/* ===== BBIN 线上官网 · 共享样式 /assets/site.css ===== */

*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body,h1,h2,h3,h4,h5,p,ul,ol,li,figure,blockquote,dl,dd{margin:0;padding:0;}
ul,ol{list-style:none;}
img,svg{display:block;max-width:100%;}
button{font:inherit;color:inherit;background:none;border:0;}
a{color:inherit;text-decoration:none;}
table{border-collapse:collapse;width:100%;}
:focus-visible{outline:2px solid #2FD6B4;outline-offset:3px;}

:root{
  --ink-green:#16342C;
  --ink-green-deep:#0E231E;
  --copper:#C08A3E;
  --copper-bright:#E3B872;
  --copper-deep:#8A5A22;
  --clay:#C4643A;
  --bean:#A8545B;
  --electric:#2FD6B4;
  --paper:#F6F2E9;
  --paper-2:#E4DED1;
  --ink:#1B1F1C;
  --muted:#6E7A72;

  --font-sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Source Han Sans SC","Noto Sans CJK SC",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,"Courier New",monospace;

  --wrap:1180px;
  --gutter:clamp(20px,4vw,48px);
  --header-h:74px;
  --shadow-layer:0 18px 42px -26px rgba(14,35,30,.6);
  --ease:cubic-bezier(.22,.61,.36,1);
}

body{
  font-family:var(--font-sans);
  background:var(--paper);
  color:var(--ink);
  font-size:16px;
  line-height:1.85;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
@media (min-width:768px){ body{font-size:17px;} }

h1,h2,h3,h4{
  font-weight:900;
  letter-spacing:-.02em;
  line-height:1.16;
  color:var(--ink-green-deep);
}
h1{font-size:clamp(34px,6vw,64px);}
h2{font-size:clamp(26px,3.6vw,42px);}
h3{font-size:clamp(19px,2.1vw,25px);}
h4{font-size:17px;}

.mono{
  font-family:var(--font-mono);
  font-weight:600;
  letter-spacing:.02em;
  font-variant-numeric:tabular-nums;
}
.muted{color:var(--muted);}
.sr-only{
  position:absolute;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}

/* ---------- 跳至主要内容 ---------- */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:200;
  transform:translateY(-180%);
  padding:10px 18px;font-size:14px;font-weight:800;
  background:var(--copper-bright);color:var(--ink-green-deep);
  clip-path:polygon(0 0,calc(100% - 12px) 0,100% 12px,100% 100%,0 100%);
  transition:transform .2s var(--ease);
}
.skip-link:focus{transform:none;}

/* ---------- 头部 ---------- */
.site-header{
  position:fixed;top:0;left:0;right:0;z-index:120;
  background:linear-gradient(180deg,rgba(14,35,30,.88),rgba(14,35,30,.34) 68%,rgba(14,35,30,0));
  color:var(--paper);
  transition:background .35s var(--ease),box-shadow .35s var(--ease),border-color .35s var(--ease);
  border-bottom:1px solid transparent;
}
.site-header.is-solid{
  background:var(--ink-green);
  border-bottom-color:rgba(192,138,62,.45);
  box-shadow:0 16px 36px -28px rgba(14,35,30,.95);
}
.header-inner{
  width:100%;max-width:var(--wrap);margin:0 auto;
  padding:0 var(--gutter);
  min-height:var(--header-h);
  display:flex;align-items:center;gap:clamp(14px,3vw,34px);
}

.brand{display:inline-flex;align-items:center;gap:12px;flex:none;}
.brand-mark{
  width:38px;height:38px;flex:none;
  display:grid;place-items:center;
  font-family:var(--font-mono);font-weight:700;font-size:17px;
  color:var(--ink-green-deep);background:var(--copper-bright);
  clip-path:polygon(0 0,100% 0,100% 68%,68% 100%,0 100%);
}
.brand-words{display:flex;flex-direction:column;line-height:1.25;}
.brand-name{font-size:17px;font-weight:900;letter-spacing:-.01em;color:inherit;}
.brand-sub{font-size:11px;letter-spacing:.14em;color:var(--copper-bright);}

