/* ============================================================
   看懂软件：AI 时代的技术常识课 — 设计系统
   概念：审查者的笔记本。整个站的视觉语言来自"代码审查"本身——
   注解、批注、diff 般的高亮，而不是装饰性的插画。
   ============================================================ */

:root {
  /* ---- 色彩 ---- */
  --bg: #f6f5f1;
  --bg-elevated: #fffefb;
  --bg-code: #21231f;
  --ink: #1c1f1b;
  --ink-muted: #63665c;
  --ink-faint: #9a9c8f;
  --border: #dedad0;
  --border-strong: #c8c4b7;

  --teal: #2f8f7f;
  --teal-ink: #1f5c50;
  --teal-bg: #e5f4f1;
  --teal-border: #a9d6cc;

  --amber: #b8791f;
  --amber-ink: #8a5a17;
  --amber-bg: #fdf1e0;
  --amber-border: #eecd94;

  --blue: #3f66a6;
  --blue-ink: #22447a;
  --blue-bg: #e8f0fb;
  --blue-border: #b7cced;

  --gray-bg: #f2f1ee;
  --gray-border: #d8d6cd;

  --danger: #b8452f;
  --danger-bg: #fbeae5;

  /* ---- 字型 ---- */
  --font-display: 'Space Grotesk', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', Consolas, 'Noto Sans Mono CJK SC', monospace;

  /* ---- 版面 ---- */
  --sidebar-w: 300px;
  --content-max: 760px;
  --radius: 10px;
  --radius-sm: 6px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--teal-bg); color: var(--teal-ink); }

a { color: var(--teal-ink); text-decoration-color: var(--teal-border); text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--teal-ink); }

/* focus visibility */
a:focus-visible, button:focus-visible, summary:focus-visible, input:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ============================================================
   版面骨架
   ============================================================ */

.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  min-height: 100vh;
}

/* ---- 侧栏 ---- */

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: var(--bg-elevated);
  padding: 28px 22px 60px;
}

.sidebar__brand {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 15px;
  letter-spacing: 0.01em;
  color: var(--ink);
  margin: 0 0 4px;
  display: flex;
  align-items: baseline;
  gap: 8px;
}
.sidebar__brand .dot { color: var(--teal); }
.sidebar__tagline {
  font-size: 12.5px;
  color: var(--ink-faint);
  margin: 0 0 26px;
}

.progress-track {
  height: 4px;
  border-radius: 4px;
  background: var(--gray-bg);
  overflow: hidden;
  margin-bottom: 26px;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: var(--teal);
  transition: width 0.25s ease;
}
.progress-label {
  font-size: 11.5px;
  color: var(--ink-faint);
  margin: 6px 0 0;
  font-family: var(--font-mono);
}

.lang-switch {
  display: flex;
  gap: 4px;
  margin: 18px 0 22px;
  background: var(--gray-bg);
  border-radius: 20px;
  padding: 3px;
  width: fit-content;
}
.lang-switch button {
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  border: none;
  background: none;
  color: var(--ink-faint);
  padding: 5px 13px;
  border-radius: 16px;
  cursor: pointer;
}
.lang-switch button.is-active {
  background: var(--bg-elevated);
  color: var(--ink);
  box-shadow: 0 1px 2px rgba(0,0,0,0.06);
}

.mobile-bar__lang {
  font-family: var(--font-mono);
  font-size: 12px;
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  border-radius: 20px;
  padding: 6px 12px;
  cursor: pointer;
  margin-right: 8px;
}

.tr-banner {
  display: none;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--amber-ink);
  background: var(--amber-bg);
  border: 1px solid var(--amber-border);
  border-radius: var(--radius-sm);
  padding: 9px 14px;
  margin: 0 0 22px;
}
html.lang-en .tr-banner[data-translated="false"] { display: flex; }

.nav-module { margin-bottom: 4px; }
.nav-module__head {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  background: none;
  border: none;
  text-align: left;
  padding: 8px 8px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
}
.nav-module__head:hover { background: var(--gray-bg); }
a.nav-module__head { text-decoration: none; }
a.nav-module__head.is-active {
  background: var(--teal-bg);
  color: var(--teal-ink);
}
a.nav-module__head.is-active .nav-module__num { color: var(--teal-ink); }
.nav-module__num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-faint);
  min-width: 20px;
}
.nav-module__head .chev {
  margin-left: auto;
  transition: transform 0.15s ease;
  color: var(--ink-faint);
  font-size: 10px;
}
.nav-module.is-open .chev { transform: rotate(90deg); }

