/* ============================================================
   VG棋牌电玩 · 共享样式表 /assets/site.css
   基调：深靛蓝夜底 + 精密网格 + 霓虹脉冲 + 编辑感衬线标题
   ============================================================ */

:root{
  --ink-0:#0B1020;
  --ink-1:#131A33;
  --line:#1E2745;
  --line-2:#2A3560;
  --magenta:#FF3D8B;
  --lime:#B6FF3C;
  --cyan:#35E0D6;
  --amber:#FFC24B;
  --violet:#8A6BFF;
  --text:#E8ECF8;
  --muted:#98A2C0;
  --font-display:"Source Han Serif SC","Noto Serif SC","Songti SC","SimSun",serif;
  --font-body:"Source Han Sans SC","HarmonyOS Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",ui-monospace,Consolas,monospace;
  --font-heavy:"Archivo Black","Arial Black",Impact,"Helvetica Neue",sans-serif;
  --w-page:1200px;
  --w-wide:1360px;
  --ease:cubic-bezier(.22,.8,.28,1);
}

/* 1. Reset --------------------------------------------------- */
*,*::before,*::after{box-sizing:border-box;}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  background:var(--ink-0);
}
body{
  margin:0;
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.8;
  letter-spacing:.01em;
  color:var(--text);
  background-color:var(--ink-0);
  background-image:
    linear-gradient(rgba(30,39,69,.42) 1px, transparent 1px),
    linear-gradient(90deg, rgba(30,39,69,.42) 1px, transparent 1px);
  background-size:72px 72px,72px 72px;
  background-attachment:fixed;
  overflow-x:hidden;
}
img,svg,video{display:block;max-width:100%;}
a{color:inherit;text-decoration:none;}
button,input,select{font:inherit;color:inherit;}
button{background:none;border:0;padding:0;}
ul,ol{margin:0;padding:0;list-style:none;}
h1,h2,h3,h4,h5,h6,p,dl,dd,figure{margin:0;}
h1,h2,h3,h4{line-height:1.28;}
[hidden]{display:none !important;}
::selection{background:var(--magenta);color:var(--ink-0);}
:focus-visible{outline:2px solid var(--cyan);outline-offset:3px;}
#main-content{scroll-margin-top:110px;}
#main-content:focus-visible{outline:2px solid var(--cyan);}

/* 2. 排版工具 ------------------------------------------------ */
.display-1{
  font-family:var(--font-display);
  font-weight:800;
  font-size:clamp(34px,5.4vw,68px);
  line-height:1.12;
  letter-spacing:-.02em;
}
.display-2{
  font-family:var(--font-display);
  font-weight:700;
  font-size:clamp(24px,3.2vw,36px);
  line-height:1.26;
  letter-spacing:-.01em;
}
.lede{font-size:clamp(17px,1.4vw,19px);margin-top:16px;max-width:66ch;}
.muted{color:var(--muted);}
.mono{font-family:var(--font-mono);font-size:14px;letter-spacing:.08em;}
.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.18em;
  color:var(--lime);
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--lime);}
.big-num{
  font-family:var(--font-heavy);
  font-size:clamp(72px,12vw,160px);
  line-height:.82;
  letter-spacing:-.02em;
  color:var(--ink-1);
  display:block;
}
@supports ((-webkit-text-stroke:1px #fff) or (text-stroke:1px #fff)){
  .big-num{color:transparent;-webkit-text-stroke:1px var(--lime);text-stroke:1px var(--lime);}
  .big-num--magenta{-webkit-text-stroke-color:var(--magenta);text-stroke-color:var(--magenta);}
}
.hairline{height:1px;background:var(--line);border:0;margin:clamp(20px,3vw,36px) 0;}
.stack{display:grid;gap:16px;}
.cluster{display:flex;flex-wrap:wrap;gap:10px;align-items:center;}
.notice{
  border-left:2px solid var(--amber);
  background:rgba(255,194,75,.08);
  padding:16px 18px;
  font-size:15px;
  color:var(--text);
}
.rule-list li{position:relative;padding-left:20px;margin-bottom:10px;color:var(--muted);}
.rule-list li::before{content:"";position:absolute;left:0;top:.85em;width:10px;height:1px;background:var(--cyan);}
.rule-list strong{color:var(--text);font-weight:600;}

