/* =========================================================
   QuickQ 网络加速 - 全站样式 LIGHT v2
   设计语言：浅色简约 · 大量留白 · 干净轻盈
   主色：数据蓝 #2563eb → 天空青 #0ea5e9
   适用：index.html / download.html / 404.html
   ========================================================= */

:root {
  --bg: #f7f9fc;
  --bg2: #eef2f8;
  --panel: #ffffff;
  --panel2: #f8fafd;
  --line: #e7ecf3;
  --line2: #d9e1ec;
  --txt: #12203a;
  --mut: #5b6b80;
  --dim: #8b99ad;
  --cy: #2563eb;        /* 数据蓝 */
  --bl: #0ea5e9;        /* 天空青 */
  --gr: #16a34a;        /* 在线绿 */
  --amb: #b45309;       /* 琥珀 */
  --red: #dc2626;
  --grad: linear-gradient(120deg, #2563eb 0%, #0ea5e9 100%);
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --shadow-sm: 0 2px 10px rgba(18, 32, 58, 0.05);
  --shadow-md: 0 14px 34px -18px rgba(18, 32, 58, 0.18);
  --shadow-lg: 0 30px 60px -28px rgba(18, 32, 58, 0.20);
}

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

::selection { background: rgba(37, 99, 235, 0.16); color: #0f172a; }

html { height: 100%; scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, system-ui, -apple-system, sans-serif;
  min-height: 100vh;
  display: flex; flex-direction: column;
  background:
    radial-gradient(1000px 460px at 90% -160px, rgba(37, 99, 235, 0.06), transparent 60%),
    radial-gradient(820px 400px at -6% -120px, rgba(14, 165, 233, 0.05), transparent 58%),
    var(--bg);
  color: var(--txt);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }

.container { width: 100%; max-width: 1160px; margin: 0 auto; padding: 0 24px; }

.mono { font-family: var(--mono); }

/* =========================================================
   顶栏
   ========================================================= */
header {
  position: sticky; top: 0; z-index: 60;
  background: rgba(255, 255, 255, 0.8);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border-bottom: 1px solid rgba(223, 229, 238, 0.9);
  transition: box-shadow .25s;
}
header.scrolled { box-shadow: 0 10px 30px -20px rgba(18, 32, 58, 0.18); }

.bar { height: 68px; display: flex; align-items: center; gap: 18px; }

.logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; font-size: 17px; letter-spacing: -0.2px; color: var(--txt); }
.logo .mark {
  width: 30px; height: 30px; border-radius: 8px;
  display: grid; place-items: center;
  background: var(--grad);
  color: #fff;
  box-shadow: 0 6px 16px -6px rgba(37, 99, 235, 0.5);
}
.logo .mark svg { width: 17px; height: 17px; }
.logo b { color: var(--bl); font-weight: 900; }

.bar nav { margin-left: auto; display: flex; align-items: center; gap: 2px; }
.bar nav a {
  color: var(--mut); padding: 7px 14px; border-radius: 8px;
  font-size: 14px; transition: color .18s, background .18s;
}
.bar nav a:hover { color: var(--txt); background: rgba(18, 32, 58, 0.05); }

.bar .btn { flex-shrink: 0; }

/* 汉堡 */
.menu {
  display: none; margin-left: auto;
  background: none; border: 0; cursor: pointer;
  padding: 8px; border-radius: 7px; color: var(--txt);
}
.menu span { display: block; width: 18px; height: 2px; background: currentColor; margin: 3px 0; border-radius: 1px; }

/* =========================================================
   按钮
   ========================================================= */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  padding: 13px 26px; border-radius: 10px;
  font-size: 14.5px; font-weight: 700; letter-spacing: 0.2px;
  transition: transform .15s, box-shadow .2s, background .2s, border-color .2s, color .2s;
  white-space: nowrap;
}
.btn svg { width: 15px; height: 15px; flex: 0 0 auto; }
.btn.p {
  background: var(--grad); color: #fff;
  box-shadow: 0 10px 22px -10px rgba(37, 99, 235, 0.55);
}
.btn.p:hover { transform: translateY(-2px); box-shadow: 0 16px 28px -10px rgba(37, 99, 235, 0.6); }
.btn.g {
  background: #fff;
  border: 1px solid var(--line2);
  color: var(--txt);
}
.btn.g:hover { border-color: rgba(37, 99, 235, 0.55); color: var(--cy); background: #f3f7ff; transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn.sm { padding: 9px 18px; font-size: 13.5px; border-radius: 9px; }

