/* ===== reset ===== */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0}
img,svg,video{display:block;max-width:100%;height:auto}
button{font:inherit;color:inherit;background:none;border:0}
ul,ol{margin:0;padding:0;list-style:none}
p{margin:0}
a{color:var(--pulse);text-decoration:none}

/* ===== tokens ===== */
:root{
  --abyss:#061320;
  --harbor:#0D2A42;
  --steel:#1B4A66;
  --pulse:#2CE8C8;
  --mist:#A8F5E6;
  --coral:#FF6B4A;
  --lemon:#F2E24B;
  --stone:#8FA3B0;
  --cream:#F2EDE3;
  --ink:#0A1219;
  --moss:#6F8A6A;
  --terracotta:#C06A45;

  --rail-w:88px;
  --quickbar-h:54px;
  --mobile-bar-h:60px;
  --shell-max:1320px;
  --gutter:clamp(20px,4vw,48px);

  --font-display:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --ease:cubic-bezier(.2,.8,.2,1);
  --dur:.24s;
  --line:rgba(27,74,102,.8);
  --line-soft:rgba(27,74,102,.55);
}

/* ===== base ===== */
body{
  background-color:var(--abyss);
  background-image:
    radial-gradient(58% 42% at 92% -8%,rgba(44,232,200,.13),transparent 68%),
    radial-gradient(46% 46% at 102% 108%,rgba(255,107,74,.09),transparent 70%);
  background-attachment:fixed;
  background-repeat:no-repeat;
  background-size:cover;
  color:var(--cream);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  padding-left:var(--rail-w);
  -webkit-font-smoothing:antialiased;
}

h1,h2,h3,h4{
  margin:0;
  font-family:var(--font-display);
  font-weight:900;
  letter-spacing:-.02em;
  line-height:1.06;
  color:var(--cream);
  text-wrap:balance;
}
h1{font-size:clamp(38px,6.2vw,72px);line-height:.98}
h2{font-size:clamp(28px,3.6vw,44px);line-height:1.04}
h3{font-size:clamp(20px,2.1vw,26px);line-height:1.24;font-weight:800}

:focus-visible{outline:2px solid var(--pulse);outline-offset:3px;border-radius:2px}

main{display:block;padding-top:clamp(28px,4vw,56px)}
main:focus{outline:none}

/* ===== skip link ===== */
.skip-link{
  position:fixed;top:10px;left:calc(var(--rail-w) + 12px);z-index:130;
  transform:translateY(-180%);
  padding:10px 20px;
  background:var(--pulse);color:var(--abyss);
  font-size:14px;font-weight:700;letter-spacing:.06em;
  border-radius:2px;
  transition:transform var(--dur) var(--ease);
}
.skip-link:focus,.skip-link:focus-visible{transform:none}

/* ===== header shell ===== */
.site-header{position:relative;z-index:80}

/* ===== quickbar ===== */
.quickbar{
  position:fixed;top:0;left:var(--rail-w);right:0;z-index:70;
  height:var(--quickbar-h);
  background:rgba(6,19,32,.86);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);
  transform:translateY(-104%);
  opacity:0;
  visibility:hidden;
  transition:transform var(--dur) var(--ease),opacity var(--dur) var(--ease),visibility var(--dur) linear;
}
.quickbar[data-visible="true"]{transform:none;opacity:1;visibility:visible}
.quickbar-inner{
  max-width:var(--shell-max);margin:0 auto;height:100%;
  padding:0 var(--gutter);
  display:flex;align-items:center;gap:clamp(14px,3vw,36px);
}
.quickbar-hint{display:flex;align-items:baseline;gap:10px;margin:0}
.quickbar-hint-cn{font-size:11px;letter-spacing:.18em;color:var(--stone)}
.quickbar-actions{display:flex;align-items:center;gap:8px;margin-left:auto}
.quick-action{
  display:inline-flex;align-items:center;height:34px;padding:0 16px;
  border:1px solid var(--steel);border-radius:999px;
  color:var(--mist);font-size:13px;letter-spacing:.06em;
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.quick-action:hover{border-color:var(--pulse);color:var(--pulse);background:rgba(44,232,200,.08)}
.quick-action--data{color:var(--lemon);border-color:rgba(242,226,75,.42)}
.quick-action--data:hover{color:var(--lemon);border-color:var(--lemon);background:rgba(242,226,75,.1)}
.quickbar-progress{position:absolute;left:0;right:0;bottom:-1px;height:2px;overflow:hidden}
.progress-bar{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--pulse),var(--lemon));transition:width .12s linear}

