:root{
  --bg:#eef2f8; --card:#ffffff; --text:#1e293b; --muted:#64748b; --border:#e2e8f0;
  --primary:#2563eb; --primary-dark:#1d4ed8; --primary-soft:#dbeafe;
  --ok:#15803d; --ok-soft:#dcfce7; --warn:#b45309; --warn-soft:#fef3c7;
  --err:#dc2626; --err-soft:#fee2e2; --purple:#7c3aed; --purple-soft:#ede9fe;
  --teal:#0f766e; --teal-soft:#ccfbf1;
  --radius:14px; --radius-sm:10px;
  --shadow:0 1px 3px rgba(15,23,42,.08),0 4px 14px rgba(15,23,42,.05);
  --shadow-lg:0 8px 28px rgba(15,23,42,.13);
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Roboto,Helvetica,Arial,sans-serif;
  line-height:1.6;font-size:15px}
button,input,select,textarea{font-family:inherit;font-size:15px}
img{max-width:100%}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}

/* ---------- 头部 ---------- */
.site-header{position:sticky;top:0;z-index:30;background:linear-gradient(135deg,#172554 0%,#1e40af 45%,#2563eb 80%,#0ea5e9 100%);
  color:#fff;box-shadow:0 2px 12px rgba(23,37,84,.35)}
.site-header-inner{max-width:1040px;margin:0 auto;padding:12px 16px 6px;display:flex;flex-wrap:wrap;gap:8px 18px;align-items:center}
.brand{display:flex;align-items:center;gap:10px;min-width:0}
.school-brand{width:196px;height:42px;object-fit:contain;object-position:left center;background:#fff;border-radius:5px;padding:2px 5px}
.school-brand-fallback{display:none;width:196px;height:42px;box-sizing:border-box;align-items:center;justify-content:center;flex-direction:column;background:#fff;color:#124aa1;border-radius:5px;line-height:1.05;letter-spacing:1px;font-family:"Microsoft YaHei",sans-serif}
.school-brand-fallback b{font-size:16px}.school-brand-fallback small{font-size:10px;letter-spacing:2px;margin-top:3px}
.brand-title{font-size:18px;font-weight:700;letter-spacing:.5px;margin:0;white-space:nowrap}
.brand-sub{font-size:12px;opacity:.85;margin-top:1px}
.topnav{display:flex;gap:6px;margin-left:auto;flex-wrap:wrap}
.topnav a{color:#e8efff;padding:6px 12px;border-radius:999px;border:1px solid rgba(255,255,255,.28);font-size:13px;font-weight:600;transition:.18s;white-space:nowrap}
.topnav a:hover{background:rgba(255,255,255,.18);text-decoration:none}
.topnav a.current{background:#fff;color:var(--primary-dark);border-color:#fff}
.xp-chip{background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.28);padding:5px 12px;border-radius:999px;font-size:13px;font-weight:600;white-space:nowrap}
.levelbar{height:6px;background:rgba(255,255,255,.22);border-radius:3px;overflow:hidden;flex:1 1 140px;min-width:120px;max-width:240px}
.levelbar i{display:block;height:100%;background:linear-gradient(90deg,#fbbf24,#f59e0b);border-radius:3px;transition:width .5s}

/* ---------- 布局 ---------- */
.wrap{max-width:1040px;margin:0 auto;padding:18px 14px 56px}
.hero{background:linear-gradient(135deg,#eff6ff 0%,#e0f2fe 55%,#dcfce7 100%);border:1px solid var(--border);
  border-radius:18px;padding:26px 24px;margin-bottom:20px;box-shadow:var(--shadow)}
.hero h1{margin:0 0 8px;font-size:26px;color:#0f172a}
.hero p{margin:0;color:var(--muted);max-width:820px}
.hero-stats{display:flex;flex-wrap:wrap;gap:10px;margin-top:16px}
.stat{background:#fff;border:1px solid var(--border);border-radius:var(--radius-sm);padding:8px 16px;min-width:110px;text-align:center;box-shadow:var(--shadow)}
.stat .v{font-size:20px;font-weight:800;color:var(--primary-dark)}
.stat .k{font-size:12px;color:var(--muted)}
.section-title{display:flex;align-items:center;gap:8px;margin:26px 0 12px;font-size:19px;color:#0f172a}
.section-title::after{content:"";flex:1;height:1px;background:var(--border)}
.muted{color:var(--muted)}
.text-sm{font-size:13px}

