/* ==========================================================================
   黃哲斌個人網站 ｜ 共用設計系統
   《AI 時代的生存遊戲》書系視覺語言

   設計邏輯：
   - 首頁安靜、內容頁豐富──反差本身就是動線提示
   - 每個主題（A/B/C/D）有自己的識別色，貫穿代碼徽章、標籤、強調線
   - 代碼徽章（A01、B03…）取自書中真實的章節編碼系統，是全站唯一的
     裝飾系統，其餘一律克制
   - 新書／行動呼籲另用暖橘金強調色，與四大主題色區隔，避免混淆
   - 全站字級下限＝導覽列品牌字重，階層改以粗細、色彩、大小寫呈現，
     不再依賴縮小字級
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+TC:wght@400;700;900&family=Noto+Sans+TC:wght@300;400;500;700;900&family=JetBrains+Mono:wght@500;700&display=swap');

:root {
  /* ── 中性色：紙感與墨色 ── */
  --ink:        #15172a;
  --ink-mid:    #3d3f56;
  --ink-soft:   #6b6d85;
  --ink-faint:  #9a9cb0;
  --paper:      #f7f5f0;
  --card:       #ffffff;
  --card-warm:  #f1ede3;
  --border:     #e1dccf;
  --border-mid: #cdc6b3;
  --white:      #ffffff;

  /* ── 品牌主色：靛紫，用於導覽列與焦點狀態 ── */
  --brand:       #423d94;
  --brand-dark:  #2e2a6b;
  --brand-faint: #edebf7;

  /* ── 強調色：暖橘金，用於新書／行動呼籲，與主題色區隔 ── */
  --highlight:      #f0a93a;
  --highlight-dark: #c97f1e;
  --highlight-faint:#fdf0da;

  /* ── 四大主題色（對應書中 A / B / C / D 編碼系統） ── */
  --a-ink:   #423d94;   /* A．AI素養──靛紫，理性與思辨 */
  --a-faint: #edebf7;
  --b-ink:   #c1502b;   /* B．短影音──赭橙，速度與能量 */
  --b-faint: #fbeae1;
  --c-ink:   #a8790f;   /* C．網紅────金褐，聚光燈 */
  --c-faint: #faf1dc;
  --d-ink:   #1f7a5c;   /* D．資訊素養──青綠，查證與安全 */
  --d-faint: #e5f3ec;

  /* ── 型態 ── */
  --font-display: 'Noto Serif TC', serif;
  --font-body:    'Noto Sans TC', sans-serif;
  --font-mono:    'JetBrains Mono', monospace;

  --container: 1080px;
  --container-narrow: 760px;
}

/* ── Reset ── */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.8;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

.wrap { max-width: var(--container); margin: 0 auto; padding: 0 1.5rem; }
.wrap-narrow { max-width: var(--container-narrow); margin: 0 auto; padding: 0 1.5rem; }

/* ==========================================================================
   導覽列 ── 全站共用，姓名即首頁入口，四個主題平行並列
   ========================================================================== */
nav.site-nav {
  position: sticky; top: 0; left: 0; right: 0;
  background: rgba(21,23,42,0.97);
  backdrop-filter: blur(8px);
  z-index: 1000;
  border-bottom: 2px solid var(--brand);
}
nav.site-nav .nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 64px;
  display: flex; align-items: center; gap: 2.5rem;
}
nav.site-nav .nav-brand {
  font-family: var(--font-display);
  font-weight: 900;
  color: var(--white);
  font-size: 1.2rem;
  letter-spacing: 0.06em;
  white-space: nowrap;
}
nav.site-nav .nav-links {
  display: flex; gap: 0.4rem;
  overflow-x: auto;
  scrollbar-width: none;
  margin-left: auto;
}
nav.site-nav .nav-links::-webkit-scrollbar { display: none; }
nav.site-nav .nav-links a {
  color: rgba(255,255,255,0.7);
  font-size: 1.05rem;
  font-weight: 500;
  padding: 0.5rem 0.9rem;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}
nav.site-nav .nav-links a:hover { color: var(--white); }
nav.site-nav .nav-links a[data-cat="a"]:hover { border-color: #8b83e0; }
nav.site-nav .nav-links a[data-cat="b"]:hover { border-color: #e0906c; }
nav.site-nav .nav-links a[data-cat="c"]:hover { border-color: #d9b04e; }
nav.site-nav .nav-links a[data-cat="d"]:hover { border-color: #4fb894; }
nav.site-nav .nav-links a.is-current { color: var(--white); font-weight: 700; }
nav.site-nav .nav-links a[data-cat="a"].is-current { border-color: #8b83e0; }
nav.site-nav .nav-links a[data-cat="b"].is-current { border-color: #e0906c; }
nav.site-nav .nav-links a[data-cat="c"].is-current { border-color: #d9b04e; }
nav.site-nav .nav-links a[data-cat="d"].is-current { border-color: #4fb894; }