/* ===== side rail ===== */
.site-rail{
  position:fixed;top:0;left:0;bottom:0;width:var(--rail-w);z-index:85;
  display:flex;flex-direction:column;align-items:center;gap:18px;
  padding:22px 0 20px;
  background:linear-gradient(180deg,#08192a 0%,#061320 62%);
  border-right:1px solid var(--line);
}
.site-rail::after{
  content:"";position:absolute;top:0;right:0;width:1px;height:100%;
  background:linear-gradient(180deg,transparent,var(--pulse) 45%,transparent);
  opacity:.32;pointer-events:none;
}
.rail-brand{
  display:flex;flex-direction:column;align-items:center;gap:7px;
  color:var(--cream);
}
.rail-brand-mark{
  width:38px;height:38px;display:grid;place-items:center;
  background:var(--pulse);color:var(--abyss);
  font-family:var(--font-mono);font-size:14px;font-weight:700;letter-spacing:.04em;
}
.rail-brand-name{font-size:11px;letter-spacing:.16em;color:var(--mist);white-space:nowrap}
.rail-nav{flex:1 1 auto;min-height:0;overflow-y:auto;display:flex;align-items:center;scrollbar-width:none}
.rail-nav::-webkit-scrollbar{width:0;height:0}
.rail-nav ul{display:flex;flex-direction:column;align-items:center;gap:4px;width:100%}
.rail-link{
  display:flex;flex-direction:column;align-items:center;gap:8px;
  padding:10px 4px;width:100%;
  color:var(--stone);
  border-left:2px solid transparent;
  transition:color var(--dur) var(--ease),background var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.rail-index{font-family:var(--font-mono);font-size:10px;letter-spacing:.12em;color:var(--steel);transition:color var(--dur) var(--ease)}
.rail-label{writing-mode:vertical-rl;text-orientation:upright;font-size:12.5px;letter-spacing:.16em;line-height:1.1}
.rail-link:hover{color:var(--mist);background:rgba(44,232,200,.07)}
.rail-link:hover .rail-index{color:var(--mist)}
.rail-link[aria-current="page"]{color:var(--pulse);border-left-color:var(--coral);background:rgba(44,232,200,.08)}
.rail-link[aria-current="page"] .rail-index{color:var(--lemon)}
.rail-cta{
  writing-mode:vertical-rl;text-orientation:upright;
  display:flex;align-items:center;justify-content:center;
  padding:16px 8px;min-height:118px;
  background:var(--coral);color:var(--ink);
  font-size:12px;font-weight:700;letter-spacing:.16em;
  border-radius:2px;
  transition:background var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.rail-cta:hover{background:#ff8266;transform:translateX(-2px)}

/* ===== mobile bar ===== */
.rail-mobile{display:none}
.nav-toggle{display:none}
.nav-toggle-bar{display:none}
.nav-toggle-text{display:none}

/* ===== drawer ===== */
.nav-drawer{
  display:none;
  position:fixed;top:0;right:0;bottom:0;z-index:115;
  width:min(360px,88vw);
  padding:22px 22px 32px;
  background:linear-gradient(160deg,#0a1e30 0%,#061320 74%);
  border-left:1px solid var(--steel);
  flex-direction:column;gap:20px;
  overflow-y:auto;
  transform:translateX(102%);
  visibility:hidden;
  transition:transform .3s var(--ease),visibility .3s linear;
}
.nav-drawer[data-open="true"]{transform:none;visibility:visible}
.drawer-head{display:flex;align-items:center;justify-content:space-between;gap:16px;padding-bottom:12px;border-bottom:1px solid var(--line)}
.drawer-close{
  padding:7px 14px;border:1px solid var(--steel);border-radius:999px;
  color:var(--mist);font-size:12px;letter-spacing:.12em;cursor:pointer;
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.drawer-close:hover{border-color:var(--pulse);color:var(--pulse)}
.drawer-nav ul{display:flex;flex-direction:column}
.drawer-link{
  display:flex;align-items:baseline;gap:14px;
  padding:13px 2px;
  border-bottom:1px solid var(--line-soft);
  color:var(--cream);
  font-family:var(--font-display);font-size:19px;font-weight:800;letter-spacing:.02em;
  transition:color var(--dur) var(--ease),padding-left var(--dur) var(--ease);
}
.drawer-link:hover,.drawer-link:focus-visible{color:var(--pulse);padding-left:6px}
.drawer-link[aria-current="page"]{color:var(--pulse)}
.drawer-link[aria-current="page"] .drawer-index{color:var(--lemon)}
.drawer-index{font-family:var(--font-mono);font-size:11px;font-weight:400;letter-spacing:.14em;color:var(--steel)}
.drawer-cta{justify-content:center;width:100%}
.drawer-scrim{
  position:fixed;inset:0;z-index:110;
  background:rgba(3,10,16,.68);
  -webkit-backdrop-filter:blur(2px);
  backdrop-filter:blur(2px);
  display:block;
}
.drawer-scrim[hidden]{display:none}
body.nav-open{overflow:hidden}

