/* ============================================================================
   LarkReader Landing · style.css
   Generator: 2026-09-06 · WorkBuddy
   主题：飞书蓝 + 深色模式 + 渐变 Hero + 毛玻璃导航
   ============================================================================ */

/* ---- 0. Reset / Base ---- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC',
               'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }
code { font-family: 'JetBrains Mono', Consolas, 'Courier New', monospace; }
ul { list-style: none; padding: 0; margin: 0; }
pre { margin: 0; }

/* ---- 1. 设计 token（CSS 变量）---- */
:root {
  /* 主色 · 飞书蓝 */
  --c-primary: #3370ff;
  --c-primary-hover: #2860e6;
  --c-primary-soft: rgba(51, 112, 255, 0.08);
  --c-primary-glow: rgba(51, 112, 255, 0.25);

  /* 节点类型 6 色编码 */
  --c-doc: #3370ff;
  --c-sheet: #639922;
  --c-bitable: #7f77dd;
  --c-file: #ba7517;
  --c-folder: #888780;
  --c-other: #b4b2a9;

  /* 语义色 */
  --c-success: #639922;
  --c-warning: #ba7517;
  --c-danger: #e24b4a;
  --c-info: #378add;

  /* 圆角 */
  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 16px;
  --r-xl: 24px;

  /* 间距 */
  --s-1: 4px;
  --s-2: 8px;
  --s-3: 12px;
  --s-4: 16px;
  --s-5: 24px;
  --s-6: 32px;
  --s-7: 48px;
  --s-8: 64px;
  --s-9: 96px;

  /* 阴影 */
  --sh-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --sh-md: 0 4px 16px rgba(0, 0, 0, 0.06);
  --sh-lg: 0 12px 32px rgba(0, 0, 0, 0.08);
  --sh-glow: 0 0 40px rgba(51, 112, 255, 0.18);
}

/* ---- 2. 主题：light + dark ---- */
:root,
[data-theme="light"] {
  --bg: #f7f8fc;
  --bg-alt: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #fbfcff;
  --fg: #1a1f36;
  --fg-muted: #5f6789;
  --fg-dim: #8a91b0;
  --border: rgba(31, 37, 64, 0.08);
  --border-strong: rgba(31, 37, 64, 0.16);
  --code-bg: #f3f5fb;
  --code-fg: #2d3450;
  --hero-bg-start: #eaf1ff;
  --hero-bg-end: #ffffff;
  --hero-glow-1: rgba(51, 112, 255, 0.18);
  --hero-glow-2: rgba(127, 119, 221, 0.16);
  --hero-grid-line: rgba(31, 37, 64, 0.04);
}

[data-theme="dark"] {
  --bg: #0d0f1c;
  --bg-alt: #141628;
  --bg-card: #1a1d33;
  --bg-card-hover: #21253f;
  --fg: #e7eaf6;
  --fg-muted: #a0a8c8;
  --fg-dim: #6b7393;
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --code-bg: #0f1224;
  --code-fg: #c5cae9;
  --hero-bg-start: #0d0f1c;
  --hero-bg-end: #141628;
  --hero-glow-1: rgba(51, 112, 255, 0.28);
  --hero-glow-2: rgba(127, 119, 221, 0.22);
  --hero-grid-line: rgba(255, 255, 255, 0.04);
}

/* 跟随系统偏好 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d0f1c;
    --bg-alt: #141628;
    --bg-card: #1a1d33;
    --bg-card-hover: #21253f;
    --fg: #e7eaf6;
    --fg-muted: #a0a8c8;
    --fg-dim: #6b7393;
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.16);
    --code-bg: #0f1224;
    --code-fg: #c5cae9;
    --hero-bg-start: #0d0f1c;
    --hero-bg-end: #141628;
    --hero-glow-1: rgba(51, 112, 255, 0.28);
    --hero-glow-2: rgba(127, 119, 221, 0.22);
    --hero-grid-line: rgba(255, 255, 255, 0.04);
  }
}

/* ---- 3. 布局容器 ---- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 96px 0;
  position: relative;
}
.section-alt { background: var(--bg-alt); }

.section-head {
  text-align: center;
  margin-bottom: 56px;
}
.eyebrow {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--c-primary);
  padding: 4px 12px;
  background: var(--c-primary-soft);
  border-radius: 100px;
  margin-bottom: 16px;
}
.section-head h2 {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
  line-height: 1.2;
}
.section-head p {
  font-size: 16px;
  color: var(--fg-muted);
  margin: 0 auto;
  max-width: 640px;
}

