; }
  .notes-chapter { margin-top: 28px; padding-top: 22px; }
  .notes-chapter[data-depth="1"], .notes-chapter[data-depth="2"] { margin-left: 0; }
}
@media (prefers-reduced-motion: reduce) { .canvas-notes-spinner { animation: none; } }

/* Keep a readable line width, and let the writing determine the height. */
.node.chat.knowledge-expanded {
  display: flex; flex-direction: column; height: auto;
  box-sizing: border-box;
}
.node.chat.knowledge-expanded:not([data-shell-phase="complete"]) { border-color: transparent; box-shadow: none; }
.knowledge-main { position: relative; z-index: 1; display: flex; flex-direction: column; width: calc(var(--knowledge-main-width) - 2px); flex: none; min-width: 0; }
.knowledge-expanded .knowledge-head { flex: 0 0 auto; min-height: 0; padding: 22px 26px 14px; box-sizing: border-box; }
.knowledge-expanded .chat-title { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; font-size: 23px; line-height: 1.35; }
.knowledge-expanded .knowledge-source { flex: 0 0 auto; min-height: 0; height: auto; box-sizing: border-box; margin: 0 0 10px; padding: 0 26px; font-size: 12px; }
.knowledge-expanded .knowledge-source:empty { display: none; }
.knowledge-expanded .chat-answer, .knowledge-narrow.knowledge-expanded .chat-answer { flex: 0 0 auto; max-height: none; overflow: visible; font-size: 15px; line-height: 1.95; }
.knowledge-expanded .knowledge-footer { position: relative; flex: 0 0 auto; padding: 0; }
.knowledge-expanded .knowledge-actions { padding-bottom: 16px; }
.knowledge-expanded .chat-branches { max-height: none; overflow: visible; }
.knowledge-card-outline { position: absolute; inset: 0; z-index: 3; width: 100%; height: 100%; overflow: visible; pointer-events: none; }
.knowledge-expanded[data-shell-phase="complete"] > .knowledge-card-outline { visibility: hidden; }
.knowledge-card-outline path { fill: none; stroke: #7cb6ca; stroke-width: 1.25; stroke-linecap: round; vector-effect: non-scaling-stroke; }
.node.chat.knowledge-expanded[data-shell-phase="waiting"], .node.chat.knowledge-expanded[data-shell-phase="writing"], .node.chat.knowledge-expanded[data-shell-phase="framing"], .node.chat.knowledge-expanded[data-shell-phase="connecting"] { background: transparent; }
.knowledge-expanded:not([data-shell-phase="complete"]) .knowledge-actions,
.knowledge-expanded:not([data-shell-phase="complete"]) .chat-branches { visibility: hidden; pointer-events: none; }
.knowledge-expanded:not([data-shell-phase="complete"]) .chat-ask,
.knowledge-expanded:not([data-shell-phase="complete"]) .knowledge-parent { background: transparent; border-color: transparent; }
.knowledge-expanded .knowledge-head, .knowledge-expanded .knowledge-source, .knowledge-expanded .chat-answer, .knowledge-expanded .knowledge-footer { position: relative; z-index: 1; }

