/* ===== 重置 ===== */
*,*::before,*::after{box-sizing:border-box}
body,h1,h2,h3,h4,h5,h6,p,figure,blockquote,dl,dd,ul,ol{margin:0}
ul,ol{padding:0;list-style:none}
img,svg{display:block;max-width:100%}
button{font:inherit;color:inherit;background:none;border:0}
a{color:inherit}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

/* ===== 变量 ===== */
:root{
  --ink:#071A2B;
  --coal:#111418;
  --slate:#1B3348;
  --coral:#FF6B4A;
  --coral-soft:#FF9A7A;
  --cyan:#2DE2E6;
  --fog:#F2F6F8;
  --mist:#8FA6B8;
  --line:#385064;
  --deep-teal:#0B4F55;
  --font-title:"Noto Sans SC","Source Han Sans SC","Microsoft YaHei",sans-serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","Microsoft YaHei",sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono","SFMono-Regular",Consolas,monospace;
  --band-h:64px;
  --maxw:1240px;
  --gutter:clamp(18px,4vw,48px);
  --cut:14px;
  --ease:cubic-bezier(0.2,0.8,0.2,1);
}

/* ===== 基座 ===== */
body{
  background:var(--ink);
  color:var(--fog);
  font-family:var(--font-body);
  font-size:16px;
  font-weight:400;
  line-height:1.8;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
main{display:block}
#main-content{scroll-margin-top:calc(var(--band-h) + 24px)}
h1,h2,h3,h4{font-family:var(--font-title);font-weight:900;letter-spacing:-.03em;line-height:1.15}
:where(a,button,[tabindex]):focus-visible{outline:2px solid var(--cyan);outline-offset:2px}
.mono{font-family:var(--font-mono);letter-spacing:.06em}
.data-figure{font-family:var(--font-mono);letter-spacing:.04em;font-variant-numeric:tabular-nums;color:var(--cyan)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}

/* ===== 页头工具带 ===== */
.site-header{
  --band-h:64px;
  position:sticky;top:0;z-index:60;
  background:var(--coal);
  border-bottom:1px solid var(--line);
}
.site-header::before{
  content:"";display:block;height:2px;
  background:linear-gradient(90deg,var(--coral) 0 26%,var(--cyan) 26% 34%,var(--line) 34% 100%);
}
.site-header.is-compact{--band-h:52px}
.band-inner{
  width:100%;max-width:var(--maxw);margin-inline:auto;
  padding-inline:var(--gutter);
  min-height:var(--band-h);
  display:flex;align-items:center;gap:clamp(12px,2vw,32px);
  transition:min-height .22s var(--ease);
}
.skip-link{
  position:absolute;left:var(--gutter);top:-72px;z-index:100;
  background:var(--cyan);color:var(--ink);
  font-size:13px;font-weight:700;letter-spacing:.02em;
  padding:10px 16px;text-decoration:none;
  transition:top .18s var(--ease);
}
.skip-link:focus{top:8px}

.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;flex:0 0 auto;position:relative;padding-left:11px}
.brand::before{content:"";position:absolute;left:0;top:50%;transform:translateY(-50%);width:3px;height:24px;background:var(--coral)}
.brand-mark{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;
  color:var(--fog);border:1px solid var(--line);
  padding:4px 7px;line-height:1;white-space:nowrap;
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.brand-slash{color:var(--coral);margin:0 1px}
.brand:hover .brand-mark{border-color:var(--cyan);color:var(--cyan)}
.brand:hover .brand-slash{color:var(--coral-soft)}
.brand-text{display:flex;flex-direction:column;line-height:1.1}
.brand-name{font-family:var(--font-title);font-weight:800;font-size:15px;letter-spacing:-.02em;color:var(--fog)}
.brand-sub{font-family:var(--font-mono);font-size:9px;letter-spacing:.18em;color:var(--mist);margin-top:3px}

.primary-nav{flex:1 1 auto;display:flex;justify-content:center;min-width:0}
.nav-list{display:flex;align-items:center;gap:clamp(4px,1.3vw,20px);flex-wrap:nowrap}
.nav-link{
  position:relative;display:inline-flex;align-items:baseline;gap:5px;
  padding:9px 2px;text-decoration:none;
  color:var(--mist);font-size:14px;font-weight:500;white-space:nowrap;
  border-bottom:2px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.nav-idx{font-family:var(--font-mono);font-size:10px;letter-spacing:.06em;color:var(--line);transition:color .18s var(--ease)}
.nav-link:hover{color:var(--fog)}
.nav-link:hover .nav-idx{color:var(--cyan)}
.nav-link[aria-current="page"]{color:var(--coral);border-bottom-color:var(--coral)}
.nav-link[aria-current="page"] .nav-idx{color:var(--coral-soft)}
.nav-utility{display:none}
.nav-service{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;
  color:var(--mist);text-decoration:none;padding:10px 2px;border-bottom:1px solid var(--line);
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.nav-service:hover{color:var(--cyan);border-color:var(--cyan)}

