:root{
  --ink:#06121F;
  --ink-2:#0C2233;
  --teal-deep:#0E2E2C;
  --wine:#3A132F;
  --neon:#2BE3D0;
  --neon-soft:#8CF6EA;
  --amber:#E9B23C;
  --magenta:#E0447C;
  --text:#E9F0F6;
  --muted:#93A9BC;
  --line:#1C3A52;
  --maxw:1260px;
  --gutter:clamp(18px,4.4vw,56px);
  --header-h:72px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --t:160ms;
  --t-slow:320ms;
  --font-display:"Arial Narrow","Helvetica Neue Condensed","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --font-body:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC",sans-serif;
  --font-num:"SFMono-Regular",Menlo,Consolas,"PingFang SC",monospace;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:96px}
body{margin:0;background:var(--ink);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.85;text-rendering:optimizeLegibility;overflow-x:hidden}
img,svg,video{max-width:100%;display:block}
a{color:var(--neon);text-decoration:none}
ul,ol{margin:0;padding:0;list-style:none}
h1,h2,h3,h4,p,figure,blockquote{margin:0}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
table{border-collapse:collapse;width:100%}
hr{border:0;border-top:1px solid var(--line);margin:0}
:focus-visible{outline:2px solid var(--neon);outline-offset:3px}

/* ---------- shell ---------- */
.wrap{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--gutter)}
#main-content{padding-top:var(--header-h)}
#main-content.main--overlay{padding-top:0}
.skip-link{position:fixed;left:12px;top:-60px;z-index:120;background:var(--neon);color:var(--ink);padding:10px 16px;font-size:14px;font-weight:700;transition:top var(--t) var(--ease)}
.skip-link:focus{top:12px}

/* ---------- header ---------- */
.site-header{position:fixed;top:0;left:0;right:0;z-index:80;background:transparent;border-bottom:1px solid transparent;transition:background var(--t) var(--ease),border-color var(--t) var(--ease)}
.site-header[data-solid]{background:rgba(6,18,31,.94);border-bottom-color:var(--line);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px)}
.site-header__progress{position:absolute;left:0;right:0;bottom:-1px;height:2px;background:linear-gradient(90deg,var(--neon),var(--neon-soft));transform:scaleX(0);transform-origin:0 50%;transition:transform 120ms linear}
.site-header__inner{display:flex;align-items:center;gap:clamp(12px,2vw,26px);min-height:var(--header-h);padding-block:8px}
.brand{display:inline-flex;align-items:center;gap:11px;color:var(--text);flex:0 0 auto}
.brand__mark{display:grid;place-items:center;width:34px;height:34px;border:1px solid var(--neon);color:var(--neon);font-family:var(--font-num);font-size:13px;font-weight:700;clip-path:polygon(0 0,100% 0,100% 72%,72% 100%,0 100%);transition:background var(--t) var(--ease),color var(--t) var(--ease)}
.brand:hover .brand__mark{background:var(--neon);color:var(--ink)}
.brand__text{display:grid;line-height:1.25}
.brand__name{font-family:var(--font-display);font-size:17px;font-weight:800;letter-spacing:.14em}
.brand__descriptor{font-size:11px;letter-spacing:.26em;color:var(--muted)}
.version-badge{display:inline-block;font-family:var(--font-num);font-size:12px;font-weight:700;letter-spacing:.1em;color:var(--amber);border:1px solid rgba(233,178,60,.45);padding:4px 10px;white-space:nowrap;background:rgba(233,178,60,.06)}
.version-badge--footer{margin:14px 0 0;font-size:11px}
.nav-toggle{display:none;align-items:center;gap:9px;border:1px solid var(--line);padding:9px 12px;color:var(--muted);letter-spacing:.14em;font-size:12px;transition:border-color var(--t) var(--ease),color var(--t) var(--ease)}
.nav-toggle:hover{border-color:var(--neon);color:var(--neon-soft)}
.nav-toggle__bars{position:relative;width:16px;height:10px;flex:0 0 auto}
.nav-toggle__bars::before,.nav-toggle__bars::after{content:"";position:absolute;left:0;right:0;height:1px;background:currentColor;transition:transform var(--t) var(--ease),top var(--t) var(--ease)}
.nav-toggle__bars::before{top:0}
.nav-toggle__bars::after{top:9px}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{top:4px;transform:rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{top:4px;transform:rotate(-45deg)}
.nav-toggle__label{line-height:1}
.site-nav{display:flex;align-items:center;gap:clamp(14px,2.4vw,30px);margin-left:auto}
.site-nav__list{display:flex;align-items:center;gap:clamp(13px,2vw,26px);flex-wrap:wrap}
.site-nav__link{position:relative;display:inline-block;padding:6px 1px;color:var(--muted);font-size:14px;letter-spacing:.06em;transition:color var(--t) var(--ease)}
.site-nav__link::after{content:"";position:absolute;left:0;right:0;bottom:0;height:1px;background:var(--neon);transform:scaleX(0);transform-origin:0 50%;transition:transform var(--t) var(--ease),background var(--t) var(--ease)}
.site-nav__link:hover{color:var(--neon-soft)}
.site-nav__link:hover::after{transform:scaleX(1)}
.site-nav__link[aria-current="page"]{color:var(--text)}
.site-nav__link[aria-current="page"]::after{transform:scaleX(1);background:var(--amber)}
.nav-cta{flex:0 0 auto}