/* Compact history/navigation; personal notes live in the card's canvas margin. */
.knowledge-footer > .tutor-anchor { margin: 0; padding: 12px 0; border-top: 1px solid #dbe6e9; border-bottom: 0; }
.knowledge-node .knowledge-footer .learning-guide { margin: 0; padding: 12px 0; border-left: 0; border-top: 1px solid #dbe6e9; }
.knowledge-node .knowledge-footer .learning-guide-return { padding: 5px 0; }
.knowledge-footer .learning-guide-return .learning-guide-secondary { min-height: 36px; font-size: 13px; color: var(--board-blue); }
.knowledge-footer .learning-guide-eyebrow { margin-bottom: 4px; font-size: 12px; color: #536b77; }
.knowledge-footer .learning-guide p { margin-bottom: 7px; line-height: 1.7; }
.knowledge-footer .learning-guide-note { margin-top: 6px; font-size: 12px; }
.knowledge-expanded .knowledge-footer > :is(.tutor-anchor, .learning-guide) { padding-left: 26px; padding-right: 26px; }
.knowledge-parent button { min-height: 32px; font-size: 12px; color: var(--board-blue); }
.card-notes { position: absolute; inset-block: 0; right: 0; z-index: 2; display: flex; flex-direction: column; box-sizing: border-box; width: 300px; min-height: 0; padding: 22px 16px 14px 18px; border-left: 1px solid #dbe6e9; border-radius: 0 15px 15px 0; background: #f7faf9; color: var(--board-ink); font: 13px/1.7 var(--ce-font-sans); cursor: default; }
.card-notes[hidden], .card-notes input[hidden], .card-notes-status[hidden] { display: none; }
.card-notes-head { display: flex; flex: none; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 12px; }
.card-notes-head h3 { margin: 0; font: 500 19px/1.5 var(--board-hand); color: var(--board-ink); }
.card-notes-head > div { display: flex; gap: 7px; }
.card-notes button { min-height: 30px; padding: 3px 2px; border: 0; border-radius: 4px; background: transparent; color: var(--board-blue); font: 12px/1.5 var(--ce-font-sans); cursor: pointer; }
.card-notes button:hover { text-decoration: underline; }
.card-notes-scroll { flex: 1; min-height: 0; padding: 2px 5px 4px 2px; overflow-x: hidden; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; scrollbar-color: #b6cbd3 transparent; scrollbar-gutter: stable; }
.card-notes-scroll:focus-visible { outline: 2px solid var(--board-blue); outline-offset: 2px; border-radius: 4px; }
.card-notes-content { display: grid; gap: 12px; }
.card-note { min-width: 0; padding: 12px 14px; border: 1px solid #d7e3e8; border-radius: 7px; background: #f5f9fb; box-shadow: 0 2px 5px #263f4b08; }
.card-note-heading { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 5px; color: #4d6875; font-size: 12px; }
.card-notes .card-note-remove { width: 26px; min-height: 26px; margin: -4px -6px -2px 0; color: #5d727c; font-size: 20px; line-height: 1; }
.card-note-remove:hover { background: #e6eff3; }
.card-note-input { display: block; box-sizing: border-box; width: 100%; min-height: 32px; max-height: 280px; resize: none; padding: 3px 0; border: 0; border-radius: 0; background: transparent; color: var(--board-ink); font: 14px/1.8 var(--ce-font-sans); overflow-y: auto; cursor: text; }
.card-note-input::placeholder { color: #617482; font-size: 12px; }
.card-note-input:focus { outline: none; }
.card-note:focus-within { border-color: #7ca9bc; box-shadow: 0 0 0 2px #dceaf1; }
.card-note-image { background: #fffdf8; }
.card-note-image img { display: block; width: 100%; max-height: 280px; object-fit: contain; border-radius: 3px; user-select: none; -webkit-user-drag: none; }
.card-note-image .card-note-input { margin-top: 5px; font-size: 12px; }
.card-note-annotation, .card-note-highlight { background: #fffbec; border-color: #e5dfbd; border-left: 4px solid #e5c658; }
.card-note[data-note-color="green"] { background: #f3faf3; border-color: #b7d3bd; }
.card-note blockquote { margin: 3px 0 5px; padding: 0; color: var(--board-ink); font-size: 13px; overflow-wrap: anywhere; }
.card-note-anchor-actions { display: flex; gap: 16px; }
.card-note-excerpt { overflow-wrap: anywhere; font-size: 13px; }
.card-note-excerpt > :first-child { margin-top: 0; }
.card-note-excerpt > :last-child { margin-bottom: 0; }
.card-notes-empty { margin: 8px 0 10px; color: #536b77; font-size: 12px; line-height: 1.9; }
.card-notes .card-notes-add { margin-top: 10px; padding: 3px 6px; }
.card-notes-status { flex: none; margin: 0 0 8px; font-size: 12px; color: #8b4d28; overflow-wrap: anywhere; }
.card-note-link { position: absolute; inset: 0; z-index: 3; width: 100%; height: 100%; overflow: visible; pointer-events: none; }
.card-note-link rect { fill: #f2d66526; stroke: #bd9b39; stroke-width: 1; }
.card-note-link path { fill: none; stroke: #bd9b39; stroke-width: 1.2; stroke-dasharray: 3 4; vector-effect: non-scaling-stroke; }
@media (max-width: 700px) {
  .knowledge-expanded .knowledge-head { display: grid; grid-template-columns: minmax(0, 1fr) auto; padding: 18px 18px 10px; gap: 4px 8px; }
  .knowledge-expanded .knowledge-heading { grid-column: 1 / -1; }
  .node.chat.knowledge-expanded .knowledge-head > .node-tools { grid-column: 1 / -1; justify-self: end; margin: 0; opacity: 1; align-self: center; }
  .knowledge-expanded .knowledge-source { padding: 0 18px; }
  .knowledge-expanded .knowledge-footer > :is(.tutor-anchor, .learning-guide) { padding-left: 18px; padding-right: 18px; }
  .card-notes button { min-height: 36px; }
  .card-notes .card-note-remove { min-height: 32px; width: 32px; }
  .card-notes .card-note-input { font-size: 16px; }
  .tutor-record dl { grid-template-columns: 1fr; gap: 3px; }
  .tutor-record dd + dt { margin-top: 7px; }
  .tutor-note-saved { margin-left: 0; }
}