.site-nav{display:flex;align-items:center;flex:1;gap:clamp(12px,2.4vw,28px);}
.nav-list{display:flex;align-items:center;gap:clamp(10px,1.6vw,22px);margin-right:auto;}
.nav-list a{
  position:relative;display:inline-block;padding:10px 2px;
  font-size:14.5px;font-weight:500;color:rgba(246,242,233,.86);
  white-space:nowrap;transition:color .2s var(--ease);
}
.nav-list a::after{
  content:"";position:absolute;left:0;right:0;bottom:4px;height:2px;
  background:var(--electric);transform:scaleX(0);transform-origin:left center;
  transition:transform .22s var(--ease);
}
.nav-list a:hover{color:#fff;}
.nav-list a:hover::after{transform:scaleX(1);}
.nav-list a[aria-current="page"]{color:var(--copper-bright);font-weight:800;}
.nav-list a[aria-current="page"]::after{transform:scaleX(1);background:var(--copper);}

.nav-actions{display:flex;align-items:center;gap:10px;}
.nav-foot{display:none;}

.nav-toggle{
  display:none;align-items:center;gap:9px;margin-left:auto;
  padding:9px 14px;
  border:1px solid rgba(227,184,114,.5);
  background:rgba(14,35,30,.42);color:var(--paper);
  clip-path:polygon(0 0,calc(100% - 10px) 0,100% 10px,100% 100%,0 100%);
  cursor:pointer;
}
.nav-toggle-text{font-size:13px;font-weight:800;letter-spacing:.06em;}
.nav-toggle-bars{display:inline-flex;flex-direction:column;gap:4px;width:18px;}
.nav-toggle-bars span{display:block;height:2px;background:var(--copper-bright);transition:transform .2s var(--ease),opacity .2s var(--ease);}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(1){transform:translateY(6px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(2){opacity:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(3){transform:translateY(-6px) rotate(-45deg);}

.scroll-progress{
  position:absolute;left:0;bottom:0;width:100%;height:2px;
  background:linear-gradient(90deg,var(--copper),var(--clay) 55%,var(--electric));
  transform:scaleX(var(--progress,0));transform-origin:left center;
  opacity:0;transition:transform .12s linear,opacity .3s var(--ease);
}
.site-header.is-solid .scroll-progress{opacity:1;}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:11px 20px;font-size:14px;font-weight:800;letter-spacing:.02em;line-height:1;
  border:1px solid transparent;cursor:pointer;
  clip-path:polygon(0 0,calc(100% - 12px) 0,100% 12px,100% 100%,12px 100%,0 calc(100% - 12px));
  transition:background .2s var(--ease),color .2s var(--ease),border-color .2s var(--ease),transform .2s var(--ease);
}
.btn:hover{transform:translateY(-1px);}
.btn-copper{background:var(--copper);border-color:var(--copper);color:#1A1206;}
.btn-copper:hover{background:var(--copper-bright);border-color:var(--copper-bright);}
.btn-ghost{background:transparent;border-color:rgba(227,184,114,.55);color:var(--paper);}
.btn-ghost:hover{border-color:var(--copper-bright);color:var(--copper-bright);}
.btn-deep{background:var(--ink-green);border-color:var(--ink-green);color:var(--paper);}
.btn-deep:hover{background:var(--ink-green-deep);border-color:var(--ink-green-deep);}
.btn-line{background:transparent;border-color:var(--copper);color:var(--copper-deep);}
.btn-line:hover{background:var(--copper);color:#1A1206;}

/* ---------- 布局容器与章节 ---------- */
.container{width:100%;max-width:var(--wrap);margin:0 auto;padding:0 var(--gutter);}
.container--narrow{max-width:820px;}
.page-head{padding-top:calc(var(--header-h) + 44px);}
.section{padding:clamp(46px,7vw,96px) 0;}
.section--paper{background:var(--paper);}
.section--grey{background:var(--paper-2);}
.section--deep{background:var(--ink-green);color:var(--paper);}
.section--deep h2,.section--deep h3,.section--deep h4{color:var(--paper);}

.section-head{position:relative;max-width:760px;margin-bottom:clamp(24px,4vw,44px);}
.section-index{
  display:inline-flex;align-items:center;gap:12px;
  font-family:var(--font-mono);font-size:12.5px;font-weight:600;
  letter-spacing:.22em;text-transform:uppercase;
  color:var(--copper-deep);margin-bottom:12px;
}
.section-index::after{content:"";width:36px;height:1px;background:currentColor;transform:skewY(-14deg);}
.section--deep .section-index{color:var(--copper-bright);}
.section-title{max-width:22em;}
.section-lede{margin-top:14px;font-size:17px;color:var(--muted);max-width:34em;}
.section--deep .section-lede{color:rgba(246,242,233,.78);}