/* ===== buttons ===== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:13px 24px;border:1px solid transparent;border-radius:2px;
  font-size:15px;font-weight:600;line-height:1;letter-spacing:.02em;
  cursor:pointer;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.btn--primary{background:var(--coral);color:var(--ink)}
.btn--primary:hover{background:#ff8266;transform:translateY(-1px)}
.btn--ghost{border-color:var(--steel);color:var(--mist);background:transparent}
.btn--ghost:hover{border-color:var(--pulse);color:var(--pulse);background:rgba(44,232,200,.08)}

/* ===== copy button ===== */
.copy-btn{
  padding:3px 10px;border:1px solid var(--steel);border-radius:999px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
  color:var(--mist);cursor:pointer;
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.copy-btn:hover{border-color:var(--pulse);color:var(--pulse)}
.copy-btn[data-copied="true"]{border-color:var(--pulse);color:var(--pulse);background:rgba(44,232,200,.1)}

/* ===== layout helpers ===== */
.container{width:100%;max-width:var(--shell-max);margin:0 auto;padding:0 var(--gutter)}
.grid-12{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(16px,2vw,28px)}
.prose{max-width:34em;font-size:17px;line-height:1.75;color:#cfdae1}
.prose p+p{margin-top:1em}
.prose p{max-width:34em}

.breadcrumbs{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--stone);
}
.breadcrumbs ol{display:flex;flex-wrap:wrap;align-items:center;gap:10px}
.breadcrumbs li{display:flex;align-items:center;gap:10px;color:var(--stone)}
.breadcrumbs li+li::before{content:"/";color:var(--steel)}
.breadcrumbs a{color:var(--stone);border-bottom:1px solid transparent;transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease)}
.breadcrumbs a:hover{color:var(--pulse);border-bottom-color:currentColor}

/* ===== editorial bits ===== */
.label-en{
  font-family:var(--font-mono);font-size:11px;font-weight:500;
  letter-spacing:.18em;text-transform:uppercase;
  color:var(--stone);margin:0;
}
.section-index{
  display:block;
  font-family:var(--font-mono);font-size:clamp(40px,6vw,72px);
  line-height:.9;letter-spacing:-.03em;
  color:rgba(44,232,200,.16);
  -webkit-text-stroke:1px rgba(44,232,200,.5);
}
.annotation{
  writing-mode:vertical-rl;text-orientation:mixed;
  font-size:13px;letter-spacing:.22em;color:var(--stone);
}
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 10px;border:1px solid currentColor;border-radius:999px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--mist);
}
.tag--lemon{color:var(--lemon)}
.tag--coral{color:var(--coral)}
.tag--moss{color:#9AB294}

/* ===== media frame ===== */
.media-frame{
  position:relative;overflow:hidden;isolation:isolate;
  border:1px solid var(--line);border-radius:2px;
  background:
    radial-gradient(120% 120% at 16% 0%,rgba(44,232,200,.16),transparent 56%),
    radial-gradient(90% 90% at 100% 100%,rgba(255,107,74,.12),transparent 60%),
    linear-gradient(152deg,var(--harbor),var(--abyss));
}
.media-frame::before{
  content:"";position:absolute;inset:0;pointer-events:none;z-index:0;
  background-image:repeating-linear-gradient(116deg,rgba(168,245,230,.07) 0 1px,transparent 1px 13px);
  opacity:.75;
}
.media-frame img,.media-frame picture,.media-frame video,.media-frame svg{
  position:relative;z-index:1;display:block;width:100%;height:100%;object-fit:cover;
}
.media-frame--wide{aspect-ratio:16/9}
.media-frame--tall{aspect-ratio:3/4}
.media-frame--square{aspect-ratio:1/1}
.media-frame__caption{
  position:absolute;left:14px;bottom:12px;z-index:2;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;text-transform:uppercase;
  color:var(--mist);
}

