:root{--bg:#F4F7FA;--card:#FFFFFF;--card2:#f5f7fa;--line:rgba(0,0,0,.08);--text:#1D2129;--muted:#86909C;--blue:#1677FF;--green:#52C41A;--red:#ef4444;--yellow:#f59e0b;--purple:#722ED1;--shadow:0 2px 8px rgba(0,0,0,.05)}html.dark{--bg:#0f172a;--card:#1e293b;--card2:#1a2332;--line:rgba(255,255,255,.1);--text:#e2e8f0;--muted:#94a3b8;--blue:#60a5fa;--green:#34d399;--red:#fb7185;--yellow:#fbbf24;--purple:#a78bfa;--shadow:0 2px 12px rgba(0,0,0,.3)}html.dark .logo{background:#1e293b;border-color:rgba(255,255,255,.15)}html.dark .tabs{border-bottom-color:rgba(255,255,255,.1)}html.dark .card,.html.dark .hero{border-color:rgba(255,255,255,.08)}html.dark .item{border-color:rgba(255,255,255,.08)}html.dark .q{border-color:rgba(255,255,255,.08)}html.dark input,html.dark select,html.dark textarea{background:#0f172a;border-color:rgba(255,255,255,.15);color:#e2e8f0}html.dark .btn,html.dark button{background:#1e293b}html.dark button.primary,html.dark .btn.primary{background:var(--blue)}html.dark button.green,html.dark .btn.green{background:rgba(96,165,250,.15);color:#93c5fd}html.dark .pill{background:rgba(96,165,250,.15);color:#93c5fd}html.dark .pill.green{background:#064e3b;color:#6ee7b7}html.dark .pill.red{background:#450a0a;color:#fca5a5}html.dark .pill.yellow{background:#451a03;color:#fcd34d}html.dark .pill.purple{background:#2e1065;color:#c4b5fd}html.dark .option{background:#0f172a}html.dark .option.selected{background:rgba(96,165,250,.15)}html.dark .report{background:#0f172a}html.dark .hero{background:#1e293b}html.dark .hero p{color:#94a3b8}html.dark .notice{background:#451a03;border-color:#92400e;color:#fcd34d}*{box-sizing:border-box}body{margin:0;background:var(--bg);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;color:var(--text)}.app{max-width:1280px;margin:0 auto;padding:24px}.top{display:flex;justify-content:space-between;gap:16px;align-items:flex-start;margin-bottom:18px}.brand{display:flex;gap:12px;align-items:center}.logo{width:54px;height:54px;border-radius:12px;background:#fff;display:grid;place-items:center;font-size:26px;font-weight:950;color:var(--blue);box-shadow:0 2px 8px rgba(0,0,0,.06);border:1px solid #e8ecf0}h1{font-size:26px;margin:0}.sub{font-size:14px;color:var(--muted);line-height:1.6;margin-top:4px}.tabs{display:flex;gap:0;flex-wrap:nowrap;background:transparent;padding:0;border:0;border-radius:0;margin-bottom:18px;box-shadow:none;border-bottom:1px solid #e8ecf0}.tab{border:0;background:transparent;color:var(--muted);border-radius:0;padding:12px 18px;font-weight:600;cursor:pointer;position:relative;white-space:nowrap}.tab.active{color:var(--blue);background:transparent}.tab.active::after{content:'';position:absolute;bottom:0;left:10px;right:10px;height:2px;background:var(--blue);border-radius:1px 1px 0 0}.grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.card,.hero{background:var(--card);border:1px solid #e8ecf0;border-radius:12px;padding:24px;box-shadow:var(--shadow);backdrop-filter:none}.hero{background:var(--card);min-height:260px}.hero h2{font-size:34px;line-height:1.15;margin:0 0 14px}.hero p{color:var(--muted);line-height:1.85}.pill{display:inline-flex;align-items:center;gap:6px;border-radius:6px;padding:4px 8px;background:#E6F4FF;color:var(--blue);font-size:12px;font-weight:600;margin:3px}.pill.green{background:#F6FFED;color:#389E0D}.pill.red{background:#fff1f0;color:#cf1322}.pill.yellow{background:#fffbe6;color:#d48806}.pill.purple{background:#f9f0ff;color:#531dab}.muted{color:var(--muted)}.small{font-size:12px}.btn,button{border:0;border-radius:10px;padding:10px 16px;font-weight:600;cursor:pointer;background:#f5f7fa;color:var(--text)}button.primary,.btn.primary{background:var(--blue);color:white}button.green,.btn.green{background:#E6F4FF;color:var(--blue)}button.ghost,.btn.ghost{background:transparent;border:1px solid var(--line);color:var(--muted)}button.ghost:hover{background:var(--card2)}button:disabled{opacity:.45;cursor:not-allowed}.