/* 快连 - 风格：深空蓝 · 霓虹青绿 · 速度仪表 */
:root{
  --accent:#00e0a4;
  --accent-2:#38bdf8;
  --accent-3:#7c5cff;
  --warn:#ff7a59;
  --star:#ffc44d;
  --bg:#05080f;
  --panel:#0f1622;
  --panel-2:#141d2c;
  --line:#1e2a3d;
  --line-2:#2b3d57;
  --text:#d7e3f0;
  --muted:#8494a8;
  --white:#fff;
  --radius:16px;
  --mono:"SFMono-Regular",Consolas,"Liberation Mono",Menlo,monospace;
  --max:1160px;
  --shadow:0 18px 44px rgba(0,0,0,.45);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
[id]{scroll-margin-top:92px}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Segoe UI",sans-serif;
  background:var(--bg);color:var(--text);line-height:1.8;font-size:16px;overflow-x:hidden;
}
body::before{
  content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;
  background:radial-gradient(900px 500px at 10% -10%,rgba(0,224,164,.17),transparent 62%),
             radial-gradient(780px 430px at 88% 0%,rgba(56,189,248,.13),transparent 62%),
             radial-gradient(720px 520px at 50% 112%,rgba(124,92,255,.12),transparent 62%);
}
a{color:var(--accent-2);text-decoration:none}
a:hover{text-decoration:underline}
::selection{background:rgba(0,224,164,.28);color:#fff}

/* 顶栏 */
.navbar{
  position:sticky;top:0;z-index:40;
  background:rgba(5,8,15,.78);backdrop-filter:blur(14px);
  border-bottom:1px solid transparent;transition:border-color .25s,box-shadow .25s,background .25s;
}
.navbar.scrolled{border-bottom-color:var(--line);background:rgba(5,8,15,.92);box-shadow:0 10px 34px rgba(0,0,0,.5)}
.navbar .inner{max-width:var(--max);margin:0 auto;padding:0 20px;height:64px;display:flex;align-items:center;gap:26px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--white);font-size:19px;letter-spacing:.5px}
.brand .dot{width:10px;height:10px;border-radius:50%;background:var(--accent);box-shadow:0 0 14px var(--accent);animation:pulse 2.4s ease-in-out infinite}
@keyframes pulse{0%,100%{opacity:1;transform:scale(1)}50%{opacity:.55;transform:scale(.82)}}
.brand small{color:var(--muted);font-weight:400;font-size:12px;letter-spacing:2px;font-family:var(--mono)}
.menu{display:flex;gap:24px;font-size:15px}
.menu a{color:var(--muted);position:relative;padding:4px 0;transition:color .2s}
.menu a::after{
  content:"";position:absolute;left:0;right:0;bottom:-4px;height:2px;border-radius:2px;
  background:linear-gradient(90deg,var(--accent),var(--accent-2));transform:scaleX(0);transition:transform .25s;
}
.menu a:hover,.menu a.active{color:var(--white);text-decoration:none}
.menu a:hover::after,.menu a.active::after{transform:scaleX(1)}
.badge{
  margin-left:auto;font-family:var(--mono);font-size:12px;color:var(--accent);
  border:1px solid var(--line);padding:5px 12px;border-radius:999px;background:rgba(0,224,164,.08);white-space:nowrap;
}
@media(max-width:820px){
  .navbar .inner{gap:14px}
  .brand small{display:none}
  .menu{gap:16px;font-size:14px;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none}
  .menu::-webkit-scrollbar{display:none}
  .badge{padding:4px 10px}
}

