:root{
  --bg:#e6f1fd;
  --card:rgba(255,255,255,.92);
  --card-border:rgba(10,52,100,.30);
  --ink:#052142;
  --muted:#4c6c9a;
  --accent:#0b4488;
  --blue:#092e5c;
  --cyan:#1873bd;
}
*{margin:0;padding:0;box-sizing:border-box;}
html,body{height:100%;}
body{
  font-family:"PingFang SC","Microsoft YaHei","Segoe UI",sans-serif;
  background:linear-gradient(160deg,#d9ebfb 0%,#eff6ff 45%,#ffffff 100%);
  color:var(--ink);
  overflow:hidden;
  line-height:1.6;
}
a{text-decoration:none;}

/* ---------- 背景层 ---------- */
.bg-grid{
  position:fixed;inset:0;z-index:0;pointer-events:none;
  background-image:
    linear-gradient(rgba(10,52,100,.11) 1px,transparent 1px),
    linear-gradient(90deg,rgba(10,52,100,.11) 1px,transparent 1px);
  background-size:48px 48px;
  mask-image:radial-gradient(ellipse 90% 60% at 50% 0%,#000 40%,transparent 100%);
  -webkit-mask-image:radial-gradient(ellipse 90% 60% at 50% 0%,#000 40%,transparent 100%);
}
.glow{position:fixed;border-radius:50%;filter:blur(90px);z-index:0;pointer-events:none;}
.glow.g1{width:520px;height:520px;background:rgba(13,77,150,.22);top:-180px;left:-120px;}
.glow.g2{width:420px;height:420px;background:rgba(29,124,201,.16);top:30%;right:-160px;}
.glow.g3{width:460px;height:460px;background:rgba(13,77,150,.16);bottom:-180px;left:30%;}
#particles{position:fixed;inset:0;z-index:0;pointer-events:none;}

/* ---------- 吸顶导航 ---------- */
.topbar{
  position:fixed;top:0;left:0;right:0;z-index:50;
  display:flex;align-items:center;gap:20px;padding:0 26px;height:54px;
  background:rgba(255,255,255,.85);backdrop-filter:blur(14px);
  border-bottom:1px solid rgba(10,52,100,.16);
  box-shadow:0 2px 18px rgba(10,52,100,.10);
}
.logo{display:flex;align-items:center;gap:10px;color:var(--ink);font-size:15px;font-weight:700;letter-spacing:2px;white-space:nowrap;}
.logo em{font-style:normal;font-size:12px;color:var(--muted);font-weight:400;}
.logo-dot{width:9px;height:9px;flex:none;background:linear-gradient(135deg,#1873bd,var(--blue));border-radius:2px;box-shadow:0 0 10px rgba(13,77,150,.5);transform:rotate(45deg);animation:pulse 1.6s infinite;}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.35}}
.nav-links{margin-left:auto;display:flex;gap:4px;overflow-x:auto;scrollbar-width:none;}
.nav-links::-webkit-scrollbar{display:none;}
.nav-links a{
  padding:5px 13px;border-radius:8px;font-size:13.5px;color:#3a5f95;
  letter-spacing:1px;white-space:nowrap;transition:.2s;
}
.nav-links a:hover{color:var(--accent);background:rgba(13,77,150,.08);}
.nav-links a.on{
  color:#fff;font-weight:700;
  background:linear-gradient(90deg,var(--accent),var(--blue));
  box-shadow:0 4px 14px rgba(10,52,100,.35);
}

/* ---------- 一屏页面骨架 ---------- */
.screen{
  position:relative;z-index:2;height:100vh;
  display:flex;flex-direction:column;
  max-width:1280px;width:100%;margin:0 auto;
  padding:70px 26px 18px;
}

/* 学科页头 */
.sub-head{display:flex;align-items:center;gap:16px;margin-bottom:14px;animation:fadeUp .5s ease;}
.sub-icon{
  width:52px;height:52px;flex:none;border-radius:14px;
  display:flex;align-items:center;justify-content:center;
  font-size:24px;font-weight:800;color:#fff;
  background:linear-gradient(135deg,#1873bd,var(--blue));
  box-shadow:0 8px 24px rgba(10,52,100,.35);
}
.sub-info h1{font-size:25px;letter-spacing:3px;color:#052142;line-height:1.3;}
.sub-info h1 span{
  font-size:13px;letter-spacing:2px;font-weight:400;
  background:linear-gradient(90deg,#0b4488,#092e5c);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
  margin-left:10px;
}
.sub-info p{font-size:13px;color:var(--muted);margin-top:2px;}
.sub-info p b{color:var(--accent);font-weight:600;}

