/* =========================================================
   28圈指南 · 全站共享样式 /assets/site.css
   ========================================================= */

/* ---------- 01 变量 ---------- */
:root{
  --ink:#070B1F;
  --ink-2:#101736;
  --navy:#1B2A63;
  --jade:#0E4F4A;
  --wine:#5A1233;
  --violet:#3A1A6B;
  --cyan:#3DF2E0;
  --orange:#FF8A3C;
  --amber:#F5C451;
  --text:#E9EDFA;
  --muted:#A3AECF;
  --line:rgba(233,237,250,.14);
  --line-strong:rgba(233,237,250,.28);
  --accent-wine:#D2507E;
  --accent-jade:#2FBFAE;
  --accent-violet:#9B6BFF;
  --font-display:"HarmonyOS Sans SC","Source Han Sans SC","Source Han Sans CN","PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-body:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:ui-monospace,"JetBrains Mono","IBM Plex Mono","SFMono-Regular",Menlo,Consolas,"Liberation Mono",monospace;
  --rail-w:220px;
  --toc-w:160px;
  --maxw:1240px;
  --radius:8px;
  --ease:cubic-bezier(.32,.72,.28,1);
  --shadow-glass:0 18px 48px rgba(3,6,18,.55);
}

/* ---------- 02 重置 ---------- */
*,*::before,*::after{box-sizing:border-box}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:96px;
}
body{
  margin:0;
  min-height:100vh;
  color:var(--text);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.8;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  background-color:var(--ink);
  background-image:
    radial-gradient(1100px 720px at 88% -6%, rgba(61,242,224,.11), transparent 62%),
    radial-gradient(900px 700px at 0% 38%, rgba(58,26,107,.32), transparent 68%),
    radial-gradient(1000px 720px at 62% 106%, rgba(255,138,60,.09), transparent 66%);
  background-repeat:no-repeat;
}
h1,h2,h3,h4,h5,h6,p,figure,blockquote,dl,dd,ol,ul{margin:0}
ol,ul{padding:0;list-style:none}
img,svg,video{max-width:100%;display:block;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}
strong{font-weight:800}

/* ---------- 03 中文排版与基础排版 ---------- */
.prose{
  font-size:17px;
  line-height:1.85;
  color:var(--text);
  max-width:38em;
}
.prose p + p{margin-top:1.1em}
.prose h2,.prose h3{
  font-family:var(--font-display);
  font-weight:800;
  letter-spacing:-.01em;
  line-height:1.3;
  margin-top:2.2em;
  margin-bottom:.6em;
}
.prose h2{font-size:clamp(24px,2.6vw,32px)}
.prose h3{font-size:clamp(19px,2vw,23px)}
.prose ul,.prose ol{margin:1em 0 1em 1.2em;list-style:disc}
.prose ol{list-style:decimal}
.prose li{margin:.4em 0}
.prose a{color:var(--cyan);border-bottom:1px solid rgba(61,242,224,.35)}
.prose a:hover{border-bottom-color:var(--cyan)}
.prose blockquote{
  margin:1.6em 0;
  padding:.2em 0 .2em 20px;
  border-left:3px solid var(--orange);
  color:var(--muted);
}
.numeral,.mono{
  font-family:var(--font-mono);
  font-size:.82em;
  letter-spacing:.08em;
}
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 10px;
  border:1px solid var(--line);
  border-radius:999px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
  color:var(--muted);
  background:rgba(233,237,250,.04);
}
.sec-head{
  display:flex;
  align-items:baseline;
  gap:14px;
  flex-wrap:wrap;
  padding-bottom:14px;
  border-bottom:1px solid var(--line);
  margin-bottom:26px;
}
.sec-head__num{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.16em;
  color:var(--orange);
}
.sec-head__title{
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(26px,3.4vw,40px);
  line-height:1.2;
  letter-spacing:-.02em;
}
.sec-head__desc{
  font-size:14px;
  color:var(--muted);
  width:100%;
}

/* ---------- 04 布局容器 ---------- */
.wrap{
  width:100%;
  max-width:var(--maxw);
  margin:0 auto;
  padding:0 40px;
  position:relative;
}
@media (min-width:1024px){
  body{padding-left:var(--rail-w)}
}
@media (max-width:640px){
  .wrap{padding:0 20px}
}

