/* 轻取视频助手 · 官网样式（深色科技风，与桌面客户端配色一致） */

:root {
  --bg: #0b0d11;
  --bg-soft: #0f1115;
  --panel: #171a21;
  --panel-2: #1d2129;
  --border: #272c36;
  --border-soft: #1f232c;
  --text: #e6e9ef;
  --muted: #8b93a7;
  --dim: #7c859a;
  --primary: #2f6bff;
  --primary-hover: #4a7dff;
  --cyan: #22d3ee;
  --success: #22c55e;
  --warning: #f59e0b;
  --radius: 14px;
  --radius-sm: 10px;
  --maxw: 1180px;
  --nav-h: 66px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.75 "Microsoft YaHei UI", "Microsoft YaHei", -apple-system, "Segoe UI", "PingFang SC", sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: var(--cyan); text-decoration: none; }
a:hover { color: #7ee8f7; }

h1, h2, h3, h4 { margin: 0; line-height: 1.3; font-weight: 700; letter-spacing: -.01em; }
p { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }
img { max-width: 100%; display: block; }

.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* 通用：页面顶部光晕背景（绝对定位，只覆盖页面顶部一段） */
.page-glow {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1040px;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(760px 460px at 12% 40px, rgba(47, 107, 255, .22), transparent 62%),
    radial-gradient(660px 400px at 88% 20px, rgba(34, 211, 238, .13), transparent 60%);
}
.page-grid {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1040px;
  z-index: 0;
  pointer-events: none;
  opacity: .5;
  background-image:
    linear-gradient(rgba(255, 255, 255, .022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, .022) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(circle at 50% 0%, #000 0%, transparent 78%);
  -webkit-mask-image: radial-gradient(circle at 50% 0%, #000 0%, transparent 78%);
}
main, .site-nav, .site-footer { position: relative; z-index: 1; }

/* ===================== 导航 ===================== */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--nav-h);
  border-bottom: 1px solid transparent;
  background: rgba(11, 13, 17, .72);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  transition: border-color .2s, background .2s;
}
.site-nav.scrolled { border-bottom-color: var(--border-soft); background: rgba(11, 13, 17, .9); }

.nav-inner { display: flex; align-items: center; gap: 32px; height: var(--nav-h); }

.brand { display: flex; align-items: center; gap: 11px; flex: none; }
.brand img { width: 34px; height: 34px; border-radius: 9px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-name { font-size: 16px; font-weight: 700; color: var(--text); letter-spacing: .2px; }
.brand-sub { font-size: 11px; color: var(--dim); letter-spacing: .6px; }

.nav-links { display: flex; align-items: center; gap: 4px; margin-left: 8px; }
.nav-links a {
  display: block;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  color: var(--muted);
  font-size: 14px;
  transition: color .15s, background .15s;
}
.nav-links a:hover { color: var(--text); background: rgba(255, 255, 255, .045); }
.nav-links a.active { color: var(--text); background: rgba(47, 107, 255, .14); }

.nav-cta { margin-left: auto; display: flex; align-items: center; gap: 10px; }

.nav-toggle {
  display: none;
  margin-left: auto;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
}
.nav-toggle span { display: block; width: 17px; height: 2px; background: currentColor; border-radius: 2px; position: relative; }
.nav-toggle span::before, .nav-toggle span::after {
  content: ""; position: absolute; left: 0; width: 17px; height: 2px; background: currentColor; border-radius: 2px;
}
.nav-toggle span::before { top: -6px; }
.nav-toggle span::after { top: 6px; }

.nav-mobile { display: none; border-bottom: 1px solid var(--border-soft); background: var(--bg-soft); }
.nav-mobile.open { display: block; }
.nav-mobile .wrap { padding-top: 10px; padding-bottom: 14px; }
.nav-mobile a {
  display: block;
  padding: 12px 4px;
  color: var(--muted);
  border-bottom: 1px solid var(--border-soft);
  font-size: 15px;
}
.nav-mobile a:last-of-type { border-bottom: 0; }
.nav-mobile .btn { margin-top: 12px; }

