/* ==========================================================================
   FB赛场 · 共享样式 /assets/site.css
   1 重置 · 2 变量 · 3 基础排版 · 4 头部 · 5 页脚 · 6 组件 · 7 响应式
   ========================================================================== */

/* ---------- 1. 重置 ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:120px}
body,h1,h2,h3,h4,h5,p,ul,ol,li,figure,blockquote{margin:0;padding:0}
ul,ol{list-style:none}
img,svg,video{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
hr{border:0;margin:0}
:focus-visible{outline:2px solid var(--fb-cyan);outline-offset:3px;border-radius:4px}

/* ---------- 2. 变量 ---------- */
:root{
  --fb-void:#070B14;
  --fb-ink:#101725;
  --fb-paper:#F4EEE2;
  --fb-paper-dim:#D8CFC0;
  --fb-cyan:#2DE2E6;
  --fb-orange:#FF7A1A;
  --fb-scarlet:#E63946;
  --fb-amber:#FFB703;
  --fb-mist:#8A9BB0;
  --fb-white:#FFFFFF;
  --fb-line:rgba(138,155,176,.26);
  --fb-line-strong:rgba(138,155,176,.46);
  --fb-shell:1240px;
  --fb-gutter:18px;
  --fb-radius:14px;
  --fb-cut:20px;
  --fb-font-sans:"Inter Tight","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --fb-font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --fb-shadow:0 22px 60px rgba(0,0,0,.48);
  --fb-ease:cubic-bezier(.22,.61,.36,1);
}

/* ---------- 3. 基础排版 ---------- */
body{
  min-height:100vh;
  background-color:var(--fb-void);
  background-image:
    radial-gradient(1100px 520px at 84% -10%,rgba(45,226,230,.10),transparent 62%),
    radial-gradient(900px 480px at 4% 6%,rgba(255,122,26,.07),transparent 60%),
    repeating-linear-gradient(115deg,rgba(138,155,176,.05) 0 1px,transparent 1px 28px);
  color:var(--fb-white);
  font-family:var(--fb-font-sans);
  font-size:16px;
  line-height:1.75;
  letter-spacing:.01em;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4,h5{line-height:1.2;letter-spacing:-.02em;font-weight:800}
h1{font-size:clamp(34px,6vw,68px)}
h2{font-size:clamp(26px,3.6vw,44px)}
h3{font-size:clamp(19px,2.2vw,26px);font-weight:700}
strong{font-weight:700;color:var(--fb-white)}
#main-content{display:block}

/* ---------- 4. 头部：悬浮胶囊浮岛 ---------- */
.fb-skip{
  position:fixed;top:10px;left:10px;z-index:200;
  padding:10px 18px;border-radius:999px;
  background:var(--fb-cyan);color:var(--fb-void);
  font-size:14px;font-weight:700;
  transform:translateY(-180%);
  transition:transform .22s var(--fb-ease);
}
.fb-skip:focus{transform:translateY(0);outline:2px solid var(--fb-white);outline-offset:2px}

.fb-header{
  position:sticky;top:0;z-index:90;
  padding:14px var(--fb-gutter) 0;
  transition:padding .24s var(--fb-ease);
}
.fb-header[data-compact="yes"]{padding-top:8px}
.fb-header__shell{
  position:relative;
  display:flex;align-items:center;gap:14px;
  max-width:var(--fb-shell);margin:0 auto;
  padding:9px 12px 9px 16px;
  background:rgba(16,23,37,.9);
  border:1px solid var(--fb-line);
  border-radius:999px;
  box-shadow:var(--fb-shadow);
  -webkit-backdrop-filter:blur(14px) saturate(1.15);
  backdrop-filter:blur(14px) saturate(1.15);
  transition:border-radius .24s var(--fb-ease),background .24s var(--fb-ease);
}
.fb-header[data-compact="yes"] .fb-header__shell{background:rgba(16,23,37,.96)}

