*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:calc(var(--header-h) + 12px)}
body{margin:0}
h1,h2,h3,h4,h5,p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
img,svg{max-width:100%}
a{color:inherit}
button{font:inherit;color:inherit}
table{border-collapse:collapse;width:100%}

:root{
  --sea:#0B1F33;
  --sea-deep:#071523;
  --paper:#F4EFE4;
  --ink:#111417;
  --orange:#FF5A1F;
  --cyan:#38F2D0;
  --cool:#C9D1D6;
  --mid:#1E4E79;
  --cream:#FFFDF7;
  --warn:#F2C94C;
  --line:rgba(17,20,23,.16);
  --line-strong:rgba(17,20,23,.42);
  --line-light:rgba(201,209,214,.24);
  --header-h:102px;
  --maxw:1440px;
  --pad:clamp(16px,4vw,56px);
  --font-display:"Noto Sans SC","Archivo Narrow","Barlow Condensed","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}

body{
  background:var(--paper);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  padding-top:var(--header-h);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:700;
  line-height:1.16;
  letter-spacing:-.01em;
  color:var(--ink);
}
h1{font-size:clamp(2.1rem,5.2vw,4rem);letter-spacing:-.03em;line-height:1.02}
h2{font-size:clamp(1.5rem,3vw,2.25rem)}
h3{font-size:clamp(1.15rem,1.8vw,1.4rem)}
p{font-size:inherit}
strong{font-weight:700}
.mono,.footer-meta--mono,.nav-num,.nav-en,.eyebrow,.utility-link,.utility-status,.breadcrumb,.tag,.footer-head span,.footer-sign,.to-top,.skip-link,.nav-toggle{font-family:var(--font-mono)}

:focus-visible{outline:2px solid var(--orange);outline-offset:3px}
.site-footer :focus-visible,.site-header :focus-visible{outline-color:var(--cyan)}

.skip-link{
  position:fixed;top:0;left:0;z-index:300;
  transform:translateY(-130%);
  background:var(--cyan);color:var(--ink);
  padding:10px 18px;font-size:13px;font-weight:700;letter-spacing:.1em;text-decoration:none;
  transition:transform .18s ease;
}
.skip-link:focus{transform:translateY(0)}

/* ---------- header ---------- */
.site-header{position:fixed;top:0;left:0;right:0;z-index:120;background:var(--sea);color:var(--paper)}

.utility-bar{background:var(--sea-deep);border-bottom:1px solid rgba(56,242,208,.18)}
.utility-inner{
  max-width:var(--maxw);margin-inline:auto;padding-inline:var(--pad);
  min-height:44px;display:flex;align-items:center;justify-content:space-between;gap:14px;
}
.utility-status{
  display:inline-flex;align-items:center;gap:9px;
  font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--cool);
  white-space:nowrap;
}
.status-dot{
  width:7px;height:7px;flex:none;background:var(--cyan);border-radius:50%;
  box-shadow:0 0 0 3px rgba(56,242,208,.16);
}
.utility-actions{display:flex;align-items:center;gap:clamp(10px,2vw,22px)}
.utility-link{
  font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--cool);
  text-decoration:none;padding-block:4px;border-bottom:1px solid transparent;
  transition:color .18s ease,border-color .18s ease;
}
.utility-link:hover{color:var(--cyan);border-bottom-color:var(--cyan)}

.frame-bar{position:relative;background:var(--sea);border-bottom:1px solid rgba(56,242,208,.3)}
.frame-inner{
  max-width:var(--maxw);margin-inline:auto;padding-inline:var(--pad);
  min-height:56px;display:flex;align-items:center;gap:clamp(14px,3vw,44px);
}

.brand{display:inline-flex;align-items:center;gap:12px;text-decoration:none;color:var(--paper);flex:none}
.brand-mark{
  position:relative;display:block;width:28px;height:28px;flex:none;
  border:1px solid var(--cyan);
}
.brand-mark::before{content:"";position:absolute;inset:4px 10px 4px 4px;background:var(--orange)}
.brand-mark::after{content:"";position:absolute;left:4px;right:4px;bottom:4px;height:1px;background:rgba(56,242,208,.6)}
.brand-name{
  font-family:var(--font-display);font-weight:700;font-size:17px;letter-spacing:.06em;
  white-space:nowrap;color:var(--paper);
}
.brand-sub{
  font-family:var(--font-mono);font-size:10px;letter-spacing:.18em;text-transform:uppercase;
  color:var(--cyan);padding-left:12px;border-left:1px solid rgba(56,242,208,.38);
  white-space:nowrap;
}

