/* chapter.css — 章节起始页（与首页区分）
   小一号标题 · 参考线网格 · 课时列表，不做首页交叠 Hero */

.chapter-page {
  background:
    linear-gradient(180deg, #f7f2ea 0%, var(--bg) 40%);
}

.chapter-page .hero,
.chapter-page .stack-sec,
.chapter-page .lab-sec {
  display: none !important;
}

/* 章节 Hero：更克制、像「目录页」 */
.ch-hero {
  position: relative;
  padding: calc(var(--nav-h) + 36px) clamp(20px, 5vw, 56px) 40px;
  max-width: 920px;
  margin: 0 auto;
}

.ch-hero-inner {
  position: relative;
  padding: 28px 0 8px;
}

.ch-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-code, monospace);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--ink-2);
  padding: 7px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--paper);
  margin-bottom: 22px;
}

.ch-kicker .tick {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
}

.ch-title {
  font-size: clamp(34px, 5.5vw, 56px);
  font-weight: 800;
  letter-spacing: -0.035em;
  line-height: 1.12;
  margin-bottom: 16px;
  color: var(--ink);
}

.ch-title .line { display: block; }

.ch-title .accent .char {
  background: linear-gradient(135deg, var(--accent), var(--accent-deep));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.ch-lead {
  font-size: 15px;
  color: var(--ink-2);
  max-width: 40ch;
  line-height: 1.85;
  margin-bottom: 16px;
}

.ch-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 22px;
}

.ch-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* 课时列表：编号行，不是首页卡片堆叠 */
.ch-lessons {
  max-width: 920px;
  margin: 0 auto;
  padding: 24px clamp(20px, 5vw, 56px) 48px;
}

.ch-lessons-head {
  margin-bottom: 18px;
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.ch-lessons-head .sec-kicker { margin: 0; }
.ch-lessons-head .sec-title {
  font-size: 22px;
  margin: 0;
  letter-spacing: -0.02em;
}

.ch-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 1px solid var(--line);
  padding-top: 8px;
}

.ch-row {
  display: grid;
  grid-template-columns: 52px 1fr 28px;
  gap: 12px;
  align-items: center;
  padding: 16px 12px;
  border-radius: 12px;
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: background 0.28s var(--ease-out), transform 0.35s var(--ease-out);
}

.ch-row:hover {
  background: var(--paper);
  transform: translateX(4px);
}

.ch-row .n {
  font-family: var(--font-code, monospace);
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.06em;
}

.ch-row .t h3 {
  font-size: 15.5px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 2px;
}

.ch-row .t p {
  font-size: 12.5px;
  color: var(--ink-3);
  line-height: 1.55;
}

.ch-row .go {
  font-family: var(--font-code, monospace);
  color: var(--accent);
  opacity: 0;
  transform: translateX(-6px);
  transition: all 0.3s var(--ease-out);
}

.ch-row:hover .go {
  opacity: 1;
  transform: none;
}

/* 章节 CTA：去掉与首页完全同款的大标题堆叠感 */
.chapter-page .ch-cta {
  padding-top: 64px;
  padding-bottom: 72px;
}

.chapter-page .ch-cta .cta-title {
  font-size: clamp(28px, 4vw, 42px);
  max-width: 12em;
}

@media (max-width: 640px) {
  .ch-row {
    grid-template-columns: 40px 1fr;
  }
  .ch-row .go { display: none; }
}