/* ==========================================================================
   宝威赛场 8TEP · 共享样式 /assets/site.css
   夜间赛场指挥中心：深墨绿底、深灰蓝压面、荧光青结构、橙色数据强调
   ========================================================================== */

/* ---------- 1. 令牌 ---------- */
:root{
  --ink:#06130F;
  --panel:#0B241D;
  --slate:#16232C;
  --cyan:#35F2D0;
  --mint:#B9FFEF;
  --orange:#FF7A1A;
  --amber:#FFC08A;
  --paper:#EAF6F1;
  --muted:#7E9C93;
  --line:#24443B;

  --font-display:'Barlow Condensed','Noto Sans SC','Source Han Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  --font-body:'Noto Sans SC','Source Han Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,-apple-system,sans-serif;
  --font-mono:'JetBrains Mono','IBM Plex Mono',ui-monospace,SFMono-Regular,'SF Mono',Menlo,Consolas,'Liberation Mono',monospace;

  --shell:1320px;
  --gutter:clamp(1rem,3vw,2.5rem);
  --radius:2px;
  --ease:cubic-bezier(.2,.7,.3,1);
}

/* ---------- 2. 重置与基础 ---------- */
*,
*::before,
*::after{box-sizing:border-box;}

html{
  -webkit-text-size-adjust:100%;
  scroll-padding-top:7rem;
}

@media (prefers-reduced-motion:no-preference){
  html{scroll-behavior:smooth;}
}

body{
  margin:0;
  min-height:100vh;
  background-color:var(--ink);
  background-image:linear-gradient(90deg,rgba(36,68,59,.45) 1px,transparent 1px);
  background-size:clamp(56px,8vw,110px) 100%;
  color:var(--paper);
  font-family:var(--font-body);
  font-size:1rem;
  font-weight:400;
  line-height:1.75;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  text-rendering:optimizeLegibility;
}

img,svg,video,canvas{display:block;max-width:100%;}
img{height:auto;}

button,input,select,textarea{font:inherit;color:inherit;}
button{background:none;border:0;padding:0;cursor:pointer;}

a{color:inherit;text-decoration:none;}

ul[class],ol[class]{list-style:none;margin:0;padding:0;}

:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:3px;
  border-radius:1px;
}

/* ---------- 3. 中文排版 ---------- */
h1,h2,h3,h4,h5,h6{
  margin:0 0 .6em;
  font-family:var(--font-display);
  font-weight:800;
  line-height:1.06;
  letter-spacing:-.02em;
  color:var(--paper);
}
h1{font-size:clamp(2.4rem,6.2vw,4.6rem);}
h2{font-size:clamp(1.75rem,3.4vw,2.6rem);}
h3{font-size:clamp(1.2rem,2vw,1.5rem);}
h4{font-size:1.05rem;letter-spacing:.01em;}

p{margin:0 0 1.1em;}
p:last-child{margin-bottom:0;}

strong{color:var(--mint);font-weight:600;}
small{font-size:.8125rem;}

/* ---------- 4. 布局 ---------- */
.shell{
  width:min(100% - 2 * var(--gutter),var(--shell));
  margin-inline:auto;
}

.section{padding-block:clamp(2.25rem,5vw,4rem);}

.section-title{
  display:flex;
  align-items:baseline;
  gap:.75rem;
  margin:0 0 1.25rem;
  font-family:var(--font-display);
  font-size:clamp(1.45rem,2.8vw,2.1rem);
  font-weight:800;
  letter-spacing:-.02em;
  color:var(--paper);
}
.section-title::after{
  content:"";
  flex:1 1 auto;
  height:1px;
  background:var(--line);
}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:.5rem;
  margin:0 0 .9rem;
  font-size:.6875rem;
  font-weight:500;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--amber);
}
.eyebrow::before{
  content:"";
  width:1.5rem;
  height:1px;
  background:var(--orange);
}