/* 学科横幅 */
.s-banner{
  margin-bottom:12px;padding:10px 18px;border-radius:10px;text-align:center;
  background:linear-gradient(90deg,rgba(13,77,150,.17),rgba(29,124,201,.10),rgba(13,77,150,.17));
  border:1px solid rgba(13,77,150,.38);font-size:14.5px;font-weight:700;
  letter-spacing:3px;color:#092e5c;animation:fadeUp .5s ease;
}

/* 日程列 */
.sessions{flex:1;display:flex;gap:18px;min-height:0;animation:fadeUp .6s ease;}
.sessions.single{max-width:900px;margin:0 auto;width:100%;}
.s-col{flex:1;display:flex;flex-direction:column;min-width:0;min-height:0;}
.s-col-head{
  padding:9px 16px;border-radius:10px;margin-bottom:10px;
  background:linear-gradient(90deg,rgba(13,77,150,.17),rgba(29,124,201,.06));
  border-left:3px solid #0b4488;
  display:flex;flex-wrap:wrap;align-items:center;gap:6px 10px;
}
.s-col-head .date{font-size:15px;font-weight:700;color:#052142;letter-spacing:1px;}
.s-col-head .tag{
  padding:2px 10px;border-radius:999px;font-size:11px;letter-spacing:2px;
  background:rgba(13,77,150,.14);color:var(--accent);border:1px solid rgba(13,77,150,.38);
}
.s-col-head .loc{margin-left:auto;font-size:12px;color:var(--muted);}
.s-col-head .loc b{color:var(--accent);font-weight:600;}

.s-list{flex:1;display:flex;flex-direction:column;gap:8px;min-height:0;}
.s-item{
  flex:1;min-height:0;overflow:hidden;
  background:var(--card);border:1px solid var(--card-border);border-radius:10px;
  padding:8px 15px;display:flex;flex-direction:column;justify-content:center;
  box-shadow:0 2px 10px rgba(10,52,100,.10);
  transition:border-color .25s, box-shadow .25s, transform .25s;
}
.s-item:hover{
  border-color:rgba(13,77,150,.5);
  box-shadow:0 8px 24px rgba(10,52,100,.18);
  transform:translateY(-2px);
}
.s-top{display:flex;flex-wrap:wrap;align-items:center;gap:8px;}
.s-time{font-family:"Consolas","DIN Alternate",monospace;font-weight:700;color:var(--accent);font-size:13px;letter-spacing:.5px;}
.s-tag{
  font-size:11px;padding:1px 9px;border-radius:4px;letter-spacing:2px;
  background:linear-gradient(90deg,rgba(13,77,150,.17),rgba(29,124,201,.17));
  border:1px solid rgba(13,77,150,.38);color:#092e5c;
}
.s-title{font-size:13.5px;color:#052142;font-weight:600;margin-top:3px;line-height:1.45;}
.s-meta{font-size:12px;color:var(--muted);margin-top:2px;}
.s-meta b{color:var(--accent);font-weight:600;}
.s-line{display:flex;flex-wrap:wrap;align-items:baseline;gap:8px;margin-top:3px;}
.s-line .st{font-size:13px;color:#052142;font-weight:600;}
.s-line .sp{font-size:12px;color:var(--muted);white-space:nowrap;}
.s-line .sp b{color:var(--accent);font-weight:600;}

/* 页底导航 */
.page-nav{display:flex;justify-content:space-between;gap:12px;margin-top:14px;animation:fadeUp .7s ease;}
.btn{
  padding:9px 24px;border-radius:999px;font-size:13.5px;letter-spacing:2px;
  border:1px solid rgba(13,77,150,.50);color:var(--accent);
  background:rgba(255,255,255,.9);transition:.25s;white-space:nowrap;
}
.btn:hover{
  border-color:var(--accent);color:#fff;
  background:linear-gradient(90deg,#0b4488,#092e5c);
  box-shadow:0 6px 20px rgba(10,52,100,.35);transform:translateY(-2px);
}
.btn.primary{
  color:#fff;font-weight:700;
  background:linear-gradient(90deg,var(--accent),var(--blue));
  border-color:transparent;box-shadow:0 6px 20px rgba(10,52,100,.35);
}
.btn.primary:hover{filter:brightness(1.08);box-shadow:0 10px 28px rgba(10,52,100,.5);}