/* Arrange explanations and evidence on one sheet, without nested card shells. */
.board-intro { max-width: 660px; }
.board-region { margin-top: 28px; }
.board-region-prose { position: relative; min-width: 0; }
.board-region-prose > [data-board-segment] { max-width: 660px; }
.board-region-split { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); column-gap: 34px; align-items: start; }
.board-region-split > .board-region-support { min-height: 0; }
.board-region-support { min-width: 0; }
.board-region-supported .board-region-support { border-left: 1px solid #dce4e7; padding-left: 25px; }
.board-region-wide .board-region-support { margin-top: 22px; border-left: 0; padding-left: 0; }
.board-aside h4 { margin: 0 0 10px; color: var(--board-blue); font-family: var(--board-hand); font-size: 19px; font-weight: 600; }
.board-aside { font-size: 14px; line-height: 1.95; }
.board-region-support .board-visual { margin: 0; }
.board-region-split .board-visual-items { flex-direction: column; gap: 20px; }
.board-region-split .board-visual-item { flex-basis: auto; min-height: 82px; }
.board-region-split .board-connector { right: auto; top: -23px; left: calc(50% - 9px); transform: rotate(90deg); }
.board-region-split .board-compare .board-visual-items { flex-direction: row; gap: 14px; }
.board-region-split .board-compare .board-visual-item { flex: 1; }
.board-media { margin: 0; }
.board-media > figcaption { margin: 0 0 12px; color: var(--board-blue); font-size: 13px; line-height: 1.8; }
.board-media > figcaption:empty { display: none; }
.board-widget { user-select: none; -webkit-user-select: none; }
.board-widget button { border: 0; padding: 4px 0; background: transparent; font: inherit; font-size: 11px; color: var(--board-blue); cursor: pointer; }
.board-widget button:hover { text-decoration: underline; }
.board-widget button:focus-visible, .board-widget input:focus-visible { outline: 2px solid var(--board-blue); outline-offset: 3px; }
.board-model { max-width: 430px; }
.board-model-heading { display: flex; justify-content: space-between; align-items: center; gap: 10px; color: var(--board-muted); font-size: 11px; }
.board-model-drawing { width: 100%; aspect-ratio: 8 / 5; }
.board-model-drawing svg { display: block; width: 100%; height: 100%; overflow: visible; }
.board-model-guide { fill: none; stroke: #b7cbd2; stroke-width: 1; stroke-dasharray: 3 5; }
.board-model-sun { fill: #e7c368; stroke: #bd9b39; stroke-width: 1; }
.board-model-point { fill: var(--board-blue); }
.board-model-line { fill: none; stroke: var(--board-blue); stroke-width: 2; stroke-linecap: round; }
.board-model-linear { stroke: #bd9b39; stroke-dasharray: 4 4; }
.board-model-result { display: block; margin: 0 0 12px; min-height: 22px; color: var(--board-blue); font-size: 12px; font-variant-numeric: tabular-nums; }
.board-model-controls { display: grid; gap: 9px; }
.board-model-controls label { display: grid; grid-template-columns: 92px minmax(30px, 1fr) 32px; align-items: center; gap: 9px; font-size: 11px; line-height: 1.5; }
.board-model-controls input { min-width: 0; width: 100%; margin: 0; accent-color: var(--board-blue); cursor: ew-resize; touch-action: pan-y; }
.board-model-controls output { text-align: right; color: var(--board-muted); font-variant-numeric: tabular-nums; white-space: nowrap; }
.board-model-note { display: block; margin-top: 14px; color: var(--board-muted); font-size: 10px; line-height: 1.7; }
.board-image-surface { display: flex; width: 100%; aspect-ratio: 8 / 5; align-items: center; justify-content: center; overflow: hidden; }
.board-image-surface img { display: block; width: 100%; height: 100%; object-fit: contain; }
.board-image-empty { flex-direction: column; gap: 10px; background: #edf5f64d; color: var(--board-muted); font-size: 11px; text-align: center; }
.board-image-empty svg { width: 86px; height: 54px; fill: none; stroke: #8eb7c3; stroke-width: 1; }
.board-image-actions { display: flex; justify-content: space-between; gap: 12px; align-items: center; font-size: 10px; color: var(--board-muted); margin-top: 7px; }
@media (max-width: 900px) {
  .board-region-split { grid-template-columns: minmax(0, 1fr); row-gap: 18px; }
  .board-region-supported .board-region-support { padding: 16px 0 0; border-left: 0; border-top: 1px solid #e4ecee; }
  .board-region-split .board-region-support { min-height: 0; }
}
@media (max-width: 700px) {
  .knowledge-expanded .chat-answer { font-size: 14px; line-height: 1.9; }
}
@media (prefers-reduced-motion: reduce) {
  .knowledge-node *, #edges path.knowledge-edge { animation: none !important; transition: none !important; }
}

/* One sheet, varied composition. Ink accents share the automatic writing clock. */
.knowledge-node .board-writing [data-board-segment] strong { background: none; }
.board-ink-layer path { fill: none; stroke: var(--board-blue); stroke-width: 1.45; stroke-linejoin: round; stroke-linecap: round; }
.board-ink-layer [data-emphasis-mark="highlight"] { stroke: #e9c96688; mix-blend-mode: multiply; }
.board-ink-layer [data-emphasis-mark="wavy"] { stroke: #b27645; }
.board-ink-layer [data-emphasis-mark="bracket"] { stroke-width: 1.8; }
.board-section-title::after { display: none; }
.board-region-reverse, .board-region-comparison { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 32px; align-items: start; }
.board-region-reverse > .board-region-support { grid-column: 1; grid-row: 1; padding: 0 24px 0 0; border-left: 0; border-right: 1px solid #dce4e7; }
.board-region-reverse > .board-region-prose { grid-column: 2; grid-row: 1; }
.board-region-comparison { column-gap: 42px; }
.board-region-comparison > .board-region-prose { border-top: 2px solid #648a9b; padding-top: 14px; }
.board-region-comparison > .board-region-support { border-top: 2px solid #bea66c; border-left: 0; padding: 14px 0 0; }
.board-step-number { display: block; position: absolute; left: -25px; top: 4px; width: 21px; color: var(--board-blue); font: 13px/1.5 var(--board-hand); font-variant-numeric: tabular-nums; text-align: right; user-select: none; }
.board-region-steps { padding: 0 0 6px; margin-left: 0; }
.board-region-steps::before { content: ''; position: absolute; left: -14px; top: 29px; bottom: 0; border-left: 1px solid #c8d9df; }
.knowledge-narrow .board-step-number { left: -18px; width: 16px; font-size: 11px; white-space: nowrap; }
.board-region-steps > .board-region-support { margin-top: 20px; border: 0; padding: 0; }
.board-region-spotlight > .board-region-support { border: 0; padding: 18px 0 0; max-width: 600px; margin: 0 auto; }
.board-region-spotlight .board-model { max-width: 540px; margin: 0 auto; }
.board-region-spotlight > .board-region-prose { max-width: 660px; }
.board-region-reverse .board-visual-items { flex-direction: column; }
.board-region-reverse .board-connector { right: auto; top: -23px; left: calc(50% - 9px); transform: rotate(90deg); }
.board-sketch { margin: 0; }
.board-sketch figcaption { color: var(--board-blue); font-family: var(--board-hand); font-size: 17px; line-height: 1.7; margin-bottom: 8px; }
.board-sketch > svg { display: block; width: 100%; max-width: 460px; margin: auto; overflow: visible; }
.board-sketch path { fill: none; stroke: var(--board-blue); stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.board-sketch text { fill: var(--board-ink); stroke: none; font: 12px var(--board-hand); }
.jev-settings { margin-top: 26px; border-top: 1px solid #e2e9ed; padding-top: 22px; }
.jev-toggle { display: flex; gap: 6px; font-size: 12px; }
.jev-field { display: grid; grid-template-columns: 80px minmax(0, 1fr); align-items: center; gap: 12px; margin: 10px 0; font-size: 12px; }
.jev-field input, .jev-field select { min-width: 0; border: 1px solid #dce4e9; border-radius: 7px; padding: 8px; font: inherit; background: white; }
.jev-actions { display: flex; gap: 9px; margin-top: 12px; }
@media (max-width: 900px) {
  .board-region-reverse, .board-region-comparison { grid-template-columns: minmax(0, 1fr); row-gap: 20px; }
  .board-region-reverse > .board-region-prose, .board-region-reverse > .board-region-support { grid-column: auto; grid-row: auto; }
  .board-region-reverse > .board-region-support { border-right: 0; border-top: 1px solid #dce4e7; padding: 16px 0 0; }
  .board-region-comparison > .board-region-support { padding-top: 14px; }
}
.board-lever-beam { stroke-width: 3; }
.board-lever-load { fill: #e7f0f3; stroke: var(--board-blue); stroke-width: 1.4; }
.board-lever-load path { fill: none; stroke-linecap: round; stroke-linejoin: round; }
.board-lever-right { fill: #f5ecd6; stroke: #a98a40; }
.board-lever-load text { fill: var(--board-ink); stroke: none; font: 11px system-ui, sans-serif; }