/* ---------- 网格与卡片 ---------- */
.grid{display:grid;gap:12px}
.grid-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(230px,1fr))}
.grid-4{grid-template-columns:repeat(auto-fit,minmax(180px,1fr))}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:16px;margin-bottom:14px}
.card > h3{margin:0 0 4px;font-size:17px;color:#0f172a}
.card > p.desc{margin:0 0 12px;color:var(--muted);font-size:13px}
.card-link{display:flex;flex-direction:column;gap:8px;background:var(--card);border:1px solid var(--border);
  border-radius:var(--radius);padding:16px;box-shadow:var(--shadow);color:inherit;transition:.18s;position:relative}
.card-link:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg);text-decoration:none;border-color:#bfdbfe}
.card-link .icon{font-size:26px}
.card-link .t{font-weight:700;color:#0f172a;font-size:15px}
.card-link .d{font-size:13px;color:var(--muted);flex:1}
.card-link .go{font-size:13px;color:var(--primary);font-weight:600}
.tag{display:inline-block;background:var(--primary-soft);color:var(--primary-dark);font-size:12px;padding:2px 9px;border-radius:999px;font-weight:600}
.tag.ok{background:var(--ok-soft);color:var(--ok)}
.tag.warn{background:var(--warn-soft);color:var(--warn)}
.tag.purple{background:var(--purple-soft);color:var(--purple)}
.tag.teal{background:var(--teal-soft);color:var(--teal)}

/* ---------- 按钮与表单 ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;background:#fff;color:var(--text);
  border:1px solid #cbd5e1;border-radius:var(--radius-sm);padding:9px 18px;font-weight:600;cursor:pointer;transition:.15s;line-height:1.2}
.btn:hover{background:#f1f5f9}
.btn:active{transform:translateY(1px)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn-primary{background:var(--primary);border-color:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-dark)}
.btn-ok{background:var(--ok);border-color:var(--ok);color:#fff}
.btn-ok:hover{background:#166534}
.btn-danger{background:var(--err);border-color:var(--err);color:#fff}
.btn-danger:hover{background:#b91c1c}
.btn-ghost{background:transparent;border-color:transparent;color:var(--primary)}
.btn-ghost:hover{background:var(--primary-soft)}
.btn-sm{padding:5px 12px;font-size:13px}
.btn-block{display:flex;width:100%}
.row{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.row > *{min-width:0}
label.fld{display:block;font-size:13px;color:var(--muted);margin:10px 0 4px;font-weight:600}
input[type=text],input[type=number],input[type=password],select,textarea{
  width:100%;padding:9px 12px;border:1px solid #cbd5e1;border-radius:var(--radius-sm);background:#fff;color:var(--text);outline:none;
  transition:border-color .15s, box-shadow .15s}
input:focus,select:focus,textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.15)}
textarea{resize:vertical;min-height:70px}
.chips{display:flex;flex-wrap:wrap;gap:6px;margin-top:12px;font-size:13px;color:var(--muted)}
.chips span{cursor:pointer;background:var(--primary-soft);color:var(--primary-dark);padding:3px 10px;border-radius:999px;font-weight:600;transition:.15s;border:1px solid transparent}
.chips span:hover{background:#bfdbfe}
.seg{display:flex;gap:12px;flex-wrap:wrap;font-size:14px;margin-bottom:8px}
.seg label{display:inline-flex;align-items:center;gap:5px;cursor:pointer}

/* ---------- 标签页 ---------- */
.tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}
.tab{border:1px solid var(--border);background:#fff;color:var(--muted);padding:7px 15px;border-radius:999px;
  cursor:pointer;font-weight:600;transition:.16s;font-size:14px}
.tab:hover{color:var(--primary);border-color:#bfdbfe}
.tab.active{background:var(--primary);color:#fff;border-color:var(--primary)}
.panel{display:none}
.panel.active{display:block;animation:fadeIn .22s ease}
@keyframes fadeIn{from{opacity:0;transform:translateY(4px)}to{opacity:1;transform:none}}

/* ---------- 表格 ---------- */
.table{width:100%;border-collapse:collapse;font-size:14px}
.table th,.table td{padding:8px 10px;border-bottom:1px solid var(--border);text-align:left;vertical-align:top}
.table th{color:var(--muted);font-weight:600;font-size:13px}
.table tr:last-child td{border-bottom:none}
.table-responsive{overflow-x:auto}
.text-center{text-align:center}
.text-end{text-align:right}
.text-nowrap{white-space:nowrap}