.fb-brand{display:inline-flex;align-items:center;gap:11px;flex:0 0 auto;padding:3px 0}
.fb-brand__mark{
  width:34px;height:34px;flex:0 0 auto;
  display:grid;grid-template-columns:1fr 1fr;grid-template-rows:1fr 1fr;gap:3px;padding:5px;
  background:rgba(45,226,230,.09);
  border:1px solid rgba(45,226,230,.34);
  border-radius:10px;
}
.fb-brand__mark i{display:block;border-radius:1px;background:var(--fb-mist)}
.fb-brand__mark i:nth-child(1){background:var(--fb-cyan)}
.fb-brand__mark i:nth-child(2){background:var(--fb-amber)}
.fb-brand__mark i:nth-child(3){background:var(--fb-scarlet)}
.fb-brand__mark i:nth-child(4){background:var(--fb-orange)}
.fb-brand__text{display:flex;flex-direction:column;justify-content:center;line-height:1.15}
.fb-brand__name{font-size:17px;font-weight:800;letter-spacing:-.01em;color:var(--fb-white)}
.fb-brand__tag{font-size:10.5px;letter-spacing:.14em;color:var(--fb-mist)}
.fb-header[data-compact="yes"] .fb-brand__tag{display:none}

.fb-nav{flex:1 1 auto;display:flex;justify-content:center;min-width:0}
.fb-nav__list{display:flex;align-items:center;gap:2px}
.fb-nav__item{display:block}
.fb-nav__link{
  display:block;padding:8px 13px;border-radius:999px;
  font-size:14px;color:var(--fb-mist);white-space:nowrap;
  transition:color .2s var(--fb-ease),background .2s var(--fb-ease),box-shadow .2s var(--fb-ease);
}
.fb-nav__link:hover{color:var(--fb-white);background:rgba(138,155,176,.12)}
.fb-nav__link[aria-current="page"]{
  color:var(--fb-cyan);
  background:rgba(45,226,230,.12);
  box-shadow:inset 0 0 0 1px rgba(45,226,230,.45);
}

.fb-header__utility{display:flex;align-items:center;gap:10px;flex:0 0 auto}
.fb-pulse{
  display:inline-flex;align-items:center;gap:7px;
  padding:6px 12px;border-radius:999px;
  font-size:11.5px;letter-spacing:.12em;color:var(--fb-cyan);
  border:1px solid rgba(45,226,230,.34);
  background:rgba(45,226,230,.07);
}
.fb-pulse__dot{
  width:7px;height:7px;border-radius:50%;background:var(--fb-cyan);
  animation:fb-beat 2.4s ease-out infinite;
}
.fb-footer__dot{
  display:inline-block;width:7px;height:7px;border-radius:50%;background:var(--fb-orange);
  animation:fb-beat-orange 3s ease-out infinite;
}
@keyframes fb-beat{
  0%{box-shadow:0 0 0 0 rgba(45,226,230,.55)}
  70%{box-shadow:0 0 0 9px rgba(45,226,230,0)}
  100%{box-shadow:0 0 0 0 rgba(45,226,230,0)}
}
@keyframes fb-beat-orange{
  0%{box-shadow:0 0 0 0 rgba(255,122,26,.5)}
  70%{box-shadow:0 0 0 8px rgba(255,122,26,0)}
  100%{box-shadow:0 0 0 0 rgba(255,122,26,0)}
}

.fb-nav-toggle{
  display:none;align-items:center;gap:8px;
  padding:8px 13px;border-radius:999px;
  border:1px solid var(--fb-line);
  background:rgba(138,155,176,.08);
  color:var(--fb-white);
  transition:background .2s var(--fb-ease),border-color .2s var(--fb-ease);
}
.fb-nav-toggle:hover{background:rgba(138,155,176,.16);border-color:var(--fb-line-strong)}
.fb-nav-toggle__bars{display:inline-flex;flex-direction:column;gap:3px;width:16px}
.fb-nav-toggle__bars span{display:block;height:2px;border-radius:2px;background:currentColor;transition:transform .22s var(--fb-ease),opacity .18s linear}
.fb-nav-toggle__label{font-size:13px;font-weight:600}
.fb-header[data-open="yes"] .fb-nav-toggle__bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
.fb-header[data-open="yes"] .fb-nav-toggle__bars span:nth-child(2){opacity:0}
.fb-header[data-open="yes"] .fb-nav-toggle__bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

.fb-progress{
  position:absolute;left:22px;right:22px;bottom:5px;height:3px;
  border-radius:999px;overflow:hidden;pointer-events:none;
  background:rgba(138,155,176,.16);
}
.fb-progress__bar{
  display:block;height:100%;width:0;border-radius:999px;
  background:linear-gradient(90deg,var(--fb-cyan),var(--fb-orange));
  transition:width .12s linear;
}