/* Hero */
.hero{max-width:var(--max);margin:0 auto;padding:72px 20px 30px;text-align:center}
.kicker{
  display:inline-flex;align-items:center;gap:8px;font-family:var(--mono);font-size:12px;letter-spacing:2.4px;
  text-transform:uppercase;color:var(--accent);border:1px solid var(--line);border-radius:999px;
  padding:6px 16px;background:rgba(0,224,164,.08);margin-bottom:22px;
}
.kicker i{width:6px;height:6px;border-radius:50%;background:var(--accent);box-shadow:0 0 8px var(--accent)}
.hero h1{
  font-size:clamp(30px,5vw,50px);line-height:1.22;color:var(--white);letter-spacing:-.6px;margin-bottom:16px;font-weight:800;
}
.hero h1 em{
  font-style:normal;background:linear-gradient(100deg,var(--accent),var(--accent-2) 60%,var(--accent-3));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
.hero p.lead{max-width:700px;margin:0 auto 30px;color:var(--muted);font-size:17.5px}
.hero .btns{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:8px;padding:13px 30px;border-radius:10px;font-weight:600;
  background:linear-gradient(135deg,var(--accent),#12c2e9);color:#04140f;
  box-shadow:0 12px 28px rgba(0,224,164,.28);transition:transform .2s,box-shadow .2s,filter .2s;
}
.btn:hover{transform:translateY(-2px);filter:brightness(1.06);box-shadow:0 16px 34px rgba(0,224,164,.34);text-decoration:none;color:#04140f}
.btn.line{background:rgba(255,255,255,.03);color:var(--text);border:1px solid var(--line);box-shadow:none}
.btn.line:hover{border-color:var(--accent);color:var(--white);background:rgba(0,224,164,.08)}
.pills{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;margin-top:28px}
.pills span{
  font-size:12.5px;color:var(--muted);border:1px solid var(--line);border-radius:999px;
  padding:5px 13px;background:rgba(255,255,255,.02);
}
.pills span b{color:var(--text);font-weight:600}

/* 数据条 */
.stats{max-width:var(--max);margin:0 auto;padding:0 20px}
.stats .row{
  display:grid;grid-template-columns:repeat(4,1fr);gap:14px;position:relative;overflow:hidden;
  border:1px solid var(--line);border-radius:var(--radius);padding:24px 18px;
  background:linear-gradient(180deg,rgba(20,29,44,.92),rgba(15,22,34,.7));backdrop-filter:blur(8px);
}
.stats .row::after{
  content:"";position:absolute;left:0;right:0;top:0;height:1px;
  background:linear-gradient(90deg,transparent,rgba(0,224,164,.6),rgba(56,189,248,.6),transparent);
}
.stats .cell{text-align:center;position:relative;z-index:1}
.stats b{display:block;font-family:var(--mono);font-size:32px;color:var(--white);line-height:1.2;font-weight:700}
.stats b i{font-style:normal;color:var(--accent)}
.stats span{font-size:13.5px;color:var(--muted)}
@media(max-width:760px){.stats .row{grid-template-columns:repeat(2,1fr)}}

/* 速度仪表 */
.meter{
  max-width:920px;margin:26px auto 40px;background:#080d16;border:1px solid var(--line);
  border-radius:var(--radius);padding:20px 22px;box-shadow:var(--shadow);
}
.meter .meter-head,.meter .top{display:flex;align-items:center;justify-content:space-between;font-family:var(--mono);font-size:12.5px;color:var(--muted);flex-wrap:wrap;gap:8px}
.meter .meter-head .on,.meter .top .on{color:var(--accent);display:flex;align-items:center;gap:8px}
.meter .meter-head .on i,.meter .top .on i{width:8px;height:8px;border-radius:50%;background:var(--accent);box-shadow:0 0 10px var(--accent);display:block;animation:pulse 2s ease-in-out infinite}
.meter .track{height:9px;border-radius:999px;background:#141d2c;margin:14px 0 12px;overflow:hidden}
.meter .fill{
  height:100%;width:78%;border-radius:999px;
  background:linear-gradient(90deg,var(--accent),var(--accent-2),var(--accent));background-size:220% 100%;
  animation:flow 3.4s linear infinite;
}
@keyframes flow{to{background-position:220% 0}}
.meter .node{display:flex;gap:18px;flex-wrap:wrap;font-size:13px;color:var(--muted)}
.meter .node b{color:var(--text);font-weight:600}

/* 区块 */
section{max-width:var(--max);margin:0 auto;padding:0 20px}
.block{padding:48px 0}
.eyebrow{font-family:var(--mono);font-size:12px;letter-spacing:2.6px;text-transform:uppercase;color:var(--accent);margin-bottom:8px}
.block h2{font-size:26px;color:var(--white);margin-bottom:8px;display:flex;align-items:center;gap:10px;letter-spacing:-.3px}
.block h2::before{content:"";width:4px;height:24px;border-radius:2px;background:linear-gradient(180deg,var(--accent),var(--accent-2))}
.block .desc{color:var(--muted);margin-bottom:26px;font-size:15.5px;max-width:720px}

