/* ============================================================
   狂野赛车官网 · 样式表
   主题：深夜赛道 / 竞速金橙 / 速度线
   ============================================================ */

:root {
  --bg:        #070a14;
  --bg-2:      #0b1020;
  --panel:     rgba(255, 255, 255, 0.045);
  --panel-2:   rgba(255, 255, 255, 0.07);
  --line:      rgba(255, 179, 71, 0.16);
  --line-soft: rgba(255, 255, 255, 0.09);
  --gold:      #ffb347;
  --gold-2:    #ff9a1f;
  --orange:    #ff7a00;
  --text:      #e9edf6;
  --muted:     #98a2b8;
  --muted-2:   #6b7488;

  --font-body:    "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-display: "Orbitron", "Noto Sans SC", var(--font-body);

  --radius:    18px;
  --radius-sm: 12px;
  --glow:      0 10px 40px -10px rgba(255, 138, 30, 0.45);
  --container: 1180px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  font-size: 16px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
code { font-family: "SF Mono", "JetBrains Mono", Consolas, monospace; }

::selection { background: rgba(255, 138, 30, 0.35); color: #fff; }

.container {
  width: min(var(--container), calc(100% - 48px));
  margin: 0 auto;
}
.container-narrow { max-width: 960px; }

/* 锚点偏移，避免被吸顶导航遮住 */
section { scroll-margin-top: 76px; }

/* ============================================================
   背景层
   ============================================================ */

.bg-layer {
  position: fixed; inset: 0; z-index: -1; overflow: hidden;
  background:
    radial-gradient(1100px 600px at 78% -8%, rgba(255, 122, 0, 0.14), transparent 60%),
    radial-gradient(900px 700px at 8% 12%, rgba(38, 80, 180, 0.18), transparent 62%),
    linear-gradient(180deg, #080c19 0%, #070a14 45%, #080b16 100%);
}

.bg-speedlines {
  position: absolute; inset: -40% -20%;
  background-image: repeating-linear-gradient(
    116deg,
    transparent 0 118px,
    rgba(255, 160, 60, 0.05) 118px 122px,
    transparent 122px 230px,
    rgba(255, 255, 255, 0.028) 230px 232px,
    transparent 232px 360px);
  animation: speed-drift 46s linear infinite;
}
@keyframes speed-drift {
  from { transform: translateX(-6%); }
  to   { transform: translateX(12%); }
}

.bg-grid-glow {
  position: absolute; left: 0; right: 0; top: 0; height: 55%;
  background-image:
    linear-gradient(rgba(255, 179, 71, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 179, 71, 0.05) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,.7), transparent 90%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,.7), transparent 90%);
}

.bg-grain {
  position: absolute; inset: 0; opacity: 0.5; mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.32'/%3E%3C/svg%3E");
}

/* ============================================================
   导航
   ============================================================ */

.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  transition: background .3s, box-shadow .3s, backdrop-filter .3s;
}
.nav.scrolled {
  background: rgba(7, 10, 20, 0.78);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 1px 0 var(--line), 0 12px 40px -24px #000;
}
.nav-inner {
  width: min(var(--container), calc(100% - 48px));
  margin: 0 auto;
  height: 72px;
  display: flex; align-items: center; gap: 24px;
}
.nav-brand { display: flex; align-items: baseline; gap: 8px; }
.brand-mark { font-size: 20px; transform: translateY(2px); }
.brand-cn { font-weight: 900; font-size: 19px; letter-spacing: 2px; }
.brand-en {
  font-family: var(--font-display);
  font-size: 11px; letter-spacing: 3px;
  color: var(--gold);
}
.nav-links {
  display: flex; gap: 4px; margin-left: auto;
}
.nav-links a {
  padding: 8px 14px; border-radius: 999px;
  font-size: 14.5px; color: var(--muted);
  transition: color .2s, background .2s;
}
.nav-links a:hover { color: var(--text); background: rgba(255,255,255,.06); }
.nav-actions { display: flex; align-items: center; gap: 8px; }

