/* ===== 28圈品牌 · 共享 Site Kit / assets/site.css ===== */

/* 1. Reset */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:150px}
body,h1,h2,h3,h4,h5,p,figure,blockquote,dl,dd,ul,ol{margin:0}
ul,ol{padding:0;list-style:none}
img,svg{max-width:100%;display:block}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0}
a{color:inherit;text-decoration:none}
[hidden]{display:none !important}

/* 2. Design tokens */
:root{
  --ink-900:#081226;
  --ink-850:#0a1526;
  --ink-800:#0b1830;
  --ink-700:#122445;
  --line:#1B3358;
  --line-soft:rgba(27,51,88,.6);
  --cyan:#38E8D2;
  --cyan-dim:#169C90;
  --coral:#FF6A45;
  --coral-soft:#FFB39E;
  --paper:#F4F8FF;
  --mist:#A9B8CE;
  --mint:#79E0A6;
  --amber:#FFC857;
  --font-head:"Noto Sans SC","Source Han Sans SC","PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-body:"Noto Serif SC","Source Han Serif SC","Songti SC","PingFang SC",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --shell:1280px;
  --gutter:clamp(16px,4vw,48px);
  --shadow-paper:6px 6px 0 rgba(4,9,20,.5);
  --shadow-paper-lift:8px 10px 0 rgba(4,9,20,.55);
}

/* 3. Base & 中文排版 */
body{
  min-height:100vh;
  background-color:var(--ink-900);
  background-image:
    linear-gradient(to right,rgba(27,51,88,.32) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(27,51,88,.32) 1px,transparent 1px),
    radial-gradient(circle at 78% 6%,rgba(56,232,210,.10),transparent 55%),
    radial-gradient(circle at 10% 94%,rgba(255,106,69,.07),transparent 48%);
  background-size:96px 96px,96px 96px,100% 100%,100% 100%;
  color:var(--paper);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.8;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{font-family:var(--font-head);font-weight:800;letter-spacing:-.02em;line-height:1.15;color:var(--paper)}
h1{font-size:clamp(36px,5vw,56px);line-height:1.12}
h2{font-size:clamp(26px,3.4vw,34px);line-height:1.22}
h3{font-size:22px;line-height:1.3}
h4{font-size:18px;line-height:1.4}
p{max-width:72ch}
::selection{background:var(--cyan);color:#04121f}
:focus-visible{outline:2px solid var(--cyan);outline-offset:2px}

/* 4. Utilities */
.shell{width:100%;max-width:var(--shell);margin-inline:auto;padding-inline:var(--gutter)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.section-label{display:inline-flex;align-items:center;gap:10px;margin-bottom:14px;font-family:var(--font-mono);font-size:11px;letter-spacing:.24em;text-transform:uppercase;color:var(--cyan)}
.section-label::before{content:"";width:26px;height:1px;background:var(--cyan)}
.breadcrumb{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-bottom:24px;font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;color:var(--mist)}
.breadcrumb li{display:inline-flex;align-items:center;gap:8px}
.breadcrumb li+li::before{content:"/";color:var(--line)}
.breadcrumb a:hover{color:var(--cyan)}
.breadcrumb [aria-current="page"]{color:var(--paper)}
.grid-12{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:24px}
.span-4{grid-column:span 4}
.span-6{grid-column:span 6}
.span-8{grid-column:span 8}
.span-12{grid-column:span 12}

/* 5. Skip link */
.skip-link{
  position:fixed;left:16px;top:-88px;z-index:120;
  display:inline-flex;align-items:center;
  padding:10px 18px;border-radius:2px;
  background:var(--cyan);color:#04121f;
  font-family:var(--font-head);font-weight:800;font-size:15px;
  transition:top .18s ease;
}
.skip-link:focus{top:14px}