.nav-module__list {
  list-style: none;
  margin: 2px 0 10px;
  padding: 0 0 0 28px;
  display: none;
  border-left: 1px solid var(--border);
  margin-left: 12px;
}
.nav-module.is-open .nav-module__list { display: block; }

.nav-module__list li a {
  display: block;
  padding: 5px 10px;
  font-size: 12.8px;
  color: var(--ink-muted);
  text-decoration: none;
  border-radius: var(--radius-sm);
}
.nav-module__list li a:hover { background: var(--gray-bg); color: var(--ink); }
.nav-module__list li a.is-active {
  background: var(--teal-bg);
  color: var(--teal-ink);
  font-weight: 600;
}

/* ---- 主内容 ---- */

.content { min-width: 0; }

.hero {
  padding: 76px 48px 56px;
  border-bottom: 1px solid var(--border);
  max-width: 980px;
}
.hero__eyebrow {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--teal-ink);
  letter-spacing: 0.04em;
  margin: 0 0 18px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.hero__eyebrow::before {
  content: "";
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--teal);
  display: inline-block;
}
.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 46px);
  line-height: 1.15;
  letter-spacing: -0.01em;
  margin: 0 0 20px;
  max-width: 16ch;
}
.hero p.lead {
  font-size: 17px;
  color: var(--ink-muted);
  max-width: 58ch;
  margin: 0 0 28px;
}
.hero__stats {
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
}
.hero__stat { }
.hero__stat b {
  font-family: var(--font-display);
  font-size: 24px;
  display: block;
  color: var(--ink);
}
.hero__stat span {
  font-size: 12.5px;
  color: var(--ink-faint);
}
.hero__note {
  margin-top: 32px;
  font-size: 13px;
  color: var(--ink-faint);
  border-left: 2px solid var(--border-strong);
  padding-left: 14px;
  max-width: 60ch;
}

.module-section {
  padding: 64px 48px;
  max-width: var(--content-max);
  scroll-margin-top: 20px;
}
.module-section + .module-section { border-top: 1px solid var(--border); }

.module-kicker {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--ink-faint);
  margin: 0 0 10px;
}
.module-section > h2 {
  font-family: var(--font-display);
  font-size: 30px;
  letter-spacing: -0.01em;
  margin: 0 0 8px;
  scroll-margin-top: 20px;
}
.module-intro {
  font-size: 16.5px;
  color: var(--ink-muted);
  max-width: 62ch;
  margin: 0 0 8px;
}

.unit-block { padding-top: 44px; scroll-margin-top: 20px; }
.unit-block > h3 {
  font-family: var(--font-display);
  font-size: 22px;
  margin: 0 0 18px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border);
  scroll-margin-top: 20px;
}

.prose h4 {
  font-family: var(--font-display);
  font-size: 17.5px;
  margin: 34px 0 12px;
  scroll-margin-top: 20px;
}
.prose h5 {
  font-size: 15px;
  font-weight: 700;
  margin: 22px 0 8px;
}
.prose p { margin: 0 0 16px; max-width: 68ch; }
.prose ul, .prose ol { margin: 0 0 16px; padding-left: 22px; max-width: 66ch; }
.prose li { margin-bottom: 6px; }
.prose strong { font-weight: 700; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 32px 0; }

.prose code {
  font-family: var(--font-mono);
  font-size: 0.86em;
  background: var(--gray-bg);
  border: 1px solid var(--border);
  padding: 0.1em 0.4em;
  border-radius: 4px;
}

.prose pre {
  background: var(--bg-code);
  color: #e3e1d8;
  border-radius: var(--radius);
  padding: 18px 20px;
  overflow-x: auto;
  margin: 0 0 20px;
  font-size: 13.5px;
  line-height: 1.65;
}
.prose pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
  font-size: 1em;
}

.prose table {
  border-collapse: collapse;
  width: 100%;
  margin: 0 0 20px;
  font-size: 14.5px;
}
.prose th, .prose td {
  border: 1px solid var(--border);
  padding: 9px 12px;
  text-align: left;
}
.prose th {
  background: var(--gray-bg);
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 12.5px;
}

.prose img { max-width: 100%; height: auto; display: block; margin: 8px 0 24px; }
.prose img + em { display: block; text-align: center; }

/* ============================================================
   信号元件：延伸资源 / 下一步
   ============================================================ */