.nav-burger {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: 0; cursor: pointer; padding: 8px;
}
.nav-burger span {
  width: 22px; height: 2px; border-radius: 2px;
  background: var(--text); transition: .3s;
}
.nav-burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-burger.open span:nth-child(2) { opacity: 0; }
.nav-burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   按钮
   ============================================================ */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  font-family: var(--font-body); font-weight: 700;
  border-radius: 999px; cursor: pointer;
  border: 1px solid transparent;
  transition: transform .22s, box-shadow .22s, background .22s, border-color .22s;
  white-space: nowrap;
}
.btn-sm { padding: 9px 20px; font-size: 14px; }
.btn-lg { padding: 16px 34px; font-size: 17px; }
.btn-ico { font-size: 1.05em; line-height: 1; }

.btn-primary {
  background: linear-gradient(135deg, var(--gold) 0%, var(--gold-2) 45%, var(--orange) 100%);
  color: #1b0f00;
  box-shadow: var(--glow), inset 0 1px 0 rgba(255,255,255,.4);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 18px 48px -10px rgba(255,138,30,.6); }
.btn-primary:active { transform: translateY(0); }

.btn-ghost {
  background: rgba(255,255,255,.045);
  border-color: rgba(255,179,71,.35);
  color: var(--text);
}
.btn-ghost:hover {
  transform: translateY(-2px);
  border-color: rgba(255,179,71,.65);
  background: rgba(255,179,71,.1);
}

/* ============================================================
   Hero
   ============================================================ */

.hero {
  min-height: 100vh;
  display: flex; align-items: center;
  position: relative;
  padding: 120px 0 90px;
  overflow: hidden;
}
.hero-inner { text-align: center; position: relative; }

.hero-eyebrow {
  display: inline-block;
  font-size: 14px; letter-spacing: 6px; color: var(--gold);
  padding: 7px 20px; border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255,179,71,.06);
  margin-bottom: 28px;
}
.hero-title { line-height: 1.05; margin-bottom: 26px; }
.hero-title-en {
  display: block;
  font-family: var(--font-display);
  font-weight: 800; font-size: clamp(18px, 2.6vw, 30px);
  letter-spacing: 10px;
  color: transparent;
  background: linear-gradient(90deg, rgba(255,179,71,.2), var(--gold), rgba(255,179,71,.2));
  -webkit-background-clip: text; background-clip: text;
  margin-bottom: 10px;
}
.hero-title-cn {
  display: block;
  font-weight: 900;
  font-size: clamp(54px, 9.5vw, 124px);
  letter-spacing: 12px;
  background: linear-gradient(180deg, #fff7ea 10%, var(--gold) 52%, var(--orange) 100%);
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
  filter: drop-shadow(0 14px 44px rgba(255,122,0,.3));
}
.hero-tagline {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--muted);
  margin-bottom: 42px;
}
.hero-cta {
  display: flex; gap: 18px; justify-content: center; flex-wrap: wrap;
  margin-bottom: 28px;
}
.hero-meta {
  display: flex; align-items: center; justify-content: center; gap: 14px;
  flex-wrap: wrap;
  font-size: 14px; color: var(--muted);
}
.hero-meta a { color: var(--gold); border-bottom: 1px solid transparent; transition: border .2s; }
.hero-meta a:hover { border-color: var(--gold); }
.version-badge {
  font-family: var(--font-display); font-weight: 700; font-size: 13px;
  color: var(--gold); border: 1px solid var(--line);
  padding: 3px 12px; border-radius: 6px;
}
.dot-sep { color: var(--muted-2); }

.hero-stats {
  display: flex; justify-content: center; gap: clamp(28px, 7vw, 90px);
  margin-top: 64px;
}
.hstat { display: flex; flex-direction: column; align-items: center; gap: 4px; }
.hstat b {
  font-family: var(--font-display); font-weight: 800;
  font-size: clamp(30px, 4vw, 44px);
  color: var(--gold);
}
.hstat span { font-size: 13.5px; color: var(--muted); letter-spacing: 1px; }