.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.grid.four{grid-template-columns:repeat(4,1fr)}
.grid.two{grid-template-columns:repeat(2,1fr)}
@media(max-width:980px){.grid,.grid.four,.grid.two{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){.grid,.grid.four,.grid.two{grid-template-columns:1fr}}
.panel{
  background:linear-gradient(180deg,var(--panel),var(--panel-2));
  border:1px solid var(--line);border-radius:var(--radius);padding:22px;
  transition:transform .25s,border-color .25s,box-shadow .25s;
}
.panel:hover{transform:translateY(-4px);border-color:var(--line-2);box-shadow:0 18px 40px rgba(0,0,0,.42)}
.panel h3{color:var(--white);font-size:17.5px;margin-bottom:8px}
.panel p{font-size:14.5px;color:var(--muted)}
.panel .tag{
  font-family:var(--mono);font-size:11px;color:var(--accent);
  border:1px solid var(--line);border-radius:5px;padding:2px 9px;display:inline-block;margin-bottom:10px;letter-spacing:1px;
}
.tile{
  width:46px;height:46px;border-radius:13px;display:flex;align-items:center;justify-content:center;font-size:22px;
  background:linear-gradient(145deg,rgba(0,224,164,.18),rgba(56,189,248,.10));
  border:1px solid var(--line);margin-bottom:14px;transition:transform .25s;
}
.panel:hover .tile{transform:translateY(-2px) rotate(-5deg)}

/* 套餐 */
.price{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;align-items:start}
@media(max-width:980px){.price{grid-template-columns:1fr;max-width:460px;margin:0 auto}}
.plan{
  position:relative;background:linear-gradient(180deg,var(--panel),var(--panel-2));
  border:1px solid var(--line);border-radius:var(--radius);padding:28px 24px;transition:transform .25s,border-color .25s;
}
.plan:hover{transform:translateY(-4px)}
.plan.hot{border-color:rgba(0,224,164,.55);box-shadow:0 18px 44px rgba(0,224,164,.13)}
.plan .flag{
  position:absolute;top:-13px;right:20px;font-size:12px;padding:4px 12px;border-radius:999px;
  background:linear-gradient(135deg,var(--accent),#12c2e9);color:#04140f;font-weight:700;letter-spacing:.5px;
}
.plan h3{color:var(--white);font-size:18px;margin-bottom:8px}
.plan .num{font-family:var(--mono);font-size:34px;color:var(--white);margin-bottom:16px;font-weight:700}
.plan .num i{font-style:normal;font-size:14px;color:var(--muted);font-weight:400}
.plan ul{list-style:none;margin-bottom:20px}
.plan li{font-size:14.5px;color:var(--muted);padding:5px 0 5px 22px;position:relative}
.plan li::before{content:"✓";position:absolute;left:0;color:var(--accent);font-size:13px}
.plan .btn{width:100%;justify-content:center}

/* 评价 */
.say .stars{color:var(--star);font-size:14px;letter-spacing:2px;margin-bottom:10px}
.say .who{display:flex;align-items:center;gap:11px;margin-top:16px}
.say .av{
  width:38px;height:38px;border-radius:50%;display:flex;align-items:center;justify-content:center;flex:none;
  background:linear-gradient(145deg,rgba(0,224,164,.2),rgba(56,189,248,.12));
  border:1px solid var(--line);color:var(--accent);font-weight:700;font-size:14px;
}
.say .who b{color:var(--white);font-size:14.5px;display:block}
.say .who span{font-size:12.5px;color:var(--muted)}

/* 折叠问答 */
details{
  border:1px solid var(--line);border-radius:12px;margin-bottom:10px;background:#0b1119;overflow:hidden;
  transition:border-color .2s,background .2s;
}
details[open]{border-color:var(--line-2);background:#0d1420}
summary{cursor:pointer;padding:16px 20px;font-weight:600;color:var(--white);list-style:none;font-size:15.5px;display:flex;justify-content:space-between;gap:14px;align-items:center}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";color:var(--accent);font-weight:700;font-size:18px;line-height:1}
details[open] summary::after{content:"−"}
details .body{padding:0 20px 18px;font-size:14.8px;color:var(--text);border-top:1px solid var(--line);padding-top:14px}
details .body p{margin-bottom:10px}
details .body p:last-child{margin-bottom:0}

.note{
  background:rgba(0,224,164,.07);border:1px solid var(--line);border-left:3px solid var(--accent);
  border-radius:10px;padding:15px 18px;margin:18px 0;font-size:14.8px;
}
.note.warn{background:rgba(255,122,89,.08);border-left-color:var(--warn)}
.note p:last-child{margin-bottom:0}

