/*
 * 大师码三科经典课程统一阅读壳。
 * 原始课程 HTML/CSS 继续只读保留；本文件仅在 Next.js 同域响应中最后加载。
 */
:root {
  color-scheme: light;
  overflow-x: clip;
  --classic-header-h: 72px;
  --classic-bg: #f4f7fb;
  --classic-bg-elevated: #eef3f9;
  --classic-panel: #ffffff;
  --classic-panel-strong: #ffffff;
  --classic-panel-soft: #f7f9fc;
  --classic-text: #182538;
  --classic-text-soft: #526176;
  --classic-muted: #78869a;
  --classic-line: #dfe6ef;
  --classic-line-strong: #cdd7e4;
  --classic-code: #111827;
  --classic-code-text: #f8fafc;
  --classic-shadow: 0 16px 48px rgba(28, 48, 76, .09);
  --classic-shadow-soft: 0 8px 24px rgba(28, 48, 76, .07);
  --classic-accent: #3567e8;
  --classic-accent-deep: #2149b8;
  --classic-accent-soft: #eaf0ff;
  --classic-accent-rgb: 53, 103, 232;
}

:root[data-course-theme="dark"] {
  color-scheme: dark;
  --classic-bg: #0d131d;
  --classic-bg-elevated: #111a27;
  --classic-panel: #151f2c;
  --classic-panel-strong: #192433;
  --classic-panel-soft: #111a25;
  --classic-text: #edf3fb;
  --classic-text-soft: #bcc8d7;
  --classic-muted: #8f9daf;
  --classic-line: #293647;
  --classic-line-strong: #3a495c;
  --classic-code: #090e15;
  --classic-code-text: #eef5ff;
  --classic-shadow: 0 18px 56px rgba(0, 0, 0, .3);
  --classic-shadow-soft: 0 10px 28px rgba(0, 0, 0, .22);
  --classic-accent-soft: rgba(var(--classic-accent-rgb), .16);
}

body.course-py {
  --classic-accent: #0797da;
  --classic-accent-deep: #0574ab;
  --classic-accent-soft: #e8f7fd;
  --classic-accent-rgb: 7, 151, 218;
}

body.course-sc {
  --classic-accent: #4c97ff;
  --classic-accent-deep: #2d6dd2;
  --classic-accent-soft: #eaf2ff;
  --classic-accent-rgb: 76, 151, 255;
}

body.course-cpp {
  --classic-accent: #28a06b;
  --classic-accent-deep: #177a4d;
  --classic-accent-soft: #e7f7ef;
  --classic-accent-rgb: 40, 160, 107;
}

:root[data-course-theme="dark"] body.course-py,
:root[data-course-theme="dark"] body.course-sc,
:root[data-course-theme="dark"] body.course-cpp {
  --classic-accent-soft: rgba(var(--classic-accent-rgb), .16);
}

body.course-py,
body.course-sc,
body.course-cpp {
  --ink: var(--classic-text);
  --muted: var(--classic-muted);
  --line: var(--classic-line);
  --brand: var(--classic-accent);
  --brand-deep: var(--classic-accent-deep);
  --soft: var(--classic-accent-soft);
  --surface: var(--classic-panel);
  --shadow: var(--classic-shadow);
  min-width: 0;
  overflow-x: clip;
  color: var(--classic-text);
  background: var(--classic-bg);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}

body.course-py::before,
body.course-sc::before,
body.course-cpp::before {
  display: block;
  height: 520px;
  background:
    radial-gradient(circle at 84% 3%, rgba(var(--classic-accent-rgb), .13), transparent 35%),
    linear-gradient(180deg, var(--classic-bg-elevated), transparent);
}

body a { transition: color .18s ease, background-color .18s ease, border-color .18s ease, transform .18s ease; }
body button, body input { font: inherit; }
body :focus-visible { outline: 3px solid rgba(var(--classic-accent-rgb), .35); outline-offset: 3px; }

/* 顶部课程栏 */
body .legacy-header,
body.course-sc .legacy-header {
  position: sticky;
  top: 0;
  z-index: 80;
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: var(--classic-header-h);
  padding: 10px clamp(18px, 2.5vw, 38px);
  background: color-mix(in srgb, var(--classic-panel) 90%, transparent);
  border-bottom: 1px solid var(--classic-line);
  box-shadow: 0 5px 22px rgba(20, 36, 59, .05);
  backdrop-filter: blur(18px) saturate(1.25);
}

.classic-global-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 104px;
  width: 104px;
  height: 38px;
  padding: 4px 12px 4px 6px;
  border-right: 1px solid var(--classic-line);
  border-radius: 9px 0 0 9px;
  background: #fff;
}
.classic-global-brand img { display: block; width: 86px; height: auto; }

body .legacy-brand,
body.course-sc .legacy-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--classic-text);
  font-size: 19px;
  font-weight: 850;
  letter-spacing: -.025em;
}

body .legacy-brand::before {
  content: "";
  width: 11px;
  height: 11px;
  border-radius: 4px;
  background: var(--classic-accent);
  box-shadow: 0 0 0 5px rgba(var(--classic-accent-rgb), .13);
}

body .legacy-brand span,
body.course-sc .legacy-brand span {
  margin-left: 2px;
  padding-left: 12px;
  border-left: 1px solid var(--classic-line);
  color: var(--classic-muted);
  font-size: 11px;
  font-weight: 750;
  letter-spacing: .1em;
}

body .legacy-header nav { display: flex; align-items: center; gap: 4px; min-width: 0; overflow-x: auto; scrollbar-width: none; }
body .legacy-header nav::-webkit-scrollbar { display: none; }
body .legacy-header nav a,
body.course-sc .legacy-header nav a {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  padding: 8px 12px;
  border-radius: 11px;
  color: var(--classic-text-soft);
  font-size: 13px;
  font-weight: 720;
}
body .legacy-header nav a:hover { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body .legacy-header nav a.is-active { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }

.classic-nav-context {
  min-width: 0;
  max-width: 220px;
  padding-left: 12px;
  overflow: hidden;
  border-left: 1px solid var(--classic-line);
  color: var(--classic-muted);
  font-size: 12px;
  font-weight: 720;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.classic-nav-actions { display: flex; align-items: center; gap: 7px; flex: 0 0 auto; margin-left: auto; }
.classic-account { display: inline-flex; align-items: center; gap: 7px; white-space: nowrap; }
.classic-account-link {
  display: inline-flex;
  min-height: 38px;
  max-width: 150px;
  align-items: center;
  padding: 7px 11px;
  overflow: hidden;
  border: 1px solid var(--classic-accent);
  border-radius: 11px;
  color: #fff;
  background: var(--classic-accent);
  font-size: 12px;
  font-weight: 760;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.classic-account-link:hover { color: #fff; background: var(--classic-accent-deep); }
.classic-account button { color: var(--classic-muted); font-size: 11px; text-decoration: underline; text-underline-offset: 3px; cursor: pointer; }