/* Paper, three coherent pen treatments, and two complementary aids at most. */
[data-board-style="pencil"], [data-pen-style="pencil"] { --board-blue: var(--shell-ink-2); --board-marker: #e7e4cf; }
[data-board-style="marker"], [data-pen-style="marker"] { --board-blue: var(--shell-ink); --board-marker: #e6d891; }
[data-pen-style="ink"] { --board-blue: var(--shell-ink); }
[data-pen-style="pencil"] .board-sketch path,
[data-pen-style="pencil"] .board-ink-layer path,
[data-pen-style="pencil"] .board-model-line { stroke-width: 1.25; filter: drop-shadow(.7px .6px 0 #52687638); }
[data-pen-style="marker"] .board-sketch path,
[data-pen-style="marker"] .board-ink-layer path { stroke-width: 2.8; stroke-opacity: .82; }
[data-pen-style="pencil"] .board-section-title { text-decoration: underline; text-decoration-color: #81949b66; text-decoration-thickness: 1px; text-underline-offset: 7px; }
[data-pen-style="marker"] .board-section-title { font-weight: 700; }
.board-ink-layer [data-emphasis-mark="double"] { stroke-width: 1.25; }
.board-ink-layer [data-emphasis-mark="brace"] { stroke: #a48648; }
.board-ink-layer [data-emphasis-mark="star"] { stroke: #b58e36; fill: #f3d98026; }
.board-ink-layer [data-emphasis-mark="dotted"] { stroke-width: 2.4; }
.board-support-pair { display: grid; gap: 22px; align-content: start; }
.board-support-pair > * { min-width: 0; }
.board-support-pair > .board-aside { border-top: 1px dashed #b9ccd4; padding-top: 16px; }
.board-region-gallery > .board-region-support { border: 0; padding: 22px 0 0; margin-top: 8px; }
.board-region-gallery > .board-support-pair { grid-template-columns: repeat(2, minmax(0, 1fr)); column-gap: 30px; }
.board-region-gallery > .board-support-pair > * + * { border-left: 1px solid #d6e2e5; padding-left: 26px; }
.board-region-gallery > .board-support-pair > .board-aside { border-top: 0; padding-top: 0; }
.board-region-sidebar { display: grid; grid-template-columns: minmax(0, 1.45fr) minmax(0, .75fr); gap: 30px; }
.board-region-sidebar > .board-region-support { border-left: 2px solid #a3c3cd; padding-left: 22px; font-size: 13px; }
.board-region-sidebar .board-model-controls label { grid-template-columns: 64px minmax(24px, 1fr) 28px; gap: 5px; }
.board-model-drawing text { fill: var(--board-ink); stroke: none; font: 10px system-ui, sans-serif; }
.board-model-load { fill: #e4eef080; stroke: var(--board-blue); stroke-width: 1.5; }
.board-model-label-alt { fill: #a88a42 !important; }
.node[data-board-style="pencil"] .knowledge-card-outline path { stroke: #87979b; stroke-width: 1.1; filter: drop-shadow(.6px .6px 0 #52687630); }
.node[data-board-style="marker"] .knowledge-card-outline path { stroke: #5c9f9b; stroke-width: 2.1; opacity: .85; }

@media (max-width: 900px) {
  .board-region-sidebar, .board-region-gallery > .board-support-pair { grid-template-columns: minmax(0, 1fr); }
  .board-region-sidebar > .board-region-support { border-left: 0; border-top: 1px solid #d6e2e5; padding: 18px 0 0; }
  .board-region-gallery > .board-support-pair > * + * { border-left: 0; border-top: 1px solid #d6e2e5; padding: 20px 0 0; }
}