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

/* ===== footer ===== */
.site-footer{
  position:relative;
  margin-top:clamp(80px,12vh,140px);
  padding:clamp(40px,6vw,72px) 0 34px;
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(13,42,66,.42) 0%,rgba(6,19,32,.96) 88%);
}
.footer-inner{
  max-width:var(--shell-max);margin:0 auto;padding:0 var(--gutter);
  display:grid;grid-template-columns:minmax(240px,1.45fr) minmax(150px,.7fr) minmax(240px,1fr);
  gap:clamp(28px,5vw,64px);
}
.footer-brand{display:flex;flex-direction:column;gap:14px}
.footer-logo{
  font-family:var(--font-display);font-size:22px;font-weight:900;letter-spacing:.02em;
  color:var(--cream);
}
.footer-logo:hover{color:var(--pulse)}
.footer-tagline{font-size:14px;line-height:1.7;color:var(--mist);max-width:22em}
.footer-note{font-size:12px;line-height:1.7;color:var(--stone);max-width:24em}
.footer-col{display:flex;flex-direction:column;gap:14px}
.footer-col-title{padding-bottom:10px;border-bottom:1px solid var(--line-soft)}
.footer-list{display:flex;flex-direction:column;gap:10px;font-size:14px}
.footer-list a{color:var(--stone);transition:color var(--dur) var(--ease)}
.footer-list a:hover{color:var(--pulse)}
.footer-list--contact{gap:14px}
.footer-list--contact li{display:flex;flex-wrap:wrap;align-items:baseline;gap:8px 10px}
.footer-contact-label{
  flex:0 0 100%;
  font-family:var(--font-mono);font-size:10px;letter-spacing:.18em;text-transform:uppercase;
  color:var(--steel);
}
.footer-contact-value{font-size:13px;line-height:1.6;color:var(--mist);word-break:break-word;max-width:15em}
.footer-meta{
  max-width:var(--shell-max);margin:clamp(28px,4vw,44px) auto 0;
  padding:16px var(--gutter) 0;
  border-top:1px solid var(--line-soft);
  display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px 28px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--stone);
}
.footer-meta-item{margin:0}

/* ===== help dock ===== */
.help-dock{
  position:fixed;right:24px;bottom:32px;z-index:96;
  display:inline-flex;align-items:center;gap:9px;
  padding:12px 18px;border-radius:999px;
  background:rgba(13,42,66,.94);
  border:1px solid var(--steel);
  color:var(--mist);font-size:13px;letter-spacing:.06em;
  box-shadow:0 12px 32px rgba(0,0,0,.5);
  -webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.help-dock:hover{border-color:var(--pulse);color:var(--pulse);transform:translateY(-2px)}
.help-dock-dot{
  width:7px;height:7px;border-radius:50%;background:var(--coral);
  box-shadow:0 0 0 4px rgba(255,107,74,.18);
}

/* ===== tablet / mobile ===== */
@media (max-width:1100px){
  .footer-inner{grid-template-columns:1fr 1fr;gap:32px 40px}
  .footer-brand{grid-column:1 / -1}
}

@media (max-width:900px){
  body{padding-left:0;padding-top:var(--mobile-bar-h)}
  .skip-link{left:14px}

  .site-rail{display:none}
  .quickbar{left:0;top:var(--mobile-bar-h)}
  .quickbar-hint{display:none}
  .quickbar-actions{margin-left:0;width:100%;justify-content:space-between}
  .quick-action{padding:0 14px;font-size:12px;height:32px}

  .rail-mobile{
    display:flex;position:fixed;top:0;left:0;right:0;z-index:92;
    height:var(--mobile-bar-h);align-items:center;justify-content:space-between;
    padding:0 16px;
    background:rgba(6,19,32,.94);
    -webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
    border-bottom:1px solid var(--line);
  }
  .rail-brand--bar{flex-direction:row;align-items:center;gap:10px}
  .rail-brand--bar .rail-brand-mark{width:30px;height:30px;font-size:12px}
  .rail-brand--bar .rail-brand-name{font-size:12px;letter-spacing:.14em}
  .nav-toggle{
    display:inline-flex;align-items:center;gap:8px;
    padding:8px 14px;border:1px solid var(--steel);border-radius:999px;
    cursor:pointer;
    transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease);
  }
  .nav-toggle:hover{border-color:var(--pulse)}
  .nav-toggle-bar{display:block;width:14px;height:1.5px;background:var(--pulse)}
  .nav-toggle-text{display:block;font-size:12px;letter-spacing:.14em;color:var(--mist)}
  .nav-toggle[aria-expanded="true"] .nav-toggle-text{color:var(--pulse)}

  .nav-drawer{display:flex}
  main{padding-top:26px}
}

@media (max-width:600px){
  .footer-inner{grid-template-columns:1fr;gap:28px}
  .footer-meta{flex-direction:column;gap:8px}
  .site-footer{padding-bottom:94px}
  .help-dock{right:14px;bottom:16px;padding:10px 14px;font-size:12px}
  .quickbar-inner{padding:0 14px}
}

@media (min-width:901px){
  .nav-drawer,.drawer-scrim,.nav-toggle{display:none !important}
}

@media (max-height:780px) and (min-width:901px){
  .site-rail{gap:12px;padding:14px 0 14px}
  .rail-link{padding:6px 3px;gap:6px}
  .rail-index{font-size:9px}
  .rail-label{font-size:11px;letter-spacing:.1em}
  .rail-cta{padding:10px 6px;min-height:0;font-size:11px;letter-spacing:.12em}
  .rail-brand-mark{width:32px;height:32px;font-size:12px}
}

/* ===== 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;
  }
  [data-reveal]{opacity:1;transform:none}
  .quickbar{transition:none}
  .progress-bar{transition:none}
}