.classic-nav-short { display: none; }
.classic-theme-toggle,
.classic-course-toggle {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 7px 11px;
  border: 1px solid var(--classic-line);
  border-radius: 11px;
  color: var(--classic-text-soft);
  background: var(--classic-panel-soft);
  cursor: pointer;
}
.classic-theme-toggle:hover,
.classic-course-toggle:hover { border-color: var(--classic-line-strong); color: var(--classic-text); background: var(--classic-panel); }
.classic-theme-icon { display: grid; width: 18px; height: 18px; place-items: center; font-size: 16px; line-height: 1; }
.classic-theme-icon > * { grid-area: 1/1; font-style: normal; transition: opacity .18s, transform .18s; }
.classic-sun { opacity: 0; transform: rotate(-35deg) scale(.7); }
:root[data-course-theme="dark"] .classic-moon { opacity: 0; transform: rotate(35deg) scale(.7); }
:root[data-course-theme="dark"] .classic-sun { opacity: 1; transform: none; }
.classic-theme-label { font-size: 12px; font-weight: 760; }
.classic-course-toggle { display: none; }

/* 经典课程库首页 */
body .legacy-index,
body.course-sc .legacy-index {
  width: min(1680px, 100%);
  max-width: none;
  margin: 0 auto;
  padding: clamp(20px, 2.5vw, 40px) clamp(16px, 3vw, 48px) 72px;
}

body .legacy-hero,
body.course-sc .legacy-hero {
  position: relative;
  display: grid;
  min-height: 300px;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  overflow: hidden;
  padding: clamp(34px, 5vw, 68px);
  border: 1px solid color-mix(in srgb, var(--classic-accent) 24%, var(--classic-line));
  border-radius: 28px;
  color: var(--classic-text);
  text-align: left;
  background:
    linear-gradient(110deg, var(--classic-panel) 0 57%, color-mix(in srgb, var(--classic-accent-soft) 78%, var(--classic-panel)) 100%);
  box-shadow: var(--classic-shadow);
}
body .legacy-hero::before { content: ""; position: absolute; inset: 0 auto 0 0; width: 6px; background: var(--classic-accent); }
body .legacy-hero::after {
  display: block;
  width: 360px;
  height: 360px;
  right: -110px;
  bottom: -210px;
  border: 70px solid rgba(var(--classic-accent-rgb), .1);
}
body .legacy-label,
body.course-sc .legacy-label { color: var(--classic-accent); font-size: 12px; letter-spacing: .14em; }
body .legacy-hero h1,
body.course-sc .legacy-hero h1 {
  max-width: 760px;
  margin: 8px 0 0;
  color: var(--classic-text);
  font-size: clamp(38px, 5vw, 62px);
  font-weight: 880;
  line-height: 1.08;
  letter-spacing: -.05em;
}
body .hero-copy,
body.course-sc .hero-copy {
  max-width: 700px;
  margin: 18px 0 24px;
  color: var(--classic-text-soft);
  font-size: 16px;
}
body .hero-stats { justify-content: flex-start; }
body .hero-stats span,
body.course-sc .hero-stats span {
  padding: 8px 12px;
  border: 1px solid var(--classic-line);
  border-radius: 999px;
  color: var(--classic-text-soft);
  background: var(--classic-panel-soft);
  box-shadow: none;
}
body .hero-stats strong { color: var(--classic-text); }
body .hero-mark,
body.course-sc .hero-mark {
  position: relative;
  z-index: 1;
  display: flex;
  color: rgba(var(--classic-accent-rgb), .12);
  font-size: clamp(70px, 9vw, 124px);
}

body .search-panel,
body.course-sc .search-panel {
  position: relative;
  z-index: 2;
  max-width: none;
  margin: 22px 0 26px;
  padding: 20px;
  border: 1px solid var(--classic-line);
  border-radius: 18px;
  background: var(--classic-panel);
  box-shadow: var(--classic-shadow-soft);
}
body .search-panel label,
body.course-sc .search-panel label { display: block; margin: 0 0 8px 2px; color: var(--classic-text-soft); font-size: 12px; }
body .search-box,
body.course-sc .search-box { border: 1px solid var(--classic-line); border-radius: 13px; background: var(--classic-panel-soft); box-shadow: none; }
body .search-box:focus-within { border-color: var(--classic-accent); background: var(--classic-panel); box-shadow: 0 0 0 4px rgba(var(--classic-accent-rgb), .12); }
body .legacy-search { color: var(--classic-text); }
body .legacy-search::placeholder { color: var(--classic-muted); }
body .search-box button { color: var(--classic-text-soft); background: var(--classic-bg-elevated); }

body .library-layout,
body.course-sc .library-layout { grid-template-columns: 292px minmax(0, 1fr); gap: 28px; margin-top: 0; }
body .category-panel,
body.course-sc .category-panel {
  top: calc(var(--classic-header-h) + 18px);
  max-height: calc(100dvh - var(--classic-header-h) - 36px);
  margin: 0;
  padding: 18px 14px;
  border: 1px solid var(--classic-line);
  border-radius: 18px;
  background: var(--classic-panel);
  box-shadow: var(--classic-shadow-soft);
  scrollbar-color: var(--classic-line-strong) transparent;
}
body .category-panel .section-title { border-color: var(--classic-line); }
body .section-title h2,
body .content-heading h2 { color: var(--classic-text); }
body .category-links a,
body.course-sc .category-links a { color: var(--classic-text-soft); background: transparent; border-left-color: transparent; }
body .category-links a:hover { color: var(--classic-accent-deep); background: var(--classic-accent-soft); border-left-color: var(--classic-accent); }
body .category-links a.is-active { color: var(--classic-accent-deep); background: var(--classic-accent-soft); border-left-color: var(--classic-accent); }
body .sidebar-actions { border-color: var(--classic-line); }
body .sidebar-actions button,
body .sidebar-actions a { color: var(--classic-text-soft); border-color: var(--classic-line); background: var(--classic-panel-soft); }
body .sidebar-actions a { color: #fff; border-color: var(--classic-accent); background: var(--classic-accent); }

body .legacy-group,
body.course-sc .legacy-group {
  margin-top: 16px;
  border: 1px solid var(--classic-line);
  border-radius: 18px;
  background: var(--classic-panel);
  box-shadow: var(--classic-shadow-soft);
}
body .groups .legacy-group:first-child { margin-top: 0; }
body .group-heading,
body.course-sc .group-heading { padding: 20px 22px; color: var(--classic-text); background: var(--classic-panel); }
body .group-heading:hover { background: var(--classic-panel-soft); }
body .group-heading strong,
body.course-sc .group-heading strong { color: var(--classic-text); font-size: 19px; }
body .group-heading small { color: var(--classic-accent); }
body .group-count b { color: var(--classic-accent); background: var(--classic-accent-soft); }
body .legacy-group ol,
body.course-sc .legacy-group ol {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border-color: var(--classic-line);
  background: var(--classic-line);
}
body .legacy-group li { background: var(--classic-panel); }
body .legacy-group li a,
body.course-sc .legacy-group li a { min-height: 58px; color: var(--classic-text-soft); background: var(--classic-panel); }
body .legacy-group li a:hover { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body .empty-state { color: var(--classic-text); border-color: var(--classic-line-strong); background: var(--classic-panel); }