/* 区块通用 */
.sec { padding: 96px 0 8px; }
[id] { scroll-margin-top: 92px; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--mono); font-size: 11px; letter-spacing: 3px;
  color: var(--cy); text-transform: uppercase;
}
.eyebrow::before { content: ""; width: 22px; height: 1px; background: linear-gradient(90deg, transparent, var(--cy)); }

.sec h2 {
  margin-top: 14px;
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 800; letter-spacing: -1px; line-height: 1.25;
  color: var(--txt);
}
.sec .lead { margin-top: 12px; color: var(--mut); font-size: 15px; max-width: 620px; }

/* 入场动画 */
@keyframes rise {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* =========================================================
   首页 Hero
   ========================================================= */
.hero { position: relative; overflow: hidden; padding: 84px 0 72px; }

.hero .bgfx { position: absolute; inset: 0; pointer-events: none; }
.hero .bgfx::before {
  content: ""; position: absolute; inset: 0;
  background-image: radial-gradient(rgba(37, 99, 235, 0.11) 1px, transparent 1px);
  background-size: 26px 26px;
  -webkit-mask-image: radial-gradient(ellipse 72% 66% at 58% 8%, #000 8%, transparent 70%);
  mask-image: radial-gradient(ellipse 72% 66% at 58% 8%, #000 8%, transparent 70%);
}
.hero .bgfx::after {
  content: ""; position: absolute;
  right: -160px; top: -220px; width: 600px; height: 600px;
  background: radial-gradient(closest-side, rgba(14, 165, 233, 0.13), rgba(37, 99, 235, 0.05) 50%, transparent 72%);
}

.hero-grid {
  position: relative;
  display: grid; grid-template-columns: 1.06fr 0.94fr; gap: 64px;
  align-items: center;
}

.hero-copy { animation: rise .7s cubic-bezier(.22, .8, .36, 1) both; }
.hero h1 {
  margin-top: 20px;
  font-size: clamp(40px, 5.8vw, 64px);
  font-weight: 900; letter-spacing: -2.5px; line-height: 1.1;
  color: var(--txt);
}
.hero h1 .g {
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero .sub { margin-top: 20px; color: var(--mut); font-size: 15.5px; max-width: 520px; }
.hero .sub b { color: var(--txt); font-weight: 700; }

.hero-cta { margin-top: 30px; display: flex; gap: 14px; flex-wrap: wrap; }

.hero-stats {
  margin-top: 40px; display: flex; gap: 0; flex-wrap: wrap;
  border-top: 1px solid var(--line); padding-top: 24px;
}
.hero-stats .st { padding: 2px 30px 2px 0; margin-right: 30px; border-right: 1px solid var(--line); }
.hero-stats .st:last-child { border-right: 0; margin-right: 0; }
.hero-stats b {
  display: block; font-family: var(--mono); font-size: 24px; font-weight: 800;
  color: var(--txt); letter-spacing: -0.5px; line-height: 1.2;
}
.hero-stats b em { font-style: normal; color: var(--cy); font-size: 15px; }
.hero-stats span { font-size: 12px; color: var(--dim); letter-spacing: 0.5px; }

/* 客户端模拟窗 */
.hero-panel { position: relative; animation: rise .7s cubic-bezier(.22, .8, .36, 1) .1s both; }
.win {
  border: 1px solid var(--line2); border-radius: 16px;
  background: #fff;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.win-bar { display: flex; align-items: center; gap: 7px; padding: 13px 16px; border-bottom: 1px solid var(--line); background: #edf1f7; }
.win-bar i { width: 10px; height: 10px; border-radius: 50%; display: block; }
.win-bar i.r { background: #ff5f57; }
.win-bar i.y { background: #febc2e; }
.win-bar i.g { background: #28c840; }
.win-bar span { margin-left: 10px; font-size: 12px; color: var(--mut); font-weight: 600; }
.win-bar em { margin-left: auto; font-family: var(--mono); font-style: normal; font-size: 10.5px; color: var(--dim); }