/* ---------- 实验室通用 ---------- */
.stage{background:#f8fafc;border:1px solid var(--border);border-radius:var(--radius);
  padding:14px;margin:10px 0;overflow-x:auto}
.courseware-frame{display:block;width:100%;height:620px;border:1px solid #bfdbfe;border-radius:10px;background:#fff;margin-top:12px}
.node{display:inline-flex;flex-direction:column;align-items:center;gap:2px;background:#fff;border:2px solid var(--primary);
  color:var(--primary-dark);border-radius:10px;padding:8px 12px;font-size:13px;font-weight:700;min-width:72px;
  transition:.2s;position:relative}
.node.pc{border-color:#0ea5e9;background:#f0f9ff;color:#0369a1}
.node.switch{border-color:var(--purple);background:var(--purple-soft);color:var(--purple)}
.node.router{border-color:var(--warn);background:var(--warn-soft);color:var(--warn)}
.node.server{border-color:var(--ok);background:var(--ok-soft);color:var(--ok)}
.node.active{box-shadow:0 0 0 4px rgba(37,99,235,.25);transform:scale(1.06)}
.node .n{font-size:11px;color:var(--muted);font-weight:500}
.net{display:flex;flex-wrap:wrap;gap:14px;align-items:center;justify-content:center;padding:8px 0}
.net .wire{color:var(--muted);font-size:18px;letter-spacing:-3px}
.log-box{background:#0f172a;color:#a5f3fc;border-radius:var(--radius-sm);padding:10px 12px;font-family:Consolas,"Courier New",monospace;
  font-size:13px;line-height:1.7;max-height:210px;overflow-y:auto;margin-top:10px}
.log-line{padding:1px 0;border-bottom:1px dashed rgba(148,163,184,.18)}
.log-line b{color:#fbbf24}
.log-line.ok{color:#86efac}
.log-line.warn{color:#fde68a}
.log-line.err{color:#fca5a5}
.layer-stack{display:flex;flex-direction:column;gap:4px;margin:8px 0}
.layer{border:1px solid var(--border);border-left:5px solid var(--primary);background:#fff;border-radius:8px;
  padding:7px 12px;cursor:pointer;transition:.15s;font-size:14px}
.layer:hover{background:var(--primary-soft)}
.layer.active{border-left-color:var(--ok);background:var(--ok-soft)}
.layer .ln{font-weight:700;color:#0f172a}
.layer .ld{color:var(--muted);font-size:13px}
.flow-step{border-left:3px solid var(--primary);background:#fff;border-radius:8px;padding:9px 12px;margin:7px 0;
  box-shadow:var(--shadow);font-size:14px;animation:fadeIn .3s ease}
.flow-step b{color:var(--primary-dark)}
.flow-step .who{display:inline-block;font-size:12px;font-weight:700;padding:1px 8px;border-radius:999px;margin-right:6px}
.who.c{background:#e0f2fe;color:#0369a1}
.who.s{background:var(--ok-soft);color:var(--ok)}
.who.r{background:var(--warn-soft);color:var(--warn)}
.who.d{background:var(--purple-soft);color:var(--purple)}
.pdu-chip{display:inline-block;background:var(--primary-soft);color:var(--primary-dark);border-radius:8px;
  padding:3px 10px;font-size:13px;font-weight:700;margin:2px}
.kbd{display:inline-block;background:#f1f5f9;border:1px solid #cbd5e1;border-bottom-width:2px;border-radius:6px;padding:0 7px;font-size:12px;font-family:Consolas,monospace}

/* ---------- 闯关游戏通用 ---------- */
.game-head{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-bottom:12px}
.game-head .q-meta{font-size:13px;color:var(--muted)}
.qbox{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px 18px;margin-bottom:14px}
.q-text{font-size:17px;font-weight:700;color:#0f172a;margin-bottom:14px;line-height:1.5}
.q-text .mono{font-family:Consolas,"Courier New",monospace;background:var(--primary-soft);padding:1px 8px;border-radius:6px;font-size:16px}
.options{display:grid;gap:9px}
.option{display:flex;align-items:center;gap:10px;border:2px solid var(--border);background:#fff;border-radius:var(--radius-sm);
  padding:11px 14px;cursor:pointer;font-size:15px;transition:.14s;text-align:left;line-height:1.45}
.option:hover{border-color:#93c5fd;background:#eff6ff}
.option .key{flex:0 0 26px;height:26px;border-radius:50%;background:#f1f5f9;color:var(--muted);font-weight:700;
  display:flex;align-items:center;justify-content:center;font-size:13px}
.option.correct{border-color:var(--ok);background:var(--ok-soft);color:var(--ok)}
.option.correct .key{background:var(--ok);color:#fff}
.option.wrong{border-color:var(--err);background:var(--err-soft);color:var(--err)}
.option.wrong .key{background:var(--err);color:#fff}
.option:disabled{cursor:default;opacity:.85}
.feedback{margin-top:12px;padding:10px 14px;border-radius:var(--radius-sm);font-size:14px;display:none;animation:fadeIn .25s ease}
.feedback.show{display:block}
.feedback.ok{background:var(--ok-soft);color:var(--ok);border:1px solid #86efac}
.feedback.err{background:var(--err-soft);color:var(--err);border:1px solid #fecaca}
.feedback .why{color:var(--muted);margin-top:4px}
.progress{height:10px;background:#e2e8f0;border-radius:5px;overflow:hidden;flex:1 1 120px}
.progress i{display:block;height:100%;background:linear-gradient(90deg,#3b82f6,#06b6d4);border-radius:5px;transition:width .35s}
.timer{font-variant-numeric:tabular-nums;font-weight:700;color:var(--warn);min-width:56px;text-align:center}
.stars{display:inline-flex;gap:2px;font-size:22px}
.stars .star{opacity:.25;transition:.2s}
.stars .star.on{opacity:1}
.result-panel{text-align:center;padding:26px 18px}
.result-panel h3{font-size:22px;margin:8px 0 4px}
.result-panel .score-big{font-size:42px;font-weight:800;color:var(--primary);line-height:1.1}
.sort-btns{display:flex;flex-wrap:wrap;gap:8px}
.sort-btns .btn{font-size:13px}
.bit-row{display:flex;flex-wrap:wrap;gap:4px;justify-content:center;margin:10px 0}
.bit{width:46px;height:42px;border:1px solid var(--border);border-radius:8px;background:#fff;display:flex;flex-direction:column;
  align-items:center;justify-content:center;font-size:15px;font-weight:700;line-height:1.2;white-space:nowrap;transition:.15s}
.bit b{font-size:11px;color:var(--muted);font-weight:600}
.bit.on{background:var(--primary-soft);border-color:var(--primary);color:var(--primary-dark)}