/* 课内三栏阅读器 */
body .document-shell,
body.course-sc .document-shell {
  display: grid;
  grid-template-columns: clamp(278px, 20vw, 336px) minmax(0, 1fr) clamp(190px, 15vw, 246px);
  width: 100%;
  min-height: calc(100dvh - var(--classic-header-h));
  margin: 0;
  gap: 0;
  align-items: start;
  background: var(--classic-bg);
}

body .document-sidebar,
body.course-sc .document-sidebar {
  position: sticky;
  top: var(--classic-header-h);
  z-index: 20;
  display: flex;
  height: calc(100dvh - var(--classic-header-h));
  max-height: none;
  flex-direction: column;
  overflow: hidden;
  padding: 0;
  border: 0;
  border-right: 1px solid var(--classic-line);
  border-radius: 0;
  background: var(--classic-panel);
  box-shadow: none;
}
body .document-sidebar .sidebar-top,
body.course-sc .document-sidebar .sidebar-top { padding: 17px 18px; border-color: var(--classic-line); background: var(--classic-panel-strong); }
body .document-sidebar .sidebar-top p { color: var(--classic-text); font-size: 16px; }
body .document-sidebar .sidebar-top a { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body .document-sidebar > nav,
body.course-sc .document-sidebar > nav { flex: 1; overflow-y: auto; padding: 10px; scrollbar-color: var(--classic-line-strong) transparent; }
body .lesson-nav-group,
body.course-sc .lesson-nav-group { border-color: var(--classic-line); }
body .lesson-nav-group summary,
body.course-sc .lesson-nav-group summary { color: var(--classic-text-soft); border-radius: 10px; }
body .lesson-nav-group summary:hover,
body .lesson-nav-group[open] summary,
body.course-sc .lesson-nav-group[open] summary { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body .lesson-nav-group summary b { color: var(--classic-muted); background: var(--classic-bg-elevated); }
body .lesson-nav-group > div a,
body.course-sc .lesson-nav-group > div a { color: var(--classic-text-soft); }
body .lesson-nav-group > div a:hover { color: var(--classic-accent-deep); background: var(--classic-panel-soft); }
body .lesson-nav-group > div a.is-current,
body.course-sc .lesson-nav-group > div a.is-current { color: var(--classic-accent-deep); border-left-color: var(--classic-accent); background: var(--classic-accent-soft); }
body .sidebar-footer { border-color: var(--classic-line); background: var(--classic-panel-strong); }
body .sidebar-footer a { color: var(--classic-text-soft); border-color: var(--classic-line); }
body .sidebar-footer a:first-child { color: #fff; border-color: var(--classic-accent); background: var(--classic-accent); }

body .document-shell .legacy-document,
body.course-sc .document-shell .legacy-document {
  width: 100%;
  max-width: none;
  min-width: 0;
  min-height: calc(100dvh - var(--classic-header-h));
  margin: 0;
  padding: clamp(42px, 5vw, 82px) clamp(30px, 6vw, 96px) 90px;
  border: 0;
  border-right: 1px solid var(--classic-line);
  border-radius: 0;
  color: var(--classic-text);
  background: var(--classic-panel);
  box-shadow: none;
}
body .document-meta,
body .legacy-document > h1,
body .document-content,
body .classic-lesson-pager { width: min(100%, 980px); max-width: 980px; margin-left: auto; margin-right: auto; }
body .document-meta { color: var(--classic-muted); border-color: var(--classic-line); }
body .document-meta span { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body .legacy-document > h1,
body.course-sc .legacy-document > h1 {
  margin-top: 30px;
  margin-bottom: 38px;
  color: var(--classic-text);
  font-size: clamp(36px, 4.5vw, 58px);
  font-weight: 850;
  line-height: 1.15;
  letter-spacing: -.04em;
}
body .document-content,
body.course-sc .document-content { color: var(--classic-text-soft); font-size: 17px; line-height: 1.82; }
body .document-content h2 { position: relative; margin-top: 2.2em; padding-left: 16px; color: var(--classic-text); font-size: 1.55em; }
body .document-content h2::before { content: ""; position: absolute; left: 0; top: .14em; width: 5px; height: 1.05em; border-radius: 4px; background: var(--classic-accent); }
body .document-content h3 { color: var(--classic-text); font-size: 1.22em; }
body .document-content a { text-decoration: underline; text-decoration-color: rgba(var(--classic-accent-rgb), .35); text-underline-offset: 3px; }
body .legacy-document img { border-radius: 12px; box-shadow: 0 3px 18px rgba(24, 39, 62, .08); }
body .document-content figcaption { color: var(--classic-muted); }
body .legacy-document pre { color: var(--classic-code-text); background: var(--classic-code); border: 1px solid var(--classic-line); border-radius: 13px; }
body .legacy-document :not(pre) > code { padding: .12em .36em; border-radius: 5px; color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body .legacy-document table { color: var(--classic-text-soft); background: var(--classic-panel); }
body .legacy-document td,
body .legacy-document th { border-color: var(--classic-line); }

body .document-toc,
body.course-sc .document-toc {
  position: sticky;
  top: var(--classic-header-h);
  height: calc(100dvh - var(--classic-header-h));
  padding: 34px 20px;
  overflow-y: auto;
  color: var(--classic-text-soft);
  background: var(--classic-panel-soft);
  scrollbar-color: var(--classic-line-strong) transparent;
}
body .document-toc strong { color: var(--classic-text); border-color: var(--classic-line); }
body .document-toc a,
body.course-sc .document-toc a { color: var(--classic-muted); }
body .document-toc a:hover { color: var(--classic-accent); }

.classic-reading-progress { position: fixed; top: calc(var(--classic-header-h) - 3px); left: 0; right: 0; z-index: 90; height: 3px; pointer-events: none; }
.classic-reading-progress i { display: block; width: 100%; height: 100%; transform: scaleX(0); transform-origin: left; background: var(--classic-accent); transition: transform .1s linear; }
.classic-skip-link { position: fixed; top: 8px; left: 12px; z-index: 120; padding: 9px 13px; border-radius: 9px; color: #fff; background: var(--classic-accent-deep); transform: translateY(-150%); }
.classic-skip-link:focus { transform: none; }

.classic-lesson-pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 72px; padding-top: 28px; border-top: 1px solid var(--classic-line); }
.classic-lesson-pager a { display: flex; min-width: 0; min-height: 88px; flex-direction: column; justify-content: center; padding: 16px 18px; border: 1px solid var(--classic-line); border-radius: 14px; color: var(--classic-text-soft); background: var(--classic-panel-soft); text-decoration: none; }
.classic-lesson-pager a:hover { border-color: rgba(var(--classic-accent-rgb), .45); color: var(--classic-accent-deep); background: var(--classic-accent-soft); transform: translateY(-2px); }
.classic-lesson-pager small { margin-bottom: 4px; color: var(--classic-muted); font-size: 11px; }
.classic-lesson-pager strong { overflow: hidden; font-size: 14px; line-height: 1.4; text-overflow: ellipsis; white-space: nowrap; }
.classic-pager-next { text-align: right; }
.classic-sidebar-backdrop { display: none; }