/* ===================== 按钮 ===================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  white-space: nowrap;
  transition: background .16s, border-color .16s, transform .16s, box-shadow .16s;
}
.btn:hover { background: #252a34; color: var(--text); transform: translateY(-1px); }
.btn-primary {
  background: linear-gradient(135deg, var(--primary), #1e4fd8);
  border-color: transparent;
  color: #fff;
  box-shadow: 0 8px 24px -10px rgba(47, 107, 255, .9);
}
.btn-primary:hover { background: linear-gradient(135deg, var(--primary-hover), #2a5ce8); color: #fff; }
.btn-ghost { background: transparent; }
.btn-ghost:hover { background: rgba(255, 255, 255, .05); }
.btn-lg { padding: 14px 30px; font-size: 15px; }
.btn-block { width: 100%; }
.btn-sm { padding: 8px 16px; font-size: 13px; }

/* ===================== 区块骨架 ===================== */
.section { padding: 92px 0; }
.section-tight { padding: 64px 0; }
.section-head { max-width: 760px; margin-bottom: 46px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }

.eyebrow {
  display: inline-block;
  margin-bottom: 16px;
  padding: 5px 13px;
  border: 1px solid rgba(47, 107, 255, .35);
  border-radius: 999px;
  background: rgba(47, 107, 255, .1);
  color: #9dbaff;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .5px;
}
.section-title { font-size: 32px; margin-bottom: 14px; }
.section-title .hl {
  background: linear-gradient(100deg, #4a7dff 0%, #22d3ee 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.section-desc { color: var(--muted); font-size: 15px; }

/* ===================== Hero ===================== */
.hero { padding: 84px 0 76px; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.06fr) minmax(0, .94fr); gap: 56px; align-items: center; }
.hero h1 { font-size: 46px; line-height: 1.18; margin-bottom: 20px; letter-spacing: -.02em; }
.hero h1 .hl {
  background: linear-gradient(100deg, #5b8bff 0%, #22d3ee 60%, #5b8bff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-lead { color: var(--muted); font-size: 16px; max-width: 560px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin: 30px 0 22px; }
.hero-note { display: flex; align-items: center; gap: 9px; color: var(--dim); font-size: 13px; }
.hero-note .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--success); box-shadow: 0 0 0 4px rgba(34, 197, 94, .14); flex: none; }

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin-top: 38px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--border-soft);
}
.hero-stat { background: rgba(23, 26, 33, .75); padding: 18px 20px; }
.hero-stat b { display: block; font-size: 20px; color: var(--text); }
.hero-stat span { font-size: 12px; color: var(--dim); }

.hero-visual { position: relative; }
.hero-visual .shot {
  position: relative;
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  background: var(--panel);
  box-shadow: 0 30px 70px -30px rgba(0, 0, 0, .95), 0 0 0 1px rgba(255, 255, 255, .02);
}
.hero-visual .shot img { width: 100%; }
.hero-visual::after {
  content: "";
  position: absolute;
  inset: -18% 0 auto 30%;
  height: 260px;
  background: radial-gradient(closest-side, rgba(47, 107, 255, .35), transparent);
  filter: blur(28px);
  z-index: -1;
}

/* 概念面板（Hero 右侧、无截图时使用） */
.mock {
  border: 1px solid var(--border);
  border-radius: 16px;
  background: linear-gradient(180deg, #14171e, #10131a);
  box-shadow: 0 30px 70px -34px rgba(0, 0, 0, .95);
  overflow: hidden;
}
.mock-bar {
  display: flex; align-items: center; gap: 7px;
  padding: 12px 15px;
  border-bottom: 1px solid var(--border-soft);
  background: rgba(255, 255, 255, .015);
}
.mock-bar i { width: 9px; height: 9px; border-radius: 50%; background: #333a47; display: block; }
.mock-bar span { margin-left: 8px; font-size: 12px; color: var(--dim); }
.mock-body { padding: 16px; }
.mock-row {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 13px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, .018);
}
.mock-row + .mock-row { margin-top: 9px; }
.mock-ico {
  width: 30px; height: 30px; flex: none;
  display: flex; align-items: center; justify-content: center;
  border-radius: 9px;
  background: rgba(47, 107, 255, .14);
  color: #8fb0ff;
  font-size: 14px;
}
.mock-ico.ok { background: rgba(34, 197, 94, .14); color: #6ee7a0; }
.mock-main { flex: 1; min-width: 0; }
.mock-title { font-size: 13px; color: var(--text); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.mock-sub { font-size: 11px; color: var(--dim); }
.mock-bar-line { height: 4px; margin-top: 7px; border-radius: 999px; background: #232833; overflow: hidden; }
.mock-bar-line i { display: block; height: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--primary), var(--cyan)); }
.mock-tag { font-size: 11px; color: var(--dim); flex: none; }