/* 6. Header */
.site-header{
  position:sticky;top:0;z-index:60;
  background:linear-gradient(180deg,rgba(8,18,38,.97),rgba(8,18,38,.9));
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.scroll-meter{position:absolute;left:0;right:0;bottom:-1px;height:2px;background:rgba(27,51,88,.65);overflow:hidden}
.scroll-meter-fill{display:block;height:100%;width:100%;background:linear-gradient(90deg,var(--cyan-dim),var(--cyan));transform:scaleX(0);transform-origin:0 50%}
.header-shell{position:relative;padding-block:10px 12px}
.header-top{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:52px}
.header-meta{display:flex;align-items:center;gap:12px;flex:none}

.brand{display:inline-flex;align-items:center;gap:12px;padding:4px;border-radius:2px}
.brand-mark{position:relative;flex:none;width:38px;height:38px;border:1px solid var(--cyan);border-radius:50%}
.brand-mark::before{content:"";position:absolute;inset:5px;border:1px solid var(--line);border-radius:50%}
.brand-mark::after{content:"";position:absolute;top:50%;left:50%;width:8px;height:8px;margin:-4px 0 0 -4px;border-radius:50%;background:var(--cyan);box-shadow:0 0 12px var(--cyan)}
.brand-text{display:block}
.brand-name{display:block;font-family:var(--font-head);font-weight:800;font-size:18px;letter-spacing:-.02em;line-height:1.2;color:var(--paper)}
.brand-line{display:block;font-family:var(--font-mono);font-size:10px;letter-spacing:.22em;text-transform:uppercase;color:var(--mist);line-height:1.6}
.brand:hover .brand-name{color:var(--cyan)}

.header-coord{
  padding:4px 8px;border:1px dashed var(--line);border-radius:2px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;color:var(--mist);
}
.header-cta{
  display:inline-flex;align-items:center;justify-content:center;
  padding:9px 15px;border:1px solid var(--coral);border-radius:2px;
  background:var(--coral);color:#0a1526;
  font-family:var(--font-head);font-weight:800;font-size:14px;letter-spacing:.02em;
  box-shadow:3px 3px 0 rgba(27,51,88,.9);
  transition:background-color .2s ease,transform .2s ease,box-shadow .2s ease;
}
.header-cta:hover{background:var(--coral-soft);border-color:var(--coral-soft);transform:translate(-1px,-1px);box-shadow:4px 4px 0 rgba(27,51,88,.9)}

.nav-toggle{
  display:none;align-items:center;gap:8px;
  padding:8px 11px;border:1px solid var(--line);border-radius:2px;
  background:rgba(18,36,69,.6);color:var(--paper);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;text-transform:uppercase;cursor:pointer;
  transition:border-color .18s ease,color .18s ease;
}
.nav-toggle:hover{border-color:var(--cyan-dim);color:var(--cyan)}
.nav-toggle-bars{display:inline-flex;flex-direction:column;justify-content:center;gap:3px;width:16px}
.nav-toggle-bar{display:block;height:2px;width:100%;background:var(--cyan);transition:transform .2s ease,opacity .2s ease}
.site-header[data-open] .nav-toggle-bar:nth-child(1){transform:translateY(5px) rotate(45deg)}
.site-header[data-open] .nav-toggle-bar:nth-child(2){opacity:0}
.site-header[data-open] .nav-toggle-bar:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

.header-main{display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap;margin-top:6px;padding-top:10px;border-top:1px solid var(--line-soft)}
.primary-nav{flex:1 1 auto;min-width:0}
.nav-list{display:flex;flex-wrap:wrap;gap:4px;counter-reset:navidx}
.nav-item{flex:none}
.nav-link{
  display:inline-flex;align-items:baseline;gap:7px;
  padding:8px 12px;border:1px solid transparent;border-radius:2px;
  font-family:var(--font-head);font-weight:700;font-size:15px;color:var(--mist);
  transition:color .18s ease,background-color .18s ease,border-color .18s ease;
  counter-increment:navidx;
}
.nav-link::before{content:"0" counter(navidx);font-family:var(--font-mono);font-size:10px;letter-spacing:.08em;color:#2b4874;transition:color .18s ease}
.nav-link:hover{color:var(--paper);border-color:var(--line);background:rgba(18,36,69,.65)}
.nav-link:hover::before{color:var(--cyan)}
.nav-link[aria-current="page"]{color:#04121f;background:var(--cyan);border-color:var(--cyan)}
.nav-link[aria-current="page"]::before{color:rgba(4,18,31,.55)}