/* ---------- 5. 页脚 ---------- */
.fb-footer{
  position:relative;
  margin-top:clamp(60px,9vw,130px);
  padding:clamp(40px,6vw,76px) var(--fb-gutter) 30px;
  background:linear-gradient(180deg,rgba(16,23,37,.35),var(--fb-ink));
  border-top:1px solid var(--fb-line);
}
.fb-footer::before{
  content:"";position:absolute;left:0;right:0;top:0;height:1px;
  background:repeating-linear-gradient(90deg,var(--fb-cyan) 0 20px,transparent 20px 44px);
  opacity:.45;
}
.fb-footer__inner{
  display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,1.65fr);
  gap:clamp(28px,4vw,64px);
  max-width:var(--fb-shell);margin:0 auto;
}
.fb-footer__lead{display:flex;flex-direction:column;gap:14px;max-width:44ch}
.fb-footer__brand{
  font-size:clamp(24px,3vw,34px);font-weight:800;letter-spacing:-.02em;
  color:var(--fb-white);
}
.fb-footer__brand:hover{color:var(--fb-cyan)}
.fb-footer__desc{font-size:14.5px;line-height:1.85;color:var(--fb-mist)}
.fb-footer__signal{
  display:inline-flex;align-items:center;gap:9px;
  font-family:var(--fb-font-mono);font-size:12px;letter-spacing:.1em;
  color:var(--fb-orange);
}
.fb-footer__grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.fb-footer__col{display:flex;flex-direction:column;gap:12px}
.fb-footer__heading{
  font-size:11.5px;font-weight:700;letter-spacing:.2em;
  color:var(--fb-mist);
}
.fb-footer__list{display:flex;flex-direction:column;gap:9px}
.fb-footer__link{
  font-size:14.5px;color:var(--fb-paper-dim);
  transition:color .2s var(--fb-ease);
}
.fb-footer__link:hover{color:var(--fb-cyan)}
.fb-footer__data{
  font-family:var(--fb-font-mono);font-size:13.5px;color:var(--fb-paper);
  word-break:break-all;
}
.fb-footer__note{font-size:12.5px;line-height:1.7;color:var(--fb-mist)}
.fb-footer__base{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px 26px;
  max-width:var(--fb-shell);margin:clamp(32px,4.5vw,56px) auto 0;
  padding-top:22px;border-top:1px solid var(--fb-line);
}
.fb-footer__legal{font-size:13px;color:var(--fb-mist)}
.fb-footer__legal-links{display:flex;flex-wrap:wrap;gap:8px 20px}
.fb-footer__meta{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:10px 24px;
  max-width:var(--fb-shell);margin:16px auto 0;
}
.fb-footer__copy{
  font-family:var(--fb-font-mono);font-size:12.5px;color:var(--fb-mist);
}

/* ---------- 6. 通用组件 ---------- */
.fb-shell{width:100%;max-width:var(--fb-shell);margin:0 auto;padding:0 var(--fb-gutter)}
.fb-main{padding-bottom:clamp(40px,6vw,90px)}

.fb-crumbs{display:flex;flex-wrap:wrap;align-items:center;gap:8px;font-size:12.5px;color:var(--fb-mist)}
.fb-crumbs__link{color:var(--fb-mist)}
.fb-crumbs__link:hover{color:var(--fb-cyan)}
.fb-crumbs__sep{color:rgba(138,155,176,.5)}
.fb-crumbs__current{color:var(--fb-white)}

.fb-grid{display:grid;gap:clamp(16px,2.4vw,28px)}
.fb-grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.fb-grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.fb-grid--aside{grid-template-columns:minmax(0,1fr) minmax(0,320px)}
.fb-span-2{grid-column:span 2}
.fb-span-full{grid-column:1 / -1}

.fb-section{position:relative;padding:clamp(48px,7vw,100px) 0 0}
.fb-section__head{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:14px 18px;
  margin-bottom:clamp(18px,2.6vw,32px);
}
.fb-section__index{
  font-family:var(--fb-font-mono);font-size:13px;letter-spacing:.22em;
  color:var(--fb-orange);
}
.fb-section__title{font-size:clamp(26px,3.6vw,44px);font-weight:800}
.fb-section__sub{flex:1 1 100%;max-width:62ch;font-size:15px;color:var(--fb-mist)}

.fb-kicker{
  display:inline-flex;align-items:center;gap:8px;
  font-family:var(--fb-font-mono);font-size:12px;letter-spacing:.18em;
  color:var(--fb-cyan);
}
.fb-rule{height:1px;background:repeating-linear-gradient(115deg,var(--fb-line) 0 1px,transparent 1px 10px)}
.fb-note{
  padding:4px 0 4px 14px;border-left:2px solid var(--fb-cyan);
  font-size:13.5px;line-height:1.8;color:var(--fb-mist);
}