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}label{display:block;font-size:13px;color:var(--muted);font-weight:600;margin:12px 0 7px}input,select,textarea{width:100%;border:1px solid var(--line);border-radius:14px;background:#fff;color:var(--text);padding:12px 13px;outline:none;font-size:15px}textarea{min-height:120px;resize:vertical}.login{max-width:560px;margin:8vh auto}.list{display:grid;gap:10px}.item{border:1px solid #e8ecf0;border-radius:12px;padding:14px;background:var(--card)}.q{border:1px solid #e8ecf0;border-radius:12px;padding:16px;background:var(--card);margin-bottom:12px}.q b{line-height:1.7}.option{display:block;border:1px solid var(--line);border-radius:14px;padding:11px 12px;background:var(--card2);margin-top:8px;cursor:pointer}.option.selected{border-color:var(--blue);background:var(--card2)}html.dark .option.selected{background:rgba(96,165,250,.15)}html.dark .tab.active::after{background:var(--blue)}html.dark .code-brand .logo{background:#1e293b;border-color:rgba(255,255,255,.15)}html.dark .theme-toggle{border-color:rgba(255,255,255,.15)}html.dark .btn.ghost,html.dark button.ghost{border-color:rgba(255,255,255,.1)}html.dark .hero p{color:#94a3b8}html.dark .notice{background:#451a03;border-color:#92400e;color:#fcd34d}html.dark .option.correct{background:#064e3b;border-color:#34d399;color:#6ee7b7}html.dark .option.wrong{background:#450a0a;border-color:#fb7185;color:#fca5a5}html.dark .code-input{background:#0f172a}.report{white-space:pre-wrap;line-height:1.85;background:var(--card);border:1px solid var(--line);border-radius:18px;padding:18px;color:var(--text)}.option.correct{border-color:var(--green);background:#d1fae5}.option.wrong{border-color:var(--red);background:#fce7f3}
.metric{background:var(--card);border:1px solid var(--line);border-radius:20px;padding:18px}.metric b{font-size:30px}.notice{border:1px solid #fbbf24;background:#fffbeb;color:#92400e;border-radius:16px;padding:12px;line-height:1.7}.hidden{display:none!important}@media(max-width:900px){.grid,.grid3{grid-template-columns:1fr}.top{flex-direction:column}.hero h2{font-size:28px}}

/* ─── AI Lab 风格登录界面 ─── */
.code-login-wrap{min-height:100vh;display:grid;place-items:center;padding:24px;position:relative;overflow:hidden}
.code-login-wrap::before{content:'';position:fixed;top:-40%;left:-20%;width:70%;height:80%;background:radial-gradient(ellipse at center,rgba(96,165,250,0.08) 0%,transparent 70%);pointer-events:none}
.code-login-wrap::after{content:'';position:fixed;bottom:-30%;right:-10%;width:60%;height:60%;background:radial-gradient(ellipse at center,rgba(52,211,153,0.06) 0%,transparent 70%);pointer-events:none}
.code-login-card{width:min(440px,100%);background:rgba(255,255,255,0.04);border:1px solid rgba(255,255,255,0.10);border-radius:24px;padding:40px 36px;backdrop-filter:blur(24px);-webkit-backdrop-filter:blur(24px);box-shadow:0 8px 32px rgba(0,0,0,0.45);text-align:center;position:relative}
.code-label{display:block;text-align:left;font-size:13px;color:rgba(255,255,255,0.60);font-weight:500;margin:28px 0 10px;letter-spacing:0.3px}
.code-input{width:100%;height:60px;text-align:center;font-size:30px;font-weight:800;letter-spacing:12px;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;background:rgba(255,255,255,0.05);border:1px solid rgba(255,255,255,0.10);border-radius:16px;color:#fff;outline:none;transition:border-color .2s,box-shadow .2s}
.code-input:focus{border-color:rgba(96,165,250,0.4);box-shadow:0 0 0 3px rgba(96,165,250,0.12)}
.code-input::placeholder{font-size:15px;letter-spacing:1px;font-weight:600;color:rgba(255,255,255,0.35)}
.code-enter{width:100%;height:50px;margin-top:16px;font-size:16px;font-weight:600;border:0;border-radius:14px;cursor:pointer;background:linear-gradient(135deg,rgba(96,165,250,0.25),rgba(96,165,250,0.12));color:#60a5fa;border:1px solid rgba(96,165,250,0.2);transition:all .2s}
.code-enter:hover{background:linear-gradient(135deg,rgba(96,165,250,0.35),rgba(96,165,250,0.18));border-color:rgba(96,165,250,0.35)}
#loginMsg{margin-top:12px}
#loginMsg .notice{font-size:13px;padding:10px 14px;margin:0}

/* ─── 主题切换（保留）─── */
.theme-toggle{position:fixed;bottom:20px;left:20px;z-index:999;width:36px;height:36px;border-radius:50%;background:var(--card);border:1px solid var(--line);box-shadow:var(--shadow);display:grid;place-items:center;cursor:pointer;font-size:16px;padding:0;color:var(--text)}.theme-toggle:hover{background:var(--card2)}html.dark .code-input::placeholder{color:#64748b}
.code-brand{justify-content:center;text-align:left;margin-bottom:24px}
.code-brand .logo{width:62px;height:62px;border-radius:22px;background:linear-gradient(135deg,rgba(255,255,255,0.10),rgba(255,255,255,0.03));border:1px solid rgba(255,255,255,0.10);font-size:28px;color:#60a5fa}