.win-body { padding: 18px; }
.conn {
  display: flex; align-items: center; gap: 12px;
  padding: 13px 15px; border-radius: 11px;
  border: 1px solid rgba(22, 163, 74, 0.22);
  background: rgba(22, 163, 74, 0.06);
}
.conn .dot {
  width: 10px; height: 10px; border-radius: 50%; background: var(--gr); flex: 0 0 auto;
  animation: pulse 1.8s ease-out infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(22, 163, 74, 0.35); }
  70% { box-shadow: 0 0 0 8px rgba(22, 163, 74, 0); }
  100% { box-shadow: 0 0 0 0 rgba(22, 163, 74, 0); }
}
.conn b { font-size: 13.5px; font-weight: 700; color: var(--txt); }
.conn b em { font-style: normal; color: var(--gr); font-weight: 700; }
.conn .lag { margin-left: auto; font-family: var(--mono); font-size: 11px; color: var(--gr); font-weight: 600; }

.metrics { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 12px; }
.metric { border: 1px solid var(--line); border-radius: 11px; padding: 12px 14px; background: var(--panel2); }
.metric .lab { font-size: 11px; color: var(--dim); display: flex; justify-content: space-between; font-family: var(--mono); }
.metric .lab i { font-style: normal; color: var(--cy); font-weight: 600; }
.metric .val { font-family: var(--mono); font-size: 19px; font-weight: 800; margin-top: 4px; letter-spacing: -0.3px; color: var(--txt); }
.metric .val small { font-size: 11px; color: var(--dim); font-weight: 400; margin-left: 2px; }
.prog { height: 4px; border-radius: 2px; background: #e6ecf4; margin-top: 9px; overflow: hidden; }
.prog i { display: block; height: 100%; border-radius: 2px; background: var(--grad); }

.eq { display: flex; align-items: flex-end; gap: 3px; height: 26px; margin-top: 8px; }
.eq i { flex: 1; background: linear-gradient(180deg, #2563eb, rgba(14, 165, 233, 0.28)); border-radius: 1.5px; animation: eq 1.1s ease-in-out infinite; }
.eq i:nth-child(1) { animation-delay: 0s; } .eq i:nth-child(2) { animation-delay: .2s; }
.eq i:nth-child(3) { animation-delay: .35s; } .eq i:nth-child(4) { animation-delay: .12s; }
.eq i:nth-child(5) { animation-delay: .5s; } .eq i:nth-child(6) { animation-delay: .27s; }
@keyframes eq {
  0%, 100% { height: 22%; }
  50% { height: 95%; }
}

.nodes { margin-top: 12px; border: 1px solid var(--line); border-radius: 11px; overflow: hidden; background: #fff; }
.nodes .nhead {
  display: flex; justify-content: space-between; align-items: center;
  padding: 9px 14px; font-size: 11px; color: var(--dim);
  background: var(--panel2); font-family: var(--mono);
  border-bottom: 1px solid var(--line);
}
.nrow {
  display: grid; grid-template-columns: 1fr auto auto; gap: 14px; align-items: center;
  padding: 10px 14px; font-size: 12.5px; border-bottom: 1px solid var(--line);
  transition: background .15s;
}
.nrow:last-child { border-bottom: 0; }
.nrow:hover { background: #f6faff; }
.nrow .nm { display: flex; align-items: center; gap: 8px; font-weight: 600; color: var(--txt); }
.nrow .nm::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--gr); }
.nrow .ping { font-family: var(--mono); color: var(--cy); font-size: 11.5px; }

/* 底部渐变分隔 */
.hero::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(37, 99, 235, 0.28), transparent);
}

/* =========================================================
   特性（纵向卡片列表）
   ========================================================= */
.feat-list { margin-top: 52px; display: flex; flex-direction: column; gap: 12px; }
.feat {
  position: relative;
  display: grid; grid-template-columns: 56px 1fr auto; gap: 24px; align-items: center;
  padding: 24px 26px 24px 24px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 15px;
  transition: transform .2s, border-color .2s, box-shadow .25s;
}
.feat:hover { transform: translateY(-2px); border-color: rgba(37, 99, 235, 0.35); box-shadow: var(--shadow-md); }
.feat::before {
  content: ""; position: absolute; left: 0; top: 14px; bottom: 14px; width: 3px;
  background: var(--grad);
  border-radius: 0 3px 3px 0;
  opacity: 0; transform: scaleY(0.3);
  transition: opacity .25s, transform .25s;
}
.feat:hover::before { opacity: 1; transform: scaleY(1); }