/* 平台下载卡 */
.plat{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
@media(max-width:980px){.plat{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.plat{grid-template-columns:1fr}}
.plat .panel{text-align:center}
.plat .os{font-family:var(--mono);font-size:14px;color:var(--accent);margin-bottom:6px;letter-spacing:1.5px}
.plat .req{font-size:13.5px;color:var(--muted);margin-bottom:10px}
.plat .meta{font-size:12.5px;color:#5f7086;font-family:var(--mono);margin-bottom:14px}
.plat .btn{width:100%;justify-content:center;padding:10px 12px;font-size:14px}

/* 步骤 */
.steps{counter-reset:s;list-style:none;margin-top:4px}
.steps li{position:relative;padding:0 0 20px 46px;border-left:2px solid var(--line);margin-left:16px}
.steps li:last-child{border-left-color:transparent;padding-bottom:0}
.steps li::before{
  counter-increment:s;content:counter(s);
  position:absolute;left:-17px;top:0;width:32px;height:32px;border-radius:50%;
  background:rgba(0,224,164,.14);border:1px solid var(--line);
  color:var(--accent);font-family:var(--mono);font-size:13px;
  display:flex;align-items:center;justify-content:center;
}
.steps b{color:var(--white);display:block;font-size:15.5px}
.steps span{font-size:14px;color:var(--muted)}

/* 表格 */
table{width:100%;border-collapse:collapse;font-size:14.5px;margin:18px 0}
th,td{border:1px solid var(--line);padding:11px 13px;text-align:left}
thead th{background:#0d1420;color:var(--white);font-weight:600}
tbody tr:nth-child(even){background:rgba(255,255,255,.02)}
tbody tr:hover{background:rgba(0,224,164,.05)}

/* 文档页 */
main.doc{max-width:860px;margin:36px auto 56px;background:var(--panel);border:1px solid var(--line);
  border-radius:var(--radius);padding:36px 32px;box-shadow:var(--shadow)}
@media(max-width:640px){main.doc{margin:20px 14px 40px;padding:24px 18px}}
.crumb{font-size:13px;color:var(--muted);margin-bottom:16px;font-family:var(--mono)}
.crumb i{font-style:normal;margin:0 6px;color:#3c4a5e}
main.doc h1{font-size:28px;color:var(--white);line-height:1.4;margin-bottom:10px}
main.doc .meta{font-size:13px;color:var(--muted);margin-bottom:24px;padding-bottom:16px;border-bottom:1px solid var(--line)}
main.doc h2{font-size:20px;color:var(--white);margin:32px 0 12px}
main.doc h2::before{content:"# ";color:var(--accent);font-family:var(--mono)}
main.doc h3{font-size:16.5px;color:var(--accent-2);margin:22px 0 8px}
main.doc p{margin-bottom:14px}
main.doc ul,main.doc ol{margin:0 0 16px 22px}
main.doc li{margin-bottom:7px}
main.doc code{
  font-family:var(--mono);font-size:13.5px;background:#080d16;border:1px solid var(--line);
  border-radius:5px;padding:1px 6px;color:var(--accent);
}
.cta{
  margin-top:36px;text-align:center;border:1px solid var(--line);border-radius:var(--radius);
  padding:34px 26px;background:linear-gradient(180deg,rgba(0,224,164,.13),rgba(56,189,248,.04));
}
.cta h3{color:var(--white);font-size:20px;margin-bottom:8px}
.cta p{color:var(--muted);margin-bottom:18px}

/* 404 */
.err{max-width:680px;margin:96px auto 36px;text-align:center;padding:0 20px}
.err .code{
  font-family:var(--mono);font-size:clamp(76px,16vw,112px);font-weight:800;line-height:1;letter-spacing:-2px;
  background:linear-gradient(135deg,var(--accent),var(--accent-2) 55%,var(--accent-3));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
.err h1{color:var(--white);font-size:24px;margin:16px 0 10px}
.err p{color:var(--muted);margin-bottom:28px}
.err .btns{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.err .links{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;font-size:14px;margin-top:24px}
.err .links a{color:var(--muted)}
.err .links a:hover{color:var(--accent)}