/* ---- 4. 顶部导航 ---- */
.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: color-mix(in oklab, var(--bg) 70%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.topbar-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  gap: 32px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 16px;
  letter-spacing: -0.01em;
}
.brand-mark { width: 28px; height: 28px; border-radius: 6px; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  margin-left: auto;
  font-size: 14px;
  font-weight: 500;
}
.nav-links a {
  color: var(--fg-muted);
  transition: color 0.18s;
  position: relative;
}
.nav-links a:hover { color: var(--fg); }
.nav-links a.nav-github {
  color: var(--c-primary);
  font-weight: 600;
}
.nav-actions { display: flex; gap: 8px; }
.theme-toggle {
  width: 36px; height: 36px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--fg);
  cursor: pointer;
  display: grid;
  place-items: center;
  font-size: 18px;
  transition: background 0.18s, border-color 0.18s;
}
.theme-toggle:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-strong);
}
.scroll-progress {
  position: absolute;
  left: 0; bottom: 0;
  height: 2px;
  width: 0;
  background: linear-gradient(90deg, var(--c-primary), var(--c-bitable));
  transition: width 0.12s linear;
}

/* ---- 5. Hero ---- */
.hero {
  position: relative;
  padding: 140px 0 80px;
  overflow: hidden;
  isolation: isolate;
}
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(1200px 600px at 20% 0%, var(--hero-bg-start) 0%, transparent 60%),
    radial-gradient(900px 500px at 80% 30%, var(--hero-bg-end) 0%, transparent 60%),
    var(--bg);
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--hero-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--hero-grid-line) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse at 50% 30%, #000 30%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse at 50% 30%, #000 30%, transparent 80%);
}
.hero-glow {
  position: absolute;
  width: 520px; height: 520px;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.7;
}
.hero-glow-1 {
  top: -160px; left: -120px;
  background: var(--hero-glow-1);
}
.hero-glow-2 {
  bottom: -200px; right: -100px;
  background: var(--hero-glow-2);
}

.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  text-align: center;
}
.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 100px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  font-size: 12px;
  font-weight: 500;
  color: var(--fg-muted);
  margin-bottom: 24px;
}
.hero-tag .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--c-success);
  box-shadow: 0 0 0 4px rgba(99, 153, 34, 0.2);
}
.hero-title {
  font-size: clamp(40px, 7vw, 72px);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.05;
  margin: 0 0 20px;
}
.hero-title .hl {
  background: linear-gradient(135deg, var(--c-primary), var(--c-bitable));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub {
  font-size: clamp(15px, 1.8vw, 18px);
  color: var(--fg-muted);
  max-width: 720px;
  margin: 0 auto 36px;
  line-height: 1.6;
}
.hero-sub strong { color: var(--fg); font-weight: 600; }

.hero-cta {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.18s, background 0.18s, border-color 0.18s, box-shadow 0.18s;
  white-space: nowrap;
}
.btn-primary {
  background: var(--c-primary);
  color: #fff;
  box-shadow: 0 6px 20px var(--c-primary-glow);
}
.btn-primary:hover {
  background: var(--c-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 10px 28px var(--c-primary-glow);
}
.btn-ghost {
  background: var(--bg-card);
  color: var(--fg);
  border-color: var(--border-strong);
}
.btn-ghost:hover {
  background: var(--bg-card-hover);
  transform: translateY(-1px);
}
.btn-arrow { font-size: 16px; transition: transform 0.18s; }
.btn:hover .btn-arrow { transform: translateX(3px); }
.btn-block { width: 100%; justify-content: center; }

.hero-chips {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin: 0 auto 48px;
  max-width: 800px;
}
.hero-chips li {
  padding: 6px 14px;
  border-radius: 100px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  font-size: 13px;
  color: var(--fg-muted);
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.chip-ico {
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
  padding: 24px;
  border-radius: 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  box-shadow: var(--sh-md);
}
.stat { text-align: center; position: relative; }
.stat-num {
  font-size: clamp(28px, 4vw, 36px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--fg);
  font-variant-numeric: tabular-nums;
}
.stat-suffix {
  position: absolute;
  top: 0;
  margin-left: 2px;
  font-size: 24px;
  font-weight: 700;
  color: var(--c-primary);
}
.stat-label {
  font-size: 12px;
  color: var(--fg-muted);
  margin-top: 4px;
}