.rule{
  height:1px;
  border:0;
  background:var(--line);
  margin:0;
}

.prose{max-width:68ch;color:var(--paper);}
.prose h2,.prose h3{margin-top:1.6em;}
.prose a{
  color:var(--cyan);
  text-decoration:underline;
  text-decoration-thickness:1px;
  text-underline-offset:.22em;
  transition:color .18s ease;
}
.prose a:hover{color:var(--mint);}
.prose ul,.prose ol{padding-left:1.2em;}
.prose li::marker{color:var(--orange);}
.prose code{
  font-family:var(--font-mono);
  font-size:.85em;
  padding:.1em .35em;
  border:1px solid var(--line);
  border-radius:var(--radius);
  color:var(--mint);
  background:var(--panel);
}

.grid{display:grid;gap:clamp(1rem,2.5vw,2rem);}
.grid--split{grid-template-columns:repeat(2,minmax(0,1fr));}
.grid--thirds{grid-template-columns:repeat(3,minmax(0,1fr));}
.grid--wide-left{grid-template-columns:minmax(0,1.7fr) minmax(0,1fr);}

@media (max-width:1080px){
  .grid--thirds{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (max-width:900px){
  .grid--split,
  .grid--wide-left{grid-template-columns:minmax(0,1fr);}
}
@media (max-width:720px){
  .grid--thirds{grid-template-columns:minmax(0,1fr);}
}

/* ---------- 5. 按钮 ---------- */
.btn{
  --btn-bg:transparent;
  --btn-fg:var(--paper);
  --btn-bd:var(--line);
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.55rem;
  padding:.72rem 1.2rem;
  border:1px solid var(--btn-bd);
  border-radius:var(--radius);
  background-color:var(--btn-bg);
  color:var(--btn-fg);
  font-family:var(--font-body);
  font-size:.8125rem;
  font-weight:500;
  letter-spacing:.06em;
  line-height:1.2;
  text-decoration:none;
  transition:background-color .18s ease,border-color .18s ease,color .18s ease,transform .18s ease;
}
.btn:hover{
  border-color:var(--cyan);
  color:var(--mint);
}
.btn:active{transform:translateY(1px);}

.btn--primary{
  --btn-bg:var(--cyan);
  --btn-fg:#04120E;
  --btn-bd:var(--cyan);
  font-weight:700;
}
.btn--primary:hover{
  --btn-bg:var(--mint);
  --btn-bd:var(--mint);
  color:#04120E;
}

.btn--ghost{
  --btn-bg:transparent;
  --btn-fg:var(--paper);
  --btn-bd:var(--line);
}
.btn--ghost:hover{
  --btn-bd:var(--orange);
  color:var(--amber);
}

.btn--sm{padding:.48rem .85rem;font-size:.75rem;}

/* ---------- 6. 标签 / 面板 / 卡片 / 数字 ---------- */
.tag{
  display:inline-flex;
  align-items:center;
  gap:.35rem;
  padding:.22rem .6rem;
  border:1px solid var(--line);
  border-radius:999px;
  font-size:.6875rem;
  letter-spacing:.1em;
  color:var(--muted);
  white-space:nowrap;
}
.tag--data{color:var(--orange);border-color:rgba(255,122,26,.45);}
.tag--cyan{color:var(--cyan);border-color:rgba(53,242,208,.35);}
.tag--muted{color:var(--muted);}

.panel{
  background:var(--panel);
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:clamp(1.15rem,2.4vw,1.85rem);
  box-shadow:0 18px 40px -34px rgba(0,0,0,.9);
}

.card{
  position:relative;
  display:block;
  padding:clamp(1rem,2vw,1.5rem);
  border:1px solid var(--line);
  border-radius:var(--radius);
  background-color:transparent;
  color:inherit;
  transition:border-color .18s ease,background-color .18s ease,transform .18s ease;
}
.card::before{
  content:"";
  position:absolute;
  left:-1px;
  top:1rem;
  width:2px;
  height:0;
  background:var(--orange);
  transition:height .18s ease;
}
.card:hover,
a.card:hover{
  border-color:rgba(53,242,208,.6);
  background-color:rgba(53,242,208,.035);
}
.card:hover::before,
a.card:hover::before{height:1.6rem;}
.card--stat{background-color:var(--panel);}