/* 回到顶部悬浮球 */
a.top{
  position:fixed;right:22px;bottom:26px;width:44px;height:44px;border-radius:50%;z-index:99;
  display:flex;align-items:center;justify-content:center;font-size:18px;line-height:1;font-weight:700;
  background:rgba(15,22,34,.94);border:1px solid var(--line-2);color:var(--accent);
  box-shadow:0 8px 24px rgba(0,0,0,.55),0 0 14px rgba(0,224,164,.18);
  opacity:0;visibility:hidden;transform:translateY(12px);transition:opacity .25s,transform .25s,background .25s,color .25s;
  backdrop-filter:blur(10px);
}
a.top.show{opacity:1;visibility:visible;transform:none}
a.top:hover,a.top:active{background:linear-gradient(135deg,var(--accent),#12c2e9);color:#04140f;text-decoration:none;box-shadow:0 10px 28px rgba(0,224,164,.4)}

/* 入场动画 */
.reveal{opacity:0;transform:translateY(20px);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}
  .brand .dot,.meter .fill{animation:none}
}

/* 页脚 */
footer{border-top:1px solid var(--line);background:#04070d;padding:42px 20px 26px;margin-top:40px}
footer .inner{max-width:var(--max);margin:0 auto;display:grid;grid-template-columns:2fr 1fr 1fr;gap:28px}
@media(max-width:780px){footer .inner{grid-template-columns:1fr}}
footer h4{color:var(--white);font-size:15px;margin-bottom:12px}
footer ul{list-style:none}
footer li{margin-bottom:7px;font-size:14px}
footer a{color:var(--muted)}
footer a:hover{color:var(--accent)}
footer .copy{max-width:var(--max);margin:26px auto 0;padding-top:16px;border-top:1px solid var(--line);font-size:13px;color:#5f6c7d}

/* ========================================================
   移动端专属显示优化 (Mobile Display Optimization)
   纯 CSS 适配，完全保持 HTML 结构与逻辑代码不变
   ======================================================== */

.btn:active{transform:scale(.98)}

@media(max-width:768px){
  /* 滚动定位与基础行高 */
  [id]{scroll-margin-top:76px}
  body{font-size:15px;line-height:1.75}

  /* 顶栏与水平滑动菜单 */
  .navbar .inner{padding:0 16px;height:58px;gap:12px}
  .brand{font-size:18px}
  .menu{gap:14px;font-size:14px;padding:6px 0}
  .menu a{white-space:nowrap;flex-shrink:0}
  .badge{font-size:11px;padding:3px 9px}

  /* Hero 区域 */
  .hero{padding:48px 16px 24px}
  .kicker{font-size:11px;letter-spacing:1.8px;padding:5px 14px;margin-bottom:18px}
  .hero h1{font-size:clamp(26px,6.5vw,38px);line-height:1.25;margin-bottom:14px}
  .hero p.lead{font-size:15.5px;line-height:1.65;margin-bottom:24px}
  .hero .btns{gap:10px}
  .pills{margin-top:22px;gap:6px}
  .pills span{font-size:12px;padding:4px 11px}

  /* 数据统计条 */
  .stats{padding:0 16px}
  .stats .row{padding:20px 14px;gap:16px 12px;border-radius:14px}
  .stats b{font-size:26px}
  .stats span{font-size:12.5px}

  /* 速度仪表 */
  .meter{margin:20px 16px 32px;padding:18px 16px;border-radius:14px}
  .meter .meter-head,.meter .top{font-size:12px}
  .meter .track{height:8px;margin:12px 0 10px}
  .meter .node{gap:8px 14px;font-size:12.5px}

  /* 通用区块与标题 */
  section{padding:0 16px}
  .block{padding:36px 0}
  .eyebrow{font-size:11px;letter-spacing:2px;margin-bottom:6px}
  .block h2{font-size:23px;margin-bottom:6px}
  .block h2::before{height:20px;width:3.5px}
  .block .desc{font-size:14.5px;margin-bottom:20px}

  /* 网格与卡片 */
  .grid{gap:12px}
  .panel{padding:18px 16px;border-radius:14px}
  .panel h3{font-size:16.5px;margin-bottom:6px}
  .panel p{font-size:14px;line-height:1.65}
  .tile{width:40px;height:40px;font-size:19px;border-radius:11px;margin-bottom:12px}

  /* 套餐卡片 */
  .price{max-width:480px;gap:16px}
  .plan{padding:24px 20px;border-radius:14px}
  .plan h3{font-size:17px}
  .plan .num{font-size:30px;margin-bottom:14px}
  .plan ul{margin-bottom:18px}
  .plan li{font-size:14px;padding:4px 0 4px 20px}
  .plan .btn{padding:11px 20px;font-size:15px}
  .plan .flag{top:-11px;right:16px;font-size:11.5px;padding:3px 11px}