/* ==========================================================================
   代碼徽章 ── 全站唯一的裝飾系統，取自書中 A01／B03 章節編碼
   ========================================================================== */
.code-chip {
  display: inline-flex; align-items: center;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 0.03em;
  padding: 0.25rem 0.6rem;
  border: 1px solid currentColor;
}
.code-chip.cat-a { color: var(--a-ink); background: var(--a-faint); }
.code-chip.cat-b { color: var(--b-ink); background: var(--b-faint); }
.code-chip.cat-c { color: var(--c-ink); background: var(--c-faint); }
.code-chip.cat-d { color: var(--d-ink); background: var(--d-faint); }

/* ==========================================================================
   按鈕
   ========================================================================== */
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 1.05rem;
  padding: 0.75rem 1.4rem;
  border: 1.5px solid var(--ink);
  background: var(--ink);
  color: var(--white);
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(21,23,42,0.18); }
.btn-outline {
  background: transparent;
  color: var(--ink);
}
/* 新書／行動呼籲專用──暖橘金，與品牌靛紫、四大主題色都不同 */
.btn-highlight {
  background: var(--highlight);
  border-color: var(--highlight-dark);
  color: var(--ink);
}
.btn-highlight-outline {
  background: transparent;
  border-color: var(--highlight);
  color: var(--highlight);
}
/* 中性外框款──用於書封 CTA 區的第三顆按鈕，與強調色家族區隔 */
.btn-ghost {
  background: transparent;
  border-color: rgba(255,255,255,0.45);
  color: var(--white);
}
.btn-ghost:hover { border-color: #fff; }

/* ==========================================================================
   首頁 ── HERO：安靜、留白，反差是刻意的
   ========================================================================== */
.home-hero {
  padding: 5rem 0 4rem;
  position: relative;
  overflow: hidden;
}
.home-hero::before {
  /* 極淡的電路節點紋理，呼應書封的電路板意象，僅此一處使用 */
  content: '';
  position: absolute; inset: 0;
  background-image:
    radial-gradient(circle, var(--ink-faint) 1px, transparent 1px);
  background-size: 28px 28px;
  opacity: 0.12;
  mask-image: linear-gradient(to bottom, black, transparent 85%);
  pointer-events: none;
}
.home-hero .wrap { position: relative; }
.home-hero-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 2.5rem;
  align-items: center;
}
.home-portrait {
  width: 156px; height: 156px;
  border-radius: 50%;
  overflow: hidden;
  border: 3px solid var(--card);
  box-shadow: 0 4px 20px rgba(21,23,42,0.12);
  background: var(--card-warm);
}
.home-portrait img { width: 100%; height: 100%; object-fit: cover; }
.eyebrow {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--brand);
  text-transform: uppercase;
  margin-bottom: 0.7rem;
}
.home-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 4.5vw, 3rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 0.6rem;
}
.home-hero .role {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--ink-mid);
  margin-bottom: 0.9rem;
}
.home-hero .tagline {
  font-size: 1.1rem;
  color: var(--ink-mid);
  max-width: 42em;
}
@media (max-width: 640px) {
  .home-hero-grid { grid-template-columns: 1fr; text-align: left; }
  .home-portrait { width: 108px; height: 108px; }
}