/* 3. 布局 ---------------------------------------------------- */
.container{width:min(var(--w-page),calc(100% - 34px));margin-inline:auto;}
.container-wide{width:min(var(--w-wide),calc(100% - 34px));margin-inline:auto;}
.section{padding:clamp(40px,7vw,96px) 0;position:relative;}
.section--tint{background:linear-gradient(180deg,rgba(19,26,51,.9),rgba(19,26,51,.35));}
.section--grid{
  background-image:
    linear-gradient(rgba(30,39,69,.6) 1px,transparent 1px),
    linear-gradient(90deg,rgba(30,39,69,.6) 1px,transparent 1px);
  background-size:48px 48px;
}
.section-head{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:16px;
  align-items:end;
  padding-bottom:18px;
  margin-bottom:28px;
  border-bottom:1px solid var(--line);
}
.section-kicker{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.18em;
  color:var(--cyan);
}
.section-title{
  font-family:var(--font-display);
  font-weight:800;
  font-size:clamp(26px,3.6vw,44px);
  line-height:1.2;
  letter-spacing:-.02em;
  margin-top:8px;
}
.section-sub{margin-top:10px;color:var(--muted);max-width:64ch;font-size:15px;}

.grid{display:grid;gap:clamp(16px,2vw,24px);}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr));}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr));}
.grid--4{grid-template-columns:repeat(4,minmax(0,1fr));}
.grid--asym{grid-template-columns:minmax(0,7fr) minmax(0,5fr);}
.grid--asym-rev{grid-template-columns:minmax(0,5fr) minmax(0,7fr);}

/* 4. 按钮与控件 ---------------------------------------------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 20px;
  border:1px solid var(--line-2);
  border-radius:2px;
  background:rgba(11,16,32,.65);
  color:var(--text);
  font-size:15px;
  font-weight:600;
  cursor:pointer;
  transition:background .2s var(--ease),color .2s var(--ease),
             border-color .2s var(--ease),transform .2s var(--ease);
}
.btn:hover{transform:translateY(-2px);}
.btn-amber{background:var(--amber);border-color:var(--amber);color:var(--ink-0);}
.btn-amber:hover{background:#FFD37A;border-color:#FFD37A;}
.btn-lime{background:transparent;border-color:var(--lime);color:var(--lime);}
.btn-lime:hover{background:rgba(182,255,60,.12);}
.btn-ghost{background:transparent;border-color:var(--line-2);color:var(--muted);}
.btn-ghost:hover{border-color:var(--cyan);color:var(--cyan);}
.btn-compact{padding:9px 16px;font-size:14px;}
.copy-btn{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 10px;
  border:1px solid var(--line);
  border-radius:2px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--muted);
  cursor:pointer;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.copy-btn:hover{color:var(--lime);border-color:var(--lime);}
.copy-btn[data-copied]{color:var(--lime);border-color:var(--lime);}

/* 5. 标签与说明牌 -------------------------------------------- */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 10px;
  border:1px solid var(--line-2);
  border-radius:999px;
  background:rgba(11,16,32,.7);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
  color:var(--muted);
}
.tag--cyan{color:var(--cyan);border-color:rgba(53,224,214,.45);}
.tag--magenta{color:var(--magenta);border-color:rgba(255,61,139,.45);}
.tag--lime{color:var(--lime);border-color:rgba(182,255,60,.45);}
.tag--violet{color:#B9A6FF;border-color:rgba(138,107,255,.5);background:rgba(138,107,255,.14);}
.spec-tag{display:grid;gap:2px;padding:10px 12px;border:1px solid var(--line);background:var(--ink-1);}
.spec-tag dt{font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;color:var(--muted);}
.spec-tag dd{font-size:15px;color:var(--text);}

/* 6. 卡片 ---------------------------------------------------- */
.card{
  position:relative;
  padding:22px;
  border:1px solid var(--line);
  border-radius:2px;
  background:rgba(19,26,51,.85);
  transition:transform .2s var(--ease),border-color .2s var(--ease),background .2s var(--ease);
}
.card:hover{transform:translateY(-2px);border-color:var(--violet);background:rgba(19,26,51,.98);}
.card-num{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--magenta);}
.card-title{font-family:var(--font-display);font-weight:700;font-size:20px;line-height:1.35;margin-top:8px;}
.card-body{margin-top:8px;color:var(--muted);font-size:15px;}
.card-meta{
  display:flex;flex-wrap:wrap;gap:12px;
  margin-top:16px;padding-top:12px;
  border-top:1px solid var(--line);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.06em;color:var(--muted);
}
.card--link{display:block;}
.card--link:hover .card-title{color:var(--cyan);}