.command-bar{
  position:relative;flex:0 1 400px;min-width:240px;
  display:flex;align-items:center;gap:8px;
  padding:5px 8px;border:1px solid var(--line);border-radius:2px;
  background:rgba(18,36,69,.55);
  box-shadow:inset 0 0 0 1px rgba(56,232,210,.06);
}
.command-token{flex:none;padding:2px 5px;border:1px solid var(--line);border-radius:2px;background:rgba(8,18,38,.85);font-family:var(--font-mono);font-size:10px;letter-spacing:.12em;color:var(--cyan)}
.command-input{flex:1 1 auto;min-width:0;padding:4px 0;border:0;background:transparent;outline:none;font-family:var(--font-body);font-size:13px;line-height:1.6;color:var(--paper)}
.command-input::placeholder{color:var(--mist);opacity:.85;font-size:12.5px}
.command-input:focus-visible{outline:2px solid var(--cyan);outline-offset:3px;border-radius:2px}
.command-results{
  position:absolute;left:-1px;right:-1px;top:calc(100% + 8px);z-index:70;
  max-height:290px;overflow:auto;padding:4px;
  background:var(--ink-800);border:1px solid var(--line);border-top:2px solid var(--cyan);
  box-shadow:0 18px 40px rgba(4,9,20,.72);
}
.command-result{display:flex;align-items:center;gap:10px;padding:9px 10px;border-radius:2px;font-family:var(--font-head);font-weight:700;font-size:14px;color:var(--paper);transition:background-color .18s ease}
.command-result:hover,.command-result:focus-visible{background:rgba(56,232,210,.12)}
.command-result-index{flex:none;font-family:var(--font-mono);font-size:10px;letter-spacing:.1em;color:var(--cyan)}
.command-result-label{flex:1 1 auto}
.command-result-group{flex:none;font-family:var(--font-mono);font-size:10px;letter-spacing:.1em;color:var(--mist)}
.command-empty{padding:10px;font-size:13px;color:var(--mist)}