/* ---------- buttons / links ---------- */
.btn{display:inline-flex;align-items:center;gap:9px;padding:12px 20px;border:1px solid var(--line);background:transparent;color:var(--text);font-size:13px;letter-spacing:.16em;line-height:1;transition:border-color var(--t) var(--ease),color var(--t) var(--ease),background var(--t) var(--ease)}
.btn--neon{border-color:var(--neon);color:var(--neon)}
.btn--neon:hover{background:var(--neon);color:var(--ink)}
.btn--amber{border-color:var(--amber);color:var(--amber)}
.btn--amber:hover{background:var(--amber);color:var(--ink)}
.btn--ghost:hover{border-color:var(--neon);color:var(--neon-soft)}
.arrow-link{display:inline-flex;align-items:center;gap:10px;color:var(--neon);font-size:14px;letter-spacing:.1em;border-bottom:1px solid transparent;transition:color var(--t) var(--ease),border-color var(--t) var(--ease)}
.arrow-link:hover{color:var(--neon-soft);border-bottom-color:var(--neon-soft)}
.arrow-link__arrow{display:inline-block;transition:transform var(--t) var(--ease)}
.arrow-link:hover .arrow-link__arrow{transform:translateX(4px)}
.tag{display:inline-block;font-size:12px;letter-spacing:.16em;line-height:1.6;padding:2px 9px;border:1px solid currentColor;color:var(--magenta)}
.tag--cyan{color:var(--neon)}
.tag--amber{color:var(--amber)}

/* ---------- type ---------- */
.display-1,.display-2,.display-3{font-family:var(--font-display);font-weight:800;letter-spacing:.05em;line-height:1;color:var(--text)}
.display-1{font-size:clamp(38px,7.4vw,96px);line-height:.98}
.display-2{font-size:clamp(28px,4.6vw,58px)}
.display-3{font-size:clamp(21px,2.8vw,34px);letter-spacing:.08em;line-height:1.3}
.eyebrow{display:inline-block;font-size:12px;letter-spacing:.3em;color:var(--muted);text-transform:uppercase}
.lede{font-size:clamp(16px,1.5vw,19px);line-height:1.85;color:var(--muted);max-width:44em}
.prose{max-width:44em;line-height:1.85}
.prose p+p{margin-top:1.1em}
.prose h2,.prose h3{margin:1.8em 0 .6em;line-height:1.4}
.meta{font-size:13px;color:var(--muted);letter-spacing:.06em}
.num{font-family:var(--font-num);font-weight:700;color:var(--amber);font-variant-numeric:tabular-nums;letter-spacing:.02em}