@keyframes fadeUp{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}

/* ---------- 封面页 ---------- */
.cover{
  position:relative;z-index:2;height:100vh;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  text-align:center;padding:24px;
}
.cover-logo{
  width:min(340px,34vh);height:auto;object-fit:contain;margin-bottom:16px;
  filter:drop-shadow(0 12px 30px rgba(10,52,100,.35));
  animation:fadeUp .5s ease;
}
.ring{position:absolute;border-radius:50%;pointer-events:none;}
.r1{width:640px;height:640px;border:1px dashed rgba(13,77,150,.30);animation:spin 40s linear infinite;}
.r2{width:480px;height:480px;border:1px solid rgba(29,124,201,.22);animation:spin 30s linear infinite reverse;}
.r3{width:820px;height:820px;border:1px dashed rgba(13,77,150,.17);animation:spin 70s linear infinite;}
@keyframes spin{to{transform:rotate(360deg)}}
.cover-badge{
  display:inline-flex;align-items:center;gap:12px;
  padding:11px 30px;border-radius:999px;
  border:1px solid rgba(13,77,150,.50);
  background:linear-gradient(90deg,rgba(13,77,150,.10),rgba(29,124,201,.06));
  font-size:21px;font-weight:700;letter-spacing:2px;color:var(--accent);
  box-shadow:0 0 14px rgba(13,77,150,.17);
  margin-bottom:18px;animation:fadeUp .6s ease;
}
.cover-badge .dot{width:8px;height:8px;border-radius:50%;background:#0b4488;box-shadow:0 0 10px rgba(13,77,150,.6);animation:pulse 1.6s infinite;}
.cover-title{
  font-size:clamp(30px,5.4vw,54px);font-weight:800;letter-spacing:3px;line-height:1.35;
  background:linear-gradient(180deg,#052142 15%,#0b4488 60%,#1873bd 100%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
  animation:fadeUp .7s ease;
}
.cover-sub{font-size:clamp(13px,1.8vw,17px);color:#2f5286;letter-spacing:8px;margin-top:14px;animation:fadeUp .8s ease;}
.cover-line{
  width:260px;height:2px;margin:14px auto;
  background:linear-gradient(90deg,transparent,#0b4488,transparent);position:relative;
  animation:fadeUp .9s ease;
}
.cover-line::after{content:"";position:absolute;left:50%;top:-3px;width:8px;height:8px;transform:translateX(-50%) rotate(45deg);background:#0b4488;box-shadow:0 0 14px rgba(13,77,150,.5);}
.cover-org{font-size:14px;color:#2f5286;letter-spacing:4px;animation:fadeUp 1s ease;}
.cover-btn{
  margin-top:24px;padding:14px 52px;border-radius:999px;
  font-size:16px;font-weight:700;letter-spacing:5px;color:#fff;
  background:linear-gradient(90deg,#0b4488,#092e5c);
  box-shadow:0 10px 34px rgba(10,52,100,.4);
  transition:.3s;animation:fadeUp 1.1s ease;
  display:inline-flex;align-items:center;gap:10px;
}
.cover-btn:hover{transform:translateY(-3px) scale(1.03);box-shadow:0 16px 46px rgba(10,52,100,.55);}
.cover-btn .arrow{animation:nudge 1.4s infinite;}
@keyframes nudge{0%,100%{transform:translateX(0)}50%{transform:translateX(5px)}}
.cover-foot{
  position:absolute;bottom:24px;left:0;right:0;text-align:center;
  font-size:12px;color:#6f8dbb;letter-spacing:3px;
  animation:fadeUp 1.2s ease;
}