.resource-box {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 22px;
  margin: 0 0 20px;
}
.resource-box h4 { margin-top: 0 !important; }
.resource-box ul { margin-bottom: 0; padding-left: 20px; }
.resource-box a { font-weight: 600; }

.next-box {
  font-size: 14.5px;
  color: var(--ink-muted);
  background: var(--teal-bg);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 0 0 8px;
}

/* ============================================================
   动手练习 —— 审查者的批注（可展开）
   ============================================================ */

.exercise {
  margin: 26px 0 30px;
  border: 0;
  border-radius: 4px;
  background: var(--brand-bg);
  overflow: hidden;
}
.exercise__head {
  padding: 14px 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--brand-deep);
  letter-spacing: 0.02em;
  display: flex;
  align-items: center;
  gap: 8px;
}
.exercise__head::before { content: "//"; opacity: 0.6; }
.exercise__body { padding: 0 20px 20px; }
.exercise__body > *:first-child { margin-top: 0; }

.reveal { margin-top: 18px; }
.reveal > summary {
  cursor: pointer;
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 600;
  color: var(--teal-ink);
  background: var(--teal-bg);
  border: 1px solid var(--teal-border);
  padding: 8px 14px;
  border-radius: 20px;
}
.reveal > summary::-webkit-details-marker { display: none; }
.reveal > summary .n { opacity: 0.65; }
.reveal-body {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px dashed var(--border-strong);
}
.reveal-body > *:first-child { margin-top: 0; }
.reveal-body > *:last-child { margin-bottom: 0; }

/* ============================================================
   图表容器
   ============================================================ */

.figure {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  padding: 20px;
  margin: 22px 0 26px;
}
.figure img, .figure svg { width: 100%; height: auto; display: block; }
.figure figcaption {
  font-size: 12.5px;
  color: var(--ink-faint);
  margin-top: 12px;
  font-family: var(--font-mono);
}

/* ============================================================
   测验元件
   ============================================================ */

.quiz {
  margin: 34px 0 8px;
  border: 1px solid var(--teal-border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  overflow: hidden;
}
.quiz__head {
  background: var(--teal-bg);
  padding: 16px 22px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}
.quiz__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 15.5px;
  color: var(--teal-ink);
}
.quiz__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--teal-ink);
  opacity: 0.75;
  white-space: nowrap;
}
.quiz__body { padding: 22px; }

.quiz__q { display: none; }
.quiz__q.is-active { display: block; }
.quiz__progress {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-faint);
  margin-bottom: 10px;
}
.quiz__prompt {
  font-size: 15.5px;
  font-weight: 600;
  margin: 0 0 16px;
  line-height: 1.5;
}
.quiz__hint-btn {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-faint);
  background: none;
  border: 1px dashed var(--border-strong);
  border-radius: 20px;
  padding: 4px 10px;
  cursor: pointer;
  margin-bottom: 14px;
}
.quiz__hint-btn:hover { color: var(--ink-muted); border-color: var(--ink-faint); }
.quiz__hint {
  display: none;
  font-size: 13.5px;
  color: var(--ink-muted);
  background: var(--gray-bg);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  margin: -4px 0 14px;
}
.quiz__hint.is-shown { display: block; }

.quiz__options { display: flex; flex-direction: column; gap: 9px; margin-bottom: 6px; }
.quiz__opt {
  display: flex;
  align-items: flex-start;
  gap: 11px;
  text-align: left;
  width: 100%;
  padding: 11px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  font-family: var(--font-body);
  font-size: 14.5px;
  color: var(--ink);
  cursor: pointer;
  transition: border-color 0.12s ease, background 0.12s ease;
}
.quiz__opt:hover:not(:disabled) { border-color: var(--ink-faint); background: var(--gray-bg); }
.quiz__opt .tag {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-faint);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  width: 18px; height: 18px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  margin-top: 1px;
}
.quiz__opt:disabled { cursor: default; }
.quiz__opt.is-correct { border-color: var(--teal); background: var(--teal-bg); }
.quiz__opt.is-correct .tag { border-color: var(--teal); color: var(--teal-ink); background: var(--teal-bg); }
.quiz__opt.is-wrong { border-color: var(--danger); background: var(--danger-bg); }
.quiz__opt.is-wrong .tag { border-color: var(--danger); color: var(--danger); background: var(--danger-bg); }
.quiz__opt.is-dim { opacity: 0.5; }