.f-ic {
  width: 50px; height: 50px; border-radius: 12px;
  display: grid; place-items: center;
  background: #eef4ff;
  color: var(--cy);
}
.f-ic svg { width: 24px; height: 24px; }
.feat h3 { font-size: 17.5px; font-weight: 800; letter-spacing: -0.3px; color: var(--txt); }
.feat p { margin-top: 5px; color: var(--mut); font-size: 14px; max-width: 660px; }
.f-meta {
  justify-self: end;
  font-family: var(--mono); font-size: 11px; color: var(--dim);
  letter-spacing: 1.5px; text-transform: uppercase;
  border: 1px solid var(--line); border-radius: 999px; padding: 5px 13px;
  background: var(--panel2);
  white-space: nowrap;
}

/* =========================================================
   地区 / 节点
   ========================================================= */
.sec-cols { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 60px; align-items: start; }
.sec-cols .aside { position: sticky; top: 104px; }
.region-note { margin-top: 18px; font-size: 12px; color: var(--dim); font-family: var(--mono); }

.regions { margin-top: 8px; border: 1px solid var(--line); border-radius: 15px; overflow: hidden; background: #fff; box-shadow: var(--shadow-sm); }
.reg-row {
  display: grid; grid-template-columns: auto 1fr auto auto; gap: 16px; align-items: center;
  padding: 14px 20px; border-bottom: 1px solid var(--line);
  transition: background .15s;
}
.reg-row:last-child { border-bottom: 0; }
.reg-row:hover { background: #f6faff; }
.reg-row .code {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 1px;
  color: var(--cy); border: 1px solid rgba(37, 99, 235, 0.25); border-radius: 5px; padding: 3px 7px;
  background: #f0f6ff;
}
.reg-row b { font-size: 13.5px; font-weight: 700; color: var(--txt); }
.reg-row .cnt { font-size: 12px; color: var(--dim); font-family: var(--mono); }
.reg-row .ms { font-family: var(--mono); font-size: 12px; color: var(--gr); font-weight: 600; }
.reg-row .ms i { font-style: normal; color: var(--dim); font-size: 10px; margin-right: 3px; font-weight: 400; }

/* =========================================================
   步骤
   ========================================================= */
.steps { margin-top: 52px; counter-reset: step; display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.step {
  counter-increment: step; position: relative;
  background: #fff; border: 1px solid var(--line); border-radius: 15px;
  padding: 28px 28px 30px;
  transition: transform .2s, border-color .2s, box-shadow .25s;
}
.step:hover { transform: translateY(-3px); border-color: rgba(37, 99, 235, 0.35); box-shadow: var(--shadow-md); }
.step .num {
  display: grid; place-items: center;
  width: 42px; height: 42px; border-radius: 12px;
  font-family: var(--mono); font-size: 14px; font-weight: 800; color: #fff;
  background: var(--grad);
  box-shadow: 0 8px 18px -8px rgba(37, 99, 235, 0.5);
}
.step h4 { margin-top: 18px; font-size: 17px; font-weight: 800; color: var(--txt); }
.step p { margin-top: 7px; color: var(--mut); font-size: 13.5px; line-height: 1.8; }

/* =========================================================
   CTA 横幅
   ========================================================= */
.cta-strip {
  position: relative; overflow: hidden;
  margin-top: 96px;
  border: 1px solid #dbe7ff;
  border-radius: 18px;
  background:
    radial-gradient(520px 240px at 86% 18%, rgba(14, 165, 233, 0.13), transparent 65%),
    radial-gradient(420px 220px at 8% 92%, rgba(37, 99, 235, 0.10), transparent 60%),
    linear-gradient(120deg, #f2f7ff, #ecf8fe);
  padding: 50px 56px;
  display: flex; align-items: center; justify-content: space-between; gap: 30px; flex-wrap: wrap;
}
.cta-strip::before {
  content: ""; position: absolute; left: 0; right: 0; top: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(37, 99, 235, 0.5), transparent);
}
.cta-strip h2 { font-size: clamp(22px, 3vw, 30px); font-weight: 800; letter-spacing: -0.8px; color: var(--txt); }
.cta-strip p { margin-top: 8px; color: var(--mut); font-size: 14px; }
.cta-strip .btn { font-size: 16px; padding: 15px 30px; }