.stat{display:block;}
.stat__value{
  display:block;
  font-family:var(--font-mono);
  font-weight:700;
  font-size:clamp(2rem,5vw,3.4rem);
  line-height:1;
  letter-spacing:-.05em;
  color:var(--mint);
  font-variant-numeric:tabular-nums;
}
.stat__value--accent{color:var(--orange);}
.stat__label{
  display:block;
  margin-top:.45rem;
  font-size:.75rem;
  letter-spacing:.12em;
  color:var(--muted);
}

/* ---------- 7. 表格 / 折叠 / 图片容器 ---------- */
.table-scroll{
  overflow-x:auto;
  -webkit-overflow-scrolling:touch;
}

.data-table{
  width:100%;
  border-collapse:collapse;
  font-size:.875rem;
  font-variant-numeric:tabular-nums;
}
.data-table caption{
  caption-side:top;
  text-align:left;
  padding-bottom:.75rem;
  font-size:.75rem;
  letter-spacing:.1em;
  color:var(--muted);
}
.data-table th,
.data-table td{
  padding:.7rem .75rem;
  border-bottom:1px solid var(--line);
  text-align:left;
  vertical-align:top;
}
.data-table thead th{
  font-size:.6875rem;
  font-weight:500;
  letter-spacing:.12em;
  color:var(--mint);
  border-bottom:1px solid var(--cyan);
  white-space:nowrap;
}
.data-table tbody tr{transition:background-color .18s ease;}
.data-table tbody tr:hover{background-color:rgba(53,242,208,.06);}
.data-table tbody tr:hover td:first-child{box-shadow:inset 2px 0 0 var(--orange);}
.data-table td.num,
.data-table .num{
  font-family:var(--font-mono);
  color:var(--orange);
  text-align:right;
}

.accordion{border-top:1px solid var(--line);}
.accordion__item{border-bottom:1px solid var(--line);}
.accordion__summary{
  display:flex;
  align-items:center;
  gap:.75rem;
  padding:.95rem .25rem;
  cursor:pointer;
  list-style:none;
  font-size:.9375rem;
  font-weight:500;
  color:var(--paper);
  transition:color .18s ease;
}
.accordion__summary::-webkit-details-marker{display:none;}
.accordion__summary::before{
  content:"";
  flex:0 0 auto;
  width:.42rem;
  height:.42rem;
  background-color:var(--cyan);
  transform:rotate(45deg);
  transition:background-color .18s ease,transform .18s var(--ease);
}
.accordion__summary:hover{color:var(--mint);}
.accordion__item[open] > .accordion__summary::before{
  background-color:var(--orange);
  transform:rotate(135deg);
}
.accordion__body{
  padding:.1rem .25rem 1.1rem 1.45rem;
  font-size:.9375rem;
  color:var(--muted);
}

.media{
  position:relative;
  display:block;
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:var(--radius);
  aspect-ratio:16 / 9;
  background-color:var(--panel);
  background-image:
    linear-gradient(160deg,rgba(53,242,208,.14),rgba(6,19,15,.92) 62%),
    repeating-linear-gradient(90deg,rgba(36,68,59,.7) 0 1px,transparent 1px 52px),
    repeating-linear-gradient(0deg,rgba(36,68,59,.45) 0 1px,transparent 1px 52px);
}
.media img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.media--wide{aspect-ratio:21 / 9;}
.media--tall{aspect-ratio:4 / 5;}
.media--square{aspect-ratio:1 / 1;}
.media__caption{
  position:absolute;
  inset:auto 0 0 0;
  padding:.7rem 1rem;
  font-size:.75rem;
  letter-spacing:.04em;
  color:var(--mint);
  background:linear-gradient(transparent,rgba(6,19,15,.94));
}

/* ---------- 8. 面包屑 ---------- */
.breadcrumbs{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.4rem;
  margin:0 0 1.5rem;
  font-size:.75rem;
  letter-spacing:.06em;
  color:var(--muted);
}
.breadcrumbs__link{
  color:var(--muted);
  transition:color .18s ease;
}
.breadcrumbs__link:hover{color:var(--cyan);}
.breadcrumbs__sep{color:var(--line);}