.header-actions{display:flex;align-items:center;gap:8px;flex:0 0 auto}

/* ===== 按钮 ===== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  font-family:var(--font-body);font-size:13px;font-weight:600;letter-spacing:.02em;
  line-height:1;padding:10px 16px;border:1px solid transparent;border-radius:2px;
  text-decoration:none;cursor:pointer;white-space:nowrap;
  transition:background-color .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease),transform .18s var(--ease);
}
.btn-solid{background:var(--coral);color:var(--ink)}
.btn-solid:hover{background:var(--coral-soft);transform:translateY(-1px)}
.btn-ghost{background:transparent;color:var(--fog);border-color:var(--line)}
.btn-ghost:hover{color:var(--cyan);border-color:var(--cyan)}
.btn-line{
  background:transparent;color:var(--cyan);padding:4px 0;border:0;border-bottom:1px solid var(--line);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;
}
.btn-line:hover{border-color:var(--coral);color:var(--coral-soft)}

/* ===== 折叠按钮 ===== */
.nav-toggle{
  display:none;align-items:center;gap:9px;
  border:1px solid var(--line);background:transparent;color:var(--fog);
  padding:9px 12px;cursor:pointer;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle-bars{display:flex;flex-direction:column;gap:4px;width:16px}
.nav-toggle-bars span{display:block;height:1.5px;background:currentColor;transition:transform .2s var(--ease)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(1){transform:translateY(2.75px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(2){transform:translateY(-2.75px) rotate(-45deg)}

/* ===== 页脚 ===== */
.site-footer{background:var(--coal);color:var(--mist);border-top:1px solid var(--line);margin-top:clamp(48px,8vw,96px)}
.footer-sweep{height:2px;background:linear-gradient(90deg,var(--coral) 0 18%,var(--cyan) 18% 26%,var(--line) 26% 100%)}
.footer-inner{max-width:var(--maxw);margin-inline:auto;padding:clamp(36px,5vw,64px) var(--gutter) 0}
.footer-top{
  display:grid;grid-template-columns:1.5fr .9fr .9fr .9fr 1.4fr;
  gap:clamp(20px,3vw,40px);
  padding-bottom:clamp(28px,4vw,48px);
  border-bottom:1px solid var(--line);
}
.footer-brand .brand-mark{display:inline-block;margin-bottom:12px}
.footer-brand-name{font-family:var(--font-title);font-size:20px;font-weight:800;letter-spacing:-.02em;color:var(--fog);line-height:1.2}
.footer-brand-note{font-size:12px;line-height:1.7;color:var(--mist);margin-top:8px;max-width:24ch}
.footer-col-title{
  font-family:var(--font-mono);font-size:11px;font-weight:500;
  letter-spacing:.14em;color:var(--cyan);margin-bottom:14px;
}
.footer-list{display:flex;flex-direction:column;gap:2px}
.footer-link{
  display:inline-block;font-size:14px;color:var(--mist);text-decoration:none;
  padding:4px 0;border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer-link:hover{color:var(--fog);border-color:var(--coral)}
.footer-contact{min-width:0}
.footer-mail{
  display:inline-block;font-family:var(--font-mono);font-size:12px;letter-spacing:.03em;
  color:var(--cyan);text-decoration:none;word-break:break-all;
  border-bottom:1px solid var(--line);padding-bottom:2px;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer-mail:hover{color:var(--coral-soft);border-color:var(--coral)}
.contact-line{display:flex;gap:10px;font-size:13px;line-height:1.7;color:var(--fog);padding:5px 0}
.contact-label{
  font-family:var(--font-mono);font-size:10px;letter-spacing:.14em;
  color:var(--mist);flex:0 0 30px;padding-top:4px;
}
.footer-note{font-size:12px;line-height:1.75;color:var(--mist);margin-top:12px;padding-left:10px;border-left:2px solid var(--deep-teal)}
.footer-base{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:10px 24px;
  padding:20px 0 28px;
}
.footer-copy,.footer-legal{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--mist);line-height:1.6;
}
.footer-legal{color:var(--line);letter-spacing:.1em}