/* ==========================================================================
   首頁 ── 新書 strip
   ========================================================================== */
.book-strip {
  background: var(--ink);
  color: var(--white);
  padding: 2.4rem 0;
}
.book-strip-grid {
  display: grid;
  grid-template-columns: 190px 1fr auto;
  grid-template-areas:
    "cover eyebrow cta"
    "cover content cta";
  gap: 0.4rem 2.2rem;
  align-items: center;
}
.book-eyebrow { grid-area: eyebrow; align-self: end; margin-bottom: 0.3rem; }
.book-cover {
  grid-area: cover;
  align-self: start;
  width: 190px;
  border: 1px solid rgba(255,255,255,0.15);
  overflow: hidden;
  box-shadow: 0 8px 24px rgba(0,0,0,0.35);
}
.book-cover img { width: 100%; display: block; }
.book-content { grid-area: content; }
.book-strip .eyebrow { color: var(--highlight); margin-bottom: 0; }
.book-strip h2 {
  font-family: var(--font-display);
  font-size: 1.65rem; font-weight: 700;
  margin-bottom: 0.5rem;
}
.book-strip p { color: rgba(255,255,255,0.78); font-size: 1.1rem; max-width: 34em; }
.book-cta { grid-area: cta; display: flex; flex-direction: column; gap: 0.55rem; align-self: center; }
.book-cta .btn { justify-content: center; padding: 0.55rem 1.1rem; }
@media (max-width: 760px) {
  .book-strip-grid {
    grid-template-columns: 1fr;
    grid-template-areas:
      "eyebrow"
      "cover"
      "content"
      "cta";
    gap: 1rem;
    justify-items: start;
  }
  .book-cover { width: 220px; max-width: 60vw; }
  .book-eyebrow { margin-bottom: 0; }
  .book-cta { flex-direction: row; flex-wrap: wrap; width: 100%; gap: 0.5rem; }
  .book-cta .btn { padding: 0.5rem 0.6rem; font-size: 1.05rem; white-space: nowrap; }
  .book-cta .btn:first-child { flex: 1 1 100%; }
  .book-cta .btn:not(:first-child) { flex: 1 1 auto; }
}

/* ==========================================================================
   首頁 ── 四大主題卡
   ========================================================================== */
.topics { padding: 3.5rem 0; }
.section-label {
  font-family: var(--font-mono);
  font-size: 1.05rem; font-weight: 700; letter-spacing: 0.1em;
  color: var(--ink-soft); text-transform: uppercase;
  margin-bottom: 1.4rem;
}
.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.2rem;
}
@media (max-width: 640px) { .topic-grid { grid-template-columns: 1fr; } }
.topic-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-top: 4px solid var(--cat-ink, var(--brand));
  padding: 1.6rem;
  transition: transform 0.15s, box-shadow 0.15s;
}
.topic-card:hover { transform: translateY(-3px); box-shadow: 0 10px 28px rgba(21,23,42,0.08); }
.topic-card.cat-a { --cat-ink: var(--a-ink); }
.topic-card.cat-b { --cat-ink: var(--b-ink); }
.topic-card.cat-c { --cat-ink: var(--c-ink); }
.topic-card.cat-d { --cat-ink: var(--d-ink); }
.topic-card .code-chip { margin-bottom: 0.9rem; }
.topic-card h3 {
  font-family: var(--font-display);
  font-size: 1.35rem; font-weight: 700;
  margin-bottom: 0.5rem;
}
.topic-card p { font-size: 1.05rem; color: var(--ink-mid); }
.topic-card .count { font-size: 1.05rem; color: var(--ink-soft); margin-top: 0.9rem; }
.count-cta { color: var(--cat-ink, var(--brand)); font-weight: 500; }
.topic-card:hover .count-cta { text-decoration: underline; }

/* 課綱對照表──色塊連結，未來連到表格頁 */
.mapping-link {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem;
  background: var(--brand);
  color: var(--white);
  padding: 1.1rem 1.5rem;
  margin-top: 1.2rem;
  font-weight: 700;
  font-size: 1.05rem;
}
.mapping-link:hover { background: var(--brand-dark); }
.mapping-link .arrow { font-family: var(--font-mono); }

