/* ============================================================
   深度学习 · 全景基础学习站 — style.css（配合 tokens.css）
   ============================================================ */

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  transition: background var(--speed) var(--ease), color var(--speed) var(--ease);
}
img, svg { max-width: 100%; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
  border-radius: 4px;
}
.container { max-width: var(--content-width); margin: 0 auto; padding: 0 20px; }
.muted { color: var(--muted); }

/* 跳过导航 */
.skip-link {
  position: absolute; left: -999px; top: 8px; z-index: 99;
  background: var(--primary); color: #fff; padding: 8px 14px; border-radius: 8px;
}
.skip-link:focus { left: 8px; }

/* ---------------- 顶栏 ---------------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; gap: 18px; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; font-size: 17px; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: inline-flex; align-items: center; justify-content: center;
  width: 32px; height: 32px; border-radius: 9px; font-size: 18px; color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: var(--shadow-1);
}
.brand-sub { margin-left: 6px; font-size: 12px; font-weight: 500; color: var(--muted); }
.site-nav { display: flex; gap: 4px; margin-left: 6px; }
.site-nav a {
  padding: 6px 12px; border-radius: 8px; color: var(--muted); font-size: 14.5px; font-weight: 500;
}
.site-nav a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.site-nav a.on { color: var(--primary); background: var(--primary-soft); }
.header-tools { margin-left: auto; display: flex; align-items: center; gap: 10px; }
.search-wrap { position: relative; }
#search-input {
  width: 220px; height: 36px; padding: 0 12px; font-size: 14px; color: var(--text);
  background: var(--surface); border: 1px solid var(--border); border-radius: 10px;
  font-family: inherit; transition: border-color var(--speed) var(--ease), box-shadow var(--speed) var(--ease);
}
#search-input:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft); }
.search-results {
  position: absolute; top: 42px; right: 0; width: 380px; max-height: 420px; overflow: auto;
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
  box-shadow: var(--shadow-2); padding: 6px; z-index: 60;
}
.search-results[hidden] { display: none; }
.sr-item { display: block; padding: 8px 10px; border-radius: 8px; color: var(--text); }
.sr-item:hover, .sr-item.active { background: var(--primary-soft); text-decoration: none; }
.sr-item .sr-title { font-weight: 600; font-size: 14px; display: flex; gap: 8px; align-items: center; }
.sr-item .sr-sub { font-size: 12.5px; color: var(--muted); margin-top: 2px; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.sr-item mark { background: none; color: var(--primary); font-weight: 700; }
.sr-empty { padding: 12px; color: var(--muted); font-size: 13.5px; text-align: center; }
.sr-group { font-size: 11.5px; color: var(--muted); padding: 6px 10px 2px; letter-spacing: 0.06em; }
.icon-btn {
  width: 36px; height: 36px; display: inline-flex; align-items: center; justify-content: center;
  background: var(--surface); border: 1px solid var(--border); border-radius: 10px;
  color: var(--text); font-size: 16px; cursor: pointer;
  transition: transform var(--speed) var(--ease), border-color var(--speed) var(--ease);
}
.icon-btn:hover { transform: rotate(15deg); border-color: var(--primary); }

/* ---------------- 按钮 ---------------- */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 9px 18px; border-radius: 11px; border: 1px solid var(--border-strong);
  background: var(--surface); color: var(--text); font-size: 14.5px; font-weight: 600;
  cursor: pointer; font-family: inherit; line-height: 1.4;
  transition: transform var(--speed) var(--ease), box-shadow var(--speed) var(--ease), background var(--speed) var(--ease);
}
.btn:hover { text-decoration: none; transform: translateY(-1px); box-shadow: var(--shadow-1); }
.btn-primary {
  background: linear-gradient(135deg, var(--primary), #6d5ae0 60%, var(--accent));
  border: none; color: #fff;
}
.btn-primary:hover { box-shadow: 0 6px 22px rgba(74, 68, 198, 0.35); }
.btn-sm { padding: 5px 12px; font-size: 13px; border-radius: 9px; }
.btn-danger { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 45%, var(--border)); }

/* ---------------- 徽章与标签 ---------------- */
.tag { display: inline-flex; align-items: center; padding: 2px 9px; border-radius: 999px; font-size: 12px; font-weight: 600; line-height: 1.6; }
.level-a { color: var(--level-a); background: var(--level-a-bg); }
.level-b { color: var(--level-b); background: var(--level-b-bg); }
.level-c { color: var(--level-c); background: var(--level-c-bg); }
.level-d { color: var(--level-d); background: var(--level-d-bg); }
.badge-min { display: inline-flex; padding: 2px 8px; border-radius: 999px; font-size: 12px; font-weight: 700; color: var(--warn); background: color-mix(in srgb, var(--warn) 14%, transparent); }
.chip-id { font-family: var(--font-mono); font-size: 0.86em; color: var(--accent); font-weight: 600; }
.chip-min { margin-left: auto; color: var(--muted); font-size: 12px; white-space: nowrap; }
.chip-link {
  display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px; border-radius: 999px;
  background: var(--surface-2); border: 1px solid var(--border); color: var(--text); font-size: 13px;
}
.chip-link:hover { border-color: var(--primary); text-decoration: none; }
.module-chip { font-family: var(--font-mono); }