/* ---- 6. 痛点 / 场景 ---- */
.scene-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}
.scene-card {
  padding: 28px;
  border-radius: var(--r-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.scene-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
  box-shadow: var(--sh-lg);
}
.scene-ico {
  width: 48px; height: 48px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-size: 24px;
  margin-bottom: 16px;
}
.scene-ico-1 { background: rgba(51, 112, 255, 0.12); color: #3370ff; }
.scene-ico-2 { background: rgba(99, 153, 34, 0.12); color: #639922; }
.scene-ico-3 { background: rgba(127, 119, 221, 0.12); color: #7f77dd; }
.scene-ico-4 { background: rgba(186, 117, 23, 0.12); color: #ba7517; }
.scene-ico svg {
  width: 24px;
  height: 24px;
}
.scene-card h3 {
  font-size: 17px;
  font-weight: 700;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}
.scene-card p {
  font-size: 14px;
  color: var(--fg-muted);
  margin: 0;
  line-height: 1.6;
}

/* ---- 6.5 使用场景（两段分述）---- */
.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.use-case {
  position: relative;
  padding: 32px 28px;
  border-radius: var(--r-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.use-case:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
  box-shadow: var(--sh-lg);
}
.use-case-tag {
  display: inline-grid;
  place-items: center;
  width: 44px; height: 44px;
  border-radius: 12px;
  background: rgba(51, 112, 255, 0.12);
  color: var(--c-primary);
  font-family: 'Inter', sans-serif;
  font-size: 22px;
  font-weight: 800;
  margin-bottom: 18px;
  line-height: 1;
}
.use-case-tag-2 {
  background: rgba(99, 153, 34, 0.12);
  color: var(--c-success);
}
.use-case h3 {
  font-size: 19px;
  font-weight: 700;
  margin: 0 0 12px;
  letter-spacing: -0.01em;
}
.use-case > p {
  font-size: 14px;
  color: var(--fg-muted);
  margin: 0 0 14px;
  line-height: 1.65;
}
.pain-list,
.case-types {
  list-style: none;
  padding: 0;
  margin: 0 0 18px;
  font-size: 13px;
  color: var(--fg-muted);
  line-height: 1.7;
}
.pain-list li,
.case-types li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 6px;
}
.pain-list li::before {
  content: "▸";
  position: absolute;
  left: 0; top: 0;
  color: var(--c-primary);
  font-size: 13px;
  line-height: 1.7;
}
.case-types li::before {
  content: "✦";
  position: absolute;
  left: 0; top: 0;
  color: var(--c-success);
  font-size: 12px;
  line-height: 1.8;
}
.case-types strong {
  color: var(--fg);
  font-weight: 600;
}
.pain-list strong {
  color: var(--fg);
  font-weight: 600;
}
.use-case-shot {
  margin: 0 0 16px;
  border-radius: var(--r-md);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg);
}
.use-case-shot img {
  display: block;
  width: 100%;
  height: auto;
}
.use-case-shot figcaption {
  font-size: 12px;
  color: var(--fg-muted);
  padding: 10px 14px;
  border-top: 1px solid var(--border);
  background: var(--bg-alt);
  line-height: 1.55;
}
.case-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin: 0 0 18px;
  padding: 18px 10px;
  background: var(--bg-alt);
  border-radius: var(--r-md);
  border: 1px solid var(--border);
}
.case-stat {
  text-align: center;
}
.case-stat-num {
  font-size: 30px;
  font-weight: 800;
  color: var(--c-primary);
  font-family: 'JetBrains Mono', monospace;
  line-height: 1;
  letter-spacing: -0.02em;
}
.case-stat-zero {
  color: var(--fg-muted) !important;
  opacity: 0.55;
}
.case-stat-label {
  font-size: 11px;
  color: var(--fg-muted);
  margin-top: 6px;
  letter-spacing: 0.02em;
  line-height: 1.3;
}
.use-case-foot {
  margin-top: auto;
  padding-top: 14px;
  border-top: 1px dashed var(--border);
  font-size: 13px !important;
  color: var(--fg) !important;
  line-height: 1.6;
}
.case-mode-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  align-items: center;
  padding: 12px 14px;
  margin-top: 14px;
  border-radius: var(--r-md);
  background: var(--bg-alt);
  font-size: 12.5px;
  line-height: 1.5;
}
.case-mode-row-label {
  font-size: 11px;
  color: var(--fg-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-right: 4px;
}
.case-mode-row-a {
  color: var(--fg-muted);
  text-decoration: line-through;
  text-decoration-thickness: 1px;
}
.case-mode-row-c strong { color: var(--c-success); }
.case-mode-row-link {
  margin-left: auto;
  color: var(--c-primary);
  font-size: 12px;
  font-weight: 600;
}
@media (max-width: 880px) {
  .use-cases-grid { grid-template-columns: 1fr; }
  .case-stats { grid-template-columns: repeat(2, 1fr); gap: 12px; }
}
@media (max-width: 520px) {
  .use-case { padding: 24px 20px; }
  .case-stats { padding: 14px 8px; }
  .case-stat-num { font-size: 26px; }
}

