/* ════════════════════════════════════════════════════════════════
   chenyi · AI 开发入门向导 — 视觉样式
   设计北极星：干净、可信、带一抹蓝色光的学习工作台
   · 单一蓝色强调色 + 石板灰多层中性色，氛围来自冷暖渐变底色
   · 首屏主角是「检索 → 浏览 → 生成」三件事，其余信息退后
   · 图标用同一套自绘细线 SVG（stroke ≈1.75，圆头端点）
   ════════════════════════════════════════════════════════════════ */

:root {
  /* 表面与文字 */
  --bg: #f3f6fc;
  --bg-deep: #e8eefb;
  --card: #ffffff;
  --text: #0f172a;
  --text-2: #334155;
  --muted: #5b6472;
  --line: #e4e9f2;
  --line-strong: #cfd8e8;

  /* 品牌蓝（唯一强调色） */
  --primary: #2563eb;
  --primary-dark: #1e4fd0;
  --primary-soft: #eff5ff;
  --primary-line: #c7d8fb;

  /* 状态 */
  --ok: #15803d;
  --ok-bg: #ecfdf3;
  --ok-line: #a7e3c0;
  --warn: #b45309;
  --warn-bg: #fff7e6;
  --warn-line: #f5d9a2;
  --danger: #b91c1c;
  --danger-bg: #fef2f2;
  --danger-line: #f6c8c8;

  /* 检索结果分类（章节=蓝 / 名词卡=紫 / 链接=绿） */
  --violet: #5b21b6;
  --violet-bg: #f3efff;
  --violet-line: #d9ccf7;

  /* 几何 */
  --radius-lg: 18px;
  --radius: 13px;
  --radius-sm: 9px;
  --radius-pill: 999px;

  /* 阴影：卡片一层、浮起一层，投影来源统一 */
  --shadow-1: 0 1px 2px rgba(15, 23, 42, .05), 0 2px 8px rgba(15, 23, 42, .04);
  --shadow-2: 0 4px 14px rgba(15, 23, 42, .09), 0 2px 4px rgba(15, 23, 42, .05);

  --font: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --mono: ui-monospace, "Cascadia Code", Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  background:
    radial-gradient(1100px 420px at 50% -180px, rgba(37, 99, 235, .10), transparent 70%),
    linear-gradient(180deg, var(--bg-deep), var(--bg) 320px);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ── 顶栏 ───────────────────────────────────────────────────── */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 12px 22px;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(228, 233, 242, .9);
  position: sticky;
  top: 0;
  z-index: 30;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-weight: 800;
  font-size: 16.5px;
  letter-spacing: .01em;
  text-decoration: none;
  color: var(--text);
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--primary), #5b8cff);
  color: #fff;
  box-shadow: 0 3px 10px rgba(37, 99, 235, .35);
  flex-shrink: 0;
}
.brand-mark svg { display: block; }

.header-right { display: flex; align-items: center; gap: 12px; }

.site-nav { display: flex; align-items: center; gap: 4px; }
.nav-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 14.5px;
  font-weight: 600;
  padding: 7px 12px;
  border-radius: var(--radius-sm);
  transition: color .15s ease, background .15s ease;
}
.nav-link:hover { color: var(--primary); background: var(--primary-soft); }
.nav-link[aria-current="page"] {
  color: var(--primary);
  background: var(--primary-soft);
}

.gh-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--primary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  padding: 7px 12px;
  border: 1px solid var(--primary-line);
  border-radius: var(--radius-pill);
  background: #fff;
  transition: background .15s ease, box-shadow .15s ease;
}
.gh-link:hover { background: var(--primary-soft); }

/* ── 徽章（模式） ───────────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  font-weight: 600;
  padding: 4px 11px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line);
  background: #f1f4f9;
  color: var(--text-2);
  white-space: nowrap;
}
.badge-ok { background: var(--ok-bg); border-color: var(--ok-line); color: var(--ok); }
.badge-demo { background: var(--primary-soft); border-color: var(--primary-line); color: var(--primary-dark); }
#mode-badge { cursor: pointer; border: 1px dashed var(--primary-line); }
#mode-badge:hover { background: var(--primary-soft); }

