/* 51大赛（文件12）· 全新高级质感：深色瑞士网格 + 红金点缀 + 极简排版 */
:root{
  color-scheme: dark;
  --bg:#070a0f;
  --bg2:#0b101a;
  --paper: rgba(255,255,255,.06);
  --paper2: rgba(255,255,255,.09);
  --line: rgba(255,255,255,.12);
  --ink: rgba(255,255,255,.92);
  --muted: rgba(255,255,255,.72);
  --muted2: rgba(255,255,255,.56);
  --shadow: 0 18px 60px rgba(0,0,0,.50);
  --r1: 22px;
  --r2: 16px;
  --wrap: 1180px;

  --red:#ef4444;
  --gold:#f59e0b;
  --ice:#22d3ee;
}
*{ box-sizing:border-box; }
html,body{ height:100%; }
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial,
    "PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC","Noto Sans SC",sans-serif;
  color: var(--ink);
  line-height: 1.7;
  background:
    radial-gradient(1100px 520px at 10% 0%, rgba(239,68,68,.16), transparent 60%),
    radial-gradient(980px 520px at 92% 10%, rgba(245,158,11,.12), transparent 56%),
    radial-gradient(860px 520px at 55% 120%, rgba(34,211,238,.10), transparent 58%),
    linear-gradient(180deg, var(--bg), var(--bg2));
}
a{ color:inherit; text-decoration:none; }
img{ max-width:100%; display:block; }
.wrap{ width:100%; max-width: var(--wrap); margin:0 auto; padding:0 18px; }
.sr-only{
  position:absolute!important; width:1px;height:1px;
  overflow:hidden; clip: rect(1px,1px,1px,1px); white-space:nowrap;
}
.skip{
  position:absolute; left:-999px; top:10px;
  padding:10px 12px; border-radius: 12px;
  background: rgba(255,255,255,.12); border:1px solid var(--line); box-shadow: var(--shadow);
}
.skip:focus{ left:12px; z-index: 99; }

/* 顶部：细致的瑞士风格栏 */
.mast{
  position: sticky;
  top:0;
  z-index: 70;
  background: rgba(7,10,15,.62);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(255,255,255,.10);
}
.mast-top{
  display:flex; align-items:center; justify-content:space-between; gap: 12px;
  padding: 14px 0 10px;
}
.brand{
  display:flex; align-items:center; gap: 12px;
  min-width: 280px;
}
.mark{
  width: 44px; height:44px;
  border-radius: 14px;
  display:grid; place-items:center;
  background: linear-gradient(135deg, rgba(239,68,68,.20), rgba(245,158,11,.14));
  border:1px solid rgba(255,255,255,.16);
  box-shadow: 0 18px 40px rgba(239,68,68,.16);
  font-weight: 900;
  letter-spacing:.6px;
}
.brand small{ display:block; margin-top:2px; font-size:12px; color: var(--muted2); }

.search{
  display:flex; align-items:center; gap: 10px;
  min-width: 340px;
}
.search input{
  width:100%;
  padding: 10px 12px;
  border-radius: 14px;
  border:1px solid rgba(255,255,255,.14);
  background: rgba(255,255,255,.06);
  color: var(--ink);
  outline:none;
}
.search input::placeholder{ color: rgba(255,255,255,.45); }
.search input:focus{
  border-color: rgba(34,211,238,.36);
  box-shadow: 0 0 0 4px rgba(34,211,238,.12);
}
.search button{
  padding: 10px 12px;
  border-radius: 14px;
  border:1px solid rgba(255,255,255,.14);
  background: rgba(255,255,255,.06);
  color: var(--ink);
  cursor:pointer;
}
.search button:hover{ background: rgba(255,255,255,.10); }

.nav{
  display:flex;
  flex-wrap:wrap;
  gap: 8px;
  padding: 0 0 12px;
}
.nav a{
  padding: 8px 12px;
  border-radius: 999px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.05);
  color: rgba(255,255,255,.84);
  font-size: 13px;
}
.nav a:hover{ background: rgba(255,255,255,.10); }
.nav a.on{
  border-color: rgba(239,68,68,.22);
  background: linear-gradient(135deg, rgba(239,68,68,.16), rgba(245,158,11,.10));
}

main{ padding: 18px 0 48px; }

/* 卡片：克制的暗色材质 */
.card{
  border-radius: var(--r1);
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.06);
  box-shadow: var(--shadow);
}