/* ==========================================================================
   首頁 ── 聯絡與社群整合
   ========================================================================== */
.contact-strip {
  background: var(--card-warm);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 3rem 0;
}
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
}
@media (max-width: 700px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-block h4 {
  font-family: var(--font-display);
  font-size: 1.2rem; font-weight: 700; margin-bottom: 0.9rem;
}
.social-list { display: flex; flex-direction: column; gap: 0.55rem; }
.social-list a {
  display: flex; justify-content: space-between; align-items: baseline;
  flex-wrap: wrap;
  font-size: 1.1rem; padding: 0.55rem 0;
  border-bottom: 1px solid var(--border);
}
.social-list a:hover { color: var(--brand); }
.social-list .desc { font-size: 1.05rem; color: var(--ink-soft); }
.feedback-box {
  background: var(--card);
  border: 1px solid var(--border);
  padding: 1.4rem;
}
.feedback-box p { font-size: 1.05rem; color: var(--ink-mid); margin-bottom: 1rem; }
.email-copy {
  display: flex; align-items: center; flex-wrap: wrap;
  gap: 0.6rem;
  background: var(--paper);
  border: 1px solid var(--border);
  padding: 0.6rem 0.8rem;
}
.email-copy .addr {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  color: var(--ink);
  user-select: all;
}
.email-copy button {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.92rem;
  padding: 0.35rem 0.7rem;
  border: 1.5px solid var(--ink);
  background: var(--ink);
  color: var(--white);
  cursor: pointer;
  transition: transform 0.15s;
  white-space: nowrap;
}
.email-copy button:hover { transform: translateY(-1px); }

/* ==========================================================================
   首頁 ── 學經歷精簡摘要
   ========================================================================== */
.bio-section { padding: 3.5rem 0; }
.bio-timeline {
  display: flex; flex-direction: column;
  border-top: 1px solid var(--border);
}
.bio-row {
  display: grid; grid-template-columns: 120px 1fr;
  gap: 1.5rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 1.05rem;
}
.bio-row .yr { font-family: var(--font-mono); color: var(--ink-soft); font-size: 1.05rem; }
.bio-row a { border-bottom: 1px solid var(--border-mid); padding-bottom: 1px; }
.bio-row a:hover { color: var(--brand); border-bottom-color: var(--brand); }

footer.site-footer {
  padding: 2.2rem 0; text-align: center;
  font-size: 1.05rem; color: var(--ink-soft);
}

/* ==========================================================================
   類目主頁（AI素養／短影音／網紅／資訊素養）── HERO band 染色
   ========================================================================== */
.hub-hero {
  padding: 3.5rem 0 2.8rem;
  background: var(--cat-faint, var(--brand-faint));
  border-bottom: 1px solid var(--border);
}
.hub-hero .code-chip { margin-bottom: 1rem; }
.hub-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 900;
  color: var(--cat-ink, var(--brand));
  margin-bottom: 0.7rem;
}
.hub-hero .lead { font-size: 1.1rem; color: var(--ink-mid); max-width: 46em; }
.hub-hero .range { font-family: var(--font-mono); font-size: 1.05rem; color: var(--ink-soft); margin-top: 0.9rem; }

.hub-body { padding: 3rem 0 4rem; }

/* 文章清單──像目錄，也像菜單 */
.article-list { display: flex; flex-direction: column; }
.article-row {
  display: grid;
  grid-template-columns: 92px 1fr auto;
  gap: 1.5rem;
  align-items: start;
  padding: 1.6rem 0;
  border-bottom: 1px solid var(--border);
}
.article-row:first-child { border-top: 1px solid var(--border); }
.article-row:hover .article-title { color: var(--cat-ink, var(--brand)); }
.article-row-static {
  grid-template-columns: 92px 1fr;
  cursor: default;
}
.article-row-static:hover .article-title { color: var(--ink); }
.article-row .code-chip { margin-top: 0.15rem; }
.article-title {
  font-family: var(--font-display);
  font-size: 1.3rem; font-weight: 700;
  line-height: 1.4; margin-bottom: 0.45rem;
  transition: color 0.15s;
}
.article-hook { font-size: 1.05rem; color: var(--ink-mid); margin-bottom: 0.6rem; }
.article-meta {
  display: flex; flex-wrap: wrap; gap: 0.5rem;
  font-size: 1.05rem; color: var(--ink-soft);
}
.tag-comp {
  display: inline-block;
  border: 1px solid var(--border-mid);
  padding: 0.15rem 0.5rem;
  color: var(--ink-mid);
}
.article-arrow {
  font-family: var(--font-mono);
  color: var(--ink-faint); font-size: 1.2rem;
  align-self: center;
}
@media (max-width: 640px) {
  .article-row { grid-template-columns: 1fr; gap: 0.5rem; }
  .article-arrow { display: none; }
}

/* 重點速覽 box */
.hub-brief {
  background: var(--card);
  border: 1px solid var(--border);
  border-left: 4px solid var(--cat-ink, var(--brand));
  padding: 1.6rem 1.8rem;
  margin-bottom: 2.5rem;
}
.hub-brief h4 {
  font-family: var(--font-display); font-size: 1.2rem; margin-bottom: 0.6rem;
}
.hub-brief p { font-size: 1.05rem; color: var(--ink-mid); }