.popover {
  position: fixed;
  top: 58px;
  right: 22px;
  z-index: 40;
  max-width: 380px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow-2);
  padding: 16px 18px;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--text);
}
.popover-title { font-weight: 800; margin: 0 0 8px; font-size: 14.5px; }
.popover p + p { margin-top: 0; }
.popover-close {
  position: absolute;
  top: 8px;
  right: 10px;
  border: none;
  background: transparent;
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
  color: var(--muted);
  padding: 2px 7px;
  border-radius: 6px;
}
.popover-close:hover { color: var(--text); background: #f1f4f9; }

/* ── 版式容器与首屏 ─────────────────────────────────────────── */
.container { max-width: 900px; margin: 0 auto; padding: 10px 22px 80px; }

.hero {
  padding: 46px 0 12px;
  text-align: center;
}
.hero h1 {
  font-size: clamp(28px, 4.4vw, 40px);
  line-height: 1.18;
  letter-spacing: -.015em;
  margin: 0 auto 14px;
  max-width: 620px;
  font-weight: 800;
}
.hero .lead {
  max-width: 560px;
  margin: 0 auto;
  color: var(--text-2);
  font-size: 16.5px;
  line-height: 1.75;
}
.hero .lead strong { color: var(--primary-dark); font-weight: 700; }

/* 首屏图示：学习闭环路线（自绘 SVG，无外部资源） */
.hero-diagram {
  margin: 26px auto 4px;
  max-width: 640px;
}
.hero-diagram svg {
  display: block;
  width: 100%;
  height: auto;
}

/* 知识库即时检索 */
.kb-search {
  display: flex;
  gap: 10px;
  margin: 26px auto 0;
  max-width: 640px;
  position: relative;
  align-items: stretch;
}
.kb-search .search-icon {
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  pointer-events: none;
  display: grid;
  place-items: center;
}
.kb-search input {
  flex: 1;
  font-size: 16px;
  padding: 15px 15px 15px 46px;
  border-radius: 15px;
  background: #fff;
  box-shadow: var(--shadow-1);
}
.kb-search .btn {
  flex-shrink: 0;
  padding: 0 26px;
  border-radius: 15px;
}
.hero .hint { margin-top: 12px; }

.kb-results { margin: 22px auto 0; display: grid; gap: 10px; max-width: 640px; text-align: left; }
.kb-result-count { color: var(--muted); font-size: 13px; margin: 0 0 2px; }
.kb-hit {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  background: #fff;
  box-shadow: var(--shadow-1);
  transition: border-color .15s ease, box-shadow .15s ease;
}
.kb-hit:hover { border-color: var(--primary-line); box-shadow: var(--shadow-2); }
.kb-hit-head { display: flex; align-items: baseline; gap: 9px; }
.kb-kind {
  flex-shrink: 0;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .02em;
  padding: 2px 9px;
  border-radius: var(--radius-pill);
}
.kb-kind[data-kind="chapter"] { background: var(--primary-soft); border: 1px solid var(--primary-line); color: var(--primary-dark); }
.kb-kind[data-kind="term"] { background: var(--violet-bg); border: 1px solid var(--violet-line); color: var(--violet); }
.kb-kind[data-kind="link"] { background: var(--ok-bg); border: 1px solid var(--ok-line); color: var(--ok); }
.kb-hit-title { color: var(--text); font-size: 15px; font-weight: 600; }
.kb-hit-snippet { margin: 7px 0 3px; font-size: 14px; color: var(--text-2); line-height: 1.7; }
.kb-hit-url { font-size: 13px; color: var(--primary); text-decoration: none; font-weight: 600; }
.kb-hit-url:hover { text-decoration: underline; }

/* ── 本地问答（零 Token）：名词解释 / 最相关开源项目 / 相关章节 ── */
.kb-mode {
  max-width: 560px;
  margin: 4px 0 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--muted);
}
.kb-mode strong { color: var(--text-2); }
.kb-mode a { color: var(--text); font-weight: 700; text-decoration: none; }
.kb-mode a:hover { transform: scale(1.06); }