.scroll-hint {
  position: absolute; bottom: 28px; left: 50%; transform: translateX(-50%);
  width: 26px; height: 42px;
  border: 2px solid rgba(255,179,71,.5); border-radius: 14px;
  display: flex; justify-content: center; padding-top: 7px;
}
.scroll-hint span {
  width: 4px; height: 8px; border-radius: 4px;
  background: var(--gold);
  animation: scroll-dot 1.8s ease-in-out infinite;
}
@keyframes scroll-dot {
  0%   { transform: translateY(0); opacity: 1; }
  70%  { transform: translateY(12px); opacity: 0; }
  100% { transform: translateY(0); opacity: 0; }
}

/* ============================================================
   通用 Section / 标题
   ============================================================ */

.section { padding: 110px 0; position: relative; }
.section-tint {
  background: linear-gradient(180deg, rgba(255,255,255,.02), rgba(255,255,255,.035));
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}
.section-head { text-align: center; margin-bottom: 64px; }
.section-kicker {
  font-family: var(--font-display);
  font-size: 13px; letter-spacing: 5px; color: var(--gold);
  margin-bottom: 12px;
}
.section-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 900; letter-spacing: 3px;
}
.section-sub { color: var(--muted); margin-top: 14px; font-size: 15.5px; }

.glass-card {
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: transform .3s, border-color .3s, box-shadow .3s, background .3s;
}

/* ============================================================
   游戏介绍
   ============================================================ */

.about-grid {
  display: grid; grid-template-columns: 1.05fr 1fr;
  gap: 56px; align-items: center;
}
.about-text p { color: var(--muted); margin-bottom: 20px; font-size: 16.5px; }
.about-text b { color: var(--text); font-weight: 700; }

.about-cards { display: grid; gap: 18px; }
.stat-card {
  padding: 26px 30px;
  display: flex; align-items: center; gap: 24px;
}
.stat-card b {
  font-family: var(--font-display); font-weight: 800; font-size: 52px;
  color: var(--gold); min-width: 70px; text-align: center;
}
.stat-card span { color: var(--muted); font-size: 14.5px; line-height: 1.6; }

/* ============================================================
   玩法模式
   ============================================================ */

.mode-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
.mode-card {
  padding: 36px 28px 32px;
  text-align: center;
  position: relative; overflow: hidden;
}
.mode-card::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(420px 140px at 50% -20%, rgba(255,138,30,.14), transparent 70%);
  opacity: 0; transition: opacity .3s;
}
.mode-card:hover {
  transform: translateY(-6px);
  border-color: rgba(255,179,71,.5);
  box-shadow: 0 24px 50px -22px rgba(255,122,0,.4);
}
.mode-card:hover::before { opacity: 1; }
.mode-card:last-child { grid-column: 2; }
.mode-ico {
  width: 78px; height: 78px; margin: 0 auto 20px;
  display: flex; align-items: center; justify-content: center;
  font-size: 38px; border-radius: 22px;
  background: linear-gradient(150deg, rgba(255,179,71,.18), rgba(255,122,0,.06));
  border: 1px solid var(--line);
}
.mode-card h3 { font-size: 21px; margin-bottom: 10px; letter-spacing: 1px; }
.mode-card p { color: var(--muted); font-size: 14.5px; }

/* ============================================================
   游戏特色
   ============================================================ */

.feature-list { display: grid; gap: 20px; max-width: 920px; margin: 0 auto; }
.feature-row {
  display: grid; grid-template-columns: 96px 1fr; gap: 28px;
  padding: 36px 40px;
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  position: relative; overflow: hidden;
  transition: transform .3s, border-color .3s;
}
.feature-row:hover { transform: translateX(6px); border-color: rgba(255,179,71,.45); }
.feature-num {
  font-family: var(--font-display); font-weight: 800; font-size: 42px;
  background: linear-gradient(180deg, var(--gold), rgba(255,122,0,.25));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  line-height: 1.2;
}
.feature-body h3 { font-size: 21px; margin-bottom: 10px; letter-spacing: 1px; }
.feature-body p { color: var(--muted); font-size: 15px; }

/* ============================================================
   下载中心
   ============================================================ */