/* UML shares the paper and pen. Give semantic diagrams a full reading width. */
.board-uml { margin: 0; min-width: 0; }
.board-uml > figcaption { display: flex; flex-wrap: wrap; align-items: baseline; gap: 10px; margin: 0 0 10px; color: var(--board-blue); font-family: var(--board-hand); font-size: 17px; }
.board-uml-type { flex: none; border-bottom: 2px solid #a3bec9; padding-bottom: 2px; font: 11px system-ui, sans-serif; color: var(--board-muted); }
.board-uml-svg { display: block; width: 100%; max-width: 860px; height: auto; margin: 8px auto 0; overflow: visible; }
.board-uml path { fill: none; stroke: var(--board-blue); stroke-width: 1.45; stroke-linecap: round; stroke-linejoin: round; }
.board-uml path[data-uml-fill="paper"] { fill: var(--board-paper, #fffefb); }
.board-uml path[data-uml-fill="ink"] { fill: var(--board-blue); }
.board-uml text { fill: var(--board-ink); stroke: none; font: 14px var(--board-hand); }
.board-uml .uml-name { font-size: 16px; font-weight: 600; }
.board-uml .uml-abstract { font-size: 16px; font-style: italic; }
.board-uml .uml-stereotype { font: 12px system-ui, sans-serif; fill: var(--board-muted); }
.board-uml .uml-member { font: 13px ui-monospace, "SFMono-Regular", "Kaiti SC", monospace; }
.board-uml .uml-decision-label { font-size: 13px; }
.board-uml .uml-lifeline { stroke: #a5bac2; stroke-width: 1.1; }
.board-uml .uml-edge-label { paint-order: stroke; stroke: var(--board-paper, #fffefb); stroke-width: 5px; stroke-linejoin: round; font-size: 13px; }
.board-region-spotlight > .board-region-support.board-support-uml { max-width: none; }
.board-support-uml.board-support-pair { grid-template-columns: minmax(0, 1fr); }
.board-support-uml > .board-aside { max-width: 680px; border-left: 2px solid #bfd1d7; border-top: 0; padding: 4px 0 4px 18px; }
[data-pen-style="pencil"] .board-uml path { stroke-width: 1.2; filter: drop-shadow(.65px .5px 0 #52687632); }
[data-pen-style="marker"] .board-uml path { stroke-width: 2.15; stroke-opacity: .88; }
@media (max-width: 700px) { .board-uml > figcaption { font-size: 16px; } }


.board-layout-measure { position: fixed; left: -100000px; top: 0; visibility: hidden; pointer-events: none; contain: layout style; }
.board-layout-measure > .node { position: relative; left: 0 !important; top: 0 !important; }
.knowledge-expanded[data-layout-planned] .knowledge-head { flex: 0 0 auto; min-height: 0; padding: 20px 24px 16px; }
.knowledge-expanded[data-layout-planned] .chat-answer { font-size: var(--board-prose-size, 15px); line-height: 1.95; }
.knowledge-expanded[data-layout-planned] .board-intro,
.knowledge-expanded[data-layout-planned] .board-region-prose,
.knowledge-expanded[data-layout-planned] .board-region-prose > [data-board-segment] { max-width: none; }
.knowledge-node.knowledge-expanded[data-layout-planned] .chat-answer-text.md [data-board-segment]:is(div,h3,h4,figcaption,strong,span) { display: flow-root; }
.knowledge-expanded[data-layout-planned] .board-sections { margin-top: 24px; }
.knowledge-expanded[data-layout-planned] .board-region-split,
.knowledge-expanded[data-layout-planned] .board-region-sidebar,
.knowledge-expanded[data-layout-planned] .board-region-comparison {
  display: grid; grid-template-columns: minmax(0, var(--board-prose-fr)) minmax(0, var(--board-support-fr));
  column-gap: 28px; row-gap: 0; align-items: start;
}
.knowledge-expanded[data-layout-planned] .board-region-reverse {
  display: grid; grid-template-columns: minmax(0, var(--board-support-fr)) minmax(0, var(--board-prose-fr));
  column-gap: 28px; row-gap: 0; align-items: start;
}
.knowledge-expanded[data-layout-planned] :is(.board-region-split,.board-region-sidebar) > .board-region-support {
  padding: 0 0 0 22px; border-left: 1px solid #dce4e7; border-top: 0;
}
.knowledge-expanded[data-layout-planned] .board-region-reverse > .board-region-prose { grid-column: 2; grid-row: 1; }
.knowledge-expanded[data-layout-planned] .board-region-reverse > .board-region-support {
  grid-column: 1; grid-row: 1; padding: 0 22px 0 0; border-right: 1px solid #dce4e7; border-top: 0; border-left: 0;
}
.knowledge-expanded[data-layout-planned] .board-region-gallery > .board-support-pair { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.knowledge-expanded[data-layout-planned] .board-region-gallery > .board-support-pair > * + * { border-left: 1px solid #d6e2e5; border-top: 0; padding: 0 0 0 22px; }
.knowledge-expanded[data-layout-planned] .board-sections-mosaic { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px 28px; margin-top: 24px; align-items: start; }
.knowledge-expanded[data-layout-planned] .board-sections-mosaic > .board-region { margin: 0; }
.knowledge-expanded[data-layout-planned] .board-uml > figcaption { align-items: flex-start; }
.knowledge-expanded[data-layout-planned] .board-uml > figcaption [data-board-segment] { flex: 1; min-width: 0; }
.knowledge-expanded[data-layout-planned].has-planned-illustration .chat-answer > .chat-illus { height: 266px; box-sizing: border-box; }
.knowledge-expanded[data-layout-planned] .board-region[data-board-arrangement="note-beside"] { row-gap: 22px; }
.knowledge-expanded[data-layout-planned] .board-region[data-board-arrangement="note-beside"] > .board-region-support { display: contents; }
.knowledge-expanded[data-layout-planned] .board-region[data-board-arrangement="note-beside"] > .board-region-prose { grid-column: 1; grid-row: 1; }
.knowledge-expanded[data-layout-planned] .board-region[data-board-arrangement="note-beside"] > .board-region-support > :not(.board-aside) {
  grid-column: 2; grid-row: 1 / span 2; box-sizing: border-box; min-width: 0; border-left: 1px solid #dce4e7; padding-left: 22px;
}
.knowledge-expanded[data-layout-planned] .board-region[data-board-arrangement="note-beside"] > .board-region-support > .board-aside { grid-column: 1; grid-row: 2; }
.knowledge-expanded[data-layout-planned] .board-region-reverse[data-board-arrangement="note-beside"] > .board-region-prose,
.knowledge-expanded[data-layout-planned] .board-region-reverse[data-board-arrangement="note-beside"] > .board-region-support > .board-aside { grid-column: 2; }
.knowledge-expanded[data-layout-planned] .board-region-reverse[data-board-arrangement="note-beside"] > .board-region-support > :not(.board-aside) { grid-column: 1; border-left: 0; padding-left: 0; border-right: 1px solid #dce4e7; padding-right: 22px; }