.nav-toggle{
  display:none;align-items:center;gap:10px;margin-left:auto;
  background:transparent;color:var(--paper);
  border:1px solid rgba(201,209,214,.4);border-radius:0;
  padding:9px 12px;cursor:pointer;
  font-size:11px;letter-spacing:.16em;text-transform:uppercase;
  transition:border-color .18s ease,color .18s ease;
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle[aria-expanded="true"]{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle-bars{position:relative;display:block;width:16px;height:2px;background:currentColor}
.nav-toggle-bars::before,.nav-toggle-bars::after{
  content:"";position:absolute;left:0;width:16px;height:2px;background:currentColor;
}
.nav-toggle-bars::before{top:-5px}
.nav-toggle-bars::after{top:5px}

.site-nav{margin-left:auto}
.nav-list{display:flex;align-items:stretch;gap:clamp(0px,.9vw,14px)}
.nav-list a{
  position:relative;
  display:inline-flex;align-items:center;gap:7px;
  padding:18px 8px;text-decoration:none;
  color:var(--cool);font-size:14px;font-weight:500;letter-spacing:.03em;
  transition:color .18s ease;
  white-space:nowrap;
}
.nav-list a:hover{color:var(--paper)}
.nav-num{font-size:10px;letter-spacing:.1em;color:rgba(56,242,208,.66)}
.nav-en{font-size:9.5px;letter-spacing:.16em;text-transform:uppercase;color:rgba(201,209,214,.5)}
.nav-list a[aria-current="page"]{color:var(--paper)}
.nav-list a[aria-current="page"]::after{
  content:"";position:absolute;left:8px;right:8px;bottom:0;height:3px;background:var(--orange);
}
.nav-list a[aria-current="page"] .nav-num{color:var(--orange)}

.scroll-progress{
  position:absolute;left:0;right:0;bottom:-1px;height:2px;
  background:var(--orange);
  transform:scaleX(0);transform-origin:0 50%;
  will-change:transform;
}

/* ---------- layout helpers ---------- */
.container{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--pad)}
.section{padding-block:clamp(36px,5.5vw,80px)}
.prose{max-width:66ch}
.prose p+p{margin-top:1em}
.prose h2,.prose h3{margin-top:1.6em;margin-bottom:.5em}
.h-display{font-family:var(--font-display);font-weight:700;font-size:clamp(2.25rem,6vw,5.25rem);line-height:.96;letter-spacing:-.035em}

.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-size:11px;letter-spacing:.2em;text-transform:uppercase;color:var(--mid);
}
.eyebrow::before{content:"";width:22px;height:2px;background:var(--orange);flex:none}

.split-board{display:grid;grid-template-columns:1fr;gap:clamp(20px,3vw,48px)}
@media (min-width:900px){.split-board{grid-template-columns:5fr 7fr}}

.rail{
  border-top:2px solid var(--ink);padding-top:14px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--mid);
}
.rail-title{font-weight:700;color:var(--ink);display:block;margin-bottom:8px}
.rail ol{display:grid;gap:8px}
.rail a{text-decoration:none;color:var(--mid);transition:color .18s ease}
.rail a:hover{color:var(--orange)}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.55em;
  padding:.7em 1.15em;border:1px solid transparent;border-radius:0;
  font-family:var(--font-body);font-size:14px;font-weight:700;letter-spacing:.05em;
  text-decoration:none;cursor:pointer;
  transition:background-color .18s ease,color .18s ease,border-color .18s ease;
}
.btn-signal{background:var(--orange);color:#fff;border-color:var(--orange)}
.btn-signal:hover{background:#e5460c;border-color:#e5460c;color:#fff}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--line-strong)}
.btn-ghost:hover{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.btn-sm{padding:7px 13px;font-size:12px;letter-spacing:.09em}

/* ---------- tags ---------- */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 9px;border:1px solid var(--line-strong);
  font-size:11px;letter-spacing:.1em;text-transform:uppercase;
  background:var(--cream);color:var(--ink);text-decoration:none;border-radius:0;
}
.tag--signal{background:var(--orange);border-color:var(--orange);color:#fff}
.tag--cyan{background:var(--cyan);border-color:var(--cyan);color:var(--sea)}
.tag--warn{background:var(--warn);border-color:var(--warn);color:var(--ink)}

/* ---------- breadcrumb ---------- */
.breadcrumb{border-bottom:1px solid var(--line);background:var(--paper)}
.breadcrumb-inner{max-width:var(--maxw);margin-inline:auto;padding:16px var(--pad)}
.breadcrumb ol{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--mid)}
.breadcrumb li{display:inline-flex;align-items:center;gap:10px}
.breadcrumb li+li::before{content:"/";color:var(--cool)}
.breadcrumb a{text-decoration:none;color:var(--mid);transition:color .18s ease}
.breadcrumb a:hover{color:var(--orange)}
.breadcrumb [aria-current="page"]{color:var(--ink);font-weight:700}