/* ===================== 卡片网格 ===================== */
.grid { display: grid; gap: 18px; }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.card {
  position: relative;
  padding: 26px 24px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(23, 26, 33, .92), rgba(18, 21, 27, .92));
  transition: border-color .18s, transform .18s, box-shadow .18s;
}
.card:hover {
  border-color: rgba(47, 107, 255, .45);
  transform: translateY(-3px);
  box-shadow: 0 22px 46px -28px rgba(47, 107, 255, .75);
}
.card-icon {
  width: 42px; height: 42px;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 16px;
  border: 1px solid rgba(47, 107, 255, .3);
  border-radius: 12px;
  background: rgba(47, 107, 255, .12);
  color: #8fb0ff;
  font-size: 19px;
  font-weight: 700;
}
.card h3 { font-size: 16px; margin-bottom: 9px; }
.card p { color: var(--muted); font-size: 14px; }
.card-tags { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 15px; }
.tag {
  padding: 3px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: rgba(255, 255, 255, .02);
  color: var(--dim);
  font-size: 12px;
}

/* ===================== 使用流程 ===================== */
.steps { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; counter-reset: step; }
.step {
  position: relative;
  padding: 24px 22px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: rgba(19, 22, 28, .8);
}
.step::before {
  counter-increment: step;
  content: "0" counter(step);
  display: block;
  margin-bottom: 14px;
  font-size: 26px;
  font-weight: 800;
  letter-spacing: -.02em;
  background: linear-gradient(120deg, #4a7dff, #22d3ee);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.step h3 { font-size: 15px; margin-bottom: 8px; }
.step p { font-size: 13px; color: var(--muted); }

/* ===================== 分栏说明 ===================== */
.split { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 48px; align-items: start; }

.check-list li {
  position: relative;
  padding: 9px 0 9px 30px;
  color: var(--muted);
  font-size: 14px;
  border-bottom: 1px dashed var(--border-soft);
}
.check-list li:last-child { border-bottom: 0; }
.check-list li::before {
  content: "✓";
  position: absolute;
  left: 0; top: 9px;
  width: 19px; height: 19px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  background: rgba(34, 197, 94, .14);
  color: #6ee7a0;
  font-size: 12px;
  font-weight: 700;
}
.check-list li b { color: var(--text); font-weight: 600; }

/* 带序号的步骤列表 */
.num-list { counter-reset: num; list-style: none; padding: 0; margin: 0; }
.num-list li {
  position: relative;
  padding: 10px 0 10px 36px;
  color: var(--muted);
  font-size: 14px;
  border-bottom: 1px dashed var(--border-soft);
  counter-increment: num;
}
.num-list li:last-child { border-bottom: 0; }
.num-list li::before {
  content: counter(num);
  position: absolute;
  left: 0; top: 10px;
  width: 22px; height: 22px;
  display: flex; align-items: center; justify-content: center;
  border: 1px solid rgba(47, 107, 255, .32);
  border-radius: 7px;
  background: rgba(47, 107, 255, .12);
  color: #8fb0ff;
  font-size: 11px;
  font-weight: 700;
}
.num-list li b { color: var(--text); font-weight: 600; }

.notice-box {
  padding: 20px 22px;
  border: 1px solid rgba(245, 158, 11, .28);
  border-radius: var(--radius);
  background: rgba(245, 158, 11, .06);
}
.notice-box h4 { font-size: 14px; color: #f7c66b; margin-bottom: 8px; }
.notice-box p { font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.notice-box p:last-child { margin-bottom: 0; }

/* ===================== 表格 ===================== */
.table-wrap { border: 1px solid var(--border-soft); border-radius: var(--radius); overflow: hidden; overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 560px; }
th, td { padding: 14px 18px; text-align: left; border-bottom: 1px solid var(--border-soft); }
th { background: rgba(255, 255, 255, .025); color: var(--dim); font-size: 12px; font-weight: 600; letter-spacing: .4px; }
tbody tr:last-child td { border-bottom: 0; }
td { color: var(--muted); }
td b { color: var(--text); font-weight: 600; }