.quiz__feedback {
  display: none;
  margin-top: 14px;
  padding: 13px 16px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  line-height: 1.6;
}
.quiz__feedback.is-shown { display: block; }
.quiz__feedback.is-correct { background: var(--teal-bg); color: var(--teal-ink); }
.quiz__feedback.is-wrong { background: var(--danger-bg); color: var(--danger); }
.quiz__feedback b { display: block; margin-bottom: 3px; }
.quiz__feedback .expl { color: var(--ink-muted); font-weight: 400; }
.quiz__feedback.is-wrong .expl { color: var(--ink-muted); }

.quiz__nav {
  display: flex;
  justify-content: flex-end;
  margin-top: 18px;
}
.quiz__next {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--bg-elevated);
  background: var(--ink);
  border: none;
  border-radius: 20px;
  padding: 9px 18px;
  cursor: pointer;
  display: none;
}
.quiz__next.is-shown { display: inline-flex; align-items: center; gap: 6px; }
.quiz__next:hover { background: var(--teal-ink); }

.quiz__result { display: none; text-align: center; padding: 16px 0 4px; }
.quiz__result.is-shown { display: block; }
.quiz__result .score {
  font-family: var(--font-display);
  font-size: 40px;
  color: var(--teal-ink);
}
.quiz__result p { color: var(--ink-muted); margin: 6px 0 18px; }
.quiz__retry {
  font-family: var(--font-mono);
  font-size: 12.5px;
  background: none;
  border: 1px solid var(--border-strong);
  border-radius: 20px;
  padding: 7px 16px;
  cursor: pointer;
  color: var(--ink-muted);
}
.quiz__retry:hover { border-color: var(--ink); color: var(--ink); }

/* ============================================================
   互动 Demo（点餐小工具）
   ============================================================ */

.demo-frame {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 22px 0 26px;
  background: var(--bg-elevated);
}
.demo-frame__bar {
  background: var(--gray-bg);
  padding: 9px 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-faint);
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 6px;
  align-items: center;
}
.demo-frame__bar .dots { display: flex; gap: 5px; margin-right: 8px; }
.demo-frame__bar .dots span { width: 8px; height: 8px; border-radius: 50%; background: var(--border-strong); display: inline-block; }
.demo-frame__body { padding: 28px; }

.order-demo { max-width: 380px; margin: 0 auto; }
.order-demo h4 { margin: 0 0 14px !important; font-size: 15px !important; }
.order-demo__item {
  display: flex; justify-content: space-between; align-items: center;
  padding: 10px 0; border-bottom: 1px solid var(--border);
  font-size: 14.5px;
}
.order-demo__item button {
  font-family: var(--font-mono);
  font-size: 12.5px;
  background: var(--teal);
  color: #fff;
  border: none;
  padding: 6px 13px;
  border-radius: 6px;
  cursor: pointer;
}
.order-demo__item button:hover { background: var(--teal-ink); }
.order-demo__cart {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}
.order-demo__cart h5 { margin: 0 0 8px; font-size: 13px; color: var(--ink-faint); font-family: var(--font-mono); font-weight: 600; }
.order-demo__list { list-style: none; padding: 0; margin: 0 0 10px; font-size: 13.5px; color: var(--ink-muted); }
.order-demo__list li { padding: 3px 0; }
.order-demo__total { font-size: 15px; font-weight: 700; margin: 0 0 14px; }
.order-demo__checkout {
  width: 100%; padding: 11px; border: none; border-radius: 8px;
  background: var(--ink); color: #fff; font-family: var(--font-body);
  font-weight: 600; font-size: 14.5px; cursor: pointer;
}
.order-demo__checkout:hover { background: var(--teal-ink); }
.order-demo__msg {
  display: none; margin-top: 10px; font-size: 13px; color: var(--teal-ink);
  background: var(--teal-bg); padding: 9px 12px; border-radius: 6px;
}
.order-demo__msg.is-shown { display: block; }

/* ============================================================
   移动端
   ============================================================ */

.mobile-bar {
  display: none;
  position: sticky; top: 0; z-index: 20;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  padding: 14px 18px;
  align-items: center;
  justify-content: space-between;
}
.mobile-bar__brand { font-family: var(--font-display); font-weight: 600; font-size: 14.5px; }
.mobile-bar__toggle {
  font-family: var(--font-mono);
  font-size: 12px;
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  border-radius: 20px;
  padding: 7px 14px;
  cursor: pointer;
}