/* ==========================================================================
   內容頁（單篇文章）── 深度、分層、可視化
   ========================================================================== */
.article-hero {
  padding: 3rem 0 2.5rem;
  background: var(--cat-faint, var(--brand-faint));
  border-bottom: 1px solid var(--border);
}
.breadcrumb {
  font-size: 1.05rem; color: var(--ink-soft);
  margin-bottom: 1.1rem;
}
.breadcrumb a:hover { color: var(--cat-ink); }
.article-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 900;
  line-height: 1.3;
  margin: 0.8rem 0 0.9rem;
}
.article-hero .dek { font-size: 1.1rem; color: var(--ink-mid); max-width: 42em; }

.article-body { padding: 3rem 0; }
.article-body .wrap-narrow p {
  font-size: 1.15rem; color: var(--ink-mid);
  margin-bottom: 1.3rem;
}
.article-body h2 {
  font-family: var(--font-display);
  font-size: 1.6rem; font-weight: 700;
  margin: 2.6rem 0 1.2rem;
}

/* 小故事卡片群（可重用於任何「拆解型」內容） */
.story-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.3rem;
  margin: 1.8rem 0 2.6rem;
}
.story-card {
  background: var(--card);
  border: 1px solid var(--border);
  padding: 1.3rem 1.4rem;
}
.story-card .story-icon { font-size: 1.6rem; margin-bottom: 0.6rem; }
.story-card h3 {
  font-family: var(--font-display);
  font-size: 1.15rem; font-weight: 700; margin-bottom: 0.5rem;
  color: var(--cat-ink, var(--brand));
}
.story-card p { font-size: 1.05rem; color: var(--ink-mid); line-height: 1.7; }

/* 資訊站側欄 box */
.info-box {
  background: var(--ink);
  color: rgba(255,255,255,0.9);
  padding: 1.6rem 1.8rem;
  margin: 2.2rem 0;
}
.info-box .label {
  font-family: var(--font-mono); font-size: 1.05rem;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: #b5aef0; margin-bottom: 0.8rem;
}
.info-box p { color: rgba(255,255,255,0.78); font-size: 1.05rem; margin-bottom: 0.8rem; }
.info-box p:last-child { margin-bottom: 0; }

/* 查證來源 */
.article-body .wrap-narrow ol,
.article-body .wrap-narrow ul { margin: 0 0 1.3rem 1.4rem; }
.article-body .wrap-narrow li { font-size: 1.05rem; color: var(--ink-mid); margin-bottom: 0.5rem; }
.article-body .wrap-narrow hr { border: 0; border-top: 1px solid var(--border); margin: 2.6rem 0; }
.article-body .wrap-narrow strong { color: var(--ink); font-weight: 700; }
.article-body .wrap-narrow a { text-decoration: underline; text-decoration-color: var(--border-mid); }
.article-body .wrap-narrow a:hover { color: var(--cat-ink, var(--brand)); }
.article-body .wrap-narrow blockquote {
  margin: 1.4rem 0; padding: 1.1rem 1.4rem; background: var(--card-warm);
  border-left: 3px solid var(--brand); font-size: 1.02rem; color: var(--ink-mid);
}
.article-body .wrap-narrow blockquote p { margin-bottom: 0.4rem; }
.article-body .wrap-narrow blockquote p:last-child { margin-bottom: 0; }
.tablewrap { overflow-x: auto; margin: 1.4rem 0 1.8rem; }
.article-body table { border-collapse: collapse; width: 100%; min-width: 460px; font-size: 1rem; }
.article-body th, .article-body td { border: 1px solid var(--border); padding: 0.7rem 0.9rem; text-align: left; vertical-align: top; }
.article-body th { background: var(--cat-faint, var(--brand-faint)); font-weight: 700; }

.source-note {
  font-size: 1.05rem; color: var(--ink-soft);
  border-top: 1px solid var(--border);
  padding-top: 1.2rem; margin-top: 2.5rem;
}