.chapter-no{
  font-family:var(--font-mono);font-weight:700;line-height:1;
  font-size:clamp(40px,7vw,86px);letter-spacing:-.03em;
  color:rgba(192,138,62,.3);
}
.side-note{
  writing-mode:vertical-rl;text-orientation:mixed;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.4em;
  color:var(--muted);
}
.section--deep .side-note{color:rgba(227,184,114,.75);}
.slant-rule{
  height:1px;border:0;margin:0;transform:skewY(-1.2deg);
  background:linear-gradient(90deg,rgba(192,138,62,.7),rgba(192,138,62,.06));
}

/* ---------- 正文 ---------- */
.prose{max-width:100%;}
.prose p{max-width:38em;margin-bottom:1.1em;color:var(--ink);}
.prose h3{margin:1.6em 0 .6em;}
.prose ul{display:grid;gap:10px;max-width:38em;margin-bottom:1.1em;}
.prose li{position:relative;padding-left:20px;}
.prose li::before{
  content:"";position:absolute;left:0;top:.72em;width:8px;height:8px;
  background:var(--clay);
  clip-path:polygon(0 0,100% 0,100% 70%,70% 100%,0 100%);
}
.prose a{color:var(--copper-deep);border-bottom:1px solid currentColor;}
.prose a:hover{color:var(--clay);}
.section--deep .prose p,.section--deep .prose li{color:rgba(246,242,233,.86);}

/* ---------- 面包屑 ---------- */
.crumbs{padding:calc(var(--header-h) + 22px) 0 0;}
.crumbs ol{display:flex;flex-wrap:wrap;align-items:center;gap:8px;font-size:13px;color:var(--muted);}
.crumbs li{display:flex;align-items:center;gap:8px;}
.crumbs li + li::before{content:"／";color:var(--copper);}
.crumbs a{color:var(--copper-deep);font-weight:700;}
.crumbs a:hover{color:var(--clay);}
.crumbs [aria-current="page"]{color:var(--ink);font-weight:800;}

/* ---------- 面板 ---------- */
.panel{
  position:relative;padding:clamp(20px,3vw,32px);
  background:var(--paper);color:var(--ink);
  border:1px solid rgba(192,138,62,.42);
  clip-path:polygon(0 0,calc(100% - 20px) 0,100% 20px,100% 100%,20px 100%,0 calc(100% - 20px));
}
.panel--grey{background:var(--paper-2);border-color:rgba(138,90,34,.28);}
.panel--deep{background:var(--ink-green);color:var(--paper);border-color:rgba(227,184,114,.36);}
.panel--deep h3,.panel--deep h4{color:var(--paper);}
.panel--deep p{color:rgba(246,242,233,.82);}
.panel-title{font-size:19px;font-weight:800;margin-bottom:10px;}
.panel-meta{font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--copper-deep);margin-bottom:8px;}
.panel--deep .panel-meta{color:var(--copper-bright);}

/* ---------- 标签 ---------- */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 10px;font-size:12.5px;font-weight:800;letter-spacing:.04em;
  background:rgba(196,100,58,.13);color:#8E4526;
  clip-path:polygon(0 0,calc(100% - 8px) 0,100% 8px,100% 100%,0 100%);
}
.tag--gold{background:rgba(192,138,62,.18);color:var(--copper-deep);}
.tag--bean{background:rgba(168,84,91,.14);color:var(--bean);}
.tag--deep{background:rgba(14,35,30,.09);color:var(--ink-green);}

/* ---------- 数据 ---------- */
.stat{display:flex;flex-direction:column;gap:4px;}
.stat-value{font-family:var(--font-mono);font-weight:700;line-height:1;font-size:clamp(28px,4vw,44px);color:var(--copper);}
.stat-label{font-size:12.5px;letter-spacing:.16em;color:var(--muted);}
.section--deep .stat-label,.panel--deep .stat-label{color:rgba(246,242,233,.72);}

/* ---------- 叠层卡片 ---------- */
.stack{display:grid;gap:clamp(14px,2vw,22px);position:relative;}
@media (min-width:900px){
  .stack{grid-template-columns:1fr;gap:0;}
  .stack-layer + .stack-layer{margin-top:-34px;margin-left:9%;}
  .stack-layer:nth-child(even){z-index:2;}
  .stack-layer:nth-child(odd){z-index:1;}
}