/* 真实导出目录树（use-case ②） */
.file-tree {
  margin: 0 0 12px;
  border: 1px solid var(--border-strong);
  border-radius: 10px;
  background: var(--code-bg);
  overflow: hidden;
}
.file-tree-head {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-alt);
}
.file-tree-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
}
.file-tree-dot:nth-child(1) { background: #ff5f57; }
.file-tree-dot:nth-child(2) { background: #febc2e; }
.file-tree-dot:nth-child(3) { background: #28c840; }
.file-tree-path {
  margin-left: 8px;
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 12px;
  color: var(--fg-muted);
}
.file-tree-body {
  margin: 0;
  padding: 14px 16px;
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 12px;
  line-height: 1.8;
  color: var(--code-fg);
  overflow-x: auto;
}
.file-tree-body .ft-dir {
  color: var(--c-doc);
  font-weight: 600;
}
.file-tree-body .ft-img { color: var(--c-folder); }
.file-tree-body .ft-sheet { color: var(--c-sheet); }
.file-tree-body .ft-bitable { color: var(--c-bitable); }
.file-tree-body .ft-attach { color: var(--c-file); }
.file-tree-body .ft-note { color: var(--fg-dim); }
.file-tree-caption {
  font-size: 12.5px;
  color: var(--fg-muted);
  margin: 0 0 16px;
  line-height: 1.6;
}
.file-tree-caption a { color: var(--c-info); }

/* ---- 7. 核心特性 ---- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 20px;
}
.feature {
  grid-column: span 2;
  padding: 28px;
  border-radius: var(--r-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
}
.feature:hover {
  transform: translateY(-3px);
  box-shadow: var(--sh-lg);
}
.feature-wide {
  grid-column: span 6;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: center;
}
.feature-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--c-primary);
  padding: 3px 10px;
  border-radius: 100px;
  background: var(--c-primary-soft);
  margin-bottom: 12px;
}
.feature h3 {
  font-size: 20px;
  font-weight: 700;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}
.feature p {
  font-size: 14px;
  color: var(--fg-muted);
  margin: 0 0 12px;
  line-height: 1.65;
}
.feature-list {
  font-size: 13px;
  color: var(--fg-muted);
}
.feature-list li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 6px;
}
.feature-list li::before {
  content: "✓";
  position: absolute;
  left: 0; top: 0;
  color: var(--c-success);
  font-weight: 700;
}
.feature-art {
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 8px;
}
.feature-art-small { aspect-ratio: 16 / 10; }
.feature-wide .feature-art { aspect-ratio: 4 / 3; }
.feature-art svg { width: 100%; height: 100%; display: block; }

/* ---- 8. 3 步上手 ---- */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}
.step {
  padding: 28px;
  border-radius: var(--r-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
}
.step:hover { transform: translateY(-3px); box-shadow: var(--sh-lg); }
.step-num {
  width: 36px; height: 36px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 16px;
  font-weight: 800;
  color: #fff;
  background: linear-gradient(135deg, var(--c-primary), var(--c-bitable));
  margin-bottom: 16px;
}
.step h3 { font-size: 18px; font-weight: 700; margin: 0 0 8px; }
.step p { font-size: 14px; color: var(--fg-muted); margin: 0 0 16px; line-height: 1.65; }
.step-art {
  border-radius: var(--r-md);
  overflow: hidden;
  border: 1px solid var(--border);
}
.step-art svg { width: 100%; height: auto; }