/* 上下篇導覽 */
.article-pager {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 1rem; margin-top: 3rem;
}
.pager-link {
  border: 1px solid var(--border); padding: 1rem 1.2rem;
  font-size: 1.05rem;
}
.pager-link .dir { color: var(--ink-soft); font-size: 1.05rem; margin-bottom: 0.3rem; }
.pager-link .ttl { font-family: var(--font-display); font-weight: 700; font-size: 1.15rem; }
.pager-link.next { text-align: right; }
@media (max-width: 640px) { .article-pager { grid-template-columns: 1fr; } }

.back-to-hub {
  display: inline-block; margin-bottom: 2rem;
  font-size: 1.05rem; color: var(--ink-soft);
}
.back-to-hub:hover { color: var(--cat-ink); }

/* ==========================================================================
   教案資源｜課綱對照表頁 ── 刻意「打破類目」，數字徽章一律用品牌色，
   不再依主題上色，呼應「跨單元整合」的頁面主旨
   ========================================================================== */
.teach-hero {
  padding: 3.5rem 0 2.8rem;
  background: var(--brand-faint);
  border-bottom: 1px solid var(--border);
}
.teach-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 900;
  color: var(--brand-dark);
  margin: 0.9rem 0 0.7rem;
}
.teach-hero .lead { font-size: 1.1rem; color: var(--ink-mid); max-width: 50em; }

.teach-body { padding: 3rem 0 4rem; }

/* 文章代碼索引──唯一保留分單元上色，方便對照紙本書 */
.index-section { margin-bottom: 3.5rem; }
.index-units {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.8rem 2.5rem;
}
@media (max-width: 700px) { .index-units { grid-template-columns: 1fr; } }
.index-unit-title {
  display: flex; align-items: center; gap: 0.6rem;
  font-family: var(--font-display); font-weight: 700; font-size: 1.15rem;
  margin-bottom: 0.7rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--cat-ink, var(--brand));
}
.index-unit.cat-a { --cat-ink: var(--a-ink); }
.index-unit.cat-b { --cat-ink: var(--b-ink); }
.index-unit.cat-c { --cat-ink: var(--c-ink); }
.index-unit.cat-d { --cat-ink: var(--d-ink); }
.index-row {
  display: flex; align-items: baseline; gap: 0.8rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 1.05rem;
}
.index-row:last-child { border-bottom: none; }

/* 對照表主體──三面向 */
.comp-group { margin-bottom: 3rem; }
.comp-group-title {
  font-family: var(--font-display); font-weight: 900; font-size: 1.4rem;
  color: var(--ink);
  margin-bottom: 0.4rem;
}
.comp-group-desc { font-size: 1.05rem; color: var(--ink-soft); margin-bottom: 1.6rem; }

.comp-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-left: 4px solid var(--brand);
  padding: 1.6rem 1.8rem;
  margin-bottom: 1.4rem;
}
.comp-card h3 {
  font-family: var(--font-display); font-weight: 700; font-size: 1.25rem;
  margin-bottom: 0.3rem;
}
.comp-def { font-size: 1.05rem; color: var(--ink-soft); margin-bottom: 1.1rem; }

.theme-list { margin-bottom: 1.2rem; }
.theme-row {
  display: flex; align-items: baseline; gap: 0.8rem; flex-wrap: wrap;
  padding: 0.45rem 0;
  border-bottom: 1px dashed var(--border);
}
.theme-row:last-child { border-bottom: none; }
.chip-group { display: inline-flex; gap: 0.3rem; flex-shrink: 0; flex-wrap: wrap; }
.mini-chip {
  font-family: var(--font-mono); font-weight: 700; font-size: 1rem;
  padding: 0.15rem 0.45rem;
  border: 1px solid currentColor;
}
.mini-chip.cat-a { color: var(--a-ink); background: var(--a-faint); }
.mini-chip.cat-b { color: var(--b-ink); background: var(--b-faint); }
.mini-chip.cat-c { color: var(--c-ink); background: var(--c-faint); }
.mini-chip.cat-d { color: var(--d-ink); background: var(--d-faint); }
.theme-text { font-size: 1.05rem; color: var(--ink-mid); }

.actions-label {
  font-family: var(--font-mono); font-size: 1.05rem; font-weight: 700;
  letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--ink-soft); margin-bottom: 0.5rem;
}
.actions-list { display: flex; flex-direction: column; gap: 0.5rem; }
.actions-list li {
  font-size: 1.05rem; color: var(--ink-mid); line-height: 1.75;
  padding-left: 1.2rem;
  position: relative;
}
.actions-list li::before {
  content: '›'; position: absolute; left: 0; color: var(--brand); font-weight: 700;
}