/* Shared-dimension tables keep native text and the existing pen timeline. */
.board-table { margin: 0; min-width: 0; }
.board-table > figcaption { margin: 0 0 13px; color: var(--board-blue); font: 17px/1.6 var(--board-hand); }
.board-table-surface { position: relative; width: 100%; }
.board-data-table { border-collapse: collapse; width: 100%; table-layout: fixed; color: var(--board-ink); }
.board-data-table th, .board-data-table td { border: 0; padding: 14px 16px; text-align: left; vertical-align: top; overflow-wrap: anywhere; font-size: var(--board-prose-size, 15px); line-height: 1.75; }
.board-data-table thead th { color: var(--board-blue); background: #739da00a; font-weight: 600; }
.board-data-table tbody th { font-weight: 600; }
.board-data-table [data-board-segment] { box-sizing: border-box; }
.board-data-table p { margin: 0; }
.board-table-ink { position: absolute; inset: 0; width: 100%; height: 100%; overflow: visible; pointer-events: none; }
.board-table-ink path { fill: none; stroke: var(--board-blue); stroke-opacity: .7; stroke-width: 1.25; stroke-linecap: round; stroke-linejoin: round; }
[data-pen-style="pencil"] .board-table-ink path { stroke-width: 1.05; filter: drop-shadow(.6px .4px 0 #52687625); }
[data-pen-style="marker"] .board-table-ink path { stroke-width: 1.85; stroke-opacity: .72; }
.board-support-table.board-support-pair { grid-template-columns: minmax(0, 1fr); }
.board-support-table > .board-aside { border-left: 2px solid #bfd1d7; border-top: 0; padding: 3px 0 3px 18px; }
.board-region-spotlight > .board-support-table { max-width: none; }
.md-table-wrap { margin: 14px 0; width: 100%; }
.md-table-wrap table { width: 100%; border-collapse: collapse; table-layout: fixed; }
.md-table-wrap th, .md-table-wrap td { border: 1px solid #9bb4bd88; padding: 11px 13px; vertical-align: top; overflow-wrap: anywhere; }
.md-table-wrap thead { color: var(--board-blue, #447887); background: #739da00a; }
@media (max-width:700px) {
  .board-data-table th, .board-data-table td { padding: 10px; }
  .board-table > figcaption { font-size: 16px; }
  .md-table-wrap th, .md-table-wrap td { padding: 9px; }
}

.stage-wrap:has(.canvas-composer:not(.is-centered)) .mentor-presence { bottom: calc(max(18px, env(safe-area-inset-bottom)) + var(--composer-panel-height, 44px) + 10px); }
.stage-wrap:has(.canvas-composer.is-centered) .mentor-presence { bottom: max(12px, env(safe-area-inset-bottom)); }
.learning-recovery-note { padding: 10px 12px; border-left: 3px solid var(--state-warning); color: var(--shell-ink-2); background: var(--shell-surface); font-size: 12px; line-height: 1.7; }
.learner-unit-link { display: flex; width: 100%; flex-direction: column; gap: 5px; text-align: left; }
.learner-topic-score > strong { font-size: 15px; }
.learning-resume { position: absolute; top: 12%; left: 8%; right: 8%; max-width: 600px; max-height: calc(80% - 100px); overflow: auto; padding: 22px 26px; border: 1px solid var(--shell-line); border-radius: 16px; background: var(--shell-surface); color: var(--shell-ink-2); font: 13px/1.8 var(--ce-font-sans); }
.learning-resume[hidden] { display: none; }
.learning-resume h1 { margin: 6px 0; color: var(--shell-ink); font: 26px/1.5 var(--board-hand); }
.learning-resume ol { padding-left: 22px; }
body.account-mode .learning-resume { display: none; }
.mentor-presence { pointer-events: none; }
.mentor-presence button { pointer-events: auto; }