/* ---------- 栅格 ---------- */
.grid{display:grid;gap:clamp(16px,2.4vw,28px);}
.grid-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr));}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(228px,1fr));}
.grid-wide{grid-template-columns:1.4fr .8fr;align-items:start;}
@media (max-width:880px){.grid-wide{grid-template-columns:1fr;}}

/* ---------- 图片容器 ---------- */
.media{
  position:relative;overflow:hidden;background:var(--ink-green-deep);
  clip-path:polygon(0 0,calc(100% - 22px) 0,100% 22px,100% 100%,22px 100%,0 calc(100% - 22px));
}
.media img{width:100%;height:100%;object-fit:cover;object-position:center 45%;}
.media::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:radial-gradient(rgba(255,255,255,.06) 1px,transparent 1px);
  background-size:3px 3px;mix-blend-mode:overlay;
}
.media--wide{aspect-ratio:16/9;}
.media--square{aspect-ratio:1/1;}
.media--tall{aspect-ratio:4/5;}
.media--pano{aspect-ratio:21/9;}
.media--empty{
  background-color:rgba(14,35,30,.9);
  background-image:repeating-linear-gradient(135deg,rgba(227,184,114,.12) 0 12px,transparent 12px 24px);
}
.media-caption{margin-top:10px;font-family:var(--font-mono);font-size:12.5px;letter-spacing:.06em;color:var(--muted);}

/* ---------- 分段切换 ---------- */
.tabs{position:relative;}
.tab-list{display:flex;flex-wrap:wrap;gap:6px;border-bottom:1px solid rgba(138,90,34,.25);}
.tab{
  position:relative;padding:11px 16px;cursor:pointer;
  font-size:14.5px;font-weight:800;color:var(--muted);
  transition:color .18s var(--ease),background .18s var(--ease);
}
.tab::after{
  content:"";position:absolute;left:14px;right:14px;bottom:-1px;height:2px;
  background:var(--electric);transform:scaleX(0);transform-origin:left center;
  transition:transform .18s var(--ease);
}
.tab:hover{color:var(--copper-deep);}
.tab[aria-selected="true"]{color:var(--ink-green-deep);background:rgba(192,138,62,.1);}
.tab[aria-selected="true"]::after{transform:scaleX(1);}
.tab-panel{padding-top:24px;}
.tab-panel[hidden]{display:none;}

/* ---------- 筛选 ---------- */
.filter-bar{display:flex;flex-wrap:wrap;align-items:center;gap:8px;}
.filter-chip{
  padding:7px 13px;cursor:pointer;
  font-family:var(--font-mono);font-size:12.5px;font-weight:600;letter-spacing:.06em;
  border:1px solid rgba(138,90,34,.35);color:var(--copper-deep);background:transparent;
  clip-path:polygon(0 0,calc(100% - 9px) 0,100% 9px,100% 100%,0 100%);
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.filter-chip:hover{border-color:var(--copper);}
.filter-chip[aria-pressed="true"]{background:var(--ink-green);border-color:var(--ink-green);color:var(--copper-bright);}
.filter-count{margin-left:auto;font-family:var(--font-mono);font-size:12.5px;color:var(--muted);}
[data-filter-item][hidden]{display:none;}

/* ---------- 显现 ---------- */
[data-reveal]{opacity:0;transform:translateY(12px);transition:opacity .5s var(--ease),transform .5s var(--ease);}
[data-reveal].is-in{opacity:1;transform:none;}

/* ---------- 页脚 ---------- */
.site-footer{
  position:relative;margin-top:clamp(48px,7vw,96px);
  padding:clamp(40px,6vw,72px) 0 28px;
  background:var(--ink-green-deep);color:rgba(246,242,233,.82);
}
.footer-rail{
  position:absolute;top:0;left:0;right:0;height:3px;
  background:linear-gradient(90deg,var(--copper) 0%,var(--clay) 36%,rgba(47,214,180,.8) 100%);
  transform:skewY(-.4deg);
}
.footer-grid{
  display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;
  gap:clamp(22px,3.4vw,44px);
}
.footer-brand{max-width:34em;}
.brand--footer .brand-name{color:var(--paper);}
.brand--footer .brand-sub{color:var(--copper);}
.footer-line{margin:16px 0 18px;font-size:15px;color:rgba(246,242,233,.74);max-width:30em;}