/* 7. Footer */
.site-footer{position:relative;margin-top:96px;overflow:hidden;background:linear-gradient(180deg,#071021,#081226 42%);border-top:1px solid var(--line)}
.footer-orbit{position:absolute;right:-140px;top:-140px;width:440px;height:440px;pointer-events:none;opacity:.55}
.footer-orbit span{position:absolute;inset:0;border:1px solid rgba(56,232,210,.18);border-radius:50%}
.footer-orbit span:nth-child(2){inset:54px;border-color:rgba(27,51,88,.85)}
.footer-orbit span:nth-child(3){inset:124px;border-style:dashed;border-color:rgba(255,106,69,.28)}
.footer-shell{position:relative;padding-block:56px 28px}
.footer-top{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,2fr);gap:40px;align-items:start}
.footer-brand{display:flex;flex-direction:column;gap:14px}
.footer-brand .brand-name{font-size:22px}
.footer-tagline{font-family:var(--font-mono);font-size:11px;letter-spacing:.2em;text-transform:uppercase;color:var(--mist)}
.footer-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:28px}
.footer-col{min-width:0}
.footer-col-title{margin-bottom:14px;padding-bottom:10px;border-bottom:1px solid var(--line);font-family:var(--font-head);font-weight:800;font-size:13px;letter-spacing:.18em;color:var(--cyan)}
.footer-links{display:grid;gap:9px}
.footer-links a{font-size:15px;color:var(--mist);transition:color .18s ease}
.footer-links a:hover{color:var(--paper);text-decoration:underline;text-underline-offset:4px;text-decoration-color:var(--cyan)}
.footer-contact{display:grid;gap:10px}
.footer-contact-line{display:flex;flex-wrap:wrap;gap:8px;font-size:14px;line-height:1.7;color:var(--mist);overflow-wrap:anywhere}
.footer-contact-label{flex:none;font-family:var(--font-mono);font-size:10px;letter-spacing:.16em;color:var(--cyan);padding-top:4px;min-width:32px}
.footer-legal{display:flex;flex-wrap:wrap;align-items:center;gap:12px 22px;margin-top:40px;padding-top:18px;border-top:1px solid var(--line)}
.footer-legal-line{font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--mist)}
.footer-note{flex:1 1 340px;max-width:640px;font-family:var(--font-body);font-size:12.5px;line-height:1.75;color:rgba(169,184,206,.85)}
.to-top{
  display:inline-flex;align-items:center;gap:6px;margin-left:auto;
  padding:7px 12px;border:1px solid var(--line);border-radius:2px;
  background:transparent;color:var(--paper);cursor:pointer;
  font-family:var(--font-mono);font-size:10px;letter-spacing:.14em;
  transition:border-color .18s ease,color .18s ease,transform .18s ease;
}
.to-top:hover{border-color:var(--cyan);color:var(--cyan);transform:translateY(-1px)}

/* 8. Buttons */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  padding:12px 20px;border:1px solid var(--line);border-radius:2px;
  background:rgba(18,36,69,.65);color:var(--paper);
  font-family:var(--font-head);font-weight:800;font-size:15px;letter-spacing:.01em;
  transition:border-color .2s ease,color .2s ease,transform .2s ease,background-color .2s ease;
}
.btn:hover{border-color:var(--cyan);color:var(--cyan);transform:translateY(-1px)}
.btn-primary{background:var(--coral);border-color:var(--coral);color:#0a1526;box-shadow:4px 4px 0 rgba(27,51,88,.85)}
.btn-primary:hover{background:var(--coral-soft);border-color:var(--coral-soft);color:#0a1526;transform:translate(-1px,-1px);box-shadow:5px 5px 0 rgba(27,51,88,.85)}
.btn-ghost{background:transparent;border-color:var(--line);color:var(--mist)}
.btn-ghost:hover{border-color:var(--cyan);color:var(--cyan)}

/* 9. Tags */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 8px;border:1px solid var(--line);border-radius:2px;
  background:rgba(8,18,38,.75);color:var(--cyan);
  font-family:var(--font-mono);font-size:10px;letter-spacing:.14em;text-transform:uppercase;
}
.tag--coral{color:var(--coral-soft);border-color:rgba(255,106,69,.45)}
.tag--mint{color:var(--mint);border-color:rgba(121,224,166,.4)}
.tag--amber{color:var(--amber);border-color:rgba(255,200,87,.4)}

/* 10. Panels */
.panel{
  position:relative;
  padding:22px 22px 20px;
  border:1px solid var(--line);border-radius:2px;
  background:linear-gradient(180deg,rgba(18,36,69,.85),rgba(11,24,48,.92));
  box-shadow:var(--shadow-paper);
  transition:border-color .2s ease,transform .2s ease,box-shadow .2s ease;
}
.panel:hover{border-color:var(--cyan-dim);transform:translateY(-2px);box-shadow:var(--shadow-paper-lift)}
.panel-title{font-family:var(--font-head);font-weight:800;font-size:22px;line-height:1.3;letter-spacing:-.01em;color:var(--paper)}
.panel-text{margin-top:10px;font-size:15.5px;line-height:1.8;color:var(--mist)}