/* ---------- sections & rhythm ---------- */
.section{position:relative;padding:clamp(52px,8.5vw,124px) 0}
.section--deep{background:var(--ink)}
.section--panel{background:var(--ink-2)}
.section--teal{background:var(--teal-deep)}
.section--wine{background:var(--wine)}
.checker::before{content:"";position:absolute;inset:0;pointer-events:none;opacity:.9;background-image:linear-gradient(45deg,rgba(233,240,246,.035) 25%,transparent 25%,transparent 75%,rgba(233,240,246,.035) 75%),linear-gradient(45deg,rgba(233,240,246,.035) 25%,transparent 25%,transparent 75%,rgba(233,240,246,.035) 75%);background-size:18px 18px;background-position:0 0,9px 9px}
.rule{border:0;border-top:1px solid var(--line);margin:clamp(24px,4vw,48px) 0}
.rule--amber{border-top-color:var(--amber);width:56px}
.section-head{display:flex;align-items:baseline;justify-content:space-between;gap:20px;flex-wrap:wrap;margin-bottom:clamp(22px,3.4vw,42px)}

/* ---------- layout ---------- */
.split{display:grid;grid-template-columns:minmax(0,7fr) minmax(0,5fr);gap:clamp(22px,4vw,64px);align-items:start}
.split--tools{grid-template-columns:minmax(0,5fr) minmax(0,7fr)}
.split--legal{grid-template-columns:minmax(0,3fr) minmax(0,9fr)}
.grid-12{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(14px,2.4vw,32px)}
.span-3{grid-column:span 3}
.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}
.span-9{grid-column:span 9}
.span-12{grid-column:span 12}
.bleed-right{margin-right:calc(var(--gutter) * -1)}

/* ---------- surfaces ---------- */
.card{position:relative;background:var(--ink-2);border:1px solid var(--line);padding:clamp(18px,2.4vw,30px);transition:border-color var(--t) var(--ease)}
.card:hover{border-color:var(--neon)}
.card--stack::before{content:"";position:absolute;inset:0;transform:translate(8px,8px);border:1px solid var(--line);z-index:-1;pointer-events:none}
.card--flush{padding:0;background:transparent}
.card__title{font-family:var(--font-display);font-size:clamp(18px,2vw,24px);font-weight:800;letter-spacing:.06em;line-height:1.3;margin-bottom:10px}
.card__meta{margin-top:16px}
.panel{background:var(--ink-2);border:1px solid var(--line);padding:clamp(16px,2.2vw,28px)}

/* ---------- horizontal rail ---------- */
.rail{position:relative}
.rail__track{display:flex;gap:clamp(12px,1.6vw,20px);overflow-x:auto;scroll-snap-type:x mandatory;padding:4px 0 16px;scrollbar-width:thin;scrollbar-color:var(--line) transparent}
.rail__track::-webkit-scrollbar{height:6px}
.rail__track::-webkit-scrollbar-track{background:transparent}
.rail__track::-webkit-scrollbar-thumb{background:var(--line)}
.rail__item{flex:0 0 auto;scroll-snap-align:start;min-width:min(76vw,300px)}
.rail__nav{display:flex;gap:8px;justify-content:flex-end}
.rail__btn{width:36px;height:36px;display:grid;place-items:center;border:1px solid var(--line);color:var(--muted);font-size:15px;line-height:1;transition:border-color var(--t) var(--ease),color var(--t) var(--ease)}
.rail__btn:hover{border-color:var(--neon);color:var(--neon-soft)}

/* ---------- skill path ---------- */
.path{position:relative;margin:0;padding:0}
.path__item{position:relative;padding:2px 0 30px 46px;margin-left:16px;border-left:1px solid var(--line)}
.path__item:last-child{border-left-color:transparent;padding-bottom:0}
.path__item::before{content:attr(data-step);position:absolute;left:-17px;top:0;width:32px;height:32px;display:grid;place-items:center;background:var(--ink);border:1px solid var(--amber);color:var(--amber);font-family:var(--font-num);font-size:13px;font-weight:700}
.path__title{font-size:16px;font-weight:700;letter-spacing:.04em}
.path__desc{color:var(--muted);font-size:14px;margin-top:4px}