@media (max-width: 880px) {
  .layout { display: block; }
  .mobile-bar { display: flex; }
  .sidebar {
    position: fixed;
    top: 53px; left: 0; right: 0; bottom: 0;
    height: auto;
    z-index: 19;
    transform: translateX(-100%);
    transition: transform 0.2s ease;
    width: 100%;
  }
  .sidebar.is-open { transform: translateX(0); }
  .hero { padding: 40px 22px 36px; }
  .module-section { padding: 44px 22px; }
  .demo-frame__body { padding: 18px; }
}

.footer {
  padding: 50px 48px 90px;
  color: var(--ink-faint);
  font-size: 13px;
  max-width: var(--content-max);
}
@media (max-width: 880px) { .footer { padding: 40px 22px 70px; } }

/* ============================================================
   Scalebar 品牌化 + 多页结构（首页门户 / 模块页）
   ============================================================ */
:root {
  --brand: #e35a00;        /* Scalebar 橙 — 大标题 */
  --brand-deep: #b8500f;   /* 深橙 — 小标题 / 更佳对比 */
  --brand-bg: #fdeede;
  --brand-border: #f2c79a;
}

/* 标题统一改成品牌橙 */
.module-section > h2,
.module-page > h2,
.unit-block > h3,
.prose h3 { color: var(--brand); }
.prose h4, .acc > summary { color: var(--brand-deep); }
.module-kicker { color: var(--brand-deep); }
.prose h3 {
  font-family: var(--font-display); font-size: 17px; font-weight: 600;
  margin: 26px 0 10px;
}

/* ---- 顶栏：Logo + 课程名 + 语言 ---- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 16px;
  padding: 12px 28px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
}
.topbar__logo { display: flex; align-items: center; text-decoration: none; }
.topbar__logo img { height: 30px; width: auto; display: block; }
.topbar__title {
  font-family: var(--font-display); font-weight: 600; font-size: 14px;
  color: var(--ink); border-left: 1px solid var(--border-strong);
  padding-left: 16px; line-height: 1.25;
}
.topbar__spacer { margin-left: auto; }
.topbar__back {
  font-family: var(--font-mono); font-size: 12.5px; color: var(--ink-muted);
  text-decoration: none; margin-right: 4px;
}
.topbar__back:hover { color: var(--brand); }
@media (max-width: 640px) {
  .topbar { padding: 10px 16px; gap: 10px; }
  .topbar__title { display: none; }
}

/* ---- 顶部阅读进度条（模块页）---- */
.read-progress {
  position: fixed; top: 0; left: 0; right: 0; z-index: 90;
  height: 3px; background: transparent; pointer-events: none;
}
.read-progress__fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, #f57303, #f5af08);
  transition: width 0.1s linear;
}

/* ---- 首页门户 ---- */
.portal { max-width: 940px; margin: 0 auto; padding: 60px 32px 120px; }
.portal__eyebrow {
  font-family: var(--font-mono); font-size: 12.5px; color: var(--brand-deep);
  letter-spacing: .04em; margin: 0 0 16px;
}
.portal h1 {
  font-family: var(--font-display); font-size: clamp(30px, 4vw, 44px);
  line-height: 1.15; margin: 0 0 18px; max-width: 20ch;
}
.portal__lead { font-size: 17px; color: var(--ink-muted); max-width: 60ch; margin: 0 0 28px; }
.portal__stats { display: flex; gap: 30px; flex-wrap: wrap; margin: 0 0 40px; }
.portal__stat b { font-family: var(--font-display); font-size: 22px; display: block; color: var(--ink); }
.portal__stat span { font-size: 12.5px; color: var(--ink-faint); }

.overall {
  display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
  background: var(--bg-elevated); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px 20px; margin: 0 0 34px;
}
.overall__bar { flex: 1; min-width: 160px; height: 8px; border-radius: 8px; background: var(--gray-bg); overflow: hidden; }
.overall__fill { height: 100%; width: 0%; background: linear-gradient(90deg,#f57303,#f5af08); transition: width .3s ease; }
.overall__label { font-family: var(--font-mono); font-size: 13px; color: var(--ink-muted); white-space: nowrap; }
.overall__reset { font-family: var(--font-mono); font-size: 11.5px; background: none; border: none; color: var(--ink-faint); cursor: pointer; text-decoration: underline; }