.fb-panel{
  position:relative;
  padding:clamp(18px,2.4vw,28px);
  background:linear-gradient(160deg,rgba(16,23,37,.96),rgba(7,11,20,.92));
  border:1px solid var(--fb-line);
  clip-path:polygon(0 var(--fb-cut),var(--fb-cut) 0,100% 0,100% calc(100% - var(--fb-cut)),calc(100% - var(--fb-cut)) 100%,0 100%);
}
.fb-panel--signal{
  border-color:rgba(255,122,26,.42);
  background:linear-gradient(160deg,rgba(255,122,26,.13),rgba(7,11,20,.94));
}
.fb-panel__title{font-size:19px;font-weight:700;letter-spacing:-.01em;margin-bottom:8px}
.fb-panel__text{font-size:14.5px;line-height:1.8;color:var(--fb-mist)}
.fb-panel__foot{margin-top:16px;display:flex;flex-wrap:wrap;align-items:center;gap:10px}

.fb-stat{display:flex;flex-direction:column;gap:3px}
.fb-stat__num{
  font-family:var(--fb-font-mono);font-weight:700;line-height:1;letter-spacing:-.02em;
  font-size:clamp(28px,4vw,46px);color:var(--fb-cyan);
}
.fb-stat__num--orange{color:var(--fb-orange)}
.fb-stat__num--amber{color:var(--fb-amber)}
.fb-stat__num--scarlet{color:var(--fb-scarlet)}
.fb-stat__label{font-size:13px;letter-spacing:.04em;color:var(--fb-mist)}

.fb-tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 11px;border-radius:999px;
  font-size:12px;font-weight:600;letter-spacing:.05em;
  border:1px solid transparent;
}
.fb-tag--cyan{color:var(--fb-cyan);background:rgba(45,226,230,.12);border-color:rgba(45,226,230,.36)}
.fb-tag--orange{color:var(--fb-orange);background:rgba(255,122,26,.12);border-color:rgba(255,122,26,.36)}
.fb-tag--red{color:#FF7B85;background:rgba(230,57,70,.16);border-color:rgba(230,57,70,.46)}
.fb-tag--amber{color:var(--fb-amber);background:rgba(255,183,3,.13);border-color:rgba(255,183,3,.4)}
.fb-tag--pulse{animation:fb-tag-pulse 2.6s ease-in-out infinite}
@keyframes fb-tag-pulse{0%,100%{opacity:1}50%{opacity:.6}}

.fb-btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 20px;border-radius:999px;
  border:1px solid transparent;
  font-size:14px;font-weight:600;letter-spacing:.02em;
  transition:background .2s var(--fb-ease),color .2s var(--fb-ease),border-color .2s var(--fb-ease),transform .2s var(--fb-ease);
}
.fb-btn--signal{background:var(--fb-orange);color:#170800}
.fb-btn--signal:hover{background:#FF9143;transform:translateY(-1px)}
.fb-btn--ghost{border-color:var(--fb-line-strong);color:var(--fb-white)}
.fb-btn--ghost:hover{border-color:var(--fb-cyan);color:var(--fb-cyan)}
.fb-btn--quiet{background:rgba(45,226,230,.1);color:var(--fb-cyan);border-color:rgba(45,226,230,.32)}
.fb-btn--quiet:hover{background:rgba(45,226,230,.18)}
.fb-btn--sm{padding:8px 15px;font-size:13px}

.fb-prose{max-width:72ch;font-size:16.5px;line-height:1.85;color:#CBD5E1}
.fb-prose h2{margin:1.6em 0 .6em;font-size:clamp(22px,2.6vw,30px)}
.fb-prose h3{margin:1.4em 0 .5em;font-size:19px}
.fb-prose p + p{margin-top:16px}
.fb-prose ul{margin:16px 0}
.fb-prose li{position:relative;padding-left:20px;margin-bottom:8px}
.fb-prose li::before{content:"";position:absolute;left:0;top:.72em;width:10px;height:1px;background:var(--fb-cyan)}
.fb-prose a{color:var(--fb-cyan);border-bottom:1px solid rgba(45,226,230,.35)}
.fb-prose a:hover{border-bottom-color:var(--fb-cyan)}
.fb-prose strong{color:var(--fb-white)}