/* Shared material list and source references. */
.library-head { display: flex; align-items: center; gap: 8px; }
.library-head strong { color: var(--board-ink); font: 650 14px var(--ce-font-sans); }
.library-count { color: var(--board-muted); font-size: 11px; }
.library-list { flex: 1; min-height: 0; margin: 0; padding: 0; overflow-y: auto; overscroll-behavior: contain; list-style: none; display: flex; flex-direction: column; gap: 6px; }
.library-item { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; align-items: center; gap: 4px 8px; padding: 9px 10px; border: 1px solid #e4ebee; border-radius: 11px; background: #fff; }
.library-name { overflow: hidden; color: var(--board-ink); font-size: 12px; text-overflow: ellipsis; white-space: nowrap; }
.library-meta { grid-column: 2 / 3; color: var(--board-muted); font-size: 10px; }
.library-remove { grid-row: 1 / 3; grid-column: 3; width: 22px; height: 22px; padding: 0; border: 0; border-radius: 6px; background: transparent; color: #9aabb4; font-size: 15px; line-height: 1; cursor: pointer; }
.library-remove:hover { background: #fdeceb; color: #b4453c; }
.library-empty { padding: 18px 10px; color: var(--board-muted); font-size: 12px; line-height: 1.7; text-align: center; }
.library-hint { margin: 0; color: var(--board-muted); font-size: 10.5px; line-height: 1.6; }
.chat-sources { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; padding-top: 10px; border-top: 1px dashed #dde7ea; }
.chat-source { padding: 3px 8px; border: 1px solid var(--shell-accent-line); border-radius: 999px; background: var(--shell-accent-soft); color: var(--shell-accent); font: 500 10.5px var(--ce-font-sans); white-space: nowrap; }
.canvas-row-open { display: flex; align-items: center; gap: 8px; flex: 1; min-width: 0; border: 0; padding: 3px 0; background: transparent; color: inherit; font: inherit; text-align: left; cursor: pointer; }
.library-retry { align-self: flex-start; border: 0; background: transparent; color: var(--board-blue); font: 11px var(--ce-font-sans); cursor: pointer; }
.library-error,.library-warning { margin: 0; color: #956035; font: 12px/1.75 var(--ce-font-sans); }
.library-source-dialog { width: min(720px,calc(100vw - 32px)); box-sizing: border-box; max-height: 85dvh; padding: 22px; border: 1px solid #cadce3; border-radius: 16px; color: var(--board-ink); background: #fffefa; }
.library-source-dialog::backdrop { background: #20394750; backdrop-filter: blur(3px); }
.library-source-dialog header { display: flex; align-items: flex-start; gap: 12px; }
.library-source-dialog h2 { flex: 1; margin: 0; font: 600 16px/1.6 var(--ce-font-sans); }
.library-source-dialog header button { border: 0; padding: 2px 7px; background: none; color: var(--board-muted); font-size: 22px; cursor: pointer; }
.library-source-dialog pre { white-space: pre-wrap; overflow-wrap: anywhere; font: 14px/1.95 var(--ce-font-sans); }
.chat-source { cursor: pointer; white-space: normal; text-align: left; }
.learning-unit-source, .learning-course-source { color: var(--board-muted); font: 11px/1.7 var(--ce-font-sans); overflow-wrap: anywhere; }
/* Source attachments belong to the same composer as optional learning goals. */
.canvas-composer .composer-attachments { max-height: 180px; overflow-y: auto; }
.composer-material { display: flex; align-items: center; gap: 9px; flex: 1 1 240px; min-width: 0; padding: 10px 11px; border: 1px solid var(--shell-line); border-radius: 12px; background: var(--shell-surface); color: var(--shell-ink); }
.composer-material-icon { display: grid; place-items: center; flex: 0 0 34px; height: 38px; border-radius: 7px; background: #edf4f7; color: var(--board-blue); font: 600 10px var(--ce-font-sans); }
.composer-material-info { flex: 1; min-width: 0; }
.composer-material-info strong { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font: 500 12px/1.6 var(--ce-font-sans); }
.composer-material-info small { display: block; color: var(--shell-ink-2); font: 11px/1.6 var(--ce-font-sans); overflow-wrap: anywhere; }
.composer-material.is-error { border-color: #d4b69f; }
.composer-material.is-error small { color: #956035; }
.composer-material-remove, .composer-material-retry, .library-reuse { flex: none; border: 0; background: transparent; color: var(--board-blue); cursor: pointer; font: 12px var(--ce-font-sans); }
.composer-material-remove { padding: 5px; font-size: 19px; color: var(--shell-ink-2); }
.composer-material-remove:disabled { opacity: .4; cursor: default; }
.composer-material-remove:focus-visible, .composer-material-retry:focus-visible, .library-reuse:focus-visible { outline: 2px solid var(--board-blue); outline-offset: 2px; }
.library-reuse { grid-column: 1/-1; justify-self: start; padding: 5px 0; }
@media(max-width:600px) { .composer-material { flex-basis: 100%; padding: 8px; } .canvas-composer .composer-attachments { max-height: 145px; } }

.learning-web-sources { margin: 8px 0 12px; color: var(--shell-ink-2); font: 11px/1.7 var(--ce-font-sans); }
.learning-web-sources summary { cursor: pointer; color: var(--board-blue); }
.learning-web-sources ul { padding: 8px 0 8px 16px; margin: 0; }
.learning-web-sources li { padding: 3px 0; }
.learning-web-sources a { color: var(--board-blue); overflow-wrap: anywhere; }
.learning-web-sources li small { display: block; color: var(--shell-ink-2); }
a.chat-source { text-decoration: none; }