/* ---- 9. 架构简图 ---- */
.arch-wrap {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 32px;
  text-align: center;
}
.arch-img {
  width: 100%;
  max-width: 880px;
  margin: 0 auto 16px;
  border-radius: var(--r-md);
}
.arch-cap {
  font-size: 14px;
  color: var(--fg-muted);
  max-width: 720px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ---- 10. 下载安装 ---- */
.dl-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.dl-card {
  padding: 28px;
  border-radius: var(--r-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.dl-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin: 0;
}
.dl-sub {
  font-size: 14px;
  color: var(--fg-muted);
  margin: 0;
}
.req-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.req-list li {
  font-size: 14px;
  color: var(--fg-muted);
  padding: 8px 12px;
  background: var(--bg);
  border-radius: var(--r-sm);
  border: 1px solid var(--border);
}
.req-list strong {
  display: inline-block;
  min-width: 64px;
  color: var(--fg);
  font-weight: 600;
}
.req-list code {
  background: var(--code-bg);
  color: var(--code-fg);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 13px;
}
.cmd {
  background: var(--code-bg);
  color: var(--code-fg);
  padding: 16px;
  border-radius: var(--r-md);
  font-size: 12.5px;
  line-height: 1.7;
  overflow-x: auto;
  border: 1px solid var(--border);
}
.cmd code { color: var(--code-fg); }
.dl-version {
  font-size: 13px;
  color: var(--fg-dim);
  margin: 0;
}
.dl-version strong { color: var(--c-primary); font-weight: 700; }

/* ---- 11. FAQ ---- */
.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.faq-item {
  border-radius: var(--r-md);
  background: var(--bg-card);
  border: 1px solid var(--border);
  overflow: hidden;
  transition: border-color 0.2s;
}
.faq-item:hover { border-color: var(--border-strong); }
.faq-item summary {
  padding: 18px 24px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  position: relative;
  padding-right: 56px;
  transition: background 0.18s;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 22px;
  color: var(--fg-muted);
  transition: transform 0.2s;
  font-weight: 300;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item summary:hover { background: var(--bg-card-hover); }
.faq-item p {
  padding: 0 24px 20px;
  margin: 0;
  font-size: 14px;
  color: var(--fg-muted);
  line-height: 1.7;
}
.faq-item p strong { color: var(--fg); font-weight: 600; }
.faq-item p code {
  background: var(--code-bg);
  color: var(--code-fg);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 13px;
}

/* ---- 12. Footer ---- */
.footer {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  padding-top: 56px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1.4fr 2fr;
  gap: 48px;
  padding-bottom: 48px;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 14px;
}
.footer-mark { width: 40px; height: 40px; border-radius: 10px; }
.footer-name { font-size: 18px; font-weight: 700; letter-spacing: -0.01em; }
.footer-tag { font-size: 13px; color: var(--fg-muted); margin-top: 2px; }
.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.footer-col { display: flex; flex-direction: column; gap: 8px; }
.footer-col-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--fg);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 8px;
}
.footer-col a {
  font-size: 14px;
  color: var(--fg-muted);
  transition: color 0.18s;
}
.footer-col a:hover { color: var(--c-primary); }
.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 20px 0;
  font-size: 12px;
  color: var(--fg-dim);
}

/* ---- 13. 返回顶部 ---- */
.back-top {
  position: fixed;
  right: 24px; bottom: 24px;
  width: 44px; height: 44px;
  border-radius: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  color: var(--fg);
  cursor: pointer;
  font-size: 20px;
  box-shadow: var(--sh-md);
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px);
  transition: opacity 0.25s, transform 0.25s;
  z-index: 90;
}
.back-top.show {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.back-top:hover {
  background: var(--c-primary);
  color: #fff;
  border-color: var(--c-primary);
}

/* ---- 14. 响应式 ---- */
@media (max-width: 960px) {
  .hero-stats { grid-template-columns: repeat(2, 1fr); gap: 20px; }
  .feature-wide { grid-template-columns: 1fr; }
  .feature-wide .feature-art { order: -1; }
  .footer-inner { grid-template-columns: 1fr; gap: 32px; }
}
@media (max-width: 720px) {
  .section { padding: 64px 0; }
  .hero { padding: 110px 0 60px; }
  .nav-links { display: none; }
  .topbar-inner { gap: 16px; }
  .feature-grid { grid-template-columns: 1fr; }
  .feature, .feature-wide { grid-column: span 1; }
  .footer-cols { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .hero-stats { grid-template-columns: 1fr 1fr; padding: 20px 16px; }
  .footer-cols { grid-template-columns: 1fr; }
}

/* ---- 15. 入场动画（IntersectionObserver）---- */
.reveal-init {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}
.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* ---- 16. 减弱动画（无障碍）---- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}