/* ---------- 9. 页头 ---------- */
.skip-link{
  position:absolute;
  left:1rem;
  top:-4rem;
  z-index:200;
  padding:.7rem 1.1rem;
  border-radius:var(--radius);
  background-color:var(--cyan);
  color:#04120E;
  font-size:.8125rem;
  font-weight:600;
  letter-spacing:.08em;
  text-decoration:none;
  transition:top .18s ease;
}
.skip-link:focus{top:.6rem;}

.site-header{
  position:sticky;
  top:0;
  z-index:90;
  background-color:var(--ink);
  border-bottom:1px solid var(--line);
  box-shadow:0 14px 34px -28px rgba(0,0,0,.95);
}

.header-mast{
  display:flex;
  align-items:center;
  gap:clamp(.75rem,2vw,1.75rem);
  padding-block:.8rem;
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:.65rem;
  flex:0 0 auto;
  color:var(--paper);
  text-decoration:none;
}
.brand__mark{
  position:relative;
  display:grid;
  place-items:center;
  width:2.35rem;
  height:2.35rem;
  border:1px solid var(--cyan);
  border-radius:var(--radius);
  background-image:linear-gradient(150deg,rgba(53,242,208,.18),transparent 68%);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:.8125rem;
  font-weight:700;
  letter-spacing:.02em;
}
.brand__mark::after{
  content:"";
  position:absolute;
  right:4px;
  bottom:4px;
  width:5px;
  height:5px;
  border-radius:50%;
  background-color:var(--orange);
}
.brand__copy{
  display:flex;
  flex-direction:column;
  line-height:1.2;
}
.brand__name{
  font-family:var(--font-display);
  font-size:1.12rem;
  font-weight:800;
  letter-spacing:.01em;
  color:var(--paper);
  white-space:nowrap;
}
.brand__tag{
  font-size:.6875rem;
  letter-spacing:.1em;
  color:var(--muted);
  white-space:nowrap;
}

.header-mast__line{
  flex:1 1 auto;
  max-width:32rem;
  margin:0;
  padding-left:clamp(.75rem,2vw,1.5rem);
  border-left:1px solid var(--line);
  color:var(--muted);
  font-size:.8125rem;
  line-height:1.5;
  letter-spacing:.02em;
}

.header-mast__side{
  display:flex;
  align-items:center;
  gap:.85rem;
  margin-left:auto;
  flex:0 0 auto;
}

.live-flag{
  display:inline-flex;
  align-items:center;
  gap:.45rem;
  margin:0;
  color:var(--mint);
  font-size:.6875rem;
  letter-spacing:.08em;
  white-space:nowrap;
}
.live-flag__dot{
  width:.45rem;
  height:.45rem;
  border-radius:50%;
  background-color:var(--orange);
  box-shadow:0 0 0 3px rgba(255,122,26,.18);
  animation:live-pulse 2.6s ease-in-out infinite;
}
@keyframes live-pulse{
  0%,100%{box-shadow:0 0 0 3px rgba(255,122,26,.18);}
  50%{box-shadow:0 0 0 6px rgba(255,122,26,.05);}
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:.55rem;
  margin-left:auto;
  padding:.55rem .8rem;
  border:1px solid var(--line);
  border-radius:var(--radius);
  background-color:var(--panel);
  color:var(--paper);
  font-size:.75rem;
  letter-spacing:.1em;
  transition:border-color .18s ease,color .18s ease;
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan);}
.nav-toggle__bars{
  display:flex;
  flex-direction:column;
  gap:3px;
  width:1rem;
}
.nav-toggle__bars span{
  display:block;
  height:1.5px;
  background-color:currentColor;
  transition:transform .18s ease,opacity .18s ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1){transform:translateY(4.5px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2){opacity:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3){transform:translateY(-4.5px) rotate(-45deg);}

.header-bar{
  background-color:var(--slate);
  border-top:1px solid var(--line);
}
.header-bar__inner{
  display:flex;
  align-items:center;
  gap:1rem;
}