@media (max-width: 1280px) {
  body .document-shell,
  body.course-sc .document-shell { grid-template-columns: 290px minmax(0, 1fr); }
  body .document-toc,
  body.course-sc .document-toc { display: none; }
  body .legacy-group ol,
  body.course-sc .legacy-group ol { grid-template-columns: 1fr; }
}

@media (max-width: 980px) {
  body .library-layout,
  body.course-sc .library-layout { grid-template-columns: 1fr; }
  body .category-panel,
  body.course-sc .category-panel { position: static; max-height: none; }
  body .category-links,
  body.course-sc .category-links { display: flex; flex-direction: row; overflow-x: auto; margin: 12px -14px 0; padding: 0 14px 4px; }
  body .category-links a { flex: 0 0 auto; border-left: 0; border-bottom: 3px solid transparent; }

  body .document-shell,
  body.course-sc .document-shell { display: block; }
  body .document-sidebar,
  body.course-sc .document-sidebar {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 110;
    width: min(360px, calc(100vw - 46px));
    height: 100dvh;
    max-height: none;
    border-right: 1px solid var(--classic-line);
    box-shadow: var(--classic-shadow);
    transform: translateX(-105%);
    transition: transform .22s ease;
  }
  body.classic-sidebar-open .document-sidebar { transform: none; }
  body.classic-sidebar-open { overflow: hidden; }
  .classic-course-toggle { display: inline-flex; }
  .classic-sidebar-backdrop {
    position: fixed;
    inset: 0;
    z-index: 105;
    display: block;
    visibility: hidden;
    border: 0;
    background: rgba(4, 10, 18, .56);
    opacity: 0;
    cursor: pointer;
    transition: opacity .22s, visibility .22s;
  }
  body.classic-sidebar-open .classic-sidebar-backdrop { visibility: visible; opacity: 1; }
  body .document-shell .legacy-document,
  body.course-sc .document-shell .legacy-document { min-height: calc(100dvh - var(--classic-header-h)); border-right: 0; }
}

@media (max-width: 1180px) {
  .classic-nav-context { display: none; }
  body .legacy-header nav a { padding-inline: 9px; font-size: 12px; }
}

@media (max-width: 760px) {
  :root { --classic-header-h: 60px; }
  body .legacy-header,
  body.course-sc .legacy-header { min-height: var(--classic-header-h); padding: 8px 11px; }
  body .legacy-brand,
  body.course-sc .legacy-brand { font-size: 16px; }
  body .legacy-brand::before { width: 9px; height: 9px; }
  body .legacy-brand span { display: none; }
  .classic-global-brand { flex-basis: 76px; width: 76px; height: 36px; padding: 5px 8px 5px 4px; }
  .classic-global-brand img { width: 64px; }
  body .legacy-header nav { gap: 5px; }
  body .legacy-header nav > a { display: none; }
  .classic-nav-full { display: none; }
  .classic-nav-short { display: inline; }
  .classic-theme-toggle,
  .classic-course-toggle { min-height: 38px; padding: 6px 9px; }
  .classic-theme-label { display: none; }
  .classic-course-toggle span:last-child { display: none; }
  .classic-account-link { max-width: 78px; padding-inline: 9px; }
  .classic-account button { display: none; }

  body .legacy-index,
  body.course-sc .legacy-index { padding: 12px 12px 42px; }
  body .legacy-hero,
  body.course-sc .legacy-hero { display: block; min-height: auto; padding: 30px 22px; border-radius: 20px; }
  body .legacy-hero h1,
  body.course-sc .legacy-hero h1 { font-size: 34px; }
  body .hero-copy { font-size: 14px; }
  body .hero-mark,
  body.course-sc .hero-mark { display: none; }
  body .search-panel,
  body.course-sc .search-panel { margin: 14px 0 18px; padding: 14px; border-radius: 15px; }
  body .category-panel,
  body.course-sc .category-panel,
  body .legacy-group,
  body.course-sc .legacy-group { border-radius: 14px; }
  body .content-heading { display: block; }
  body .content-heading > span { display: block; margin-top: 5px; }
  body .group-heading { padding: 17px; }
  body .legacy-group li a { min-height: 54px; padding: 9px 13px; }

  body .document-shell .legacy-document,
  body.course-sc .document-shell .legacy-document { padding: 28px 17px 68px; }
  body .legacy-document > h1,
  body.course-sc .legacy-document > h1 { margin: 25px 0 30px; font-size: 32px; }
  body .document-content,
  body.course-sc .document-content { font-size: 16px; line-height: 1.78; }
  body .document-content h2 { padding-left: 13px; font-size: 1.35em; }
  .classic-lesson-pager { grid-template-columns: 1fr; margin-top: 48px; }
  .classic-pager-next { text-align: left; }
}

/* 经典课程脑图：按原课脑图的“左侧主题 + 右向分支线”重绘，信息在线上直接展开。 */
:root[data-course-theme="dark"] .classic-unified-header .course-global-brand img { opacity: 0; }
:root[data-course-theme="dark"] .classic-unified-header .course-global-brand::after { display: block; }

body.course-sc .classic-thinking-map { background: var(--classic-panel); }
body.course-sc .classic-thinking-tree {
  display: grid;
  grid-template-columns: 176px minmax(0,1fr);
  gap: 34px;
  align-items: center;
  padding: 30px;
  background: var(--classic-panel);
}
body.course-sc .classic-thinking-root {
  grid-column: auto;
  justify-self: stretch;
  width: auto;
  padding: 20px 15px;
  border: 0;
  border-radius: 11px;
  color: #10233b;
  background: #79d5ef;
  box-shadow: none;
}
body.course-sc .classic-thinking-root::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 100%;
  display: block;
  width: 34px;
  height: 4px;
  background: #ff8c1a;
  transform: translateY(-50%);
}
body.course-sc .classic-thinking-root small { color: #2e6375; }
body.course-sc .classic-thinking-root strong { color: #10233b; }
body.course-sc .classic-thinking-branches {
  position: relative;
  display: grid;
  gap: 16px;
  padding-left: 32px;
}
body.course-sc .classic-thinking-branches::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 3px;
  border-radius: 999px;
  background: linear-gradient(to bottom,#f04b43 0%,#ff8c1a 34%,#ffbf00 68%,#59c059 100%);
}
body.course-sc .classic-thinking-branch {
  --mind-line: #ff8c1a;
  position: relative;
  min-width: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
}
body.course-sc .classic-thinking-idea { --mind-line: #f04b43; }
body.course-sc .classic-thinking-topics { --mind-line: #ff8c1a; }
body.course-sc .classic-thinking-flow { --mind-line: #ffbf00; }
body.course-sc .classic-thinking-check { --mind-line: #59c059; }
body.course-sc .classic-thinking-branch::before {
  content: none;
}
body.course-sc .classic-thinking-main {
  position: relative;
  display: grid;
  grid-template-columns: minmax(116px,.34fr) minmax(0,1fr);
  gap: 16px;
  align-items: end;
  min-height: 34px;
  padding: 0 9px 7px 4px;
  border-bottom: 2px solid var(--mind-line);
}
body.course-sc .classic-thinking-main::before {
  content: "";
  position: absolute;
  right: 100%;
  bottom: -2px;
  width: 32px;
  height: 2px;
  background: var(--mind-line);
}
body.course-sc .classic-thinking-main strong { color: var(--classic-text); font-size: 15px; line-height: 1.5; }
body.course-sc .classic-thinking-main p,
body.course-sc .classic-thinking-main > span { margin: 0; color: var(--classic-text-soft); font-size: 13px; line-height: 1.55; }
body.course-sc .classic-thinking-twigs { position: relative; display: grid; gap: 6px; margin: 8px 0 0 min(118px,22%); padding: 0 0 0 28px; list-style: none; }
body.course-sc .classic-thinking-twigs::before {
  content: "";
  position: absolute;
  top: -8px;
  bottom: -2px;
  left: 0;
  width: 2px;
  border-radius: 999px;
  background: var(--mind-line);
}
body.course-sc .classic-thinking-twigs li {
  position: relative;
  display: grid;
  grid-template-columns: 30px minmax(0,1fr);
  gap: 9px;
  align-items: center;
  min-height: 30px;
  padding: 0 7px 5px 0;
  border-bottom: 2px solid color-mix(in srgb,var(--mind-line) 86%,transparent);
}
body.course-sc .classic-thinking-twigs li::before {
  content: "";
  position: absolute;
  right: 100%;
  bottom: -2px;
  left: auto;
  width: 28px;
  height: 2px;
  border: 0;
  border-radius: 0;
  background: var(--mind-line);
}
body.course-sc .classic-thinking-twigs li b { display: grid; place-items: center; width: 28px; height: 24px; border-radius: 7px; color: #6c5000; background: #fff0bd; font-size: 10px; }
:root[data-course-theme="dark"] body.course-sc .classic-thinking-twigs li b { color: #ffe5a0; background: rgba(255,191,0,.16); }
body.course-sc .classic-thinking-twigs li p { margin: 0; color: var(--classic-text); font-size: 12px; line-height: 1.45; }