/* =========================================================
   下载页 Hero / 发行卡
   ========================================================= */
.dl-hero { padding: 72px 0 60px; position: relative; overflow: hidden; }
.dl-hero::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image: radial-gradient(rgba(37, 99, 235, 0.1) 1px, transparent 1px);
  background-size: 26px 26px;
  -webkit-mask-image: radial-gradient(ellipse 60% 90% at 12% 0%, #000 10%, transparent 70%);
  mask-image: radial-gradient(ellipse 60% 90% at 12% 0%, #000 10%, transparent 70%);
}
.dl-hero-grid {
  position: relative;
  display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 64px; align-items: center;
}
.dl-hero h1 { margin-top: 18px; font-size: clamp(34px, 4.6vw, 52px); font-weight: 900; letter-spacing: -2px; line-height: 1.12; color: var(--txt); }
.dl-hero h1 .g { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.dl-hero .sub { margin-top: 16px; color: var(--mut); font-size: 15px; max-width: 500px; }
.sys { margin-top: 24px; display: flex; gap: 10px; flex-wrap: wrap; }
.sys span {
  font-size: 12.5px; color: var(--mut);
  border: 1px solid var(--line2); background: #fff;
  border-radius: 999px; padding: 6px 14px; font-family: var(--mono);
  box-shadow: var(--shadow-sm);
}
.sys span b { color: var(--cy); font-weight: 700; }

/* 发行信息卡 */
.release { border: 1px solid var(--line2); border-radius: 16px; background: #fff; box-shadow: var(--shadow-md); overflow: hidden; }
.rel-head { display: flex; align-items: center; gap: 11px; padding: 16px 20px; border-bottom: 1px solid var(--line); background: var(--panel2); }
.rel-head .chip {
  font-family: var(--mono); font-size: 11px; color: var(--gr);
  border: 1px solid rgba(22, 163, 74, 0.3); background: rgba(22, 163, 74, 0.07);
  border-radius: 6px; padding: 3px 8px; letter-spacing: 1px; font-weight: 700;
}
.rel-head span { font-weight: 700; font-size: 14px; color: var(--txt); }
.rel-head em { margin-left: auto; font-style: normal; font-family: var(--mono); font-size: 11px; color: var(--dim); }
.rel-row { display: flex; justify-content: space-between; gap: 16px; padding: 13px 20px; font-size: 13px; border-bottom: 1px solid var(--line); }
.rel-row:last-child { border-bottom: 0; }
.rel-row .k { color: var(--dim); font-family: var(--mono); font-size: 12px; }
.rel-row .v { font-weight: 600; text-align: right; color: var(--txt); }
.rel-row .v.hash { font-family: var(--mono); font-size: 11px; color: var(--mut); font-weight: 400; word-break: break-all; }

/* =========================================================
   平台下载卡 2×2
   ========================================================= */
.dl-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.pcard {
  position: relative;
  border: 1px solid var(--line2); border-radius: 16px;
  background: #fff;
  box-shadow: var(--shadow-sm);
  padding: 26px 26px 24px;
  display: flex; flex-direction: column;
  transition: transform .2s, border-color .2s, box-shadow .25s;
}
.pcard:hover { transform: translateY(-4px); border-color: rgba(37, 99, 235, 0.45); box-shadow: var(--shadow-md); }
.pcard .ph { display: flex; align-items: center; gap: 14px; }
.pcard .pa {
  width: 48px; height: 48px; border-radius: 13px; flex: 0 0 auto;
  display: grid; place-items: center;
  font-family: var(--mono); font-weight: 800; font-size: 19px; color: #fff;
  background: var(--cy);
  box-shadow: 0 8px 18px -8px rgba(18, 32, 58, 0.45);
}
.pcard.win .pa { background: linear-gradient(135deg, #2563eb, #0ea5e9); }
.pcard.mac .pa { background: linear-gradient(135deg, #7b8796, #475569); }
.pcard.and .pa { background: linear-gradient(135deg, #16a34a, #22c55e); }
.pcard.ios .pa { background: linear-gradient(135deg, #64748b, #0f172a); }
.pcard h3 { font-size: 19px; font-weight: 800; color: var(--txt); }
.pcard .pv { font-family: var(--mono); font-size: 11px; color: var(--dim); letter-spacing: 0.5px; }
.pcard .req { margin: 18px 0 20px; display: flex; gap: 8px; flex-wrap: wrap; }
.pcard .req span { font-size: 11.5px; color: var(--mut); border: 1px solid var(--line); border-radius: 7px; padding: 4px 10px; font-family: var(--mono); background: var(--panel2); }
.pcard .dl { margin-top: auto; display: flex; align-items: center; justify-content: space-between; gap: 12px; border-top: 1px solid var(--line); padding-top: 16px; }
.pcard .dl .sz { font-family: var(--mono); font-size: 11.5px; color: var(--dim); }
.pcard .dl .btn { padding: 10px 20px; font-size: 13.5px; }