.site-nav{
  display:flex;
  align-items:center;
  gap:1rem;
  flex:1 1 auto;
  min-width:0;
}
.site-nav__list{
  display:flex;
  align-items:center;
  flex:1 1 auto;
  min-width:0;
  overflow-x:auto;
  scrollbar-width:none;
}
.site-nav__list::-webkit-scrollbar{display:none;}
.site-nav__item{flex:0 0 auto;}

.site-nav__link{
  position:relative;
  display:block;
  padding:.92rem clamp(.55rem,1.4vw,1.05rem);
  color:var(--muted);
  font-size:.8125rem;
  letter-spacing:.04em;
  white-space:nowrap;
  transition:color .18s ease;
}
.site-nav__link::before{
  content:"";
  position:absolute;
  left:0;
  bottom:0;
  width:100%;
  height:2px;
  background-color:var(--orange);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform .18s var(--ease);
}
.site-nav__link:hover{color:var(--paper);}
.site-nav__link:hover::before{transform:scaleX(1);}
.site-nav__link[aria-current="page"]{color:var(--mint);}
.site-nav__link[aria-current="page"]::before{
  background-color:var(--cyan);
  transform:scaleX(1);
}

.site-nav__cta{
  flex:0 0 auto;
  display:inline-flex;
  align-items:center;
  padding:.48rem .9rem;
  border:1px solid var(--line);
  border-radius:var(--radius);
  color:var(--cyan);
  font-size:.75rem;
  letter-spacing:.08em;
  text-decoration:none;
  transition:background-color .18s ease,border-color .18s ease,color .18s ease;
}
.site-nav__cta:hover{
  border-color:var(--cyan);
  background-color:rgba(53,242,208,.1);
  color:var(--mint);
}

/* 移动端抽屉 */
@media (max-width:960px){
  .header-mast{
    gap:.75rem;
    padding-block:.62rem;
  }
  .header-mast__line,
  .header-mast__side{display:none;}
  .nav-toggle{display:inline-flex;}

  .header-bar{
    background-color:transparent;
    border-top:0;
  }
  .header-bar__inner{display:block;}

  .site-nav{display:none;}

  .site-nav[data-open]{
    display:flex;
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding-block:.4rem 1rem;
    background-color:var(--panel);
    border-top:1px solid var(--line);
    border-bottom:1px solid var(--line);
  }
  .site-nav[data-open] .site-nav__list{
    flex-direction:column;
    align-items:stretch;
    width:100%;
    overflow:visible;
  }
  .site-nav[data-open] .site-nav__link{
    padding:.8rem .25rem;
    font-size:.9375rem;
    color:var(--paper);
    white-space:normal;
    border-bottom:1px solid var(--line);
  }
  .site-nav[data-open] .site-nav__link::before{
    left:-.1rem;
    top:50%;
    bottom:auto;
    width:.55rem;
    height:2px;
    transform:translateY(-50%) scaleX(0);
    transform-origin:left center;
  }
  .site-nav[data-open] .site-nav__link:hover::before,
  .site-nav[data-open] .site-nav__link[aria-current="page"]::before{
    transform:translateY(-50%) scaleX(1);
  }
  .site-nav[data-open] .site-nav__link[aria-current="page"]{
    color:var(--mint);
  }
  .site-nav[data-open] .site-nav__item:last-child .site-nav__link{border-bottom:0;}
  .site-nav[data-open] .site-nav__cta{
    margin-top:.9rem;
    justify-content:center;
    padding:.7rem 1rem;
  }
}

/* ---------- 10. 页脚 ---------- */
.site-footer{
  margin-top:clamp(3rem,8vw,6rem);
  background-color:var(--slate);
  border-top:1px solid var(--line);
  color:var(--muted);
}

.footer-main{
  display:grid;
  grid-template-columns:minmax(240px,1.15fr) minmax(0,1.55fr) minmax(230px,.95fr);
  gap:clamp(1.5rem,4vw,3.5rem);
  padding-block:clamp(2.25rem,5vw,3.5rem);
}

.footer-brand{min-width:0;}
.brand--footer{margin-bottom:1rem;}
.footer-brand__summary{
  max-width:44ch;
  margin:0;
  color:var(--muted);
  font-size:.875rem;
  line-height:1.7;
}