/* ---------- 05 跳转链接 ---------- */
.skip-link{
  position:fixed;
  left:-9999px;
  top:0;
  z-index:200;
  padding:10px 18px;
  background:var(--cyan);
  color:#04121F;
  font-weight:800;
  font-size:14px;
  border-radius:0 0 8px 0;
}
.skip-link:focus{left:0}

/* ---------- 06 侧边轨道（页头） ---------- */
.site-rail{
  position:fixed;
  top:0;
  left:0;
  bottom:0;
  width:var(--rail-w);
  z-index:60;
  padding:26px 20px 22px;
  display:flex;
  background:linear-gradient(180deg,#111838 0%,#0A1026 58%,#070B1F 100%);
  border-right:1px solid var(--line);
  -webkit-backdrop-filter:blur(16px);
  backdrop-filter:blur(16px);
}
.site-rail::after{
  content:"";
  position:absolute;
  top:0;
  right:-1px;
  width:1px;
  height:100%;
  background:linear-gradient(180deg,transparent 0%,rgba(61,242,224,.45) 26%,rgba(255,138,60,.34) 68%,transparent 100%);
  pointer-events:none;
}
.rail-inner{
  display:flex;
  flex-direction:column;
  gap:22px;
  width:100%;
  height:100%;
  min-height:0;
}

/* 品牌 */
.rail-brand{
  display:flex;
  align-items:center;
  gap:12px;
  flex:0 0 auto;
  border-radius:var(--radius);
}
.rail-brand__mark{
  flex:0 0 auto;
  width:42px;
  height:42px;
  display:grid;
  place-items:center;
  border-radius:8px;
  font-family:var(--font-mono);
  font-size:15px;
  font-weight:700;
  letter-spacing:.02em;
  color:#04121F;
  background:linear-gradient(135deg,var(--cyan) 0%,#2FBFAE 60%,#1B8E86 100%);
  box-shadow:0 0 22px rgba(61,242,224,.35);
}
.rail-brand__text{
  display:flex;
  flex-direction:column;
  line-height:1.25;
  min-width:0;
}
.rail-brand__name{
  font-family:var(--font-display);
  font-size:16px;
  font-weight:800;
  letter-spacing:.02em;
}
.rail-brand__sub{
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.2em;
  color:var(--muted);
}

/* 移动导航按钮 */
.rail-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:9px 13px;
  border:1px solid var(--line);
  border-radius:6px;
  font-size:13px;
  font-weight:700;
  color:var(--text);
  transition:background .2s ease,border-color .2s ease;
}
.rail-toggle:hover,.rail-toggle:focus-visible{
  background:rgba(233,237,250,.07);
  border-color:rgba(61,242,224,.45);
}
.rail-toggle__bars{
  position:relative;
  width:16px;
  height:2px;
  background:currentColor;
  border-radius:2px;
  box-shadow:0 -5px 0 currentColor,0 5px 0 currentColor;
  transition:transform .24s var(--ease),box-shadow .24s ease;
}
.rail-toggle__text{
  font-size:13px;
  letter-spacing:.06em;
}
.site-rail[data-open] .rail-toggle__bars{
  box-shadow:none;
  transform:rotate(45deg);
}
.site-rail[data-open] .rail-toggle__bars::after{
  content:"";
  position:absolute;
  inset:0;
  background:currentColor;
  border-radius:2px;
  transform:rotate(90deg);
}