/* 正文里的行内跳转：黑字加粗、去掉蓝色下划线，悬停轻微放大 */
a.text-link {
  display: inline-block;
  color: var(--text);
  font-weight: 700;
  text-decoration: none;
  transition: transform .15s ease;
}
a.text-link:hover,
a.text-link:focus-visible {
  transform: scale(1.06);
}
.kb-mode-tag {
  display: inline-block;
  margin-right: 8px;
  padding: 2px 9px;
  border-radius: var(--radius-pill);
  background: var(--primary-soft);
  border: 1px solid var(--primary-line);
  color: var(--primary);
  font-size: 12px;
  font-weight: 600;
  vertical-align: 1px;
}
.kb-answer-block { margin-top: 18px; }
.kb-block-title {
  margin: 0 0 10px;
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.01em;
}
.kb-term-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}
.kb-term-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow-1);
}
.kb-card-label {
  display: inline-block;
  margin-bottom: 8px;
  padding: 1px 8px;
  border-radius: var(--radius-pill);
  font-size: 11.5px;
  font-weight: 600;
}
.kb-card-label[data-kind="term"] { background: var(--violet-bg); border: 1px solid var(--violet-line); color: var(--violet); }
.kb-card-label[data-kind="link"] { background: var(--ok-bg); border: 1px solid var(--ok-line); color: var(--ok); }
.kb-term-name { display: block; font-size: 15.5px; color: var(--text); margin-bottom: 6px; }
.kb-term-def { margin: 0 0 6px; font-size: 14px; line-height: 1.7; color: var(--text-2); }
.kb-term-analogy,
.kb-term-pitfall { margin: 0 0 4px; font-size: 13.5px; line-height: 1.65; }
.kb-term-analogy { color: var(--ok); }
.kb-term-pitfall { color: var(--danger); }
.kb-term-card .meta { margin-top: 8px; }
.kb-link-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow-1);
}
.kb-link-title { display: block; font-size: 15.5px; color: var(--text); margin-bottom: 6px; }
.kb-link-card .why { margin: 0 0 6px; font-size: 14px; line-height: 1.7; color: var(--text-2); }
.kb-link-card .btn { margin-top: 8px; }
.kb-chapter-list { margin: 0; padding-left: 20px; display: grid; gap: 10px; }
.kb-chapter-list li { padding-left: 2px; }
.kb-chapter-title { font-size: 14.5px; color: var(--text); }
.kb-chapter-list .kb-hit-snippet { margin: 4px 0 2px; }

/* ── 首屏点缀：DSH 鲸鱼娘（装饰性，不参与读屏） ─────────────── */
.hero { position: relative; }
/* 搜索框右侧的小立绘：浅蓝白虚化底图用径向遮罩柔化边缘，像一枚贴纸 */
.kb-search-wrap {
  position: relative;
  max-width: 640px;
  margin: 26px auto 0;
}
.kb-search-wrap .kb-search {
  margin: 0;
  max-width: none;
}
.kb-mascot {
  position: absolute;
  left: calc(100% + 20px);
  bottom: -2px;
  width: 112px;
  height: auto;
  pointer-events: none;
  user-select: none;
  /* Q 版立绘已是透明底 + 边缘羽化，直接叠在页面底色上，不再需要遮罩 */
}
@media (max-width: 1120px) {
  .kb-mascot { width: 100px; left: calc(100% + 12px); }
}
@media (max-width: 900px) {
  .kb-mascot { display: none; }
}

/* 极淡的浪花/鲸尾底纹：只做氛围，不影响文字可读性 */
body::before {
  content: "";
  position: fixed;
  right: -60px;
  bottom: -80px;
  width: 480px;
  height: 480px;
  background: url("/static/img/whale-pattern.png") repeat;
  background-size: 240px auto;
  opacity: .055;
  mix-blend-mode: multiply;
  pointer-events: none;
  z-index: -1;
}

/* 空结果旁的小鲸鱼（点缀） */
.kb-empty {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 6px 0 0;
}
.kb-empty img {
  width: 72px;
  height: auto;
  flex: none;
  mix-blend-mode: multiply;
}
.kb-empty p { margin: 0; }

/* ── 卡片 ────────────────────────────────────────────────────── */
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 26px 28px;
  margin: 20px 0;
  box-shadow: var(--shadow-1);
}
.card h2 {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 19.5px;
  font-weight: 800;
  letter-spacing: -.01em;
  margin: 0 0 8px;
}
.card h2 .heading-icon {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 9px;
  background: var(--primary-soft);
  color: var(--primary);
  flex-shrink: 0;
}
.card h2 .heading-icon svg { display: block; }
.card > .muted { margin: 0 0 14px; max-width: 640px; }