/* ===== 容器与网格 ===== */
.wrap{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--gutter)}
.wrap--narrow{width:100%;max-width:720px;margin-inline:auto;padding-inline:var(--gutter)}
.grid-12{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(16px,2.4vw,24px)}
.grid-12 > *{grid-column:1 / -1;min-width:0}

/* ===== 章节 ===== */
.section{padding-block:clamp(44px,7vw,92px)}
.section-head{display:flex;flex-direction:column;gap:14px;margin-bottom:clamp(24px,3.4vw,40px)}
.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--cyan);
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--coral)}
.section-title{font-size:clamp(28px,3.2vw,42px);color:var(--fog)}
.lead{font-size:clamp(15px,1.3vw,17px);line-height:1.85;color:var(--mist);max-width:62ch}

/* ===== 面板 ===== */
.panel{
  position:relative;background:var(--slate);color:var(--fog);
  padding:clamp(20px,2.4vw,28px);
  box-shadow:inset 0 0 0 1px var(--line);
  clip-path:polygon(0 0,calc(100% - var(--cut)) 0,100% var(--cut),100% 100%,var(--cut) 100%,0 calc(100% - var(--cut)));
  transition:box-shadow .2s var(--ease),background-color .2s var(--ease),transform .2s var(--ease);
}
.panel:hover{box-shadow:inset 0 0 0 1px var(--cyan);transform:translateY(-2px)}
.panel--accent{box-shadow:inset 0 0 0 1px var(--line),inset 3px 0 0 0 var(--coral)}
.panel--accent:hover{box-shadow:inset 0 0 0 1px var(--coral),inset 3px 0 0 0 var(--coral)}
.panel--data{background:var(--deep-teal);box-shadow:inset 0 0 0 1px #14626A}
.panel--data:hover{box-shadow:inset 0 0 0 1px var(--cyan)}
.panel-title{font-size:19px;font-weight:800;letter-spacing:-.02em;color:var(--fog);line-height:1.35}
.panel-meta{font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;color:var(--mist);margin-top:10px}

/* ===== 标签 ===== */
.tag{
  display:inline-flex;align-items:center;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
  color:var(--mist);background:rgba(242,246,248,.03);
  border:1px solid var(--line);padding:3px 9px;line-height:1.6;
}
.tag--accent{color:var(--coral-soft);border-color:rgba(255,107,74,.5);background:rgba(255,107,74,.08)}
.tag--data{color:var(--cyan);border-color:rgba(45,226,230,.42);background:rgba(45,226,230,.07)}

/* ===== 线条与路径 ===== */
.rule{height:1px;border:0;background:var(--line);margin:0}
.path-line{
  position:relative;height:1px;
  background-image:repeating-linear-gradient(90deg,var(--line) 0 6px,transparent 6px 14px);
}
.path-line::after{
  content:"";position:absolute;right:0;top:-2px;width:5px;height:5px;
  background:var(--cyan);border-radius:50%;
}

/* ===== 面包屑 ===== */
.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
  color:var(--mist);padding-block:18px 0;
}
.breadcrumb a{color:var(--mist);text-decoration:none;transition:color .18s var(--ease)}
.breadcrumb a:hover{color:var(--coral)}
.breadcrumb .sep{color:var(--line)}
.breadcrumb [aria-current="page"]{color:var(--fog)}

/* ===== 正文 ===== */
.prose{max-width:720px;font-size:16px;line-height:1.85;color:#DCE6EE}
.prose p + p{margin-top:1.1em}
.prose h2{font-size:clamp(22px,2.4vw,28px);color:var(--fog);margin:1.8em 0 .6em}
.prose h3{font-size:19px;color:var(--fog);margin:1.6em 0 .5em}
.prose ul,.prose ol{margin:1em 0;padding-left:1.3em;list-style:disc}
.prose ol{list-style:decimal}
.prose li{margin:.35em 0}
.prose a{color:var(--cyan);text-underline-offset:3px}
.prose a:hover{color:var(--coral-soft)}
.prose strong{color:var(--fog);font-weight:700}
.prose hr{border:0;height:1px;background:var(--line);margin:2em 0}