/* 7. 索引 / 时间轴 / 面包屑 ---------------------------------- */
.index-list{border-top:1px solid var(--line);}
.index-row{
  display:grid;
  grid-template-columns:auto minmax(0,1fr) auto;
  gap:14px;
  align-items:baseline;
  padding:14px 6px;
  border-bottom:1px solid var(--line);
  transition:background .18s var(--ease);
}
.index-row:hover{background:rgba(138,107,255,.12);}
.idx{font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--magenta);}
.idx-title{font-size:16px;color:var(--text);}
.idx-meta{font-family:var(--font-mono);font-size:12px;color:var(--muted);letter-spacing:.06em;}
.timeline{position:relative;padding-left:24px;border-left:1px solid var(--line);}
.timeline-item{position:relative;padding-bottom:28px;}
.timeline-item::before{
  content:"";position:absolute;left:-29px;top:10px;
  width:9px;height:9px;
  background:var(--ink-0);
  border:1px solid var(--cyan);
}
.timeline-item[data-state="new"]::before{background:var(--lime);border-color:var(--lime);}
.timeline-date{font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--muted);}
.timeline-title{font-family:var(--font-display);font-weight:700;font-size:19px;margin-top:6px;}
ol.breadcrumb{
  display:flex;flex-wrap:wrap;gap:8px;align-items:center;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--muted);
}
ol.breadcrumb li{display:flex;align-items:center;gap:8px;}
ol.breadcrumb li + li::before{content:"/";color:var(--line-2);}
ol.breadcrumb a:hover{color:var(--cyan);}
ol.breadcrumb [aria-current="page"]{color:var(--text);}

/* 8. 折叠 / 筛选 / 步骤 / 轨道 ------------------------------- */
.fold{border:1px solid var(--line);background:rgba(19,26,51,.6);}
.fold + .fold{margin-top:-1px;}
.fold summary{
  display:flex;align-items:baseline;gap:12px;
  padding:16px 18px;
  font-size:16px;font-weight:600;
  cursor:pointer;
  list-style:none;
  transition:color .18s var(--ease);
}
.fold summary::-webkit-details-marker{display:none;}
.fold summary::after{content:"+";margin-left:auto;font-family:var(--font-mono);color:var(--lime);}
.fold[open] summary{color:var(--cyan);border-bottom:1px solid var(--line);}
.fold[open] summary::after{content:"–";color:var(--magenta);}
.fold-body{padding:16px 18px;color:var(--muted);font-size:15px;}

.filter-bar{
  display:flex;flex-wrap:wrap;gap:8px;align-items:center;
  padding:12px;
  border:1px solid var(--line);
  background:rgba(19,26,51,.72);
}
.filter-btn{
  padding:8px 14px;
  border:1px solid var(--line-2);
  border-radius:2px;
  font-size:14px;
  color:var(--muted);
  cursor:pointer;
  transition:color .18s var(--ease),border-color .18s var(--ease),
             background .18s var(--ease);
}
.filter-btn:hover{color:var(--text);border-color:var(--violet);}
.filter-btn[aria-pressed="true"]{background:var(--lime);border-color:var(--lime);color:var(--ink-0);font-weight:700;}
.filter-count{margin-left:auto;font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--muted);}
.filter-empty{
  display:none;
  padding:16px;
  border:1px dashed var(--line-2);
  color:var(--muted);
  font-size:14px;
}
.filter-empty[data-active]{display:block;}