/* ---------- 提示/页脚 ---------- */
.toast{position:fixed;left:50%;bottom:26px;transform:translateX(-50%) translateY(20px);background:#0f172a;color:#fff;
  padding:10px 20px;border-radius:999px;font-size:14px;opacity:0;pointer-events:none;transition:.25s;z-index:99;box-shadow:var(--shadow-lg)}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* ---------- 学号姓名登记 ---------- */
#regMask{position:fixed;inset:0;background:linear-gradient(135deg,#172554 0%,#1e40af 55%,#0ea5e9 100%);
  z-index:80;display:flex;align-items:center;justify-content:center;padding:16px}
#regMask .reg-card{background:#fff;border-radius:18px;box-shadow:var(--shadow-lg);max-width:430px;width:100%;padding:28px 24px;text-align:center}
#regMask .reg-network-mark{width:42px;height:42px;margin:0 auto 8px;color:#2563eb}
#regMask .reg-network-mark svg{display:block;width:100%;height:100%;fill:#dbeafe;stroke:currentColor;stroke-width:3.2;stroke-linecap:round;stroke-linejoin:round}
#regMask .reg-card h2{margin:0 0 6px;color:#0f172a;font-size:20px}
#regMask .reg-card p{color:var(--muted);font-size:13px;margin:0 0 14px;line-height:1.6}
#regMask .reg-card input{text-align:center;font-size:16px}
#regMask .reg-card .err{color:var(--err);font-size:13px;min-height:20px;margin:8px 0 2px}
#regMask .reg-card .tip{margin-top:12px;font-size:12px;color:var(--muted)}

/* ---------- 我的成绩 ---------- */
#reportMask{position:fixed;inset:0;background:rgba(15,23,42,.55);z-index:75;display:flex;align-items:center;justify-content:center;padding:16px}
#reportMask .report-card{background:#fff;border-radius:16px;box-shadow:var(--shadow-lg);max-width:580px;width:100%;max-height:88vh;overflow-y:auto;padding:22px 20px}
#reportMask .report-card h2{margin:0 0 4px;color:#0f172a}
#reportMask .report-card h3{margin:14px 0 6px;font-size:15px;color:#0f172a}
.site-footer{margin-top:34px;padding:18px 14px;text-align:center;color:var(--muted);font-size:13px;border-top:1px solid var(--border)}
.site-footer .flinks{display:flex;flex-wrap:wrap;gap:8px 14px;justify-content:center;margin-bottom:8px}

@media (max-width:560px){
  body{font-size:14px}
  .hero h1{font-size:21px}
  .brand-title{font-size:15px}
  .school-brand{width:150px;height:34px}
  .school-brand-fallback{width:150px;height:34px}.school-brand-fallback b{font-size:13px}.school-brand-fallback small{font-size:8px;margin-top:2px}
  .q-text{font-size:15px}
  .courseware-frame{height:520px}
  .node{min-width:60px;padding:6px 8px;font-size:12px}
}
@media print{
  .site-header,.toast,.site-footer{display:none}
  body{background:#fff}
  .card{box-shadow:none}
}