/* 学习状态圆点 */
.dot { display: inline-block; width: 9px; height: 9px; border-radius: 50%; background: var(--st-todo); flex: none; }
.dot.st-learning { background: var(--st-learning); box-shadow: 0 0 0 3px color-mix(in srgb, var(--st-learning) 25%, transparent); }
.dot.st-done { background: var(--st-done); box-shadow: 0 0 0 3px color-mix(in srgb, var(--st-done) 22%, transparent); }

/* ---------------- 首页 hero ---------------- */
.hero {
  background: var(--hero-grad);
  border-bottom: 1px solid var(--border);
  padding: 64px 0 44px;
}
.hero-eyebrow { color: var(--accent); font-weight: 700; letter-spacing: 0.14em; font-size: 13px; margin: 0 0 10px; }
.hero-title { font-size: clamp(34px, 6vw, 54px); line-height: 1.15; margin: 0 0 16px; letter-spacing: -0.01em; }
.hero-title-sub { display: block; font-size: 0.42em; color: var(--muted); font-weight: 600; letter-spacing: 0.32em; margin-top: 10px; }
.hero-lead { max-width: 680px; color: var(--muted); font-size: 16.5px; margin: 0 0 22px; }
.hero-lead strong { color: var(--text); }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 30px; }
.hero-stats { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; margin: 0; }
.hero-stats > div { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; box-shadow: var(--shadow-1); }
.hero-stats dt { font-size: 12.5px; color: var(--muted); }
.hero-stats dd { margin: 4px 0 0; font-size: 22px; font-weight: 800; color: var(--primary); font-variant-numeric: tabular-nums; }

/* ---------------- 区块通用 ---------------- */
.section { padding: 40px 0 10px; }
.section h2 { font-size: 24px; margin: 0 0 8px; }
.section-sub { color: var(--muted); margin: 0 0 22px; }
.reading-note { padding-bottom: 56px; }
.reading-note p { max-width: 780px; color: var(--muted); }

/* ---------------- 进度面板 ---------------- */
.progress-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px; box-shadow: var(--shadow-1);
}
.progress-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
.progress-head h2 { margin: 0; font-size: 18px; }
.progress-actions { display: flex; gap: 8px; }
.progress-bar {
  height: 10px; background: var(--surface-2); border-radius: 999px; overflow: hidden;
  border: 1px solid var(--border);
}
.progress-bar .progress-fill {
  display: block; height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--primary));
  border-radius: 999px;
  transition: width 400ms var(--ease);
}
.progress-bar.slim { height: 7px; display: inline-block; width: 110px; vertical-align: middle; }
.progress-note { color: var(--muted); font-size: 13.5px; margin: 10px 0 0; }
.progress-note span { color: var(--text); font-weight: 600; font-variant-numeric: tabular-nums; }
.progress-note .pct { color: var(--primary); }

/* ---------------- 模块卡片 ---------------- */
.module-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.module-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px; box-shadow: var(--shadow-1);
  transition: transform var(--speed) var(--ease), box-shadow var(--speed) var(--ease);
}
.module-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-2); }
.module-card-head { display: flex; gap: 14px; align-items: flex-start; }
.module-card-head h3 { margin: 0 0 4px; font-size: 17.5px; }
.module-num {
  flex: none; font-family: var(--font-mono); font-weight: 700; font-size: 14px; color: var(--primary);
  background: var(--primary-soft); border-radius: 10px; padding: 6px 9px; line-height: 1;
}
.module-blurb { margin: 0; color: var(--muted); font-size: 13.5px; line-height: 1.6; }
.module-meta { margin: 10px 0 12px; color: var(--accent); font-size: 12.5px; font-weight: 700; }
.module-kps { display: flex; flex-direction: column; gap: 6px; }
.kp-chip {
  display: flex; align-items: center; gap: 8px;
  padding: 7px 12px; border-radius: 10px; border: 1px solid transparent;
  color: var(--text); font-size: 13.8px;
}
.kp-chip:hover { background: var(--surface-2); border-color: var(--border); text-decoration: none; }
.kp-chip .dot { width: 8px; height: 8px; }