@media (max-width: 760px) {
  .classic-unified-header .course-global-brand { width: 96px; flex-basis: 96px; padding-right: 9px; }
  .classic-unified-header .course-global-brand img { width: 82px; }
  body.course-sc .classic-thinking-tree { grid-template-columns: 1fr; gap: 20px; padding: 20px 15px 24px; }
  body.course-sc .classic-thinking-root { width: 100%; }
  body.course-sc .classic-thinking-branches { gap: 17px; padding-left: 18px; }
  body.course-sc .classic-thinking-main::before { width: 18px; }
  body.course-sc .classic-thinking-main { grid-template-columns: 1fr; gap: 3px; }
  body.course-sc .classic-thinking-twigs { margin-left: 16px; padding-left: 22px; }
  body.course-sc .classic-thinking-twigs li::before { width: 22px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; }
}

/* ========================================================================
   2026-08-15：经典课时与新版课程共用同一页面骨架
   左侧全高课程树 / 右侧单层课程顶栏 / 中间正文 / 右侧本课目录
   ======================================================================== */
:root { --classic-header-h: 62px; }
:root[data-course-theme="dark"] {
  color-scheme: dark;
  --classic-bg: #0f1822;
  --classic-bg-elevated: #121e29;
  --classic-panel: #172330;
  --classic-panel-strong: #15212c;
  --classic-panel-soft: #111d27;
  --classic-text: #edf4f8;
  --classic-text-soft: #afbfca;
  --classic-muted: #8295a3;
  --classic-line: #2b3c49;
  --classic-line-strong: #3b5060;
  --classic-code: #081018;
  --classic-shadow: 0 18px 56px rgba(0,0,0,.3);
  --classic-shadow-soft: 0 10px 28px rgba(0,0,0,.22);
  --classic-accent-soft: rgba(var(--classic-accent-rgb),.16);
}
body.classic-lesson-page::before { display: none; }
body.classic-lesson-page {
  --classic-sidebar-w: 264px;
  --classic-toc-w: 224px;
  display: grid;
  grid-template-columns: var(--classic-sidebar-w) minmax(0,1fr) var(--classic-toc-w);
  grid-template-rows: var(--classic-header-h) minmax(calc(100dvh - var(--classic-header-h)),auto);
  min-height: 100dvh;
  margin: 0;
  background: var(--classic-bg);
}
body.classic-lesson-page.course-py { --classic-sidebar-w: 304px; }
body.classic-lesson-page.classic-left-collapsed { --classic-sidebar-w: 56px; }
body.classic-lesson-page.classic-toc-collapsed { --classic-toc-w: 44px; }

body.classic-lesson-page .legacy-header {
  position: sticky;
  top: 0;
  z-index: 80;
  grid-column: 2 / -1;
  grid-row: 1;
  display: block;
  width: 100%;
  height: var(--classic-header-h);
  min-height: var(--classic-header-h);
  padding: 0 18px;
  border: 0;
  border-bottom: 1px solid var(--classic-line);
  border-radius: 0;
  background: color-mix(in srgb,var(--classic-panel) 94%,transparent);
  box-shadow: none;
  backdrop-filter: saturate(140%) blur(10px);
}
.classic-unified-header .course-local-nav-inner { display: flex; height: 100%; align-items: center; gap: 12px; padding: 10px 0; }
.classic-unified-header .course-global-brand {
  display: flex;
  width: 136px;
  height: 46px;
  flex: 0 0 136px;
  align-items: center;
  justify-content: flex-start;
  padding: 4px 14px 4px 2px;
  border: 0;
  border-right: 1px solid var(--classic-line);
  border-radius: 0;
  background: transparent;
}
.classic-unified-header .course-global-brand img { display: block; width: 118px; height: auto; }
.classic-unified-header .course-local-links { display: flex; min-width: 0; flex: 0 1 auto; align-items: center; gap: 2px; overflow-x: auto; scrollbar-width: none; }
.classic-unified-header .course-local-links::-webkit-scrollbar { display: none; }
.classic-unified-header .course-local-links > a {
  display: inline-flex;
  min-height: 36px;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  padding: 7px 13px;
  border-radius: 8px;
  color: var(--classic-text-soft);
  font-size: 14px;
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
}
.classic-unified-header .course-local-links > a:hover,
.classic-unified-header .course-local-links > a.is-active { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
.classic-unified-header .course-local-context {
  min-width: 0;
  max-width: 240px;
  margin-left: 2px;
  padding-left: 12px;
  overflow: hidden;
  border-left: 1px solid var(--classic-line);
  color: var(--classic-muted);
  font-size: 12px;
  font-weight: 700;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.classic-unified-header .course-local-actions { display: flex; flex: 0 0 auto; align-items: center; gap: 8px; margin-left: auto; }
.classic-unified-header .course-theme-toggle {
  display: inline-flex;
  width: auto;
  min-width: 72px;
  height: 40px;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 0 12px;
  border: 1px solid var(--classic-line);
  border-radius: 999px;
  color: var(--classic-text-soft);
  background: var(--classic-panel-soft);
  cursor: pointer;
}
.classic-unified-header .course-theme-toggle span { font-size: 17px; }
.classic-unified-header .course-theme-toggle b { font-size: 12px; }
.classic-unified-header .course-local-account { display: flex; flex: 0 0 auto; align-items: center; }
.classic-unified-header .auth-status { display: inline-flex; align-items: center; gap: 4px; padding: 3px; border: 1px solid var(--classic-line); border-radius: 14px; background: var(--classic-panel-soft); white-space: nowrap; }
.classic-unified-header .auth-login { display: inline-flex; height: 36px; align-items: center; padding: 0 16px; border-radius: 10px; color: #fff; background: var(--classic-accent); font-size: 12px; font-weight: 800; }
.classic-unified-header .auth-chip { display: flex; min-width: 0; max-width: 190px; height: 40px; align-items: center; gap: 8px; padding: 0 10px 0 5px; border-radius: 11px; color: var(--classic-text); }
.classic-unified-header .auth-chip:hover { background: var(--classic-panel); }
.classic-unified-header .auth-avatar { display: grid; width: 31px; height: 31px; flex: 0 0 auto; place-items: center; border-radius: 9px; color: #fff; background: linear-gradient(145deg,var(--classic-accent),var(--classic-accent-deep)); font-size: 12px; font-weight: 900; }
.classic-unified-header .auth-copy { display: grid; min-width: 0; gap: 2px; line-height: 1; }
.classic-unified-header .auth-copy small { color: var(--classic-muted); font-size: 9px; font-weight: 700; }
.classic-unified-header .auth-copy strong { max-width: 106px; overflow: hidden; color: inherit; font-size: 12px; text-overflow: ellipsis; white-space: nowrap; }
.classic-unified-header .auth-logout { display: inline-flex; height: 34px; align-items: center; justify-content: center; gap: 5px; padding: 0 10px; border: 1px solid transparent; border-radius: 9px; color: var(--classic-muted); background: var(--classic-panel); font-size: 11px; font-weight: 700; cursor: pointer; }
.classic-unified-header .auth-logout svg { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }

body.classic-lesson-page .document-shell { display: contents; }
body.classic-lesson-page .document-sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  z-index: 90;
  grid-column: 1;
  grid-row: 1 / 3;
  width: var(--classic-sidebar-w);
  height: 100dvh;
  max-height: 100dvh;
  border: 0;
  border-right: 1px solid var(--classic-line);
  background: var(--classic-panel-strong);
}
body.classic-lesson-page.course-py .document-sidebar { width: var(--classic-sidebar-w); }
body.classic-lesson-page.course-sc .document-sidebar { background: var(--classic-panel-strong); }
body.classic-lesson-page .document-sidebar .sidebar-top { display: block; flex: 0 0 auto; width: 100%; padding: 0; border-bottom: 1px solid var(--classic-line); background: inherit; }
.classic-sidebar-brand { width: 100%; box-sizing: border-box; }
.classic-sidebar-brand { display: flex; align-items: center; gap: 10px; padding: 16px 18px 14px; color: var(--classic-text); }
.classic-sidebar-mark { display: grid; width: 38px; height: 38px; flex: 0 0 auto; place-items: center; border-radius: 12px; color: #fff; background: var(--classic-accent); font-size: 13px; font-weight: 900; }
body.course-cpp .classic-sidebar-mark { width: 42px; font-size: 11px; }
.classic-sidebar-brand > span:last-child { display: grid; min-width: 0; gap: 2px; }
.classic-sidebar-brand b { overflow: hidden; font-size: 15px; text-overflow: ellipsis; white-space: nowrap; }
.classic-sidebar-brand small { color: var(--classic-muted); font-size: 11px; }
.classic-sidebar-search { display: grid; gap: 5px; padding: 0 14px 13px; }
.classic-sidebar-search > span { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.classic-sidebar-search input { width: 100%; height: 38px; padding: 0 11px; border: 1px solid var(--classic-line); border-radius: 10px; color: var(--classic-text); background: var(--classic-panel); font-size: 12px; outline: none; }
.classic-sidebar-search input:focus { border-color: var(--classic-accent); box-shadow: 0 0 0 3px rgba(var(--classic-accent-rgb),.12); }
.classic-rail-toggle { display: inline-flex; align-items: center; justify-content: center; gap: 6px; min-height: 34px; padding: 6px 9px; border: 1px solid var(--classic-accent); border-radius: 9px; color: var(--classic-accent-deep); background: var(--classic-panel); font-size: 10px; font-weight: 800; cursor: pointer; }
.classic-rail-toggle span { font: 900 17px/1 Arial,sans-serif; }.classic-rail-toggle-left { position: absolute; z-index: 3; top: 18px; right: 12px; }.classic-rail-toggle-right { margin: 0 0 14px auto; }
body.classic-lesson-page .document-sidebar .sidebar-top { position: relative; }
body.classic-left-collapsed .document-sidebar .sidebar-top { height: var(--classic-header-h); min-height: var(--classic-header-h); }
body.classic-left-collapsed .document-sidebar .sidebar-top > :not(.classic-rail-toggle), body.classic-left-collapsed .document-sidebar > nav { display: none; }
body.classic-left-collapsed .classic-rail-toggle-left { inset: 18px 10px auto; width: 36px; padding: 5px; }
body.classic-left-collapsed .classic-rail-toggle-left b { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
body.classic-lesson-page .document-sidebar > nav { flex: 1 1 auto; min-height: 0; padding: 10px 12px 24px; }
body.classic-lesson-page .lesson-nav-group { margin: 0 0 4px; border: 0; }
body.classic-lesson-page .lesson-nav-group summary { display: flex; align-items: center; gap: 8px; min-height: 38px; padding: 8px 7px; border-radius: 10px; color: var(--classic-text-soft); font-size: 13px; font-weight: 700; }
body.classic-lesson-page .lesson-nav-group summary small { display: none; }
body.classic-lesson-page .lesson-nav-group summary b { margin-left: auto; color: var(--classic-muted); background: transparent; font-size: 11px; }
body.classic-lesson-page .lesson-nav-group > div { padding: 2px 0 7px 14px; }
body.classic-lesson-page .lesson-nav-group > div a { display: flex; align-items: baseline; gap: 8px; min-height: 0; padding: 6px 8px; border: 0; border-radius: 8px; color: var(--classic-text-soft); font-size: 13px; }
body.classic-lesson-page .lesson-nav-group > div a:hover { color: var(--classic-accent-deep); background: var(--classic-accent-soft); }
body.classic-lesson-page .lesson-nav-group > div a.is-current { color: #fff; border: 0; background: var(--classic-accent); }