/* ---------- media ---------- */
.media{
  position:relative;display:block;width:100%;overflow:hidden;
  background:var(--cool);border:1px solid var(--line-strong);
}
.media::after{content:"";position:absolute;inset:0;border:1px solid rgba(11,31,51,.08);pointer-events:none}
.media img,.media video{display:block;width:100%;height:100%;object-fit:cover}
.media--21x9{aspect-ratio:21/9}
.media--16x9{aspect-ratio:16/9}
.media--3x2{aspect-ratio:3/2}
.media--4x3{aspect-ratio:4/3}
.media--1x1{aspect-ratio:1/1}
.media-caption{margin-top:8px;font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--mid)}

/* ---------- reveal ---------- */
[data-reveal]{opacity:0;transform:translateY(14px);transition:opacity .5s ease,transform .5s ease}
[data-reveal].is-revealed{opacity:1;transform:none}

/* ---------- footer ---------- */
.site-footer{background:var(--sea);color:var(--cool);margin-top:clamp(48px,8vw,120px);border-top:2px solid var(--orange)}
.footer-inner{max-width:var(--maxw);margin-inline:auto;padding:clamp(40px,6vw,72px) var(--pad) 28px}
.footer-top{display:grid;gap:clamp(28px,4vw,56px);grid-template-columns:1fr}
@media (min-width:900px){.footer-top{grid-template-columns:minmax(240px,1fr) 3fr}}
.footer-brand .brand{padding-block:0}
.footer-tag{
  margin-top:16px;max-width:34ch;font-size:14px;line-height:1.75;
  color:rgba(201,209,214,.82);
}
.footer-nav{display:grid;gap:clamp(22px,3vw,34px);grid-template-columns:repeat(2,minmax(0,1fr))}
@media (min-width:700px){.footer-nav{grid-template-columns:repeat(4,minmax(0,1fr))}}
.footer-col{min-width:0}
.footer-head{
  display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:6px;
  font-family:var(--font-display);font-size:13px;font-weight:700;letter-spacing:.1em;
  color:var(--paper);text-transform:uppercase;
  padding-bottom:10px;border-bottom:1px solid var(--line-light);
}
.footer-head span{font-size:10px;font-weight:400;letter-spacing:.14em;color:var(--cyan)}
.footer-list{margin-top:14px;display:grid;gap:9px}
.footer-list a{
  font-size:14px;text-decoration:none;color:var(--cool);
  border-bottom:1px solid transparent;transition:color .18s ease,border-color .18s ease;
}
.footer-list a:hover{color:var(--cyan);border-bottom-color:rgba(56,242,208,.5)}
.footer-meta{
  margin-top:10px;font-size:12.5px;line-height:1.8;letter-spacing:.03em;
  color:rgba(201,209,214,.74);
}
.footer-meta--mono{font-family:var(--font-mono);letter-spacing:.05em;color:rgba(56,242,208,.86);word-break:break-all}
.footer-bottom{
  margin-top:clamp(30px,5vw,56px);padding-top:20px;
  border-top:1px solid var(--line-light);
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px 26px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.09em;text-transform:uppercase;
  color:rgba(201,209,214,.66);
}
.footer-sign{margin:0}

.to-top{
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 14px;border-radius:0;
  background:var(--ink);color:var(--paper);
  border:1px solid rgba(56,242,208,.45);
  font-size:10px;letter-spacing:.16em;text-transform:uppercase;cursor:pointer;
  position:fixed;right:clamp(12px,3vw,28px);bottom:clamp(12px,3vw,28px);z-index:110;
  opacity:0;visibility:hidden;transform:translateY(8px);
  transition:opacity .22s ease,transform .22s ease,visibility .22s,background-color .18s ease,border-color .18s ease;
}
.to-top[data-visible]{opacity:1;visibility:visible;transform:translateY(0)}
.to-top:hover{background:var(--orange);border-color:var(--orange);color:#fff}

/* ---------- responsive ---------- */
@media (max-width:1160px){
  .nav-en{display:none}
}
@media (max-width:960px){
  :root{--header-h:98px}
  .nav-toggle{display:inline-flex}
  .site-nav{
    position:absolute;top:100%;left:0;right:0;margin-left:0;
    display:none;background:var(--sea-deep);
    border-top:1px solid rgba(56,242,208,.28);
    border-bottom:1px solid rgba(56,242,208,.28);
    max-height:calc(100vh - var(--header-h));
    overflow-y:auto;
  }
  .site-nav[data-open]{display:block}
  .nav-list{flex-direction:column;gap:0;padding:6px var(--pad) 22px}
  .nav-list li{border-bottom:1px solid rgba(201,209,214,.14)}
  .nav-list li:last-child{border-bottom:0}
  .nav-list a{padding:15px 2px;width:100%;font-size:16px;gap:12px}
  .nav-list a[aria-current="page"]::after{left:0;right:auto;top:14px;bottom:14px;width:3px;height:auto}
  .nav-en{display:inline}
}
@media (max-width:620px){
  .brand-sub{display:none}
  .utility-link{display:none}
  .utility-status{font-size:10px;letter-spacing:.1em}
  .footer-bottom{font-size:10px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  [data-reveal]{opacity:1;transform:none}
  .to-top{transform:none}
}