/* ---------- table of contents ---------- */
.toc{position:sticky;top:calc(var(--header-h) + 26px);border-left:1px solid var(--line);padding-left:2px}
.toc__link{display:block;padding:8px 0 8px 14px;margin-left:-2px;border-left:2px solid transparent;color:var(--muted);font-size:14px;line-height:1.6;transition:color var(--t) var(--ease),border-color var(--t) var(--ease)}
.toc__link:hover{color:var(--neon-soft)}
.toc__link[aria-current="true"]{border-left-color:var(--neon);color:var(--text)}

/* ---------- fold ---------- */
.fold{border:1px solid var(--line);background:var(--ink-2);margin-bottom:12px}
.fold__summary{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 20px;cursor:pointer;font-size:15px;letter-spacing:.06em;list-style:none;transition:color var(--t) var(--ease)}
.fold__summary::-webkit-details-marker{display:none}
.fold__summary:hover{color:var(--neon-soft)}
.fold__summary::after{content:"+";font-family:var(--font-num);color:var(--amber);font-size:16px}
.fold[open] .fold__summary::after{content:"–"}
.fold__body{padding:0 20px 20px;color:var(--muted);font-size:15px}

/* ---------- breadcrumb ---------- */
.breadcrumb{padding:clamp(14px,2vw,22px) 0 0}
.breadcrumb ol{display:flex;flex-wrap:wrap;gap:8px;font-size:13px;color:var(--muted)}
.breadcrumb li{display:inline-flex;align-items:center;gap:8px}
.breadcrumb li+li::before{content:"/";color:var(--line)}
.breadcrumb a{color:var(--muted);transition:color var(--t) var(--ease)}
.breadcrumb a:hover{color:var(--neon-soft)}
.breadcrumb [aria-current="page"]{color:var(--text)}

/* ---------- media ---------- */
.media{position:relative;overflow:hidden;background:var(--ink-2);border:1px solid var(--line);aspect-ratio:16/10}
.media img{width:100%;height:100%;object-fit:cover}
.media--wide{aspect-ratio:21/9}
.media--tall{aspect-ratio:3/4}
.media--square{aspect-ratio:1/1}
.media--cut{clip-path:polygon(0 0,100% 0,100% 84%,0 100%)}
.media--light{background:linear-gradient(125deg,#06121F 0%,#0E2E2C 46%,#12263F 74%,#06121F 100%)}
.media--light::after{content:"";position:absolute;inset:-20% -60%;background:linear-gradient(78deg,transparent 42%,rgba(43,227,208,.22) 46%,transparent 51%),linear-gradient(96deg,transparent 60%,rgba(233,178,60,.16) 64%,transparent 68%);pointer-events:none}
.media__label{position:absolute;left:0;bottom:0;z-index:2;padding:6px 12px;background:var(--ink);border-top:1px solid var(--line);border-right:1px solid var(--line);font-size:12px;letter-spacing:.1em;color:var(--muted)}

/* ---------- reveal ---------- */
[data-reveal]{opacity:0;transform:translateY(14px);transition:opacity 420ms var(--ease),transform 420ms var(--ease)}
[data-reveal].is-in{opacity:1;transform:none}