/* 安全提示 */
.secure {
  margin-top: 26px;
  display: flex; align-items: center; gap: 16px;
  border: 1px solid #f0e2c4;
  background: #fdf8ee;
  border-radius: 14px; padding: 15px 19px;
}
.secure .sh {
  width: 40px; height: 40px; border-radius: 11px; flex: 0 0 auto;
  display: grid; place-items: center; color: var(--amb);
  border: 1px solid #ecdcb6; background: #fbf1dc;
}
.secure .sh svg { width: 20px; height: 20px; }
.secure p { font-size: 13px; color: var(--mut); }
.secure p b { color: #92400e; font-weight: 700; }

/* =========================================================
   FAQ（双栏）
   ========================================================= */
.faq-cols { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 60px; align-items: start; }
.faq-cols .aside { position: sticky; top: 104px; }
.support-card {
  margin-top: 26px; border: 1px solid #dbe7ff; border-radius: 15px;
  padding: 20px 22px; background: linear-gradient(135deg, #f4f8ff, #edf7fd);
}
.support-card b { font-size: 14px; display: block; color: var(--txt); }
.support-card p { font-size: 12.5px; color: var(--mut); margin-top: 4px; }
.support-card a { display: inline-flex; align-items: center; gap: 7px; margin-top: 12px; font-family: var(--mono); font-size: 12.5px; color: var(--cy); font-weight: 600; }

details {
  border: 1px solid var(--line); border-radius: 13px; margin-bottom: 10px;
  background: #fff; overflow: hidden;
  transition: border-color .2s, box-shadow .2s;
}
details[open] { border-color: rgba(37, 99, 235, 0.45); box-shadow: var(--shadow-sm); }
details summary {
  list-style: none; cursor: pointer;
  display: flex; align-items: center; gap: 12px;
  padding: 16px 20px; font-size: 14.5px; font-weight: 700; color: var(--txt);
}
details summary::-webkit-details-marker { display: none; }
details summary::after {
  content: "+"; margin-left: auto; flex: 0 0 auto;
  width: 22px; height: 22px; border-radius: 50%;
  display: grid; place-items: center;
  font-family: var(--mono); font-size: 15px; font-weight: 500; line-height: 1;
  color: var(--cy); background: #eef4ff;
  transition: transform .22s, background .2s, color .2s;
}
details[open] summary::after { transform: rotate(45deg); background: var(--grad); color: #fff; }
details p { padding: 2px 20px 17px 20px; color: var(--mut); font-size: 13.5px; line-height: 1.85; }

/* =========================================================
   页脚
   ========================================================= */
footer { margin-top: auto; border-top: 1px solid var(--line); padding: 46px 0 0; background: #fff; }
.ft-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.2fr; gap: 34px; padding-bottom: 40px; }
.ft-brand .logo { font-size: 16px; }
.ft-brand p { margin-top: 14px; font-size: 13px; color: var(--mut); max-width: 260px; }
.ft h5 { font-size: 12px; letter-spacing: 2px; color: var(--dim); font-weight: 700; margin-bottom: 14px; text-transform: uppercase; font-family: var(--mono); }
.ft ul li { margin-bottom: 8px; }
.ft ul a { font-size: 13.5px; color: var(--mut); transition: color .18s; }
.ft ul a:hover { color: var(--cy); }
.ft-bar {
  border-top: 1px solid var(--line);
  padding: 18px 0 22px;
  display: flex; justify-content: space-between; gap: 14px; flex-wrap: wrap;
  font-size: 12px; color: var(--dim);
}
.ft-bar .mono { font-size: 11px; }
footer .ft-bar a { color: var(--mut); transition: color .18s; }
footer .ft-bar a:hover { color: var(--cy); }