/* ---------------- 学习路径页 ---------------- */
.stage { margin: 30px 0 8px; }
.stage-head { margin-bottom: 14px; }
.stage-head h2 { margin: 0 0 6px; font-size: 21px; }
.stage-desc { margin: 0 0 6px; color: var(--muted); font-size: 14.5px; max-width: 760px; }
.stage-meta { margin: 0; font-size: 13px; color: var(--muted); }
.stage-meta .stage-progress { display: inline-flex; align-items: center; gap: 8px; }
.stage-progress-text { font-variant-numeric: tabular-nums; color: var(--primary); font-weight: 700; }
.stage-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 7px; }
.stage-item {
  display: flex; align-items: center; gap: 10px;
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
  padding: 9px 14px;
}
.stage-item.is-minimal { border-left: 3px solid var(--warn); }
.stage-link { color: var(--text); font-weight: 600; font-size: 14.5px; flex: 1; min-width: 0; }
.stage-link:hover { color: var(--primary); }
.stage-item .chip-min { margin-left: 0; }
.minimal-box {
  margin: 36px 0 56px; padding: 20px 22px;
  background: var(--surface); border: 1px dashed var(--warn); border-radius: var(--radius);
}
.minimal-box h2 { margin: 0 0 10px; font-size: 18px; }
.minimal-box p { font-family: var(--font-mono); font-size: 13.5px; line-height: 2; word-break: break-all; }
.minimal-note { font-family: var(--font-sans) !important; color: var(--muted); font-size: 14px !important; }

/* ---------------- 知识地图 ---------------- */
.map-legend { display: flex; gap: 8px; margin-bottom: 14px; }
.map-scroll {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  overflow: auto; padding: 8px; box-shadow: var(--shadow-1);
}
.map-svg { display: block; min-width: 100%; }
.map-edge { fill: none; stroke: var(--edge); stroke-width: 1.6; transition: stroke var(--speed) var(--ease), opacity var(--speed) var(--ease); }
.map-svg.dim .map-edge { opacity: 0.15; }
.map-svg.dim .map-edge.hot { opacity: 1; stroke: var(--edge-hot); stroke-width: 2.4; }
.map-node { cursor: pointer; }
.map-node rect { fill: var(--node-fill); stroke: var(--node-border); stroke-width: 1.4; rx: 10; transition: stroke var(--speed) var(--ease); }
.map-node:hover rect, .map-node:focus rect { stroke: var(--primary); }
.map-node .n-id { font: 600 10.5px var(--font-mono); fill: var(--accent); }
.map-node .n-title { font: 500 12.5px var(--font-sans); fill: var(--text); }
.map-node .n-min { font: 500 10.5px var(--font-mono); fill: var(--muted); }
.map-colhead { font: 700 13px var(--font-sans); fill: var(--muted); }
.map-colsub { font: 500 10.5px var(--font-mono); fill: var(--muted); opacity: 0.8; }
.map-node.lv-a rect { stroke: color-mix(in srgb, var(--level-a) 55%, var(--node-border)); }
.map-node.lv-b rect { stroke: color-mix(in srgb, var(--level-b) 55%, var(--node-border)); }
.map-node.lv-c rect { stroke: color-mix(in srgb, var(--level-c) 55%, var(--node-border)); }
.map-node.lv-d rect { stroke: color-mix(in srgb, var(--level-d) 55%, var(--node-border)); }
.map-deps { margin-top: 22px; }
.map-deps h2 { font-size: 18px; margin: 0 0 8px; }
.map-deps ul { margin: 0; padding-left: 20px; color: var(--muted); font-size: 14px; }
.map-deps li { margin: 3px 0; }

/* ---------------- 术语表 ---------------- */
.glossary-group { margin: 26px 0 34px; }
.glossary-group h2 { font-size: 19px; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.glossary-group dl { margin: 14px 0 0; }
.glossary-group dt { font-weight: 700; margin-top: 12px; color: var(--primary); }
.glossary-group dd { margin: 3px 0 0 0; color: var(--muted); }

/* ---------------- 知识点详情页 ---------------- */
.kp-article { padding: 30px 20px 60px; }
.breadcrumb { font-size: 13px; color: var(--muted); margin-bottom: 18px; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--primary); }
.kp-header { margin-bottom: 20px; }
.kp-badges { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 12px; }
.kp-header h1 { font-size: clamp(26px, 4.5vw, 36px); line-height: 1.25; margin: 0 0 10px; letter-spacing: -0.01em; }
.kp-summary { color: var(--muted); font-size: 16px; margin: 0; max-width: 780px; }
.kp-aside { margin: 18px 0; }
.aside-title { font-size: 13px; letter-spacing: 0.1em; color: var(--muted); text-transform: uppercase; margin: 0 0 8px; font-weight: 700; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.kp-body { max-width: 820px; }