.toc-grid { display: grid; gap: 14px; }
.toc-card {
  display: flex; align-items: center; gap: 18px;
  padding: 20px 22px; background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: var(--radius);
  text-decoration: none; color: inherit;
  transition: border-color .15s ease, transform .12s ease, box-shadow .15s ease;
}
.toc-card:hover { border-color: var(--brand-border); transform: translateY(-2px); box-shadow: 0 6px 20px rgba(227,90,0,.08); }
.toc-card__num { font-family: var(--font-display); font-size: 22px; font-weight: 700; color: var(--brand); min-width: 40px; }
.toc-card__body { flex: 1; min-width: 0; }
.toc-card__title { font-family: var(--font-display); font-size: 17.5px; font-weight: 600; margin: 0 0 3px; color: var(--ink); }
.toc-card__desc { font-size: 13.5px; color: var(--ink-muted); margin: 0; }
.toc-card__status { font-size: 20px; color: var(--border-strong); flex-shrink: 0; }
.toc-card.is-done { border-color: var(--brand-border); background: var(--brand-bg); }
.toc-card.is-done .toc-card__status { color: var(--brand); }

/* ---- 手风琴（模块页小节）---- */
.acc {
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--bg-elevated); margin: 0 0 14px; overflow: hidden;
}
.acc > summary {
  list-style: none; cursor: pointer; display: flex; align-items: center; gap: 12px;
  padding: 18px 22px; font-family: var(--font-display); font-weight: 600; font-size: 17px;
}
.acc > summary::-webkit-details-marker { display: none; }
.acc > summary::before {
  content: "+"; font-family: var(--font-mono); font-size: 18px; color: var(--brand);
  width: 16px; text-align: center; flex-shrink: 0;
}
.acc[open] > summary::before { content: "\2013"; }
.acc > summary:hover { background: var(--brand-bg); }
.acc__body { padding: 4px 22px 10px; border-top: 1px solid var(--border); }

/* ---- 浮动前后箭头 ---- */
.floatnav {
  position: fixed; bottom: 28px; right: 28px; z-index: 60;
  display: flex; gap: 12px; opacity: 0.22; transition: opacity .35s ease;
}
.floatnav.is-awake { opacity: 1; }
.floatnav a, .floatnav span {
  display: flex; align-items: center; justify-content: center;
  width: 52px; height: 52px; border-radius: 50%;
  background: var(--bg-elevated); border: 1px solid var(--border-strong);
  box-shadow: 0 4px 14px rgba(0,0,0,.1);
  color: var(--brand); font-size: 22px; text-decoration: none; font-family: var(--font-mono);
}
.floatnav a:hover { background: var(--brand); color: #fff; border-color: var(--brand); }
.floatnav .is-disabled { color: var(--ink-faint); opacity: .4; pointer-events: none; box-shadow: none; }
@media (max-width: 640px) { .floatnav { bottom: 18px; right: 16px; gap: 10px; } .floatnav a, .floatnav span { width: 46px; height: 46px; font-size: 20px; } }

/* ---- 标记完成 ---- */
.module-page { max-width: var(--content-max); margin: 0 auto; padding: 38px 48px 20px; }
.module-page > .module-kicker {
  display: inline-block;
  background: #1c1f1b;
  color: #ffc94d;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.18em;
  padding: 7px 15px;
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
}
.mark-done-wrap { max-width: var(--content-max); margin: 8px auto 0; padding: 0 48px 40px; }
.mark-done {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--font-display); font-size: 15px; font-weight: 600;
  padding: 13px 24px; border-radius: 30px; cursor: pointer;
  background: var(--brand); color: #fff; border: 1px solid var(--brand); transition: background .15s ease;
}
.mark-done:hover { background: var(--brand-deep); }
.mark-done.is-done { background: var(--bg-elevated); color: var(--brand-deep); border-color: var(--brand-border); }
@media (max-width: 640px) { .module-page, .mark-done-wrap { padding-left: 18px; padding-right: 18px; } }

/* 浮动箭头淡入淡出即使在 reduce-motion 也保留；其余动画仍尊重 */
@media (prefers-reduced-motion: reduce) {
  .floatnav { transition: opacity .35s ease !important; }
}

/* ---- 完成证书（读完全部模块后出现）---- */
.cert { max-width: var(--content-max); margin: 30px auto 0; padding: 0 48px; }
.cert__inner {
  background: linear-gradient(135deg, #fdf1e0, #fdeede);
  border: 1px solid var(--brand-border); border-radius: var(--radius);
  padding: 30px; text-align: center;
}
.cert__badge { font-size: 15px; font-weight: 600; color: var(--brand-deep); margin: 0 0 6px; }
.cert__title { font-family: 'Baloo', var(--font-display); font-weight: 400; font-size: 22px; color: var(--brand-deep); margin: 0 0 8px; }
.cert__sub { font-size: 14.5px; color: var(--ink-muted); margin: 0 0 18px; }
.cert__row { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.cert__name {
  font-size: 15px; padding: 11px 16px; border: 1px solid var(--border-strong);
  border-radius: 8px; font-family: var(--font-body); min-width: 220px; background: #fff; color: var(--ink);
}
.cert__name:focus { outline: 2px solid var(--brand); outline-offset: 1px; }
.cert__btn {
  background: var(--brand); color: #fff; border: none; font-family: var(--font-display);
  font-weight: 600; font-size: 15px; padding: 11px 24px; border-radius: 8px; cursor: pointer;
}
.cert__btn:hover { background: var(--brand-deep); }