/* =========================================================
   404
   ========================================================= */
.err-main { flex: 1; display: flex; align-items: center; justify-content: center; padding: 60px 0 90px; position: relative; overflow: hidden; }
.err-main::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image: radial-gradient(rgba(37, 99, 235, 0.1) 1px, transparent 1px);
  background-size: 26px 26px;
  -webkit-mask-image: radial-gradient(ellipse 60% 60% at 30% 45%, #000 10%, transparent 72%);
  mask-image: radial-gradient(ellipse 60% 60% at 30% 45%, #000 10%, transparent 72%);
}
.err-wrap {
  position: relative;
  display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center;
  width: 100%;
}
.err-code { position: relative; display: flex; align-items: center; justify-content: center; padding: 30px 0; }
.err-code .ring {
  position: absolute; width: 380px; height: 380px; border-radius: 50%;
  border: 1px dashed rgba(37, 99, 235, 0.3);
  animation: spin 26s linear infinite;
}
.err-code .ring.r2 { width: 300px; height: 300px; border-color: rgba(14, 165, 233, 0.25); animation-duration: 18s; animation-direction: reverse; }
@keyframes spin { to { transform: rotate(360deg); } }
.err-code .num {
  position: relative; z-index: 1;
  font-size: clamp(120px, 19vw, 190px); font-weight: 900; line-height: 1;
  letter-spacing: -6px;
  font-family: var(--mono);
  background: linear-gradient(180deg, #e8eefb 8%, #2563eb 55%, #0ea5e9 92%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  animation: rise .8s cubic-bezier(.22, .8, .36, 1) both;
}
.err-copy { animation: rise .8s cubic-bezier(.22, .8, .36, 1) .08s both; }
.err-copy h1 { margin-top: 16px; font-size: clamp(26px, 4vw, 40px); font-weight: 900; letter-spacing: -1.6px; color: var(--txt); }
.err-copy p { margin-top: 14px; color: var(--mut); font-size: 15px; max-width: 460px; }
.err-actions { margin-top: 28px; display: flex; gap: 14px; flex-wrap: wrap; }
.sigline { margin-top: 26px; display: inline-flex; align-items: center; gap: 9px; font-family: var(--mono); font-size: 11px; color: var(--dim); letter-spacing: 1.5px; }
.sigline::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--red); animation: redpulse 1.6s ease-in-out infinite; }
@keyframes redpulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 960px) {
  .hero-grid, .dl-hero-grid { grid-template-columns: 1fr; gap: 48px; }
  .hero-panel { max-width: 560px; width: 100%; }
  .hero-stats .st { padding-right: 20px; margin-right: 20px; }
  .sec-cols, .faq-cols { grid-template-columns: 1fr; gap: 32px; }
  .sec-cols .aside, .faq-cols .aside { position: static; }
  .dl-grid { gap: 14px; }
  .feat { grid-template-columns: 56px 1fr; gap: 20px; }
  .f-meta { display: none; }
  .steps { grid-template-columns: 1fr; gap: 16px; }
  .ft-grid { grid-template-columns: 1fr 1fr; }
  .err-wrap { grid-template-columns: 1fr; gap: 12px; }
  .err-code .ring { width: 320px; height: 320px; }
  .err-code .ring.r2 { width: 250px; height: 250px; }
}

@media (max-width: 620px) {
  .container { padding: 0 18px; }
  .bar { height: 60px; gap: 12px; }
  .bar nav {
    display: none;
    position: fixed; top: 60px; left: 0; right: 0; z-index: 59;
    flex-direction: column; align-items: stretch; gap: 2px;
    padding: 10px 18px 18px;
    background: rgba(255, 255, 255, 0.97);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 40px -24px rgba(18, 32, 58, 0.25);
  }
  .bar nav.open { display: flex; }
  .bar nav a { padding: 13px 6px; font-size: 15px; border-bottom: 1px solid var(--line); color: var(--txt); }
  .menu { display: block; }
  .bar > .btn { display: none; }
  .hero { padding: 56px 0 52px; }
  .sec { padding-top: 66px; }
  .hero-stats .st { margin-right: 16px; padding-right: 16px; }
  .hero-stats b { font-size: 20px; }
  .dl-hero { padding: 52px 0 48px; }
  .dl-grid { grid-template-columns: 1fr; }
  .pcard { padding: 22px 20px; }
  .cta-strip { padding: 34px 24px; }
  .cta-strip .btn { width: 100%; }
  .metrics { grid-template-columns: 1fr; }
  .err-main { padding: 40px 0 70px; }
  .err-code .ring { width: 250px; height: 250px; }
  .err-code .ring.r2 { width: 190px; height: 190px; }
  .ft-grid { grid-template-columns: 1fr; gap: 26px; }
  .ft-brand { grid-row: 1; }
}