.footer-nav{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(1rem,2.5vw,2rem);
}
.footer-nav__title{
  margin:0 0 .85rem;
  font-family:var(--font-body);
  font-size:.6875rem;
  font-weight:500;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--amber);
}
.footer-nav__col ul{
  display:grid;
  gap:.55rem;
  list-style:none;
  margin:0;
  padding:0;
}
.footer-nav__col a{
  position:relative;
  display:inline-block;
  padding-left:0;
  color:var(--muted);
  font-size:.875rem;
  transition:color .18s ease,padding-left .18s ease;
}
.footer-nav__col a::before{
  content:"";
  position:absolute;
  left:0;
  top:50%;
  width:0;
  height:1px;
  background-color:var(--orange);
  transform:translateY(-50%);
  transition:width .18s ease;
}
.footer-nav__col a:hover{
  color:var(--mint);
  padding-left:.9rem;
}
.footer-nav__col a:hover::before{width:.6rem;}

.footer-contact{
  min-width:0;
  padding-left:clamp(1rem,2vw,1.75rem);
  border-left:1px solid var(--line);
}
.footer-contact__list{
  display:grid;
  gap:.6rem;
  list-style:none;
  margin:0;
  padding:0;
  font-size:.8125rem;
  color:var(--paper);
  word-break:break-word;
}
.footer-contact__list li{
  display:flex;
  align-items:baseline;
  gap:.6rem;
}
.footer-contact__k{
  flex:0 0 auto;
  min-width:2.6em;
  font-size:.6875rem;
  letter-spacing:.12em;
  color:var(--muted);
}
.footer-contact__note{
  margin:.9rem 0 0;
  font-size:.75rem;
  line-height:1.6;
  color:var(--muted);
}

.footer-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.4rem 1.5rem;
  padding-block:1.15rem;
  border-top:1px solid var(--line);
  font-size:.75rem;
  letter-spacing:.04em;
  color:var(--muted);
}
.footer-bottom p{margin:0;}
.footer-bottom__copy{color:var(--paper);}
.footer-bottom__meta{font-family:var(--font-mono);letter-spacing:.02em;}
.footer-bottom__meta:last-child{margin-left:auto;}

@media (max-width:1080px){
  .footer-main{grid-template-columns:repeat(2,minmax(0,1fr));}
  .footer-brand{grid-column:1 / -1;}
  .footer-contact{
    padding-left:0;
    border-left:0;
  }
}
@media (max-width:720px){
  .footer-main{grid-template-columns:minmax(0,1fr);}
  .footer-nav{grid-template-columns:repeat(2,minmax(0,1fr));}
  .footer-bottom__meta:last-child{margin-left:0;}
}
@media (max-width:420px){
  .footer-nav{grid-template-columns:minmax(0,1fr);}
}

/* ---------- 11. 脚本注入的浏览辅助 ---------- */
.read-progress{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:2px;
  background-image:linear-gradient(90deg,var(--cyan),var(--orange));
  transform:scaleX(0);
  transform-origin:0 50%;
  z-index:120;
  pointer-events:none;
  will-change:transform;
}

.to-top{
  position:fixed;
  right:clamp(1rem,3vw,2rem);
  bottom:clamp(1rem,3vw,2rem);
  z-index:110;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  width:2.75rem;
  height:2.75rem;
  border:1px solid var(--line);
  border-radius:var(--radius);
  background-color:rgba(11,36,29,.94);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:.95rem;
  line-height:1;
  opacity:0;
  visibility:hidden;
  transform:translateY(8px);
  transition:opacity .2s var(--ease),transform .2s var(--ease),visibility .2s linear,border-color .18s ease,color .18s ease;
}
.to-top.is-visible{
  opacity:1;
  visibility:visible;
  transform:translateY(0);
}
.to-top:hover{
  border-color:var(--cyan);
  color:var(--mint);
}

/* ---------- 12. 动效可访问性 ---------- */
@media (prefers-reduced-motion:reduce){
  *,
  *::before,
  *::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
    scroll-behavior:auto !important;
  }
  .live-flag__dot{animation:none;}
}