.step-track{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  border:1px solid var(--line);
  background:rgba(19,26,51,.6);
}
.step-node{position:relative;padding:22px;border-right:1px solid var(--line);}
.step-node:last-child{border-right:0;}
.step-index{
  display:block;
  font-family:var(--font-heavy);
  font-size:46px;
  line-height:1;
  color:var(--ink-1);
}
@supports ((-webkit-text-stroke:1px #fff) or (text-stroke:1px #fff)){
  .step-index{color:transparent;-webkit-text-stroke:1px var(--magenta);text-stroke:1px var(--magenta);}
  .step-node[data-state="active"] .step-index{
    -webkit-text-stroke-color:var(--lime);
    text-stroke-color:var(--lime);
    animation:pulse-once .9s var(--ease) 1;
  }
}
.step-node h3{font-family:var(--font-display);font-size:19px;font-weight:700;margin-top:12px;}
.step-node p{margin-top:8px;color:var(--muted);font-size:15px;}
.step-detail{
  max-height:0;opacity:0;overflow:hidden;
  transition:max-height .35s var(--ease),opacity .35s var(--ease);
}
.step-node[data-state="active"] .step-detail{max-height:320px;opacity:1;margin-top:10px;}
@keyframes pulse-once{
  0%{transform:scale(1);}
  40%{transform:scale(1.08);}
  100%{transform:scale(1);}
}
.rail{
  position:relative;height:6px;
  background:var(--ink-1);
  border:1px solid var(--line);
  overflow:hidden;
}
.rail span{
  display:block;height:100%;width:var(--rail-value,0%);
  background:linear-gradient(90deg,var(--magenta),var(--lime));
  transition:width .45s var(--ease);
}
.stat{padding:18px;border:1px solid var(--line);background:rgba(19,26,51,.75);}
.stat-value{font-family:var(--font-heavy);font-size:clamp(32px,4vw,52px);line-height:1;color:var(--lime);}
.stat-label{margin-top:10px;font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--muted);}

/* 9. 图片容器（页面阶段放置占位） ---------------------------- */
.media-frame{
  position:relative;
  display:block;
  overflow:hidden;
  aspect-ratio:16/10;
  border:1px solid var(--line);
  border-radius:2px;
  background:linear-gradient(135deg,rgba(19,26,51,.96),rgba(11,16,32,.96));
}
.media-frame img{width:100%;height:100%;object-fit:cover;}
.media-frame::after{
  content:"";
  position:absolute;inset:0;
  background:repeating-linear-gradient(115deg,rgba(53,224,214,.07) 0 1px,transparent 1px 14px);
  pointer-events:none;
}
.media-frame--wide{aspect-ratio:21/9;}
.media-frame--square{aspect-ratio:1/1;}
.media-frame--tall{aspect-ratio:4/5;}
.media-cap{
  display:flex;gap:10px;align-items:baseline;
  margin-top:10px;
  font-size:13px;
  color:var(--muted);
}
.media-cap b{font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;color:var(--cyan);font-weight:400;}