/* ===================== FAQ ===================== */
.faq { border-top: 1px solid var(--border-soft); }
.faq details {
  border-bottom: 1px solid var(--border-soft);
  transition: background .15s;
}
.faq details[open] { background: rgba(255, 255, 255, .015); }
.faq summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 19px 4px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  margin-left: auto;
  flex: none;
  width: 24px; height: 24px;
  display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--border);
  border-radius: 7px;
  color: var(--muted);
  font-size: 15px;
  font-weight: 400;
  transition: transform .2s, color .2s, border-color .2s;
}
.faq details[open] summary::after { content: "−"; color: var(--cyan); border-color: rgba(34, 211, 238, .4); }
.faq .answer { padding: 0 4px 22px; color: var(--muted); font-size: 14px; max-width: 900px; }
.faq .answer p + p { margin-top: 10px; }

/* ===================== CTA 区块 ===================== */
.cta {
  position: relative;
  padding: 54px 48px;
  border: 1px solid rgba(47, 107, 255, .3);
  border-radius: 20px;
  background:
    radial-gradient(600px 260px at 18% 0%, rgba(47, 107, 255, .22), transparent 65%),
    radial-gradient(520px 240px at 88% 100%, rgba(34, 211, 238, .14), transparent 62%),
    linear-gradient(180deg, #161a22, #11141a);
  text-align: center;
  overflow: hidden;
}
.cta h2 { font-size: 28px; margin-bottom: 12px; }
.cta p { color: var(--muted); max-width: 620px; margin: 0 auto 26px; }
.cta-actions { display: flex; flex-wrap: wrap; gap: 14px; justify-content: center; }

/* ===================== 页面头部（内页） ===================== */
.page-head { padding: 66px 0 54px; border-bottom: 1px solid var(--border-soft); }
.page-head h1 { font-size: 36px; margin-bottom: 14px; }
.page-head p { color: var(--muted); max-width: 720px; font-size: 15px; }
.breadcrumb { display: flex; align-items: center; gap: 8px; margin-bottom: 18px; color: var(--dim); font-size: 13px; }
.breadcrumb a { color: var(--dim); }
.breadcrumb a:hover { color: var(--cyan); }

/* ===================== 下载页 ===================== */
.dl-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: 18px;
  overflow: hidden;
  background: linear-gradient(180deg, #161922, #10131a);
  box-shadow: 0 30px 70px -40px rgba(0, 0, 0, .9);
}
.dl-main { padding: 36px 34px; }
.dl-main h2 { font-size: 24px; margin-bottom: 10px; }
.dl-main .desc { color: var(--muted); font-size: 14px; margin-bottom: 24px; }
.dl-actions { display: flex; flex-wrap: wrap; gap: 13px; align-items: center; }
.dl-side {
  padding: 30px 28px;
  border-left: 1px solid var(--border-soft);
  background: rgba(255, 255, 255, .018);
}
.dl-side h3 { font-size: 13px; color: var(--dim); letter-spacing: .4px; margin-bottom: 16px; text-transform: uppercase; }
.spec-row { display: flex; justify-content: space-between; gap: 12px; padding: 9px 0; border-bottom: 1px dashed var(--border-soft); font-size: 13px; }
.spec-row:last-child { border-bottom: 0; }
.spec-row .k { color: var(--dim); }
.spec-row .v { color: var(--text); font-weight: 600; }

.version-item {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-soft);
}
.version-item:last-child { border-bottom: 0; }
.version-head { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin-bottom: 8px; }
.version-head b { font-size: 16px; }
.version-date { color: var(--dim); font-size: 13px; }
.version-badge {
  padding: 2px 10px;
  border: 1px solid rgba(34, 197, 94, .35);
  border-radius: 999px;
  background: rgba(34, 197, 94, .1);
  color: #6ee7a0;
  font-size: 12px;
  font-weight: 600;
}
.version-item ul { margin-top: 10px; }
.version-item li {
  position: relative;
  padding: 5px 0 5px 18px;
  color: var(--muted);
  font-size: 14px;
}
.version-item li::before {
  content: ""; position: absolute; left: 2px; top: 14px;
  width: 5px; height: 5px; border-radius: 50%; background: var(--primary);
}