.fb-paper{
  position:relative;
  padding:clamp(26px,4.6vw,64px);
  background:var(--fb-paper);
  color:#241E12;
  box-shadow:0 30px 70px rgba(0,0,0,.42);
  border-radius:2px;
}
.fb-paper h1,.fb-paper h2,.fb-paper h3,.fb-paper h4{color:#14100A}
.fb-paper .fb-prose{color:#3A3223}
.fb-paper .fb-prose strong{color:#14100A}
.fb-paper .fb-prose a{color:#0E6E72;border-bottom-color:rgba(14,110,114,.4)}
.fb-paper .fb-prose li::before{background:#0E6E72}
.fb-paper .fb-panel{background:rgba(255,255,255,.55);border-color:rgba(36,30,18,.16)}
.fb-paper .fb-panel__text{color:#4A4132}
.fb-paper .fb-note{border-left-color:#0E6E72;color:#4A4132}
.fb-paper .fb-section__index{color:#B4460D}

.fb-figure{margin:0}
.fb-figure__frame{
  position:relative;display:block;width:100%;aspect-ratio:16 / 9;
  overflow:hidden;border:1px solid var(--fb-line);
  background:linear-gradient(150deg,#101725,#070B14 65%);
}
.fb-figure__frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background:
    linear-gradient(90deg,rgba(45,226,230,.16),transparent 42%),
    repeating-linear-gradient(0deg,rgba(138,155,176,.12) 0 1px,transparent 1px 44px);
  mix-blend-mode:screen;
}
.fb-figure__frame img,
.fb-figure__frame svg{width:100%;height:100%;object-fit:cover;filter:saturate(.92) contrast(1.06) brightness(.84)}
.fb-figure__cap{margin-top:10px;font-size:13px;line-height:1.7;color:var(--fb-mist)}
.fb-figure--wide .fb-figure__frame{aspect-ratio:21 / 9}
.fb-figure--tall .fb-figure__frame{aspect-ratio:4 / 5}

.fb-reveal{opacity:0;transform:translateY(18px);transition:opacity .5s var(--fb-ease),transform .5s var(--fb-ease)}
.fb-reveal.is-in{opacity:1;transform:none}

/* ---------- 7. 响应式 ---------- */
@media (max-width:1180px){
  .fb-nav__link{padding:8px 10px;font-size:13.5px}
  .fb-brand__tag{display:none}
}
@media (max-width:980px){
  .fb-header{padding:10px 12px 0}
  .fb-header__shell{
    flex-wrap:wrap;gap:10px;
    padding:9px 12px;border-radius:24px;
  }
  .fb-brand{flex:1 1 auto}
  .fb-header__utility{margin-left:auto}
  .fb-pulse{display:none}
  .fb-nav-toggle{display:inline-flex}
  .fb-nav{
    order:5;flex:1 0 100%;display:block;
    max-height:0;opacity:0;visibility:hidden;overflow:hidden;
    transition:max-height .28s var(--fb-ease),opacity .2s var(--fb-ease),visibility .2s linear;
  }
  .fb-header[data-open="yes"] .fb-nav{max-height:72vh;opacity:1;visibility:visible;overflow-y:auto}
  .fb-nav__list{flex-direction:column;align-items:stretch;gap:4px;padding:8px 0 4px}
  .fb-nav__link{
    padding:12px 14px;border-radius:12px;font-size:15px;
    background:rgba(138,155,176,.07);
  }
  .fb-nav__link[aria-current="page"]{background:rgba(45,226,230,.15)}
  .fb-progress{display:none}

  .fb-grid--2,
  .fb-grid--3,
  .fb-grid--aside{grid-template-columns:minmax(0,1fr)}
  .fb-span-2{grid-column:auto}

  .fb-footer__inner{grid-template-columns:minmax(0,1fr)}
  .fb-footer__lead{max-width:none}
}
@media (max-width:620px){
  :root{--fb-gutter:14px;--fb-cut:16px}
  body{font-size:15.5px}
  .fb-footer__grid{grid-template-columns:minmax(0,1fr);gap:28px}
  .fb-footer__base{flex-direction:column;align-items:flex-start}
  .fb-footer__meta{flex-direction:column;align-items:flex-start}
  .fb-btn{padding:10px 16px}
  .fb-header .fb-btn--signal{padding:8px 13px;font-size:12.5px}
  .fb-figure--wide .fb-figure__frame{aspect-ratio:16 / 9}
}

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