/* 10. 头部：悬浮胶囊浮岛 ------------------------------------- */
.skip-link{
  position:absolute;left:16px;top:-64px;z-index:120;
  padding:10px 16px;
  background:var(--amber);
  color:var(--ink-0);
  font-weight:700;
  border-radius:2px;
  transition:top .2s var(--ease);
}
.skip-link:focus{top:14px;}
.site-header{
  position:sticky;top:0;z-index:90;
  padding:14px 0 0;
  background:linear-gradient(180deg,rgba(11,16,32,.97) 0%,rgba(11,16,32,.88) 64%,rgba(11,16,32,0) 100%);
}
.header-inner{
  width:min(var(--w-wide),calc(100% - 32px));
  margin-inline:auto;
  display:flex;align-items:center;gap:16px;
  padding:8px 10px 8px 12px;
  border:1px solid var(--line);
  border-radius:2px;
  background:rgba(19,26,51,.94);
  transition:padding .25s var(--ease),border-color .25s var(--ease),background .25s var(--ease);
}
.site-header[data-condensed] .header-inner{padding-top:5px;padding-bottom:5px;border-color:var(--line-2);background:rgba(19,26,51,.99);}
.brand{display:flex;align-items:center;gap:12px;flex:0 0 auto;}
.brand-mark{
  position:relative;
  display:grid;place-items:center;
  width:44px;height:44px;
  font-family:var(--font-heavy);
  font-size:19px;
  letter-spacing:.03em;
  color:var(--ink-0);
  background:linear-gradient(135deg,var(--magenta),var(--violet));
  border:1px solid rgba(232,236,248,.25);
}
.brand-mark::after{content:"";position:absolute;right:-1px;bottom:-1px;width:12px;height:12px;background:var(--lime);}
.brand-copy{display:flex;flex-direction:column;line-height:1.25;}
.brand-name{font-family:var(--font-display);font-weight:800;font-size:19px;letter-spacing:.02em;}
.brand-tag{font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--muted);}
.site-header[data-condensed] .brand-tag{display:none;}
.nav-capsule{
  display:flex;align-items:center;gap:8px;
  margin-left:auto;
  padding:5px;
  border:1px solid var(--line);
  border-radius:999px;
  background:rgba(11,16,32,.8);
}
.nav-list{display:flex;align-items:center;gap:2px;}
.nav-link{
  display:block;
  padding:8px 14px;
  border:1px solid transparent;
  border-radius:999px;
  font-size:15px;
  color:var(--muted);
  white-space:nowrap;
  transition:color .18s var(--ease),background .18s var(--ease),border-color .18s var(--ease);
}
.nav-link:hover{color:var(--text);background:rgba(138,107,255,.18);border-color:rgba(138,107,255,.45);}
.nav-link[aria-current="page"]{background:var(--lime);border-color:var(--lime);color:var(--ink-0);font-weight:700;}
.nav-path{
  display:flex;align-items:center;gap:6px;
  padding-left:10px;
  border-left:1px solid var(--line);
}
.path-chip{
  display:flex;align-items:center;gap:6px;
  padding:6px 10px;
  border:1px dashed var(--line-2);
  border-radius:2px;
  font-size:13px;
  color:var(--muted);
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.path-chip:hover{color:var(--cyan);border-color:var(--cyan);}
.path-num{font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;color:var(--magenta);}
.path-label{white-space:nowrap;}
.header-actions{display:flex;align-items:center;gap:10px;flex:0 0 auto;}
.nav-toggle{
  display:none;align-items:center;gap:8px;
  padding:9px 12px;
  border:1px solid var(--line-2);
  border-radius:2px;
  font-size:14px;
  color:var(--text);
  cursor:pointer;
}
.nav-toggle[aria-expanded="true"]{border-color:var(--amber);color:var(--amber);}
.nav-toggle-bars{position:relative;display:block;width:18px;height:12px;}
.nav-toggle-bars::before,.nav-toggle-bars::after{
  content:"";position:absolute;left:0;width:18px;height:2px;background:var(--lime);
  transition:transform .22s var(--ease),top .22s var(--ease),bottom .22s var(--ease);
}
.nav-toggle-bars::before{top:0;}
.nav-toggle-bars::after{bottom:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before{top:5px;transform:rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after{bottom:5px;transform:rotate(-45deg);}
.nav-toggle-text{font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;}
.scroll-rail{position:relative;height:2px;margin-top:10px;background:transparent;}
.scroll-bar{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--magenta),var(--violet),var(--lime));
}

/* 11. 页脚 --------------------------------------------------- */
.site-footer{
  position:relative;
  margin-top:clamp(48px,8vw,120px);
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(19,26,51,.55),rgba(11,16,32,1) 58%);
}
.site-footer::before{
  content:"";position:absolute;top:-1px;left:0;
  width:min(300px,42%);height:2px;
  background:linear-gradient(90deg,var(--magenta),var(--lime));
}
.footer-inner{width:min(var(--w-wide),calc(100% - 32px));margin-inline:auto;padding:clamp(34px,5vw,64px) 0 26px;}
.footer-top{
  display:grid;
  grid-template-columns:1.05fr 1.6fr 1fr;
  gap:clamp(22px,3vw,48px);
}
.footer-mark{
  display:grid;place-items:center;
  width:52px;height:52px;
  font-family:var(--font-heavy);
  font-size:21px;
  color:var(--ink-0);
  background:linear-gradient(135deg,var(--cyan),var(--violet));
}
.footer-title{font-family:var(--font-display);font-weight:800;font-size:22px;margin-top:14px;}
.footer-tagline{margin-top:6px;font-size:15px;color:var(--muted);max-width:30ch;}
.footer-note{
  margin-top:12px;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.05em;
  line-height:1.7;
  color:var(--muted);
}
.footer-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px;}
.footer-col-title{
  display:flex;align-items:baseline;gap:8px;
  margin-bottom:12px;
  font-size:14px;font-weight:700;letter-spacing:.06em;
  color:var(--text);
}
.footer-col-num{font-family:var(--font-mono);font-size:12px;color:var(--lime);}
.footer-col ul li + li{margin-top:8px;}
.footer-col a{
  font-size:15px;color:var(--muted);
  border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer-col a:hover{color:var(--cyan);border-color:var(--cyan);}
.contact-list div + div{margin-top:10px;}
.contact-list dt{font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;color:var(--muted);}
.contact-list dd{margin-top:2px;font-size:14px;color:var(--text);}
.footer-service{margin-top:12px;font-size:12px;color:var(--muted);line-height:1.7;}
.footer-bottom{
  display:flex;flex-wrap:wrap;gap:10px 24px;
  align-items:center;justify-content:space-between;
  margin-top:34px;padding-top:18px;
  border-top:1px solid var(--line);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--muted);
}
.footer-jump a{color:var(--amber);border-bottom:1px solid transparent;}
.footer-jump a:hover{border-color:var(--amber);}
.footer-filing{color:var(--muted);}