/* ===================== 教程页 ===================== */
.tut-layout { display: grid; grid-template-columns: 232px minmax(0, 1fr); gap: 52px; align-items: start; }
.tut-toc { position: sticky; top: calc(var(--nav-h) + 26px); }
.tut-toc h4 { font-size: 12px; color: var(--dim); letter-spacing: .6px; margin-bottom: 14px; text-transform: uppercase; }
.tut-toc a {
  display: block;
  padding: 8px 12px;
  margin-bottom: 3px;
  border-left: 2px solid var(--border-soft);
  color: var(--muted);
  font-size: 13.5px;
  transition: color .15s, border-color .15s, background .15s;
}
.tut-toc a:hover { color: var(--text); background: rgba(255, 255, 255, .03); }
.tut-toc a.active { color: #8fb0ff; border-left-color: var(--primary); background: rgba(47, 107, 255, .09); }

.tut-block { padding-bottom: 46px; margin-bottom: 46px; border-bottom: 1px solid var(--border-soft); }
.tut-block:last-child { border-bottom: 0; margin-bottom: 0; padding-bottom: 0; }
.tut-block h2 { font-size: 22px; margin-bottom: 12px; display: flex; align-items: center; gap: 12px; }
.tut-step-no {
  flex: none;
  width: 30px; height: 30px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 9px;
  background: rgba(47, 107, 255, .15);
  border: 1px solid rgba(47, 107, 255, .35);
  color: #8fb0ff;
  font-size: 14px;
  font-weight: 700;
}
.tut-block > p { color: var(--muted); font-size: 14.5px; margin-bottom: 16px; }
.tut-block ol { counter-reset: li; margin: 0 0 16px; padding: 0; list-style: none; }
.tut-block ol li {
  position: relative;
  padding: 7px 0 7px 34px;
  color: var(--muted);
  font-size: 14px;
  counter-increment: li;
}
.tut-block ol li::before {
  content: counter(li);
  position: absolute; left: 0; top: 7px;
  width: 21px; height: 21px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 6px;
  background: rgba(255, 255, 255, .05);
  color: var(--dim);
  font-size: 11px;
  font-weight: 700;
}
.tut-block ol li b, .tut-block p b { color: var(--text); font-weight: 600; }

kbd {
  padding: 2px 7px;
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 6px;
  background: var(--panel-2);
  color: var(--text);
  font: 12px/1.5 Consolas, "Courier New", monospace;
}
code {
  padding: 2px 6px;
  border-radius: 5px;
  background: rgba(255, 255, 255, .06);
  color: #a9c4ff;
  font: 12.5px/1.5 Consolas, "Courier New", monospace;
  overflow-wrap: anywhere;
}
.callout {
  padding: 15px 18px;
  margin: 16px 0;
  border: 1px solid rgba(47, 107, 255, .28);
  border-left-width: 3px;
  border-radius: var(--radius-sm);
  background: rgba(47, 107, 255, .07);
  color: var(--muted);
  font-size: 13.5px;
}
.callout.warn { border-color: rgba(245, 158, 11, .3); background: rgba(245, 158, 11, .07); }
.callout strong { color: var(--text); }

/* ===================== 页脚 ===================== */
.site-footer {
  margin-top: 40px;
  border-top: 1px solid var(--border-soft);
  background: rgba(9, 11, 14, .7);
  padding: 52px 0 30px;
}
.footer-grid { display: grid; grid-template-columns: minmax(0, 1.6fr) repeat(3, minmax(0, 1fr)); gap: 36px; }
.footer-brand { display: flex; align-items: center; gap: 11px; margin-bottom: 14px; }
.footer-brand img { width: 32px; height: 32px; border-radius: 9px; }
.footer-brand span { font-size: 15px; font-weight: 700; }
.footer-about { color: var(--dim); font-size: 13px; max-width: 360px; }
.footer-col h4 { font-size: 13px; color: var(--text); margin-bottom: 14px; }
.footer-col a { display: block; padding: 5px 0; color: var(--dim); font-size: 13px; }
.footer-col a:hover { color: var(--cyan); }