/* ---------- 学科导航页 ---------- */
.menu-head{display:flex;flex-wrap:wrap;align-items:flex-end;gap:14px 24px;margin-bottom:16px;animation:fadeUp .5s ease;}
.menu-head h1{font-size:24px;letter-spacing:3px;color:#052142;}
.menu-head h1 em{font-style:normal;
  background:linear-gradient(90deg,#0b4488,#092e5c);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;}
.menu-stats{margin-left:auto;display:flex;gap:10px;flex-wrap:wrap;}
.mstat{
  padding:6px 16px;border-radius:10px;text-align:center;
  background:var(--card);border:1px solid var(--card-border);
  box-shadow:0 2px 10px rgba(10,52,100,.10);
}
.mstat .n{font-size:18px;font-weight:800;color:var(--accent);font-family:"Consolas",monospace;}
.mstat .l{font-size:10.5px;color:var(--muted);letter-spacing:2px;}
.menu-grid{
  flex:1;display:grid;gap:14px;min-height:0;
  grid-template-columns:repeat(4,1fr);grid-auto-rows:1fr;
  animation:fadeUp .6s ease;
}
.mcard{
  position:relative;display:flex;flex-direction:column;justify-content:center;gap:8px;
  background:var(--card);border:1px solid var(--card-border);border-radius:14px;
  padding:18px 20px;color:var(--ink);
  box-shadow:0 2px 10px rgba(10,52,100,.10);
  transition:transform .25s, border-color .25s, box-shadow .25s;
  overflow:hidden;
}
.mcard::after{
  content:"";position:absolute;top:0;left:0;right:0;height:2px;
  background:linear-gradient(90deg,transparent,#0b4488,transparent);opacity:0;transition:.25s;
}
.mcard:hover{transform:translateY(-4px);border-color:rgba(13,77,150,.45);box-shadow:0 14px 34px rgba(10,52,100,.18);}
.mcard:hover::after{opacity:1;}
.mcard .mi{
  width:44px;height:44px;border-radius:12px;display:flex;align-items:center;justify-content:center;
  font-size:20px;font-weight:800;color:#fff;
  background:linear-gradient(135deg,#1873bd,var(--blue));
  box-shadow:0 6px 16px rgba(10,52,100,.35);
}
.mcard h3{font-size:16px;letter-spacing:2px;color:#052142;}
.mcard .mline{font-size:12px;color:var(--muted);line-height:1.6;}
.mcard .mline b{color:var(--accent);font-weight:600;}
.mcard .go{font-size:12px;color:var(--accent);letter-spacing:2px;}

/* ---------- 活动主旨页 ---------- */
.z-wrap{
  max-width:960px;width:100%;margin:0 auto;flex:1;min-height:0;
  display:flex;flex-direction:column;justify-content:center;gap:28px;
  animation:fadeUp .6s ease;overflow:hidden;
}
.z-theme{
  font-size:clamp(24px,3.4vw,34px);font-weight:800;letter-spacing:3px;
  color:#052142;line-height:1.45;margin-top:6px;
}
.z-text{max-width:840px;}
.z-text p{color:#33497c;font-size:15px;line-height:2;text-align:justify;text-indent:2em;}
.z-text p b{color:var(--accent);font-weight:600;}
.z-kws{display:flex;gap:40px;flex-wrap:wrap;}
.z-item{border-left:2px solid rgba(13,77,150,.50);padding-left:16px;}
.z-item .no{font-size:12px;letter-spacing:3px;color:var(--accent);font-family:"Consolas",monospace;}
.z-item .t{font-size:19px;font-weight:800;letter-spacing:2px;color:#052142;margin:2px 0;}
.z-item .t span{color:var(--accent);}
.z-item .d{font-size:12px;color:var(--muted);letter-spacing:1px;}
.z-foot{color:var(--muted);font-size:13px;letter-spacing:2px;}
@media (max-width:640px){.z-kws{flex-direction:column;gap:18px;}}

/* ---------- 响应式 ---------- */
@media (max-height:800px){
  .cover-logo{width:min(260px,28vh);height:auto;margin-bottom:12px;}
  .cover-badge{font-size:17px;padding:9px 24px;letter-spacing:1.5px;}
  .cover-title{font-size:clamp(24px,4.6vw,44px);}
  .sub-info h1{font-size:21px;}
  .sub-icon{width:44px;height:44px;font-size:20px;}
  .s-title,.s-line .st{font-size:12.5px;}
  .s-meta,.s-line .sp,.s-col-head .loc{font-size:11.5px;}
  .screen{padding-top:64px;}
}
@media (max-width:860px){
  .menu-grid{grid-template-columns:repeat(2,1fr);}
  .sessions{flex-direction:column;overflow-y:auto;}
  .logo em{display:none;}
}
@media (max-width:640px){
  body{overflow:auto;}
  .screen,.cover{height:auto;min-height:100vh;}
  .sessions.single{max-width:100%;}
  .menu-grid{grid-auto-rows:minmax(130px,auto);}
  .page-nav{flex-direction:column;}
  .btn{text-align:center;}
  .cover-logo{width:min(220px,55vw);height:auto;}
  .cover-badge{font-size:15px;padding:9px 18px;letter-spacing:1px;}
}