/* Settings owns the library and help; both follow the active palette. */
.settings-library-content { max-width: 760px; }
.settings-library-content .library-head { margin-bottom: 10px; }
.settings-library-content .library-head strong { font-size: 16px; color: var(--shell-ink); }
.settings-library-content .library-retry { margin-left: auto; }
.settings-library-content .library-hint { margin: 10px 0 18px; font-size: 12px; color: var(--shell-ink-2); }
.settings-library-content .library-list { overflow: visible; gap: 10px; }
.settings-library-content .library-item { grid-template-columns: minmax(0,1fr) auto; gap: 7px 16px; padding: 16px; border-color: var(--shell-line); background: var(--shell-surface); }
.settings-library-content .library-name { grid-column: 1; grid-row: 1; color: var(--shell-ink); font-size: 14px; }
.settings-library-content .library-meta { grid-column: 1; grid-row: 2; color: var(--shell-ink-3); font-size: 12px; }
.settings-library-content .library-remove { grid-column: 2; grid-row: 1; color: var(--shell-ink-3); }
.settings-library-content .library-reuse { grid-column: 2; grid-row: 2; border: 0; padding: 0; color: var(--shell-accent); background: transparent; font: 12px var(--ce-font-sans); cursor: pointer; }
.settings-library-content .library-retry { padding: 5px 10px; border: 1px solid var(--shell-line); border-radius: 6px; color: var(--shell-ink-2); background: var(--shell-surface); font: 12px var(--ce-font-sans); cursor: pointer; }
.settings-library-content .library-empty { padding: 36px 12px; text-align: left; color: var(--shell-ink-3); }
.settings-help { max-width: 760px; margin-top: 36px; border-top: 1px solid var(--shell-line); padding-top: 24px; color: var(--shell-ink-2); font-size: 13px; line-height: 1.9; }
.settings-help h2 { margin: 0 0 16px; color: var(--shell-ink); font-size: 16px; }
.settings-help ul { margin: 0; padding-left: 20px; }
.settings-help li { margin: 10px 0; }
.project-item .canvas-row-open { text-align: left; }
.composer-panel { position: relative; }
.composer-mention-menu { position: fixed; z-index: 180; box-sizing: border-box; padding: 6px; max-height: 260px; overflow-y: auto; border: 1px solid var(--shell-line); border-radius: 12px; background: var(--shell-surface); box-shadow: var(--theme-shadow-float); }
.composer-mention-menu[hidden] { display: none; }
.composer-mention-menu button { display: flex; align-items: center; gap: 10px; width: 100%; padding: 10px; border: 0; border-radius: 7px; text-align: left; background: transparent; color: var(--shell-ink); font: 13px var(--ce-font-sans); cursor: pointer; }
.composer-mention-menu button[aria-selected="true"], .composer-mention-menu button:hover { background: var(--shell-hover); }
.composer-mention-menu button > span { min-width: 0; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; }
.composer-mention-menu small { margin-left: auto; flex: none; font-size: 11px; color: var(--shell-ink-3); }
.composer-mention-menu p { margin: 6px 10px; color: var(--shell-ink-3); font-size: 12px; }

body:has(.settings-page.open) .sidebar { display: flex !important; }

/* Guest model access: a small choice card with arrows to the real controls. */
.model-access-guide { position: fixed; inset: 0; z-index: 190; pointer-events: none; }
.model-access-guide[hidden] { display: none !important; }
.model-access-arrows { position: absolute; inset: 0; z-index: 2; width: 100%; height: 100%; overflow: visible; color: var(--shell-accent); }
.model-access-arrows .access-route { fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.model-access-arrows .access-target { fill: none; stroke: currentColor; stroke-width: 1.5; }
.model-access-arrows marker path { fill: currentColor; }
.model-access-card { position: absolute; z-index: 1; box-sizing: border-box; padding: 18px; border: 1px solid var(--shell-accent-line); border-radius: 14px; background: var(--shell-surface); color: var(--shell-ink); box-shadow: var(--theme-shadow-float); pointer-events: auto; animation: model-access-in 160ms ease-out; }
.model-access-card:focus { outline: none; }
.model-access-card h2 { margin: 0 28px 14px 0; color: var(--shell-ink); font: 600 15px/1.6 var(--ce-font-sans); }
.model-access-card .access-close { position: absolute; top: 10px; right: 10px; display: grid; place-items: center; width: 26px; height: 26px; padding: 0; border: 0; border-radius: 6px; background: transparent; color: var(--shell-ink-3); cursor: pointer; }
.model-access-card .access-close svg { width: 15px; height: 15px; }
.model-access-card .access-choice { display: flex; align-items: center; gap: 10px; box-sizing: border-box; width: 100%; min-height: 42px; margin-top: 8px; padding: 9px 10px; border: 1px solid var(--shell-line); border-radius: 8px; background: var(--shell-surface); color: var(--shell-ink); text-align: left; font: 13px/1.6 var(--ce-font-sans); cursor: pointer; }
.model-access-card .access-choice > svg { width: 17px; height: 17px; flex: none; color: var(--shell-accent); }
.model-access-card button:hover { background: var(--shell-hover); color: var(--shell-accent); }
.model-access-card button:focus-visible { outline: 2px solid var(--shell-accent); outline-offset: 3px; }
@keyframes model-access-in { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }
@media (prefers-reduced-motion: reduce) { .model-access-card { animation: none; } }