/* 联系我们 */
.contact-band {
  margin-top: 40px;
  padding: 24px 26px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, .02);
}
.contact-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  margin-bottom: 18px;
}
.contact-head h4 { font-size: 15px; color: var(--text); }
.contact-head p { font-size: 13px; color: var(--dim); }

.contact-list { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
.contact-item {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 12px 14px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, .018);
  transition: border-color .16s, background .16s;
}
.contact-item:hover { border-color: rgba(47, 107, 255, .35); background: rgba(47, 107, 255, .06); }
.contact-ico {
  flex: none;
  width: 32px; height: 32px;
  display: flex; align-items: center; justify-content: center;
  border: 1px solid rgba(47, 107, 255, .3);
  border-radius: 9px;
  background: rgba(47, 107, 255, .12);
  color: #8fb0ff;
  font-size: 13px;
  font-weight: 700;
}
.contact-body { flex: 1; min-width: 0; }
.contact-k { display: block; font-size: 11px; color: var(--dim); line-height: 1.5; }
.contact-v {
  display: block;
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  line-height: 1.5;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
a.contact-v { color: var(--text); }
a.contact-v:hover { color: var(--cyan); }

.contact-copy {
  flex: none;
  padding: 5px 11px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: color .16s, border-color .16s, background .16s;
}
.contact-copy:hover { color: var(--text); background: rgba(255, 255, 255, .05); }
.contact-copy.done { color: #6ee7a0; border-color: rgba(34, 197, 94, .4); background: rgba(34, 197, 94, .1); }

.footer-bottom {
  display: flex; flex-wrap: wrap; gap: 14px; justify-content: space-between;
  margin-top: 40px; padding-top: 22px;
  border-top: 1px solid var(--border-soft);
  color: var(--dim); font-size: 12.5px;
}

/* ===================== 404 页 ===================== */
.error-page { max-width: 720px; margin: 0 auto; text-align: center; }
.error-code {
  font-size: 104px;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -.04em;
  margin-bottom: 20px;
  background: linear-gradient(120deg, #4a7dff, #22d3ee);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.error-page h1 { font-size: 30px; margin-bottom: 14px; }
.error-page .hero-lead { margin: 0 auto; }
.error-page .hero-actions { justify-content: center; }
.error-links { margin-top: 28px; color: var(--dim); font-size: 13.5px; }
.error-links a { color: var(--muted); }
.error-links a:hover { color: var(--cyan); }
.error-links span { margin: 0 10px; }

/* ===================== 进场动画 ===================== */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation: none !important; }
}

/* ===================== 响应式 ===================== */
@media (max-width: 1024px) {
  .hero-grid { grid-template-columns: minmax(0, 1fr); gap: 44px; }
  .hero h1 { font-size: 40px; }
  .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .split { grid-template-columns: minmax(0, 1fr); gap: 32px; }
  .dl-card { grid-template-columns: minmax(0, 1fr); }
  .dl-side { border-left: 0; border-top: 1px solid var(--border-soft); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 30px; }
  .contact-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tut-layout { grid-template-columns: minmax(0, 1fr); gap: 30px; }
  .tut-toc { position: static; }
}

@media (max-width: 760px) {
  .nav-links, .nav-cta { display: none; }
  .nav-toggle { display: flex; }
  .section { padding: 64px 0; }
  .section-title { font-size: 26px; }
  .hero { padding: 52px 0 56px; }
  .hero h1 { font-size: 32px; }
  .hero-lead { font-size: 15px; }
  .hero-stats { grid-template-columns: minmax(0, 1fr); }
  .grid-3, .grid-2, .grid-4, .steps { grid-template-columns: minmax(0, 1fr); }
  .cta { padding: 36px 22px; }
  .cta h2 { font-size: 22px; }
  .page-head { padding: 44px 0 38px; }
  .page-head h1 { font-size: 28px; }
  .dl-main { padding: 26px 22px; }
  .error-code { font-size: 72px; }
  .error-page h1 { font-size: 24px; }
  .error-page .hero-actions .btn { width: 100%; }
  .dl-side { padding: 24px 22px; }
  .dl-actions .btn { width: 100%; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .contact-band { padding: 20px 18px; }
  .contact-list { grid-template-columns: minmax(0, 1fr); }
  .footer-bottom { flex-direction: column; }
  .wrap { padding: 0 18px; }
}