/* 导航 */
.rail-nav{
  flex:1 1 auto;
  min-height:0;
  overflow-y:auto;
  overscroll-behavior:contain;
  scrollbar-width:thin;
}
.rail-nav__list{
  display:flex;
  flex-direction:column;
  gap:2px;
}
.rail-nav__item{--dot:var(--cyan)}
.rail-nav__item[data-accent="cyan"]{--dot:#3DF2E0}
.rail-nav__item[data-accent="wine"]{--dot:#D2507E}
.rail-nav__item[data-accent="jade"]{--dot:#2FBFAE}
.rail-nav__item[data-accent="violet"]{--dot:#9B6BFF}
.rail-nav__item[data-accent="amber"]{--dot:#F5C451}
.rail-nav__item[data-accent="orange"]{--dot:#FF8A3C}
.rail-nav__link{
  position:relative;
  display:flex;
  align-items:center;
  gap:10px;
  padding:10px 10px 10px 14px;
  border:1px solid transparent;
  border-radius:6px;
  font-size:15px;
  line-height:1.45;
  color:var(--muted);
  transition:color .22s ease,background .22s ease,border-color .22s ease;
}
.rail-nav__link::before{
  content:"";
  position:absolute;
  left:0;
  top:50%;
  width:3px;
  height:0;
  border-radius:2px;
  background:var(--dot);
  transform:translateY(-50%);
  transition:height .26s var(--ease);
}
.rail-nav__link:hover,
.rail-nav__link:focus-visible{
  color:var(--text);
  background:rgba(233,237,250,.055);
}
.rail-nav__link:hover::before{height:56%}
.rail-nav__link[aria-current="page"]{
  color:var(--text);
  background:rgba(233,237,250,.075);
  border-color:var(--line);
}
.rail-nav__link[aria-current="page"]::before{
  height:70%;
  box-shadow:0 0 12px var(--dot);
}
.rail-nav__num{
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--dot);
}
.rail-nav__label{
  display:block;
  max-width:200px;
  overflow:hidden;
  white-space:nowrap;
  transition:max-width .26s var(--ease),opacity .2s ease;
}

/* 操作区 */
.rail-actions{
  flex:0 0 auto;
  display:flex;
  flex-direction:column;
  gap:8px;
  padding-top:16px;
  border-top:1px solid var(--line);
}
.rail-btn{
  display:flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  width:100%;
  padding:10px 12px;
  border:1px solid var(--line);
  border-radius:6px;
  font-size:13px;
  font-weight:700;
  letter-spacing:.04em;
  color:var(--muted);
  transition:color .2s ease,background .2s ease,border-color .2s ease,opacity .2s ease;
}
.rail-btn:hover,.rail-btn:focus-visible{
  color:var(--text);
  background:rgba(233,237,250,.07);
  border-color:rgba(61,242,224,.45);
}
.rail-btn--index{
  color:var(--orange);
  border-color:rgba(255,138,60,.45);
}
.rail-btn--index:hover,.rail-btn--index:focus-visible{
  color:#1A0D02;
  background:var(--orange);
  border-color:var(--orange);
}
.rail-btn--top{
  opacity:.36;
  pointer-events:none;
}
.site-rail.is-scrolled .rail-btn--top{
  opacity:1;
  pointer-events:auto;
}

/* 桌面端紧凑模式 */
@media (min-width:1024px){
  .site-rail.is-compact .rail-nav__label{
    max-width:0;
    opacity:0;
  }
  .site-rail.is-compact .rail-nav__link:hover .rail-nav__label,
  .site-rail.is-compact .rail-nav__link:focus-visible .rail-nav__label{
    max-width:200px;
    opacity:1;
  }
  .site-rail.is-compact .rail-brand__sub{
    opacity:0;
    transition:opacity .2s ease;
  }
}

/* 移动端抽屉遮罩 */
.nav-scrim{
  position:fixed;
  inset:0;
  z-index:50;
  background:rgba(4,7,20,.68);
  -webkit-backdrop-filter:blur(3px);
  backdrop-filter:blur(3px);
  opacity:0;
  pointer-events:none;
  transition:opacity .28s ease;
}
.nav-scrim[data-visible]{
  opacity:1;
  pointer-events:auto;
}
@media (min-width:1024px){
  .nav-scrim{display:none}
}

/* 滚动进度 */
.scroll-progress{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:3px;
  z-index:80;
  background:rgba(233,237,250,.06);
  pointer-events:none;
}
.scroll-progress span{
  display:block;
  height:100%;
  width:0;
  background:linear-gradient(90deg,var(--cyan) 0%,var(--amber) 55%,var(--orange) 100%);
  box-shadow:0 0 14px rgba(61,242,224,.4);
  transition:width .12s linear;
}
@media (min-width:1024px){
  .scroll-progress{left:var(--rail-w)}
}