.muted { color: var(--muted); font-size: 14.5px; line-height: 1.7; }
.hint { color: var(--muted); font-size: 13px; line-height: 1.6; }
.warn-text { color: var(--warn); font-weight: 600; }

/* 表单 */
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 6px; }
.field { display: flex; flex-direction: column; gap: 7px; }
.field-wide { grid-column: 1 / -1; }
.field > span { font-size: 14px; font-weight: 700; color: var(--text-2); }

input, select, textarea {
  font: inherit;
  font-size: 15px;
  padding: 11px 13px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  background: #fff;
  color: var(--text);
  transition: border-color .15s ease, box-shadow .15s ease;
}
input::placeholder, textarea::placeholder { color: var(--muted); }
input:hover, select:hover, textarea:hover { border-color: var(--primary-line); }
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .16);
}
textarea { resize: vertical; }

.actions { flex-direction: row; align-items: center; gap: 12px; flex-wrap: wrap; }

/* 历史页：标题与刷新按钮两端对齐 */
.history-head { justify-content: space-between; }
.history-head h2 { margin: 0; display: flex; align-items: center; gap: 10px; }

/* 按钮 */
.btn {
  font: inherit;
  font-size: 15px;
  font-weight: 700;
  padding: 11px 20px;
  border-radius: 11px;
  border: 1px solid var(--line-strong);
  background: #fff;
  color: var(--text);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  text-decoration: none;
  transition: background .15s ease, color .15s ease, border-color .15s ease, box-shadow .15s ease, transform .06s ease;
}
.btn:hover { border-color: var(--primary-line); background: #f8faff; }
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }

.btn-primary { background: var(--primary); border-color: var(--primary); color: #fff; box-shadow: 0 3px 10px rgba(37, 99, 235, .25); }
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); color: #fff; }
.btn-ghost { background: transparent; }
.btn-ghost:hover { background: var(--primary-soft); }
.btn:disabled { opacity: .55; cursor: not-allowed; transform: none; box-shadow: none; }
.btn-small { padding: 5px 12px; font-size: 13px; border-radius: 8px; }

/* 提醒条 */
.warning {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  background: var(--warn-bg);
  border: 1px solid var(--warn-line);
  border-radius: 11px;
  padding: 11px 14px;
  font-size: 14px;
  color: var(--warn);
  margin-bottom: 16px;
  max-width: 640px; /* M8：控制行长，避免超长正文 */
  line-height: 1.7;
}
.warning::before { content: "⚠"; font-weight: 700; }

/* ── 知识库浏览 ──────────────────────────────────────────────── */
.topic-bar { display: flex; gap: 9px; flex-wrap: wrap; margin: 14px 0 16px; }
.topic-chip {
  font: inherit;
  font-size: 13.5px;
  font-weight: 600;
  padding: 6px 15px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text-2);
  cursor: pointer;
  transition: color .15s ease, border-color .15s ease, background .15s ease;
}
.topic-chip:hover { border-color: var(--primary-line); color: var(--primary); background: var(--primary-soft); }
.topic-chip.active { background: var(--primary); border-color: var(--primary); color: #fff; }
/* M8：用圆点区分「名词卡」与「链接」主题，替代 emoji */
.topic-chip::before {
  content: "";
  display: inline-block;
  width: 7px;
  height: 7px;
  margin-right: 7px;
  border-radius: 50%;
  background: var(--primary);
  vertical-align: 1px;
}
.topic-chip[data-kind="link"]::before { background: var(--ok); }
.topic-chip.active::before { background: #fff; }

.browse-topics { display: grid; gap: 12px; margin: 4px 0 16px; }
.browse-topic-group { display: grid; gap: 7px; }
.browse-group-label { margin: 0; font-size: 12.5px; color: var(--muted); letter-spacing: .02em; }