  /* 评价卡片 */
  .say .panel p{font-size:14px;line-height:1.65}
  .say .who{margin-top:14px}
  .say .av{width:36px;height:36px;font-size:13.5px}

  /* FAQ 问答手风琴 */
  details{border-radius:10px;margin-bottom:8px}
  summary{padding:14px 16px;font-size:15px}
  details .body{padding:0 16px 14px;font-size:14px;line-height:1.68;padding-top:12px}

  /* 提示框 */
  .note{padding:13px 15px;font-size:14px;margin:14px 0;border-radius:9px}

  /* 表格横向流畅滑动（彻底解决手机端表格溢出与挤压） */
  table{display:block;width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch;margin:14px 0;font-size:13.5px;border-radius:10px}
  th,td{padding:9px 12px;white-space:nowrap}
  th:last-child,td:last-child{white-space:normal;min-width:190px}

  /* 平台下载卡片 */
  .plat{gap:12px}
  .plat .panel{padding:18px 14px}
  .plat .os{font-size:13.5px;margin-bottom:4px}
  .plat .req{font-size:13px;margin-bottom:8px}
  .plat .meta{font-size:12px;margin-bottom:12px}
  .plat .btn{padding:10px 14px;font-size:14px}

  /* 安装步骤条 */
  .steps li{padding:0 0 18px 40px;margin-left:14px}
  .steps li::before{left:-15px;width:28px;height:28px;font-size:12px}
  .steps b{font-size:15px}
  .steps span{font-size:13.5px;line-height:1.6}

  /* CTA 底部横幅 */
  .cta{margin-top:28px;padding:26px 18px;border-radius:14px}
  .cta h3{font-size:19px}
  .cta p{font-size:14px;margin-bottom:16px}

  /* 404 错误页 */
  .err{margin:56px auto 28px;padding:0 16px}
  .err .code{font-size:clamp(68px,19vw,92px)}
  .err h1{font-size:21px;margin:14px 0 8px}
  .err p{font-size:14.5px;margin-bottom:22px}
  .err .links{gap:10px 14px;font-size:13.5px;margin-top:20px}

  /* 页脚 */
  footer{padding:32px 16px 22px;margin-top:32px}
  footer .inner{gap:22px}
  footer h4{font-size:14.5px;margin-bottom:10px}
  footer li{font-size:13.5px;margin-bottom:6px}
  footer .copy{margin-top:22px;padding-top:14px;font-size:12.5px;line-height:1.6}

  /* 回到顶部悬浮球 */
  a.top{right:16px;bottom:20px;width:40px;height:40px;font-size:16px}
}

@media(max-width:480px){
  /* 紧凑小屏手机专属适配 (<= 480px) */
  .navbar .inner{padding:0 12px;height:54px;gap:10px}
  .brand{font-size:17px;gap:8px}
  .brand .dot{width:8px;height:8px}
  .menu{gap:12px;font-size:13.5px}
  .badge{display:none} /* 收起次要版本号，为导航腾出操作空间 */

  .hero{padding:38px 12px 18px}
  .hero h1{font-size:clamp(24px,7.2vw,30px)}
  .hero p.lead{font-size:14.5px;margin-bottom:20px}
  .hero .btns{width:100%}
  .hero .btns .btn{flex:1 1 100%;justify-content:center;padding:12px 16px}
  .btn{padding:12px 20px;font-size:14.5px}

  .stats{padding:0 12px}
  .stats .row{padding:16px 10px;gap:12px 8px}
  .stats b{font-size:23px}
  .stats span{font-size:11.5px}

  .meter{margin:16px 12px 24px;padding:14px 12px}
  .meter .node{flex-direction:column;gap:6px;font-size:12px}

  section{padding:0 12px}
  .block{padding:28px 0}
  .block h2{font-size:21px}
  .block .desc{font-size:13.5px;margin-bottom:16px}

  .panel{padding:15px 13px}
  .panel h3{font-size:16px}
  .panel p{font-size:13.5px}

  .plan{padding:20px 16px}
  .plan .num{font-size:27px}
  .plan li{font-size:13.5px}

  details summary{padding:12px 14px;font-size:14.5px}
  details .body{padding:0 14px 12px;font-size:13.5px}

  .cta{padding:22px 14px}
  .cta h3{font-size:18px}
  .cta .btn{width:100%;justify-content:center}

  .err .btns{width:100%}
  .err .btns .btn{width:100%;justify-content:center}

  footer{padding:26px 12px 20px}
}