/* 正文排版 */
.kp-body h2 {
  font-size: 21px; margin: 34px 0 12px; padding-top: 18px;
  border-top: 1px solid var(--border);
}
.kp-body h2:first-child { border-top: none; padding-top: 0; margin-top: 8px; }
.kp-body h3 { font-size: 17px; margin: 22px 0 8px; }
.kp-body p { margin: 10px 0; }
.kp-body ul, .kp-body ol { margin: 10px 0; padding-left: 24px; }
.kp-body li { margin: 5px 0; }
.kp-body blockquote {
  margin: 14px 0; padding: 10px 16px; border-left: 3px solid var(--accent);
  background: var(--accent-soft); border-radius: 0 10px 10px 0; color: var(--text);
}
.kp-body code {
  font-family: var(--font-mono); font-size: 0.88em;
  background: var(--surface-2); border: 1px solid var(--border);
  padding: 1px 6px; border-radius: 6px;
}
.code-block { margin: 16px 0; }
.code-block pre {
  margin: 0; padding: 16px 18px; overflow-x: auto;
  background: var(--code-bg); color: var(--code-text);
  border-radius: var(--radius); border: 1px solid var(--border);
  font-family: var(--font-mono); font-size: 13.5px; line-height: 1.7;
  position: relative;
}
.code-block pre[data-lang]::before {
  content: attr(data-lang);
  position: absolute; top: 8px; right: 12px;
  font-size: 10.5px; letter-spacing: 0.08em; color: var(--tok-comment);
  font-family: var(--font-mono);
}
.code-block code { background: none; border: none; padding: 0; }
.tok-kw { color: var(--tok-kw); font-weight: 600; }
.tok-str { color: var(--tok-str); }
.tok-num { color: var(--tok-num); }
.tok-comment { color: var(--tok-comment); font-style: italic; }
.formula { margin: 18px 0; }
.formula pre {
  margin: 0; padding: 16px 20px; overflow-x: auto;
  background: var(--formula-bg); border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono); font-size: 14.5px; line-height: 1.9; color: var(--text);
}

/* 学习状态面板 */
.kp-status-panel {
  max-width: 820px; margin: 30px 0 8px; padding: 16px 20px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow-1);
}
.status-buttons { display: inline-flex; gap: 0; border: 1px solid var(--border-strong); border-radius: 11px; overflow: hidden; }
.st-btn {
  padding: 8px 20px; font-size: 14px; font-weight: 600; font-family: inherit;
  background: var(--surface); color: var(--muted); border: none; cursor: pointer;
  transition: background var(--speed) var(--ease), color var(--speed) var(--ease);
}
.st-btn + .st-btn { border-left: 1px solid var(--border); }
.st-btn:hover { background: var(--surface-2); color: var(--text); }
.st-btn.active[data-st="todo"] { background: var(--surface-2); color: var(--text); }
.st-btn.active[data-st="learning"] { background: color-mix(in srgb, var(--st-learning) 18%, var(--surface)); color: var(--st-learning); }
.st-btn.active[data-st="done"] { background: color-mix(in srgb, var(--st-done) 18%, var(--surface)); color: var(--st-done); }
.status-hint { margin: 10px 0 0; font-size: 12.5px; color: var(--muted); }

/* 上一节 / 下一节 */
.kp-pager { display: flex; gap: 12px; max-width: 820px; margin-top: 26px; }
.pager {
  flex: 1; display: flex; flex-direction: column; gap: 3px;
  padding: 14px 16px; border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface); color: var(--text);
}
.pager:hover { text-decoration: none; border-color: var(--primary); box-shadow: var(--shadow-1); }
.pager.next { text-align: right; align-items: flex-end; }
.pager-label { font-size: 12px; color: var(--muted); }
.pager-title { font-size: 14px; font-weight: 600; }
.pager.disabled { opacity: 0.45; pointer-events: none; }

/* ---------------- 页脚 ---------------- */
.site-footer { border-top: 1px solid var(--border); margin-top: 40px; padding: 26px 0 34px; color: var(--muted); font-size: 13px; }
.footer-inner p { margin: 4px 0; }

/* ---------------- 响应式 ---------------- */
@media (max-width: 960px) {
  .module-grid { grid-template-columns: 1fr; }
  #search-input { width: 160px; }
}
@media (max-width: 760px) {
  .site-nav { display: none; }
  .hero { padding: 44px 0 32px; }
  .hero-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .kp-pager { flex-direction: column; }
  .pager.next { text-align: left; align-items: flex-start; }
  .search-results { width: min(92vw, 380px); right: -40px; }
}
@media (max-width: 520px) {
  .header-inner { gap: 10px; }
  .brand-sub { display: none; }
  #search-input { width: 120px; }
  .hero-title-sub { letter-spacing: 0.18em; }
  .stage-item { flex-wrap: wrap; }
}

/* ---------------- 动效降级 ---------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}