/* 首页：大会总览（左）+ 互动入口（右） */
.hero{
  display:grid;
  grid-template-columns: minmax(0,1fr) 420px;
  gap: 12px;
  align-items:start;
  margin: 12px 0 14px;
}
.hero-main{
  padding: 16px;
  position: relative;
  overflow:hidden;
}
.hero-main:before{
  content:"";
  position:absolute; inset:-2px;
  background:
    radial-gradient(740px 320px at 12% 0%, rgba(239,68,68,.18), transparent 60%),
    radial-gradient(740px 340px at 92% 10%, rgba(245,158,11,.12), transparent 58%),
    radial-gradient(740px 360px at 55% 120%, rgba(34,211,238,.10), transparent 60%);
  pointer-events:none;
  opacity:.9;
}
.hero-main > *{ position: relative; }
.hero h1{
  margin:0 0 10px;
  font-size: 34px;
  line-height: 1.12;
  letter-spacing:.2px;
}
.lead{
  margin:0;
  color: var(--muted);
  max-width: 76ch;
}
.actions{
  display:flex; flex-wrap:wrap; gap: 10px;
  margin-top: 14px;
}
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  padding: 10px 12px;
  border-radius: 14px;
  border:1px solid rgba(255,255,255,.14);
  background: rgba(255,255,255,.06);
  color: rgba(255,255,255,.88);
  font-weight: 800;
}
.btn.primary{
  border-color: rgba(239,68,68,.24);
  background: linear-gradient(135deg, rgba(239,68,68,.22), rgba(245,158,11,.12));
}
.btn.ice{
  border-color: rgba(34,211,238,.22);
  background: rgba(34,211,238,.08);
}
.btn:hover{ background: rgba(255,255,255,.10); }
.hero-media{
  margin-top: 14px;
  border-radius: 18px;
  border:1px solid rgba(255,255,255,.12);
  overflow:hidden;
  background: rgba(255,255,255,.05);
}
.hero-media img{ width:100%; height: 260px; object-fit: cover; }

.hero-side{
  padding: 14px;
}
.hero-side h2{ margin:0 0 10px; font-size: 14px; letter-spacing:.3px; }
.tiles{
  display:grid;
  gap: 10px;
}
.mini{
  border-radius: 18px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.05);
  padding: 12px;
}
.mini strong{ display:block; font-size: 13px; }
.mini p{ margin: 6px 0 0; color: var(--muted2); font-size: 12px; }
.pill{
  display:inline-flex;
  margin-top: 10px;
  padding: 6px 10px;
  border-radius: 999px;
  border:1px solid rgba(245,158,11,.22);
  background: rgba(245,158,11,.10);
  color: rgba(255,230,190,.92);
  font-size: 12px;
}
.pill.r{ border-color: rgba(239,68,68,.22); background: rgba(239,68,68,.10); color: rgba(255,210,210,.92); }
.pill.i{ border-color: rgba(34,211,238,.22); background: rgba(34,211,238,.10); color: rgba(189,247,255,.92); }

/* 中段：节奏区块（双行网格） */
.section{
  margin-top: 18px;
}
.section-head{
  display:flex;
  align-items:flex-end;
  justify-content:space-between;
  gap: 12px;
  margin-bottom: 10px;
}
.section-head h2{ margin:0; font-size: 18px; letter-spacing:.2px; }
.section-head p{ margin:0; color: var(--muted2); font-size: 12px; }

.bento{
  display:grid;
  grid-template-columns: repeat(12, minmax(0,1fr));
  gap: 12px;
}
.box{
  grid-column: span 4;
  border-radius: 22px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.06);
  padding: 14px;
  box-shadow: 0 14px 40px rgba(0,0,0,.35);
}
.box.wide{ grid-column: span 8; }
.box h3{ margin:0 0 8px; font-size: 14px; }
.box p{ margin:0; color: var(--muted2); font-size: 12px; }
.list{
  margin-top: 10px;
  display:grid;
  gap: 10px;
}
.row{
  display:grid;
  grid-template-columns: 84px 1fr;
  gap: 10px;
  align-items:center;
  padding: 10px;
  border-radius: 18px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.05);
}
.k{
  justify-self:start;
  padding: 6px 10px;
  border-radius: 999px;
  border:1px solid rgba(239,68,68,.22);
  background: rgba(239,68,68,.10);
  color: rgba(255,210,210,.92);
  font-size: 12px;
  font-weight: 800;
  white-space: nowrap;
}
.k.g{ border-color: rgba(245,158,11,.22); background: rgba(245,158,11,.10); color: rgba(255,230,190,.92); }
.k.i{ border-color: rgba(34,211,238,.22); background: rgba(34,211,238,.10); color: rgba(189,247,255,.92); }
.row b{ display:block; font-size: 13px; }
.row span{ display:block; margin-top: 4px; color: var(--muted2); font-size: 12px; }