.contact-list{display:grid;gap:10px;}
.contact-item{display:flex;flex-wrap:wrap;align-items:center;gap:10px;}
.contact-key{font-size:11.5px;letter-spacing:.18em;color:var(--copper);min-width:62px;}
.contact-val{font-size:14.5px;color:var(--paper);word-break:break-all;}
.chip-copy{
  padding:5px 11px;cursor:pointer;
  font-size:12px;font-weight:800;letter-spacing:.04em;
  border:1px solid rgba(227,184,114,.45);color:var(--copper-bright);
  clip-path:polygon(0 0,calc(100% - 8px) 0,100% 8px,100% 100%,0 100%);
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.chip-copy:hover{background:var(--copper-bright);color:var(--ink-green-deep);}
.chip-copy.is-done{background:var(--electric);border-color:var(--electric);color:var(--ink-green-deep);}
.footer-note{margin-top:16px;font-size:12.5px;line-height:1.7;color:rgba(246,242,233,.55);max-width:32em;}

.footer-col-title{font-size:13px;font-weight:800;letter-spacing:.18em;color:var(--copper-bright);margin-bottom:14px;}
.footer-col ul{display:grid;gap:10px;}
.footer-col a{
  font-size:14.5px;color:rgba(246,242,233,.78);
  border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer-col a:hover{color:var(--copper-bright);border-bottom-color:var(--copper-bright);}

.footer-base{
  margin-top:clamp(30px,4vw,52px);padding-top:20px;
  border-top:1px solid rgba(246,242,233,.14);
  display:flex;flex-wrap:wrap;align-items:center;gap:12px 24px;
}
.footer-legal{font-size:12.5px;color:rgba(246,242,233,.6);}
.footer-meta{font-size:12.5px;color:rgba(246,242,233,.5);}
.to-top{
  margin-left:auto;padding:8px 15px;cursor:pointer;
  font-size:12.5px;font-weight:800;letter-spacing:.08em;
  border:1px solid rgba(227,184,114,.45);color:var(--copper-bright);
  clip-path:polygon(0 0,calc(100% - 9px) 0,100% 9px,100% 100%,0 100%);
  transition:background .18s var(--ease),color .18s var(--ease);
}
.to-top:hover{background:var(--copper-bright);color:var(--ink-green-deep);}

/* ---------- 移动端 ---------- */
@keyframes navDrop{from{opacity:0;transform:translateY(-8px);}to{opacity:1;transform:none;}}

@media (max-width:1000px){
  .nav-toggle{display:inline-flex;}
  .site-nav{
    position:fixed;top:var(--header-h);left:0;right:0;
    display:none;flex-direction:column;align-items:stretch;gap:0;
    max-height:calc(100vh - var(--header-h));overflow-y:auto;
    padding:18px var(--gutter) 32px;
    background:var(--ink-green-deep);
    border-top:1px solid rgba(192,138,62,.4);
    box-shadow:0 30px 50px -30px rgba(0,0,0,.7);
  }
  .site-nav[data-open="true"]{display:flex;animation:navDrop .22s var(--ease);}
  .nav-list{flex-direction:column;align-items:stretch;gap:0;margin-right:0;}
  .nav-list a{padding:14px 2px;font-size:17px;border-bottom:1px solid rgba(246,242,233,.1);}
  .nav-list a::after{display:none;}
  .nav-list a[aria-current="page"]{color:var(--copper-bright);}
  .nav-actions{flex-direction:column;align-items:stretch;gap:10px;margin:20px 0 0;}
  .nav-actions .btn{width:100%;padding:14px 20px;}
  .nav-foot{display:block;margin-top:18px;font-size:12px;letter-spacing:.08em;color:var(--copper);}
  .footer-grid{grid-template-columns:1fr 1fr;}
}
@media (max-width:640px){
  :root{--header-h:64px;}
  .brand-mark{width:34px;height:34px;font-size:15px;}
  .brand-name{font-size:15.5px;}
  .brand-sub{display:none;}
  .footer-grid{grid-template-columns:1fr;}
  .to-top{margin-left:0;}
}
@media (min-width:1001px) and (max-width:1140px){
  .nav-list a{font-size:13.5px;}
}

/* ---------- 可访问性偏好 ---------- */
@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;}
  .btn:hover{transform:none;}
}