/* 12. 显现 / 返回顶部 ---------------------------------------- */
.reveal{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .5s var(--ease),transform .5s var(--ease);
}
.reveal.is-visible{opacity:1;transform:none;}
.to-top{
  position:fixed;right:18px;bottom:18px;z-index:80;
  display:grid;place-items:center;
  width:46px;height:46px;
  border:1px solid var(--line-2);
  border-radius:2px;
  background:rgba(19,26,51,.96);
  color:var(--lime);
  font-family:var(--font-mono);
  font-size:14px;
  cursor:pointer;
  opacity:0;visibility:hidden;
  transition:opacity .2s var(--ease),visibility .2s var(--ease),border-color .2s var(--ease);
}
.to-top[data-visible]{opacity:1;visibility:visible;}
.to-top:hover{border-color:var(--lime);}

/* 13. 响应式 ------------------------------------------------- */
@media (max-width:1180px){
  .nav-path{display:none;}
}
@media (max-width:1024px){
  .footer-top{grid-template-columns:1fr 1fr;}
  .footer-contact{grid-column:1 / -1;}
}
@media (max-width:900px){
  .grid--2,.grid--3,.grid--4,.grid--asym,.grid--asym-rev{grid-template-columns:minmax(0,1fr);}
  .section-head{grid-template-columns:minmax(0,1fr);align-items:start;}
  .brand-tag{display:none;}
  .nav-toggle{display:inline-flex;}
  .nav-capsule{
    position:fixed;
    left:16px;right:16px;top:86px;
    flex-direction:column;
    align-items:stretch;
    gap:10px;
    padding:14px;
    border-radius:2px;
    background:rgba(19,26,51,.99);
    max-height:calc(100vh - 120px);
    overflow:auto;
    transform:translateY(-12px);
    opacity:0;visibility:hidden;pointer-events:none;
    transition:opacity .22s var(--ease),transform .22s var(--ease),visibility .22s var(--ease);
  }
  .nav-capsule[data-open]{
    opacity:1;visibility:visible;transform:none;pointer-events:auto;
  }
  .nav-list{flex-direction:column;align-items:stretch;gap:4px;}
  .nav-link{padding:12px 14px;border-radius:2px;border-color:var(--line);font-size:16px;}
  .nav-path{
    display:flex;flex-wrap:wrap;
    padding:12px 0 0;
    border-left:0;border-top:1px solid var(--line);
  }
  .footer-cols{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (max-width:640px){
  body{font-size:16px;}
  .header-inner{gap:10px;}
  .brand-mark{width:38px;height:38px;font-size:16px;}
  .btn-compact{padding:8px 12px;font-size:13px;}
  .nav-toggle-text{display:none;}
  .step-node{border-right:0;border-bottom:1px solid var(--line);}
  .step-node:last-child{border-bottom:0;}
  .index-row{grid-template-columns:auto minmax(0,1fr);}
  .idx-meta{grid-column:2;}
  .footer-cols{grid-template-columns:minmax(0,1fr);}
  .footer-bottom{justify-content:flex-start;}
  .to-top{right:12px;bottom:12px;}
}

/* 14. 动效降级 ----------------------------------------------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .reveal{opacity:1;transform:none;}
  .card:hover{transform:none;}
  .btn:hover{transform:none;}
}