.browse-list { display: grid; gap: 9px; margin-top: 8px; }
.browse-chapter {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 13px 16px;
  background: #fff;
  transition: border-color .15s ease;
}
.browse-chapter:hover { border-color: var(--primary-line); }
.browse-chapter summary {
  cursor: pointer;
  font-weight: 700;
  font-size: 15px;
  color: var(--text);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
}
.browse-chapter summary::-webkit-details-marker { display: none; }
.browse-chapter summary::before {
  content: "";
  width: 22px;
  height: 22px;
  border-radius: 7px;
  background: var(--primary-soft);
  color: var(--primary);
  flex-shrink: 0;
  display: grid;
  place-items: center;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='13' height='13' viewBox='0 0 24 24' fill='none' stroke='%232563eb' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m9 6 6 6-6 6'/%3E%3C/svg%3E");
  background-size: 13px;
  transition: transform .18s ease;
}
.browse-chapter[open] summary::before { transform: rotate(90deg); }
.browse-sections { margin: 9px 0 2px; padding-left: 0; list-style: none; display: grid; gap: 2px; }
.browse-section-link {
  border: none;
  background: none;
  color: var(--primary);
  font-size: 14px;
  font-weight: 600;
  text-align: left;
  padding: 6px 10px 6px 34px;
  border-radius: 8px;
  cursor: pointer;
  width: 100%;
  position: relative;
}
.browse-section-link::before {
  content: "";
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--primary-line);
  transition: background .15s ease;
}
.browse-section-link:hover { background: var(--primary-soft); }
.browse-section-link:hover::before { background: var(--primary); }

/* ── M7.3：服务端加密代存 ───────────────────────────────────── */
.vault-use {
  flex-direction: row;
  align-items: flex-start;
  gap: 10px;
  padding: 12px 14px;
  border: 1px dashed var(--primary-line);
  border-radius: 11px;
  background: var(--primary-soft);
  font-size: 14px;
}
.vault-use input { margin-top: 4px; accent-color: var(--primary); width: 17px; height: 17px; flex-shrink: 0; }
.vault-use span { color: var(--text-2); }
.vault-use span strong { color: var(--primary-dark); }
.vault-use:has(input:checked) { border-style: solid; border-color: var(--primary); background: #fff; }
/* 禁用态改用达标底色文字而非半透明（WCAG 4.5:1），M8 修正 lint 提示 */
.vault-use input:disabled + span { color: var(--muted); }
.vault-use input:disabled + span strong { color: var(--muted); font-weight: 700; }

.vault-block {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px dashed var(--line-strong);
}
.vault-block h3 {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 8px;
  font-size: 15.5px;
  font-weight: 800;
}
.vault-block p.muted { max-width: 640px; } /* M8：控制行长 */
.vault-scopes { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0 6px; }
.scope-chip {
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  padding: 5px 13px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--primary-line);
  background: var(--primary-soft);
  color: var(--primary-dark);
  cursor: pointer;
  transition: background .15s ease, border-color .15s ease;
}
.scope-chip:hover { border-color: var(--primary); background: #e4eeff; }

/* ── 生成流程（SSE 渲染） ────────────────────────────────────── */
.result { margin-top: 20px; border-top: 1px dashed var(--line-strong); padding-top: 18px; }
.result pre { white-space: pre-wrap; background: var(--bg); border: 1px solid var(--line); padding: 13px; border-radius: 10px; }