/* ===== 图片容器基础规则 ===== */
.media-frame{
  position:relative;overflow:hidden;display:block;
  background:var(--slate);
  box-shadow:inset 0 0 0 1px var(--line);
  aspect-ratio:16 / 10;
}
.media-frame img{width:100%;height:100%;object-fit:cover;display:block}
.media-frame--wide{aspect-ratio:21 / 9}
.media-frame--square{aspect-ratio:1 / 1}
.media-frame--cut{clip-path:polygon(0 0,calc(100% - 20px) 0,100% 20px,100% 100%,0 100%)}
.media-placeholder{
  display:grid;place-items:center;width:100%;height:100%;
  background-color:var(--slate);
  background-image:
    linear-gradient(rgba(56,80,100,.38) 1px,transparent 1px),
    linear-gradient(90deg,rgba(56,80,100,.38) 1px,transparent 1px);
  background-size:40px 40px;
  color:var(--mist);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;text-align:center;padding:16px;
}

/* ===== JS 注入组件 ===== */
.scroll-progress{
  position:fixed;top:0;left:0;right:0;height:2px;z-index:80;
  pointer-events:none;background:transparent;
}
.scroll-progress span{
  display:block;height:100%;width:100%;
  background:linear-gradient(90deg,var(--coral),var(--cyan));
  transform:scaleX(0);transform-origin:left center;
}
.to-top{
  position:fixed;right:clamp(14px,3vw,28px);bottom:clamp(14px,3vw,28px);z-index:70;
  display:none;align-items:center;gap:8px;
  padding:10px 14px;border:1px solid var(--line);background:var(--coal);color:var(--mist);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;cursor:pointer;
  transition:color .18s var(--ease),border-color .18s var(--ease),background-color .18s var(--ease);
}
.to-top[data-visible="true"]{display:inline-flex}
.to-top:hover{color:var(--cyan);border-color:var(--cyan);background:#0D1116}
.to-top-mark{font-size:13px;line-height:1}

/* ===== 平板 ===== */
@media (max-width:1023px){
  .footer-top{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-brand{grid-column:1 / -1}
  .footer-contact{grid-column:1 / -1}
  .footer-brand-note{max-width:40ch}
}

@media (min-width:720px){
  .span-4{grid-column:span 4}
  .span-5{grid-column:span 5}
  .span-6{grid-column:span 6}
  .span-7{grid-column:span 7}
  .span-8{grid-column:span 8}
}

/* ===== 移动导航与紧凑条 ===== */
@media (max-width:899px){
  .nav-toggle{display:inline-flex;order:3}
  .header-actions{margin-left:auto;order:2}
  .primary-nav{
    position:absolute;left:0;right:0;top:100%;z-index:59;
    display:block;
    background:var(--coal);
    border-bottom:1px solid var(--line);
    border-top:1px solid var(--line);
    padding:14px var(--gutter) 22px;
    max-height:calc(100vh - var(--band-h));
    overflow-y:auto;
    visibility:hidden;opacity:0;transform:translateY(-8px);
    transition:opacity .22s var(--ease),transform .22s var(--ease),visibility .22s linear;
  }
  .primary-nav[data-open="true"]{visibility:visible;opacity:1;transform:none}
  .nav-list{flex-direction:column;align-items:stretch;gap:0}
  .nav-item + .nav-item{border-top:1px solid rgba(56,80,100,.55)}
  .nav-link{
    display:flex;justify-content:flex-start;align-items:baseline;gap:12px;
    padding:14px 4px;font-size:16px;border-bottom:0;
  }
  .nav-link[aria-current="page"]{
    color:var(--coral);
    box-shadow:inset 3px 0 0 var(--coral);
    padding-left:12px;
    background:rgba(255,107,74,.07);
  }
  .nav-idx{font-size:11px;min-width:22px}
  .nav-utility{display:flex;flex-direction:column;gap:10px;margin-top:18px}
  .nav-utility .btn{width:100%;padding:12px 16px}
  .nav-service{text-align:center;border-bottom:0}
}

@media (max-width:719px){
  .grid-12{grid-template-columns:1fr}
  .footer-top{grid-template-columns:1fr;gap:24px}
  .footer-brand,.footer-contact{grid-column:auto}
  .footer-base{flex-direction:column;align-items:flex-start;gap:6px}
}

@media (max-width:559px){
  .header-actions .btn-ghost{display:none}
  .brand-sub{display:none}
  .btn{padding:9px 13px;font-size:12px}
  .nav-toggle-text{display:none}
  .footer-brand-note{max-width:none}
}

/* ===== 减少动态 ===== */
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
  }
  html{scroll-behavior:auto}
  .panel:hover{transform:none}
  .btn-solid:hover{transform:none}
  .primary-nav{transform:none}
}