.dl-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 22px; align-items: stretch;
}
.dl-card {
  padding: 32px 28px 28px;
  display: flex; flex-direction: column;
}
.dl-card-featured {
  border-color: rgba(255,179,71,.55);
  background: linear-gradient(180deg, rgba(255,138,30,.09), var(--panel) 45%);
  box-shadow: 0 24px 60px -30px rgba(255,122,0,.55);
  position: relative;
}
.dl-tag {
  position: absolute; top: 18px; right: -34px;
  transform: rotate(40deg);
  background: linear-gradient(135deg, var(--gold), var(--orange));
  color: #1b0f00; font-size: 11px; font-weight: 700;
  padding: 4px 40px;
}
.dl-platform { display: flex; align-items: center; gap: 14px; margin-bottom: 20px; }
.dl-ico { font-size: 40px; line-height: 1; }
.dl-platform h3 { font-size: 19px; letter-spacing: .5px; }
.dl-platform p { font-size: 12.5px; color: var(--muted); }

.dl-meta {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px;
  padding: 14px 0; margin-bottom: 14px;
  border-top: 1px solid var(--line-soft); border-bottom: 1px solid var(--line-soft);
}
.dl-meta li { font-size: 13px; color: var(--muted); }
.dl-meta b { color: var(--text); font-weight: 700; }

.dl-md5 {
  display: flex; align-items: center; gap: 8px;
  margin-bottom: 20px;
}
.dl-md5 code {
  flex: 1; font-size: 11.5px; color: var(--gold);
  background: rgba(255,179,71,.07);
  border: 1px solid var(--line); border-radius: 8px;
  padding: 6px 10px;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.copy-btn {
  background: rgba(255,255,255,.06);
  border: 1px solid var(--line-soft); border-radius: 8px;
  color: var(--muted); font-size: 12px; padding: 6px 10px;
  cursor: pointer; transition: .2s; font-family: var(--font-body);
  white-space: nowrap;
}
.copy-btn:hover { color: var(--gold); border-color: var(--line); }

.dl-btn { margin-top: auto; padding: 14px 20px; font-size: 15px; width: 100%; }
.dl-link {
  display: block; text-align: center; margin-top: 12px;
  font-size: 13px; color: var(--muted); transition: color .2s;
}
.dl-link:hover { color: var(--gold); }

.dl-note {
  text-align: center; color: var(--muted); font-size: 13.5px; margin-top: 34px;
}
.dl-note code { color: var(--gold); font-size: 12.5px; }

/* ============================================================
   iOS 教程
   ============================================================ */

.guide-tabs {
  display: flex; justify-content: center; gap: 14px; flex-wrap: wrap;
  margin-bottom: 36px;
}
.guide-tab {
  font-family: var(--font-body); cursor: pointer;
  background: var(--panel);
  border: 1px solid var(--line-soft); border-radius: 14px;
  color: var(--muted);
  padding: 14px 30px; font-size: 16px; font-weight: 700;
  display: flex; flex-direction: column; align-items: center; gap: 2px;
  transition: .25s;
}
.guide-tab span { font-size: 12px; font-weight: 400; color: var(--muted-2); }
.guide-tab:hover { border-color: var(--line); color: var(--text); }
.guide-tab.is-active {
  color: #1b0f00;
  background: linear-gradient(135deg, var(--gold), var(--orange));
  border-color: transparent;
  box-shadow: var(--glow);
}
.guide-tab.is-active span { color: rgba(27,15,0,.7); }

.guide-panel { display: none; max-width: 820px; margin: 0 auto; }
.guide-panel.is-active { display: block; animation: panel-in .4s ease; }
@keyframes panel-in {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

.steps li {
  position: relative;
  padding: 18px 18px 18px 66px;
  margin-bottom: 12px;
  background: var(--panel);
  border: 1px solid var(--line-soft); border-radius: var(--radius-sm);
  font-size: 15px; color: var(--muted);
  counter-increment: step;
}
.steps { counter-reset: step; }
.steps li::before {
  content: counter(step);
  position: absolute; left: 18px; top: 18px;
  width: 32px; height: 32px; border-radius: 50%;
  background: linear-gradient(135deg, var(--gold), var(--orange));
  color: #1b0f00; font-weight: 800; font-size: 14px;
  display: flex; align-items: center; justify-content: center;
}
.steps b { color: var(--text); }
.steps code { color: var(--gold); font-size: 13px; }
.steps a { color: var(--gold); border-bottom: 1px solid rgba(255,179,71,.4); }