.gen-status { font-weight: 800; margin-bottom: 12px; }
.gen-progress { margin-bottom: 14px; }
.progress-line {
  font-size: 13.5px;
  color: var(--muted);
  margin: 3px 0;
  padding-left: 12px;
  border-left: 2px solid var(--primary-line);
}
.gen-error {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  background: var(--danger-bg);
  border: 1px solid var(--danger-line);
  color: var(--danger);
  border-radius: 11px;
  padding: 12px 14px;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 14px;
}
.gen-days { display: grid; gap: 16px; margin-top: 12px; }
.lesson-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 18px 20px;
  background: #fff;
  box-shadow: var(--shadow-1);
}
.lesson-title { margin: 0 0 10px; font-size: 17.5px; font-weight: 800; color: var(--primary-dark); }
.lesson-body { white-space: pre-wrap; font-size: 14.5px; line-height: 1.75; color: var(--text-2); }
.code-snippet {
  white-space: pre-wrap;
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.6;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: 12px;
  margin: 10px 0 0;
  overflow-x: auto;
  color: var(--text-2);
}
.term-card {
  margin-top: 12px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 11px;
  padding: 13px 15px;
  font-size: 14px;
}
.term-name { color: var(--primary-dark); display: block; margin-bottom: 4px; }
.term-def, .term-analogy, .term-pitfalls { margin-top: 4px; color: var(--text-2); }
.term-analogy { color: var(--ok); font-size: 13px; }
.term-pitfalls { color: var(--danger); font-size: 13px; }
.quiz-card {
  margin-top: 12px;
  border: 1px dashed var(--warn-line);
  background: var(--warn-bg);
  border-radius: 11px;
  padding: 13px 15px;
  font-size: 14px;
}
.quiz-question { font-weight: 700; color: var(--text); }
.quiz-option { color: var(--text-2); margin-top: 3px; }
.quiz-answer { margin-top: 8px; color: var(--ok); font-size: 13px; font-weight: 600; }
.done-box {
  margin-top: 14px;
  background: var(--ok-bg);
  border: 1px solid var(--ok-line);
  color: var(--ok);
  border-radius: var(--radius);
  padding: 15px 17px;
  font-size: 14.5px;
  font-weight: 700;
}
.done-stats { margin-top: 5px; color: var(--ok); font-size: 13px; font-weight: 600; }
.result-block { margin-top: 18px; }

/* 策展链接 */
.links { display: grid; gap: 11px; }
.link-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  background: #fff;
  transition: border-color .15s ease, box-shadow .15s ease;
}
.link-item:hover { border-color: var(--primary-line); box-shadow: var(--shadow-1); }
.link-item a { color: var(--primary); font-weight: 700; text-decoration: none; font-size: 15px; }
.link-item a::after { content: " ↗"; font-size: 12px; }
.link-item a:hover { text-decoration: underline; }
.link-item .why { color: var(--text-2); font-size: 14px; margin-top: 5px; }
.link-item .meta { color: var(--muted); font-size: 12.5px; margin-top: 7px; }

/* ── 历史页 ──────────────────────────────────────────────────── */
.history-list { display: grid; gap: 13px; }
.session-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 17px 19px;
  background: #fff;
  cursor: pointer;
  box-shadow: var(--shadow-1);
  transition: border-color .15s ease, box-shadow .2s ease, transform .15s ease;
}
.session-card:hover { border-color: var(--primary-line); box-shadow: var(--shadow-2); transform: translateY(-1px); }
.session-card-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 10px; }
.session-card-top .badge { flex-shrink: 0; }
.session-goal { margin: 0 0 7px; font-size: 15.5px; font-weight: 700; line-height: 1.55; }
.session-meta { margin: 0 0 11px; color: var(--muted); font-size: 13px; }
.session-actions { display: flex; gap: 8px; }
.detail-section { margin: 16px 0 8px; font-size: 15.5px; font-weight: 800; }

/* ── 页脚 ────────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 22px 22px 44px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}
.site-footer a { color: var(--primary); text-decoration: none; font-weight: 600; }
.site-footer a:hover { text-decoration: underline; }
.site-footer .sep { margin: 0 8px; color: var(--line-strong); }
.footer-note { margin-top: 5px; }

/* ── 响应式 ──────────────────────────────────────────────────── */
@media (max-width: 680px) {
  .container { padding: 6px 16px 64px; }
  .site-header { padding: 10px 16px; flex-wrap: wrap; }
  .gh-link { display: none; }            /* 窄屏藏 GitHub 文字链，聚焦主动作 */
  .brand { font-size: 15px; }
  .brand-mark { width: 27px; height: 27px; }
  .hero { padding-top: 32px; }
  .hero h1 { font-size: 27px; }
  .hero .lead { font-size: 15.5px; }
  .kb-search { flex-direction: column; gap: 8px; margin-top: 20px; }
  .kb-search input { padding: 14px 14px 14px 44px; }
  .kb-search .search-icon { left: 13px; }
  .kb-search .btn { padding: 12px 20px; }
  .card { padding: 20px 18px; border-radius: 15px; }
  .form-grid { grid-template-columns: 1fr; }
  .popover { left: 14px; right: 14px; max-width: none; }
}

/* 动效偏好：减少动画 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}