body.classic-lesson-page .legacy-document {
  grid-column: 2;
  grid-row: 2;
  width: 100%;
  max-width: none;
  min-width: 0;
  min-height: calc(100dvh - var(--classic-header-h));
  padding: clamp(42px,5vw,78px) clamp(30px,5vw,82px) 90px;
  border: 0;
  border-right: 1px solid var(--classic-line);
  border-radius: 0;
  background: var(--classic-panel);
  box-shadow: none;
}
body.classic-lesson-page .document-toc { grid-column: 3; grid-row: 2; top: var(--classic-header-h); height: calc(100dvh - var(--classic-header-h)); padding: 30px 18px; background: var(--classic-panel-soft); }
body.classic-toc-collapsed .document-toc { padding: 8px 5px; }
body.classic-toc-collapsed .document-toc > :not(.classic-rail-toggle) { display: none; }
body.classic-toc-collapsed .classic-rail-toggle-right { width: 100%; min-height: 130px; padding: 8px 4px; }
body.classic-toc-collapsed .classic-rail-toggle-right b { writing-mode: vertical-rl; letter-spacing: .08em; }
body.classic-lesson-page .document-meta,
body.classic-lesson-page .legacy-document > h1,
body.classic-lesson-page .document-content,
body.classic-lesson-page .classic-lesson-pager { width: min(100%,980px); max-width: 980px; margin-inline: auto; }
body.classic-lesson-page .legacy-document > h1 { margin: 28px auto 36px; font-size: clamp(34px,4vw,54px); }
body.classic-lesson-page .document-content { font-size: 17px; line-height: 1.82; }
.classic-reading-progress { top: calc(var(--classic-header-h) - 3px); left: var(--classic-sidebar-w); }
body.course-py .classic-reading-progress { left: var(--classic-sidebar-w); }

/* Scratch 经典 167 课：响应阶段按每课正文生成编程思路与步骤思维导图 */
body.course-sc .classic-thinking-map {
  margin: 0 0 48px;
  overflow: hidden;
  border: 1px solid var(--classic-line);
  border-radius: 22px;
  color: var(--classic-text);
  background:
    radial-gradient(circle at 92% 10%, rgba(var(--classic-accent-rgb),.13) 0 105px, transparent 106px),
    var(--classic-panel-soft);
  box-shadow: var(--classic-shadow-soft);
}
body.course-sc .classic-thinking-head {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 22px 26px;
  border-bottom: 1px solid var(--classic-line);
  background: color-mix(in srgb,var(--classic-panel) 88%,transparent);
}
body.course-sc .classic-thinking-head > span {
  display: grid;
  place-items: center;
  min-width: 92px;
  min-height: 34px;
  padding: 5px 10px;
  border-radius: 10px;
  color: #fff;
  background: var(--classic-accent);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: .14em;
}
body.course-sc .classic-thinking-head > div { display: grid; gap: 2px; }
body.course-sc .classic-thinking-head b { font-size: 19px; line-height: 1.3; }
body.course-sc .classic-thinking-head small { color: var(--classic-muted); font-size: 11px; }
body.course-sc .classic-thinking-canvas {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0,.82fr) minmax(0,1.18fr);
  gap: 20px;
  padding: 30px;
  background-image: radial-gradient(rgba(var(--classic-accent-rgb),.18) 1px,transparent 1px);
  background-size: 18px 18px;
}
body.course-sc .classic-thinking-root {
  position: relative;
  z-index: 2;
  grid-column: 1 / -1;
  justify-self: center;
  display: grid;
  gap: 3px;
  width: min(440px,86%);
  padding: 17px 22px;
  border: 3px solid color-mix(in srgb,var(--classic-accent) 72%,#fff);
  border-radius: 18px;
  color: #fff;
  background: linear-gradient(135deg,var(--classic-accent),color-mix(in srgb,var(--classic-accent) 58%,#8ec1ff));
  text-align: center;
  box-shadow: 0 14px 28px -18px rgba(var(--classic-accent-rgb),.8);
}
body.course-sc .classic-thinking-root::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  width: 2px;
  height: 28px;
  background: color-mix(in srgb,var(--classic-accent) 46%,var(--classic-line));
}
body.course-sc .classic-thinking-root small { color: rgba(255,255,255,.76); font-size: 10px; font-weight: 800; letter-spacing: .14em; }
body.course-sc .classic-thinking-root strong { font-size: 18px; line-height: 1.45; }
body.course-sc .classic-thinking-idea,
body.course-sc .classic-thinking-flow {
  position: relative;
  z-index: 1;
  min-width: 0;
  padding: 21px;
  border: 1px solid var(--classic-line);
  border-radius: 17px;
  background: color-mix(in srgb,var(--classic-panel) 94%,var(--classic-accent));
}
body.course-sc .classic-thinking-idea::before,
body.course-sc .classic-thinking-flow::before {
  content: "";
  position: absolute;
  bottom: 100%;
  width: calc(50% + 11px);
  height: 16px;
  border-top: 2px solid color-mix(in srgb,var(--classic-accent) 46%,var(--classic-line));
}
body.course-sc .classic-thinking-idea::before { right: -11px; border-left: 2px solid color-mix(in srgb,var(--classic-accent) 46%,var(--classic-line)); border-top-left-radius: 12px; }
body.course-sc .classic-thinking-flow::before { left: -11px; border-right: 2px solid color-mix(in srgb,var(--classic-accent) 46%,var(--classic-line)); border-top-right-radius: 12px; }
body.course-sc .classic-thinking-idea > span,
body.course-sc .classic-thinking-flow > span {
  display: inline-flex;
  margin-bottom: 13px;
  padding: 5px 11px;
  border-radius: 999px;
  color: var(--classic-accent-deep);
  background: var(--classic-accent-soft);
  font-size: 11px;
  font-weight: 850;
  letter-spacing: .08em;
}
body.course-sc .classic-thinking-idea p { margin: 0; color: var(--classic-text); font-size: 14px; font-weight: 700; line-height: 1.75; }
body.course-sc .classic-thinking-flow ol { display: grid; gap: 9px; margin: 0; padding: 0; list-style: none; }
body.course-sc .classic-thinking-flow li { display: grid; grid-template-columns: 34px minmax(0,1fr); gap: 10px; align-items: center; }
body.course-sc .classic-thinking-flow li b { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 10px; color: #9a5a00; background: #fff0d6; font-size: 11px; }
:root[data-course-theme="dark"] body.course-sc .classic-thinking-flow li b { color: #ffd89f; background: rgba(255,171,25,.17); }
body.course-sc .classic-thinking-flow li p { margin: 0; color: var(--classic-text-soft); font-size: 12px; font-weight: 700; line-height: 1.55; }

@media (max-width: 1280px) {
  body.classic-lesson-page,
  body.classic-lesson-page.course-py { --classic-sidebar-w: 280px; grid-template-columns: var(--classic-sidebar-w) minmax(0,1fr); }
  body.classic-lesson-page.classic-left-collapsed,
  body.classic-lesson-page.course-py.classic-left-collapsed { --classic-sidebar-w: 56px; }
  body.classic-lesson-page .document-sidebar,
  body.classic-lesson-page.course-py .document-sidebar { width: var(--classic-sidebar-w); }
  body.classic-lesson-page .legacy-header { grid-column: 2; }
  body.classic-lesson-page .document-toc { display: none; }
  .classic-reading-progress,
  body.course-py .classic-reading-progress { left: var(--classic-sidebar-w); }
  .classic-unified-header .course-local-context { display: none; }
  .classic-unified-header .course-local-links > a { padding-inline: 9px; font-size: 12px; }
}