/* ==========================================================================
   教案資源｜推薦影片與書單頁 ── Tab 切換、分類區塊、推薦卡片
   ========================================================================== */
.rec-tabs {
  display: flex; gap: 0.7rem;
  margin-bottom: 2.2rem;
  border-bottom: 2px solid var(--border);
}
.rec-tab {
  font-family: var(--font-display); font-weight: 900; font-size: 1.4rem;
  padding: 0.9rem 1.8rem;
  color: var(--ink-soft);
  background: var(--card-warm); border: 1px solid var(--border); border-bottom: none;
  cursor: pointer;
  border-radius: 4px 4px 0 0;
  margin-bottom: -2px;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
}
.rec-tab:hover { color: var(--ink); background: var(--border); }
.rec-tab.is-active {
  color: var(--white); background: var(--brand);
  border-color: var(--brand);
  border-bottom: 3px solid var(--brand);
}

.rec-panel { display: none; }
.rec-panel.is-active { display: block; }

.rec-section { margin-bottom: 3rem; }
.rec-section-title {
  display: flex; align-items: baseline; gap: 0.7rem;
  font-family: var(--font-display); font-weight: 900; font-size: 1.3rem;
  margin-bottom: 1.3rem;
  padding-bottom: 0.6rem;
  border-bottom: 2px solid var(--cat-ink, var(--brand));
}
.rec-section.cat-a .rec-section-title { --cat-ink: var(--a-ink); }
.rec-section.cat-b .rec-section-title { --cat-ink: var(--b-ink); }
.rec-section.cat-c .rec-section-title { --cat-ink: var(--c-ink); }
.rec-section.cat-d .rec-section-title { --cat-ink: var(--d-ink); }

.rec-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 1.1rem; }

.rec-card {
  background: var(--card);
  border: 1px solid var(--border);
  padding: 1.3rem 1.4rem;
  display: flex; flex-direction: column; gap: 0.55rem;
}
.rec-card.featured { border: 2px solid var(--highlight-dark); background: var(--highlight-faint); }
.rec-card-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 0.6rem; }
.rec-title {
  font-family: var(--font-display); font-weight: 700; font-size: 1.08rem;
  line-height: 1.4;
}
.rec-title a { color: var(--ink); }
.rec-title a:hover { color: var(--brand); text-decoration: underline; }
.rec-orig { font-size: 0.92rem; color: var(--ink-soft); margin-top: 0.15rem; }
.rec-stars { font-size: 0.95rem; color: var(--highlight-dark); white-space: nowrap; letter-spacing: 1px; }

.rec-badge {
  display: inline-block; align-self: flex-start;
  font-family: var(--font-mono); font-size: 0.85rem; font-weight: 700;
  padding: 0.18rem 0.55rem;
  border: 1px solid currentColor;
}
.rec-badge.aud-student { color: var(--d-ink); background: var(--d-faint); }
.rec-badge.aud-guide { color: var(--b-ink); background: var(--b-faint); }
.rec-badge.aud-teacher { color: var(--ink-mid); background: var(--card-warm); }

.rec-desc { font-size: 0.98rem; color: var(--ink-mid); line-height: 1.7; }
.rec-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.rec-tag {
  font-size: 0.82rem; color: var(--ink-soft);
  border: 1px solid var(--border-mid); padding: 0.1rem 0.5rem;
}
.rec-warning {
  font-size: 0.88rem; color: #8a5a12; background: #fdf0da;
  border-left: 3px solid var(--highlight-dark);
  padding: 0.5rem 0.7rem;
}
.rec-footer { display: flex; justify-content: space-between; align-items: center; margin-top: 0.2rem; }
.rec-platform { font-size: 0.85rem; color: var(--ink-faint); font-family: var(--font-mono); }
.rec-link {
  font-size: 0.9rem; font-weight: 700; color: var(--brand);
}
.rec-link:hover { text-decoration: underline; }
.featured-flag {
  display: inline-block; font-family: var(--font-mono); font-size: 0.78rem; font-weight: 700;
  color: var(--highlight-dark); margin-bottom: 0.2rem;
}
@media (max-width: 640px) {
  .rec-grid { grid-template-columns: 1fr; }
  .rec-tabs { gap: 0.4rem; }
  .rec-tab { padding: 0.7rem 1.1rem; font-size: 1.1rem; }
}