/* 移动端：轨道变成顶栏 + 抽屉 */
@media (max-width:1023px){
  .site-rail{
    position:sticky;
    top:0;
    right:auto;
    bottom:auto;
    left:auto;
    width:100%;
    height:64px;
    padding:0 16px;
    align-items:center;
    border-right:0;
    border-bottom:1px solid var(--line);
    background:linear-gradient(180deg,rgba(17,24,56,.96),rgba(10,16,38,.96));
  }
  .site-rail::after{display:none}
  .rail-inner{
    flex-direction:row;
    align-items:center;
    gap:12px;
    height:auto;
  }
  .rail-brand{flex:1 1 auto;min-width:0}
  .rail-brand__mark{width:34px;height:34px;font-size:13px;border-radius:7px}
  .rail-brand__name{font-size:15px}
  .rail-brand__sub{display:none}
  .rail-toggle{display:inline-flex;flex:0 0 auto}
  .rail-actions{
    flex:0 0 auto;
    flex-direction:row;
    gap:8px;
    padding-top:0;
    border-top:0;
  }
  .rail-btn{width:auto;padding:8px 12px;font-size:12px}
  .rail-btn--index{display:none}
  .site-rail .rail-btn--top{opacity:1;pointer-events:auto}
  .rail-nav{
    position:fixed;
    top:64px;
    left:0;
    bottom:0;
    width:min(86vw,330px);
    z-index:70;
    padding:26px 20px 34px;
    background:linear-gradient(180deg,#111838 0%,#080D22 100%);
    border-right:1px solid var(--line);
    box-shadow:var(--shadow-glass);
    overflow-y:auto;
    overscroll-behavior:contain;
    transform:translateX(-102%);
    transition:transform .34s var(--ease);
  }
  .site-rail[data-open] .rail-nav{transform:translateX(0)}
  .rail-nav__link{padding:13px 14px;font-size:16px}
  .rail-nav__label{max-width:none}
}

/* ---------- 07 通用按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:12px 22px;
  border:1px solid var(--line);
  border-radius:6px;
  font-size:15px;
  font-weight:700;
  letter-spacing:.02em;
  color:var(--text);
  background:rgba(233,237,250,.04);
  transition:background .22s ease,border-color .22s ease,color .22s ease,transform .22s ease;
}
.btn:hover,.btn:focus-visible{
  background:rgba(233,237,250,.09);
  border-color:rgba(61,242,224,.5);
}
.btn--primary{
  color:#1A0D02;
  background:var(--orange);
  border-color:transparent;
  box-shadow:0 10px 28px rgba(255,138,60,.24);
}
.btn--primary:hover,.btn--primary:focus-visible{
  background:#FF9C58;
  border-color:transparent;
  transform:translateY(-1px);
}
.btn--ghost{
  color:var(--cyan);
  border-color:rgba(61,242,224,.45);
  background:transparent;
}
.btn--ghost:hover,.btn--ghost:focus-visible{
  color:#04121F;
  background:var(--cyan);
  border-color:var(--cyan);
}

/* ---------- 08 面包屑 ---------- */
.crumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--muted);
}
.crumb a{transition:color .2s ease}
.crumb a:hover,.crumb a:focus-visible{color:var(--cyan)}
.crumb__sep{opacity:.45}

/* ---------- 09 图片容器 ---------- */
.img-frame{
  position:relative;
  overflow:hidden;
  border-radius:var(--radius);
  border:1px solid var(--line);
  aspect-ratio:16/9;
  background:
    linear-gradient(140deg,#101736 0%,#1B2A63 52%,#0E4F4A 100%);
  box-shadow:var(--shadow-glass);
}
.img-frame > img{
  width:100%;
  height:100%;
  object-fit:cover;
  opacity:.88;
  transition:transform .4s var(--ease),opacity .3s ease;
}
.img-frame::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(233,237,250,.055) 1px,transparent 1px),
    linear-gradient(90deg,rgba(233,237,250,.055) 1px,transparent 1px);
  background-size:34px 34px;
  mask-image:linear-gradient(180deg,rgba(0,0,0,.9),rgba(0,0,0,.25));
  -webkit-mask-image:linear-gradient(180deg,rgba(0,0,0,.9),rgba(0,0,0,.25));
}
.img-frame:hover > img{transform:scale(1.02);opacity:1}
.img-frame--wide{aspect-ratio:21/9}
.img-frame--tall{aspect-ratio:3/4}