@media (max-width: 1024px) {
  body.classic-lesson-page,
  body.classic-lesson-page.course-py { display: block; padding-top: var(--classic-header-h); }
  body.classic-lesson-page .legacy-header { position: fixed; inset: 0 0 auto 0; width: 100%; }
  body.classic-lesson-page .document-shell { display: block; }
  body.classic-lesson-page .document-sidebar {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 110;
    width: min(360px,calc(100vw - 46px));
    height: 100dvh;
    max-height: none;
    transform: translateX(-105%);
    transition: transform .22s ease;
  }
  body.classic-sidebar-open .document-sidebar { transform: none; }
  .classic-rail-toggle { display: none; }
  body.classic-lesson-page .legacy-document { min-height: calc(100dvh - var(--classic-header-h)); border-right: 0; }
  .classic-course-toggle { display: inline-flex; order: -1; min-width: 38px; height: 36px; align-items: center; justify-content: center; gap: 5px; padding: 0 10px; border: 1px solid var(--classic-line); border-radius: 8px; color: var(--classic-text-soft); background: var(--classic-panel-soft); }
  .classic-reading-progress,
  body.course-py .classic-reading-progress { left: 0; }
}

@media (max-width: 760px) {
  :root { --classic-header-h: 58px; }
  body.classic-lesson-page .legacy-header { height: var(--classic-header-h); min-height: var(--classic-header-h); padding: 0 10px; }
  .classic-unified-header .course-local-nav-inner { gap: 6px; padding: 10px 0; }
  .classic-unified-header .course-global-brand { width: 76px; height: 34px; flex-basis: 76px; padding: 5px 8px 5px 4px; }
  .classic-unified-header .course-global-brand img { width: 64px; }
  .classic-unified-header .course-local-links { flex: 1 1 auto; }
  .classic-unified-header .course-local-links > a { min-width: max-content; padding: 7px 10px; font-size: 12px; }
  .classic-unified-header .course-local-links > a:not(.is-active) { display: none; }
  .classic-unified-header .course-theme-toggle { width: 34px; min-width: 34px; height: 34px; padding: 0; }
  .classic-unified-header .course-theme-toggle b { display: none; }
  .classic-unified-header .auth-login { height: 34px; padding-inline: 10px; }
  .classic-unified-header .auth-chip { width: 34px; height: 34px; padding: 0; }
  .classic-unified-header .auth-avatar { width: 30px; height: 30px; margin: auto; }
  .classic-unified-header .auth-copy { display: none; }
  .classic-unified-header .auth-logout { width: 32px; height: 32px; padding: 0; }
  .classic-unified-header .auth-logout span { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
  .classic-course-toggle span:last-child { display: none; }
  body.classic-lesson-page .legacy-document { padding: 28px 17px 68px; }
  body.classic-lesson-page .legacy-document > h1 { font-size: 32px; }
  body.classic-lesson-page .document-content { font-size: 16px; }
  body.course-sc .classic-thinking-map { margin-bottom: 34px; border-radius: 18px; }
  body.course-sc .classic-thinking-head { align-items: flex-start; padding: 18px; }
  body.course-sc .classic-thinking-head > span { min-width: 34px; width: 34px; padding: 5px; overflow: hidden; color: transparent; letter-spacing: 0; }
  body.course-sc .classic-thinking-head > span::before { content: "图"; color: #fff; font-size: 12px; }
  body.course-sc .classic-thinking-canvas { grid-template-columns: 1fr; gap: 13px; padding: 20px 16px; }
  body.course-sc .classic-thinking-root { grid-column: auto; width: 100%; }
  body.course-sc .classic-thinking-root::after,
  body.course-sc .classic-thinking-idea::before,
  body.course-sc .classic-thinking-flow::before { display: none; }
}

/* 放在最终阅读壳规则之后，确保原课程自带样式不会把树状脑图改回卡片。 */
body.course-sc .classic-thinking-tree {
  display: grid;
  grid-template-columns: 176px minmax(0,1fr);
  gap: 34px;
  align-items: center;
  padding: 30px;
  background: var(--classic-panel);
}
body.course-sc .classic-thinking-root {
  grid-column: auto;
  justify-self: stretch;
  width: auto;
  padding: 20px 15px;
  border: 0;
  border-radius: 11px;
  color: #10233b;
  background: #79d5ef;
  box-shadow: none;
}
body.course-sc .classic-thinking-root::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 100%;
  display: block;
  width: 34px;
  height: 4px;
  background: #ff8c1a;
  transform: translateY(-50%);
}
body.course-sc .classic-thinking-root small { color: #2e6375; }
body.course-sc .classic-thinking-root strong { color: #10233b; }
body.course-sc .classic-thinking-branch { padding: 0; border: 0; border-radius: 0; background: transparent; box-shadow: none; }
body.course-sc .classic-thinking-branch::before {
  content: none;
}
body.course-sc .classic-thinking-main {
  position: relative;
  display: grid;
  grid-template-columns: minmax(116px,.34fr) minmax(0,1fr);
  gap: 16px;
  align-items: end;
  min-height: 34px;
  padding: 0 9px 7px 4px;
  border-bottom: 2px solid var(--mind-line);
}
body.course-sc .classic-thinking-twigs { position: relative; display: grid; gap: 6px; margin: 8px 0 0 min(118px,22%); padding: 0 0 0 28px; list-style: none; }
body.course-sc .classic-thinking-twigs li {
  position: relative;
  display: grid;
  grid-template-columns: 30px minmax(0,1fr);
  gap: 9px;
  align-items: center;
  min-height: 30px;
  padding: 0 7px 5px 0;
  border-bottom: 2px solid color-mix(in srgb,var(--mind-line) 86%,transparent);
}
body.course-sc .classic-thinking-twigs li b { width: 28px; height: 24px; border-radius: 7px; font-size: 10px; }

.classic-unified-header .course-global-brand { position: relative; }
.classic-unified-header .course-global-brand::after {
  content: "";
  position: absolute;
  inset: 0 14px 0 2px;
  display: none;
  pointer-events: none;
  background: var(--course-dark-logo,#ffad42);
  -webkit-mask: url("/logo.png") left center / contain no-repeat;
  mask: url("/logo.png") left center / contain no-repeat;
}
:root[data-course-theme="dark"] .classic-unified-header .course-global-brand img { opacity: 0; }
:root[data-course-theme="dark"] .classic-unified-header .course-global-brand::after { display: block; }

@media (max-width: 760px) {
  .classic-unified-header .course-global-brand { width: 96px; flex-basis: 96px; padding-right: 9px; }
  .classic-unified-header .course-global-brand img { width: 82px; }
  body.course-sc .classic-thinking-tree { grid-template-columns: 1fr; gap: 20px; padding: 20px 15px 24px; }
  body.course-sc .classic-thinking-root { width: 100%; }
  body.course-sc .classic-thinking-root::after { display: none; }
  body.course-sc .classic-thinking-branch::before { content: none; }
  body.course-sc .classic-thinking-main::before { width: 18px; }
  body.course-sc .classic-thinking-main { grid-template-columns: 1fr; gap: 3px; }
  body.course-sc .classic-thinking-twigs { margin-left: 16px; padding-left: 22px; }
  body.course-sc .classic-thinking-twigs li::before { width: 22px; }
}