/* 列表页：主题索引（非四象限/非墙） */
.grid{
  display:grid;
  grid-template-columns: repeat(3, minmax(0,1fr));
  gap: 12px;
}
.tile{
  border-radius: 22px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.06);
  overflow:hidden;
  box-shadow: 0 14px 40px rgba(0,0,0,.32);
  transition: .15s ease;
}
.tile:hover{ transform: translateY(-2px); }
.tile img{ width:100%; height: 170px; object-fit: cover; }
.tile .meta{ padding: 12px; }
.tile h3{ margin:0 0 6px; font-size: 14px; line-height: 1.25; }
.tile p{ margin:0; color: var(--muted2); font-size: 12px; }

/* 内容页：正文 + 右侧“规格卡” */
.doc{
  display:grid;
  grid-template-columns: minmax(0,1fr) 360px;
  gap: 12px;
  align-items:start;
}
.paper{
  padding: 16px;
}
.crumb{
  display:flex;
  gap: 8px;
  flex-wrap:wrap;
  font-size: 12px;
  color: var(--muted2);
  margin-bottom: 10px;
}
.paper h1{ margin:0 0 10px; font-size: 22px; line-height: 1.25; }
.paper h2{ margin: 16px 0 8px; font-size: 16px; }
.paper p{ margin: 10px 0; color: var(--muted); }
.paper ul{ margin: 10px 0 10px 18px; color: var(--muted); }
.timeline{
  margin-top: 12px;
  border-radius: 18px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.05);
  padding: 12px;
}
.titem{
  display:grid;
  grid-template-columns: 82px 1fr;
  gap: 10px;
  padding: 10px 10px;
  border-top: 1px solid rgba(255,255,255,.10);
}
.titem:first-child{ border-top:none; }
.t{ font-weight: 900; color: rgba(255,255,255,.80); font-size: 12px; }
.titem b{ display:block; font-size: 13px; }
.titem span{ display:block; margin-top: 4px; color: var(--muted2); font-size: 12px; }
.aside{
  padding: 14px;
}
.aside h3{ margin:0 0 10px; font-size: 14px; }
.kv{
  display:grid;
  gap: 10px;
}
.kv div{
  padding: 10px;
  border-radius: 18px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.05);
  font-size: 12px;
  color: rgba(255,255,255,.78);
}
.kv b{ color: rgba(255,255,255,.92); }
.aside .img{
  margin-top: 10px;
  border-radius: 18px;
  overflow:hidden;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.05);
}

.footer{
  margin-top: 22px;
  border-top: 1px solid rgba(255,255,255,.10);
  background: rgba(255,255,255,.03);
}
.footrow{
  padding: 18px 0;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap: 12px;
  flex-wrap:wrap;
  color: rgba(255,255,255,.72);
}

/* 移动端底部导航 */
.bottom{
  display:none;
  position: fixed;
  left: 12px; right: 12px; bottom: 12px;
  z-index: 80;
  border-radius: 18px;
  border:1px solid rgba(255,255,255,.12);
  background: rgba(7,10,15,.70);
  backdrop-filter: blur(14px);
  box-shadow: var(--shadow);
  padding: 10px;
}
.bottom a{
  flex:1 1 0;
  display:flex;
  align-items:center;
  justify-content:center;
  padding: 10px;
  border-radius: 14px;
  border:1px solid transparent;
  color: rgba(255,255,255,.76);
  font-size: 12px;
  font-weight: 800;
}
.bottom a.on{
  border-color: rgba(245,158,11,.22);
  background: rgba(245,158,11,.10);
  color: rgba(255,230,190,.92);
}

@media (max-width: 1120px){
  .hero{ grid-template-columns: 1fr; }
}
@media (max-width: 980px){
  .bento .box{ grid-column: span 12; }
  .bento .box.wide{ grid-column: span 12; }
  .grid{ grid-template-columns: repeat(2, minmax(0,1fr)); }
  .doc{ grid-template-columns: 1fr; }
}
@media (max-width: 720px){
  .search{ display:none; }
  main{ padding-bottom: 92px; }
  .bottom{ display:flex; gap: 10px; }
}
@media (max-width: 420px){
  .grid{ grid-template-columns: 1fr; }
}