/* ---------- 10 页脚 ---------- */
.site-foot{
  position:relative;
  margin-top:96px;
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(16,23,54,.94) 0%,rgba(7,11,31,.98) 62%,#05081A 100%);
}
.foot-inner{
  width:100%;
  max-width:var(--maxw);
  margin:0 auto;
  padding:58px 40px 0;
  display:grid;
  grid-template-columns:minmax(210px,1.5fr) repeat(4,minmax(118px,1fr));
  gap:38px 26px;
}
.foot-brand{display:flex;flex-direction:column;gap:14px}
.foot-brand__mark{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-display);
  font-size:22px;
  font-weight:900;
  letter-spacing:-.01em;
  color:var(--text);
}
.foot-brand__mark::before{
  content:"";
  width:6px;
  height:22px;
  border-radius:3px;
  background:linear-gradient(180deg,var(--cyan),var(--orange));
  box-shadow:0 0 14px rgba(61,242,224,.45);
}
.foot-brand__note{
  font-size:14px;
  line-height:1.85;
  color:var(--muted);
  max-width:30em;
}
.foot-brand__meta{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  color:var(--muted);
  opacity:.85;
}
.foot-col{display:flex;flex-direction:column;gap:14px}
.foot-col__title{
  display:flex;
  align-items:center;
  gap:8px;
  font-family:var(--font-body);
  font-size:14px;
  font-weight:800;
  letter-spacing:.06em;
  color:var(--text);
  padding-bottom:10px;
  border-bottom:1px solid var(--line);
}
.foot-col__title::before{
  content:attr(data-num);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  font-weight:400;
  color:var(--orange);
}
.foot-col__list{display:flex;flex-direction:column;gap:9px}
.foot-col__list a{
  display:inline-block;
  font-size:14px;
  color:var(--muted);
  transition:color .2s ease,transform .2s ease;
}
.foot-col__list a:hover,.foot-col__list a:focus-visible{
  color:var(--cyan);
  transform:translateX(3px);
}
.foot-base{
  margin-top:48px;
  border-top:1px solid var(--line);
  background:rgba(5,8,26,.6);
}
.foot-base__inner{
  width:100%;
  max-width:var(--maxw);
  margin:0 auto;
  padding:26px 40px 34px;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:14px 26px;
}
.foot-contact{
  display:flex;
  flex-wrap:wrap;
  gap:10px 24px;
  flex:1 1 420px;
}
.foot-contact li{
  display:flex;
  align-items:center;
  gap:8px;
  font-size:13px;
  color:var(--muted);
}
.foot-contact__k{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  color:var(--orange);
}
.foot-contact__v{color:var(--text)}
.copy-btn{
  font-size:13px;
  color:var(--text);
  letter-spacing:.02em;
  border-bottom:1px dashed rgba(233,237,250,.3);
  transition:color .2s ease,border-color .2s ease;
}
.copy-btn:hover,.copy-btn:focus-visible{
  color:var(--cyan);
  border-bottom-color:var(--cyan);
}
.copy-btn.is-copied{
  color:var(--amber);
  border-bottom-color:var(--amber);
}
.foot-note{
  flex:1 1 100%;
  font-size:12.5px;
  line-height:1.8;
  color:var(--muted);
  opacity:.9;
}
.foot-icp{
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--muted);
  opacity:.8;
}
@media (max-width:1023px){
  .foot-inner{
    grid-template-columns:repeat(2,minmax(0,1fr));
    padding:44px 24px 0;
    gap:32px 22px;
  }
  .foot-brand{grid-column:1 / -1}
  .foot-base__inner{padding:22px 24px 30px}
}
@media (max-width:640px){
  .site-foot{margin-top:64px}
  .foot-inner{
    grid-template-columns:minmax(0,1fr);
    padding:38px 20px 0;
  }
  .foot-base__inner{padding:20px 20px 28px}
  .foot-contact{flex-direction:column;gap:10px}
}

/* ---------- 11 焦点与动效降级 ---------- */
:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:3px;
  border-radius:4px;
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .img-frame:hover > img{transform:none}
}