/* ---------- footer ---------- */
.site-footer{position:relative;background:var(--ink);border-top:1px solid var(--line);color:var(--text)}
.footer__strip{height:3px;background:linear-gradient(90deg,var(--neon) 0 42%,var(--amber) 42% 76%,var(--magenta) 76% 100%)}
.footer__top{display:grid;grid-template-columns:minmax(0,4fr) minmax(0,5fr) minmax(0,3.4fr);gap:clamp(22px,4vw,58px);padding-block:clamp(38px,6vw,74px)}
.footer__brandline{font-family:var(--font-display);font-size:clamp(17px,2vw,22px);font-weight:800;letter-spacing:.1em}
.footer__closing{margin-top:16px;color:var(--muted);font-size:14px;max-width:26em}
.footer__cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(14px,2.4vw,30px)}
.footer__heading{font-size:12px;letter-spacing:.26em;color:var(--amber);margin-bottom:14px}
.footer__list li+li{margin-top:9px}
.footer__link{position:relative;display:inline-block;color:var(--muted);font-size:14px;transition:color var(--t) var(--ease)}
.footer__link::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:1px;background:var(--neon);transform:scaleX(0);transform-origin:0 50%;transition:transform var(--t) var(--ease)}
.footer__link:hover{color:var(--neon-soft)}
.footer__link:hover::after{transform:scaleX(1)}
.footer__contact{border-left:1px solid var(--line);padding-left:clamp(14px,2vw,26px)}
.footer__contact-title{font-size:12px;letter-spacing:.26em;color:var(--amber);margin-bottom:14px}
.footer__contact-list li+li{margin-top:10px}
.footer__meta{display:block;font-size:12px;letter-spacing:.14em;color:var(--muted)}
.footer__value{display:block;font-size:14px;line-height:1.7;color:var(--text);word-break:break-word}
.footer__contact-note{margin:14px 0 16px;font-size:13px;color:var(--muted);line-height:1.7}
.footer__bottom{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;border-top:1px solid var(--line);padding-block:18px 26px}
.footer__legal{font-size:13px;color:var(--muted);letter-spacing:.08em}
.footer__bottom .footer__meta{display:inline;font-size:13px}
.to-top{position:fixed;right:18px;bottom:18px;z-index:70;padding:11px 16px;border:1px solid var(--neon);background:rgba(6,18,31,.9);color:var(--neon);font-size:12px;letter-spacing:.16em;opacity:0;visibility:hidden;transition:opacity var(--t) var(--ease),visibility var(--t) var(--ease),background var(--t) var(--ease),color var(--t) var(--ease)}
.to-top[data-visible="true"]{opacity:1;visibility:visible}
.to-top:hover{background:var(--neon);color:var(--ink)}

/* ---------- responsive ---------- */
@media (max-width:1080px){
  .footer__top{grid-template-columns:minmax(0,1fr) minmax(0,1.2fr)}
  .footer__contact{grid-column:1 / -1;border-left:0;border-top:1px solid var(--line);padding-left:0;padding-top:24px}
}
@media (max-width:900px){
  :root{--header-h:64px}
  html{scroll-padding-top:84px}
  .site-header__inner{flex-wrap:wrap;row-gap:0;column-gap:12px;padding-block:9px;min-height:var(--header-h)}
  .brand__descriptor{font-size:10px;letter-spacing:.18em}
  .version-badge{font-size:10px;padding:3px 7px;letter-spacing:.04em}
  .nav-toggle{display:inline-flex;margin-left:auto}
  .site-nav{order:9;flex:1 0 100%;display:none;flex-direction:column;align-items:stretch;gap:12px;margin-left:0;padding:14px 0 16px;border-top:1px solid var(--line)}
  .site-nav[data-open]{display:flex}
  .site-nav__list{flex-wrap:nowrap;overflow-x:auto;gap:18px;padding-bottom:8px;scrollbar-width:thin}
  .site-nav__list::-webkit-scrollbar{height:4px}
  .site-nav__list::-webkit-scrollbar-thumb{background:var(--line)}
  .site-nav__link{font-size:15px;white-space:nowrap}
  .nav-cta{align-self:flex-start}
  .split,.split--tools,.split--legal{grid-template-columns:minmax(0,1fr)}
  .grid-12{grid-template-columns:repeat(6,minmax(0,1fr))}
  .span-3,.span-4,.span-5,.span-6,.span-7,.span-8,.span-9{grid-column:span 6}
  .bleed-right{margin-right:0}
  .toc{position:static;border-left:0;padding-left:0}
  .toc__link{padding-left:12px}
  .footer__cols{grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}
  .to-top{right:10px;bottom:10px;padding:10px;font-size:11px;letter-spacing:.04em}
  .rail__item{min-width:min(84vw,300px)}
}
@media (max-width:560px){
  body{font-size:15.5px}
  .footer__top{padding-block:34px}
  .footer__cols{grid-template-columns:minmax(0,1fr)}
  .footer__bottom{flex-direction:column;align-items:flex-start;gap:8px}
  .card{padding:18px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:1ms !important;animation-duration:1ms !important;animation-iteration-count:1 !important}
  [data-reveal]{opacity:1;transform:none}
  .site-header__progress{transition:none}
}