.faq { max-width: 820px; margin: 64px auto 0; }
.faq-title { text-align: center; font-size: 22px; margin-bottom: 24px; letter-spacing: 1px; }

.accordion {
  border: 1px solid var(--line-soft); border-radius: var(--radius-sm);
  margin-bottom: 12px; overflow: hidden; background: var(--panel);
}
.acc-head {
  width: 100%; text-align: left;
  background: none; border: 0; cursor: pointer;
  color: var(--text); font-family: var(--font-body);
  font-size: 15.5px; font-weight: 700;
  padding: 18px 22px;
  display: flex; justify-content: space-between; align-items: center; gap: 16px;
}
.acc-ico {
  color: var(--gold); font-size: 22px; line-height: 1;
  transition: transform .3s; flex-shrink: 0;
}
.accordion.open .acc-ico { transform: rotate(45deg); }
.acc-body {
  max-height: 0; overflow: hidden;
  transition: max-height .35s ease;
}
.acc-body p { padding: 0 22px 20px; color: var(--muted); font-size: 14.5px; }

/* ============================================================
   Roadmap
   ============================================================ */

.roadmap { max-width: 760px; margin: 0 auto; display: grid; gap: 30px; }
.road-group {
  position: relative;
  padding: 8px 0 0 36px;
  border-left: 2px solid var(--line-soft);
}
.road-group::before {
  content: ""; position: absolute; left: -8px; top: 10px;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--bg); border: 3px solid var(--muted-2);
}
.road-group:nth-child(1)::before { border-color: #4cd97b; background: rgba(76,217,123,.25); }
.road-group:nth-child(2)::before { border-color: var(--gold); background: rgba(255,179,71,.25); }
.road-group:nth-child(3)::before { border-color: #5b8def; background: rgba(91,141,239,.25); }

.road-badge {
  display: inline-block; font-size: 13px; font-weight: 700;
  padding: 4px 14px; border-radius: 999px; margin-bottom: 14px;
}
.badge-live { color: #4cd97b; background: rgba(76,217,123,.12); border: 1px solid rgba(76,217,123,.3); }
.badge-wip  { color: var(--gold); background: rgba(255,179,71,.1); border: 1px solid var(--line); }
.badge-plan { color: #5b8def; background: rgba(91,141,239,.1); border: 1px solid rgba(91,141,239,.3); }

.road-items li {
  position: relative; padding-left: 22px;
  color: var(--muted); font-size: 15px; margin-bottom: 8px;
}
.road-items li::before {
  content: ""; position: absolute; left: 2px; top: 11px;
  width: 7px; height: 7px; border-radius: 2px;
  background: var(--gold); transform: rotate(45deg);
}

/* ============================================================
   联系创作者
   ============================================================ */

.contact-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.contact-card {
  padding: 36px 24px 28px; text-align: center;
}
.contact-card:hover { transform: translateY(-5px); border-color: rgba(255,179,71,.45); }
.contact-ico { font-size: 38px; display: block; margin-bottom: 14px; }
.contact-card h3 { font-size: 18px; margin-bottom: 8px; }
.contact-val { color: var(--gold); font-weight: 700; font-size: 16px; margin-bottom: 8px; }
.contact-val a { color: inherit; text-decoration: none; }
.contact-val a:hover { color: var(--orange); }
.contact-status { font-size: 12.5px; color: var(--muted-2); }
.contact-tip {
  text-align: center; margin-top: 40px;
  color: var(--muted); font-size: 14px;
  padding: 20px 26px; border-radius: var(--radius-sm);
  background: rgba(255,179,71,.05); border: 1px dashed var(--line);
}

/* ============================================================
   页脚
   ============================================================ */

.footer {
  position: relative;
  border-top: 1px solid var(--line-soft);
  background: rgba(5,7,14,.8);
  padding: 56px 0 64px;
}
.footer-inner {
  display: grid; grid-template-columns: 1.2fr 1fr 1.2fr;
  gap: 32px; align-items: start;
}
.footer-brand span { font-weight: 900; letter-spacing: 2px; font-size: 17px; }
.footer-brand p { color: var(--muted-2); font-size: 13px; margin-top: 8px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 8px 22px; }
.footer-links a { color: var(--muted); font-size: 14px; transition: color .2s; }
.footer-links a:hover { color: var(--gold); }
.footer-copy { text-align: right; }
.footer-copy p { color: var(--muted-2); font-size: 12.5px; }