/* 11. Prose */
.prose{max-width:760px;font-size:17px;line-height:1.85;color:#d9e4f4}
.prose h2{margin:48px 0 16px;font-size:clamp(24px,3vw,34px)}
.prose h3{margin:32px 0 12px}
.prose p{margin-bottom:18px}
.prose ul,.prose ol{margin:0 0 20px;display:grid;gap:10px}
.prose ul li{position:relative;padding-left:20px}
.prose ul li::before{content:"";position:absolute;left:0;top:.78em;width:8px;height:2px;background:var(--cyan)}
.prose ol{counter-reset:proseidx}
.prose ol li{position:relative;padding-left:28px;counter-increment:proseidx}
.prose ol li::before{content:counter(proseidx,decimal-leading-zero);position:absolute;left:0;top:2px;font-family:var(--font-mono);font-size:11px;color:var(--cyan)}
.prose a{color:var(--cyan);text-decoration:underline;text-underline-offset:3px}
.prose a:hover{color:var(--coral-soft)}
.prose strong{color:var(--paper);font-weight:700}

/* 12. Media frames */
.media-frame{
  position:relative;display:block;width:100%;aspect-ratio:16/9;overflow:hidden;
  border:1px solid var(--line);border-radius:2px;
  background:linear-gradient(160deg,rgba(18,36,69,.92),rgba(8,18,38,.96));
  box-shadow:var(--shadow-paper);
}
.media-frame img{width:100%;height:100%;object-fit:cover}
.media-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:linear-gradient(to right,rgba(56,232,210,.06) 1px,transparent 1px),linear-gradient(to bottom,rgba(56,232,210,.06) 1px,transparent 1px);
  background-size:48px 48px;
}
.media-frame--wide{aspect-ratio:21/9}
.media-frame--square{aspect-ratio:1/1}
.media-frame__label{
  position:absolute;left:12px;bottom:12px;z-index:2;
  padding:3px 7px;border:1px solid var(--line);border-radius:2px;
  background:rgba(8,18,38,.85);color:var(--paper);
  font-family:var(--font-mono);font-size:10px;letter-spacing:.12em;
}

/* 13. Responsive */
@media (max-width:1080px){
  .header-coord{display:none}
  .nav-link{font-size:14px;padding:8px 9px}
  .command-bar{flex-basis:300px}
  .footer-top{grid-template-columns:1fr;gap:32px}
}

@media (max-width:900px){
  .nav-toggle{display:inline-flex}
  .header-main{flex-direction:column;align-items:stretch;gap:10px}
  .primary-nav{
    position:absolute;left:0;right:0;top:100%;z-index:65;
    display:none;max-height:calc(100vh - 140px);overflow-y:auto;
    padding:8px var(--gutter) 16px;
    background:var(--ink-850);
    border-top:1px solid var(--line);border-bottom:1px solid var(--line);
    box-shadow:0 24px 44px rgba(3,7,16,.82);
  }
  .site-header[data-open] .primary-nav{display:block}
  .nav-list{flex-direction:column;gap:0}
  .nav-link{width:100%;justify-content:flex-start;padding:13px 10px;font-size:16px;border-bottom:1px solid rgba(27,51,88,.55);border-radius:0}
  .nav-link[aria-current="page"]{border-bottom-color:var(--cyan)}
  .command-bar{flex:1 1 auto;min-width:0}
  .span-4,.span-6,.span-8{grid-column:span 12}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (max-width:720px){
  .header-cta{padding:8px 11px;font-size:13px}
  .brand-mark{width:34px;height:34px}
  .brand-name{font-size:16px}
  .footer-shell{padding-block:44px 24px}
  .footer-grid{grid-template-columns:1fr}
  .to-top{margin-left:0}
}

@media (max-width:560px){
  .header-meta{gap:8px}
  .nav-toggle-label{display:none}
  .footer-orbit{width:320px;height:320px;right:-120px;top:-110px}
  .command-bar{flex-basis:100%}
}

/* 14. Reduced motion */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
}