.cert-modal { position: fixed; inset: 0; z-index: 210; display: none; background: rgba(20,18,16,.88); }
.cert-modal.is-open { display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 24px; }
.cert-modal__stage { max-width: 100%; overflow: auto; }
.cert-modal canvas { width: min(880px, 92vw); height: auto; border-radius: 8px; box-shadow: 0 12px 44px rgba(0,0,0,.5); background: #fff; display: block; }
.cert-modal__actions { margin-top: 18px; display: flex; gap: 12px; }
.cert-modal__actions button {
  font-family: var(--font-display); font-weight: 600; font-size: 15px;
  padding: 11px 26px; border-radius: 30px; cursor: pointer; border: none;
}
.cert-dl { background: var(--brand); color: #fff; }
.cert-dl:hover { background: var(--brand-deep); }
.cert-close2 { background: rgba(255,255,255,.16); color: #fff; }
.cert-close2:hover { background: rgba(255,255,255,.3); }

/* ---- 课程 CTA：衔接 Scalebar 服务 ---- */
.course-cta { max-width: var(--content-max); margin: 44px auto 0; padding: 0 48px; }
.course-cta__inner {
  background: linear-gradient(135deg, #fdeede, #fdf1e0);
  border: 1px solid var(--brand-border);
  border-radius: var(--radius);
  padding: 36px 34px;
  text-align: center;
}
.course-cta__eyebrow {
  font-family: var(--font-mono); font-size: 12px; letter-spacing: .14em;
  color: var(--brand-deep); margin: 0 0 12px;
}
.course-cta__title {
  font-family: 'Baloo', var(--font-display); font-weight: 400;
  font-size: 24px; color: var(--brand-deep); margin: 0 0 12px; line-height: 1.25;
}
.course-cta__body {
  font-size: 15.5px; color: var(--ink-muted); max-width: 54ch;
  margin: 0 auto 24px; line-height: 1.75;
}
.course-cta__btn {
  display: inline-block; background: var(--brand); color: #fff;
  font-family: var(--font-display); font-weight: 600; font-size: 15.5px;
  padding: 13px 30px; border-radius: 30px; text-decoration: none;
  transition: background .15s ease;
}
.course-cta__btn:hover { background: var(--brand-deep); color: #fff; }
@media (max-width: 640px) { .course-cta { padding: 0 18px; } .course-cta__inner { padding: 28px 20px; } }

/* ---- 代码语法高亮（Prism · 深色代码底，只上色不改背景/版式）---- */
.prose pre .token.comment,
.prose pre .token.prolog,
.prose pre .token.doctype,
.prose pre .token.cdata { color: #8a897c; font-style: italic; }
.prose pre .token.punctuation { color: #c9c6ba; }
.prose pre .token.property,
.prose pre .token.tag,
.prose pre .token.boolean,
.prose pre .token.number,
.prose pre .token.constant,
.prose pre .token.symbol,
.prose pre .token.deleted { color: #e8917f; }
.prose pre .token.selector,
.prose pre .token.attr-name,
.prose pre .token.string,
.prose pre .token.char,
.prose pre .token.builtin,
.prose pre .token.inserted { color: #a6cf8a; }
.prose pre .token.operator,
.prose pre .token.entity,
.prose pre .token.url { color: #74c7c4; }
.prose pre .token.atrule,
.prose pre .token.attr-value,
.prose pre .token.keyword { color: #d9a6d6; }
.prose pre .token.function,
.prose pre .token.class-name { color: #f0a35e; }
.prose pre .token.regex,
.prose pre .token.important,
.prose pre .token.variable { color: #f5cf6b; }

/* 双语内容切换：中文模式隐藏 .i18n-en，英文模式隐藏 .i18n-zh */
html.lang-en .i18n-zh { display: none; }
html:not(.lang-en) .i18n-en { display: none; }