.checker-strip {
  position: absolute; left: 0; right: 0; bottom: 0; height: 8px;
  background:
    repeating-linear-gradient(90deg,
      #15181f 0 20px, #d7dbe6 20px 40px);
}

/* ============================================================
   Toast
   ============================================================ */

.toast {
  position: fixed; left: 50%; bottom: 36px;
  transform: translate(-50%, 80px);
  background: rgba(12,16,28,.92);
  border: 1px solid var(--line);
  color: var(--text); font-size: 14px;
  padding: 12px 24px; border-radius: 999px;
  box-shadow: 0 16px 50px -14px rgba(0,0,0,.8);
  backdrop-filter: blur(10px);
  opacity: 0; pointer-events: none;
  transition: transform .35s cubic-bezier(.2,.9,.3,1.2), opacity .3s;
  z-index: 200;
}
.toast.show { transform: translate(-50%, 0); opacity: 1; }

/* ============================================================
   滚动入场动画
   ============================================================ */

.reveal {
  opacity: 0; transform: translateY(30px);
  transition: opacity .8s cubic-bezier(.2,.7,.2,1), transform .8s cubic-bezier(.2,.7,.2,1);
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }

/* Hero 元素阶梯延迟 */
.hero .reveal:nth-child(1) { transition-delay: .05s; }
.hero .reveal:nth-child(2) { transition-delay: .18s; }
.hero .reveal:nth-child(3) { transition-delay: .32s; }
.hero .reveal:nth-child(4) { transition-delay: .46s; }
.hero .reveal:nth-child(5) { transition-delay: .58s; }
.hero .reveal:nth-child(6) { transition-delay: .72s; }

/* 网格内交错 */
.mode-grid .reveal:nth-child(2),
.dl-grid .reveal:nth-child(2),
.contact-grid .reveal:nth-child(2) { transition-delay: .12s; }
.mode-grid .reveal:nth-child(3),
.dl-grid .reveal:nth-child(3),
.contact-grid .reveal:nth-child(3) { transition-delay: .24s; }
.mode-grid .reveal:nth-child(4) { transition-delay: .12s; }
.mode-grid .reveal:nth-child(5) { transition-delay: .24s; }

/* ============================================================
   响应式
   ============================================================ */

@media (max-width: 1024px) {
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .mode-grid { grid-template-columns: repeat(2, 1fr); }
  .mode-card:last-child { grid-column: auto; }
  .dl-grid { grid-template-columns: 1fr; max-width: 460px; margin: 0 auto; }
  .footer-inner { grid-template-columns: 1fr; gap: 22px; }
  .footer-copy { text-align: left; }
}

@media (max-width: 860px) {
  .nav-links {
    position: fixed; top: 72px; left: 0; right: 0;
    flex-direction: column; gap: 4px;
    background: rgba(7,10,20,.97);
    backdrop-filter: blur(18px);
    padding: 18px 24px 28px;
    border-bottom: 1px solid var(--line);
    transform: translateY(-130%); transition: transform .35s;
  }
  .nav-links.open { transform: translateY(0); }
  .nav-links a { padding: 14px 12px; font-size: 16px; }
  .nav-burger { display: flex; }
  .nav-actions .btn-sm { display: none; }
  .contact-grid { grid-template-columns: 1fr; max-width: 420px; margin: 0 auto; }
}

@media (max-width: 600px) {
  .section { padding: 80px 0; }
  .mode-grid { grid-template-columns: 1fr; }
  .feature-row { grid-template-columns: 1fr; gap: 10px; padding: 28px 24px; }
  .feature-num { font-size: 34px; }
  .hero { padding: 110px 0 100px; }
  .hero-title-cn { letter-spacing: 6px; }
  .hide-mobile { display: none; }
  .hero-stats { gap: 26px; margin-top: 46px; }
  .guide-tab { padding: 12px 22px; font-size: 15px; }
  .scroll-hint { display: none; }
}

/* ============================================================
   减少动效偏好
   ============================================================ */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}