/* ---- 品牌字体 Baloo（与主站同一支），只用在最主要的标题增加辨识度 ---- */
@font-face {
  font-family: 'Baloo';
  src: url(/assets/fonts/baloo.woff2) format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
.portal h1,
.module-page > h2 {
  font-family: 'Baloo', var(--font-display);
  font-weight: 400;
}

/* ---- 教学页尾 ---- */
.teach-footer {
  text-align: center;
  color: var(--ink-faint);
  font-size: 13px;
  padding: 40px 20px 60px;
  border-top: 1px solid var(--border);
  margin-top: 24px;
}

/* ---- 图解灯箱（点击放大、可平移）---- */
.figure img { cursor: zoom-in; }
.lightbox { position: fixed; inset: 0; z-index: 200; display: none; background: rgba(20,18,16,0.88); }
.lightbox.is-open { display: block; }
.lightbox__scroll { position: absolute; inset: 0; overflow: auto; -webkit-overflow-scrolling: touch; }
.lightbox__img {
  display: block; width: min(1100px, 190vw); max-width: none; height: auto;
  margin: 48px auto; border-radius: 10px; background: #fff;
  box-shadow: 0 12px 44px rgba(0,0,0,.45);
}
.lightbox__close {
  position: absolute; top: 14px; right: 16px; z-index: 2;
  width: 44px; height: 44px; border-radius: 50%;
  background: rgba(255,255,255,0.16); color: #fff; border: none;
  font-size: 20px; cursor: pointer; display: flex; align-items: center; justify-content: center;
}
.lightbox__close:hover { background: rgba(255,255,255,0.30); }
.lightbox__hint {
  position: absolute; bottom: 16px; left: 0; right: 0; z-index: 2;
  text-align: center; color: rgba(255,255,255,0.72);
  font-size: 12.5px; font-family: var(--font-mono); pointer-events: none;
}

/* ---------- 分享这门课（品牌圆形图标） ---------- */
.share { max-width: 760px; margin: 0 auto; padding: 44px 24px 4px; text-align: center; }
.share__label { font-size: 15px; color: #6b6e63; margin: 0 0 18px; font-weight: 600; }
.share__row { display: flex; flex-wrap: wrap; gap: 16px; justify-content: center; }
.share__icon { position: relative; width: 48px; height: 48px; border-radius: 50%; border: none; padding: 0;
  display: inline-flex; align-items: center; justify-content: center; cursor: pointer; text-decoration: none;
  transition: transform .15s ease, box-shadow .15s ease; }
.share__icon:hover { transform: translateY(-3px); box-shadow: 0 8px 18px rgba(0,0,0,.20); }
.share__icon:active { transform: translateY(-1px); }
.share__icon svg { fill: #fff; display: block; }
.share__icon--fb svg { height: 23px; }
.share__icon--li svg { height: 21px; }
.share__icon--wa svg { height: 21px; }
.share__icon--copy svg { height: 21px; }
.share__icon--fb { background: #1877F2; }
.share__icon--li { background: #0A66C2; }
.share__icon--wa { background: #25D366; }
.share__icon--copy { background: var(--brand); }
.share__icon .share__glyph--check { display: none; }
.share__icon--copy.is-copied { background: #35b862; }
.share__icon--copy.is-copied .share__glyph--link { display: none; }
.share__icon--copy.is-copied .share__glyph--check { display: block; }
.share__tip { position: absolute; bottom: calc(100% + 8px); left: 50%; transform: translateX(-50%);
  background: #1c1f1b; color: #fff; font-size: 12px; font-weight: 600; padding: 4px 9px; border-radius: 6px;
  white-space: nowrap; opacity: 0; pointer-events: none; transition: opacity .15s; }
.share__icon--copy.is-copied .share__tip { opacity: 1; }

/* ---------- 术语悬浮解释卡 ---------- */
.term { border-bottom: 1px dashed rgba(227, 90, 0, .55); cursor: help; }
.term:hover, .term:focus { border-bottom-color: var(--brand); background: rgba(227, 90, 0, .07); outline: none; border-radius: 2px; }
.glossary-pop { position: fixed; z-index: 3000; max-width: 268px; background: #1c1f1b; color: #fff;
  font-size: 13px; line-height: 1.5; font-weight: 400; padding: 9px 12px; border-radius: 8px;
  box-shadow: 0 8px 28px rgba(0, 0, 0, .28); opacity: 0; pointer-events: none; transition: opacity .12s ease; }
.glossary-pop.is-visible { opacity: 1; }