:root{color:#202827;font-synthesis:none;text-rendering:optimizelegibility;--ink:#202827;--muted:#697572;--line:#d8e0de;--surface:#fff;--accent:#087f75;--accent-dark:#06675f;--warning:#d97706;--danger:#bd3b32;letter-spacing:0;background:#f4f7f6;font-family:Inter,PingFang SC,Microsoft YaHei,system-ui,sans-serif}*{box-sizing:border-box}body{background:#f4f7f6;min-width:320px;min-height:100vh;margin:0}button,input{font:inherit;letter-spacing:0}button,a{-webkit-tap-highlight-color:transparent}a{color:var(--accent);text-decoration:none}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.58}h1,h2,p{margin-top:0}.app-shell{min-height:100vh}.app-header{color:#fff;background:#202827;justify-content:space-between;align-items:center;height:64px;padding:0 max(24px,50vw - 560px);display:flex}.brand{color:#fff;align-items:baseline;gap:10px;font-weight:700;display:flex}.brand small{color:#9db3af;font-weight:500}.student-account{align-items:center;gap:18px;font-size:14px;display:flex}.student-account button{color:#dce7e4;background:0 0;border:0;padding:8px}.workspace{width:min(1120px,100% - 40px);margin:0 auto;padding:42px 0 72px}.page-heading{justify-content:space-between;align-items:flex-end;gap:20px;min-height:74px;margin-bottom:30px;display:flex}.page-heading h1{margin:5px 0 0;font-size:30px;line-height:1.2}.eyebrow{color:var(--accent);font-size:13px;font-weight:700}.server-time{color:var(--muted);font-size:13px}.primary-button,.warning-button,.secondary-button{border:1px solid #0000;border-radius:5px;justify-content:center;align-items:center;min-height:44px;padding:0 20px;font-weight:650;display:inline-flex}.primary-button{color:#fff;background:var(--accent)}.primary-button:hover{background:var(--accent-dark)}.primary-button.compact{min-width:112px}.warning-button{color:#fff;background:var(--warning)}.secondary-button{color:var(--ink);border-color:var(--line);background:#fff}.form-error{color:var(--danger);font-size:14px}.auth-page{background:#202827;place-items:center;min-height:100vh;padding:32px 20px;display:grid}.auth-panel{border:1px solid var(--line);background:#fff;border-radius:6px;width:min(430px,100%);padding:42px;box-shadow:0 20px 50px #1826241f}.auth-brand{color:var(--accent);margin-bottom:44px;font-size:14px;font-weight:750}.auth-panel h1{margin-bottom:10px;font-size:30px}.auth-intro{color:var(--muted);margin-bottom:28px;line-height:1.65}.auth-form{gap:20px;display:grid}.auth-form label{gap:8px;font-size:14px;font-weight:650;display:grid}.auth-form input{width:100%;height:46px;color:var(--ink);background:#fff;border:1px solid #bdc9c6;border-radius:4px;outline:0;padding:0 13px}.auth-form input:focus{border-color:var(--accent);box-shadow:0 0 0 3px #087f751f}.auth-switch{color:var(--muted);text-align:center;margin:26px 0 0;font-size:14px}.success-notice{color:#06675f;border-left:3px solid var(--accent);background:#e9f6f3;margin:18px 0 24px;padding:12px 14px;font-size:14px}.tabs{border-bottom:1px solid var(--line);gap:28px;min-height:47px;display:flex}.tabs button{min-width:92px;color:var(--muted);background:0 0;border:0;border-bottom:2px solid #0000;padding:0 4px 14px}.tabs button[aria-selected=true]{color:var(--accent);border-color:var(--accent);font-weight:700}.tabs span{min-width:20px;color:inherit;margin-left:5px;font-size:12px;display:inline-block}.exam-rows{border-bottom:1px solid var(--line)}.exam-row{border-top:1px solid var(--line);grid-template-columns:90px 1fr auto;align-items:center;gap:20px;min-height:108px;padding:20px 6px;display:grid}.exam-row:first-child{border-top:0}.exam-date{border-right:1px solid var(--line);align-content:center;min-height:55px;display:grid}.exam-date strong{font-size:17px}.exam-date span{color:var(--muted);font-size:13px}.exam-main h2{margin-bottom:8px;font-size:18px}.exam-main p,.row-status{color:var(--muted);margin:0;font-size:13px}.empty-state{min-height:300px;color:var(--muted);text-align:center;place-content:center;gap:14px;display:grid}.attempt-page{background:#f7f9f8;min-height:100vh;padding-bottom:88px}.attempt-header{color:#fff;background:#202827;justify-content:space-between;align-items:center;gap:20px;height:76px;padding:0 max(24px,50vw - 590px);display:flex}.attempt-header h1{text-overflow:ellipsis;white-space:nowrap;max-width:68vw;margin:3px 0 0;font-size:19px;overflow:hidden}.exam-timer{text-align:right;font-variant-numeric:tabular-nums;grid-template-columns:1fr;align-content:center;width:168px;height:50px;display:grid}.exam-timer span{color:#9db3af;font-size:11px}.exam-timer strong{font-size:21px}.exam-timer.is-warning strong{color:#ffb04a}.attempt-layout{grid-template-columns:250px minmax(0,1fr);gap:28px;width:min(1180px,100% - 40px);min-height:calc(100vh - 164px);margin:0 auto;padding:28px 0;display:grid}.navigator-panel{border-right:1px solid var(--line);padding-right:26px}.navigator-summary{align-items:baseline;gap:5px;height:48px;margin-bottom:18px;display:flex}.navigator-summary strong{color:var(--accent);font-size:28px}.navigator-summary span{color:var(--muted);font-size:13px}.question-nav{grid-template-columns:repeat(5,36px);gap:8px;display:grid}.question-nav button{width:36px;height:36px;color:var(--muted);background:#fff;border:1px solid #cbd5d2;border-radius:4px;padding:0}.question-nav button.answered{color:#086d64;background:#e5f4f1;border-color:#7dbeb7}.question-nav button.current{color:#fff;border-color:var(--accent);background:var(--accent)}.navigator-legend{color:var(--muted);gap:18px;margin-top:20px;font-size:12px;display:flex}.navigator-legend span{align-items:center;gap:5px;display:flex}.navigator-legend i{background:#fff;border:1px solid #cbd5d2;width:11px;height:11px}.navigator-legend .answered-dot{background:#e5f4f1;border-color:#7dbeb7}.question-workspace{min-width:0;padding:12px 28px 40px}.question-meta{min-height:28px;color:var(--muted);justify-content:space-between;gap:18px;font-size:13px;display:flex}.question-workspace h2{min-height:62px;margin:22px 0 26px;font-size:22px;line-height:1.55}.option-list{gap:12px;display:grid}.option-list button{min-height:56px;color:var(--ink);text-align:left;border:1px solid var(--line);background:#fff;border-radius:5px;grid-template-columns:34px 1fr;align-items:center;gap:10px;padding:10px 16px;display:grid}.option-list button:hover{border-color:#8bada8}.option-list button.selected{border-color:var(--accent);box-shadow:inset 3px 0 var(--accent);background:#edf8f6}.option-label{border:1px solid #bdc9c6;border-radius:50%;place-items:center;width:30px;height:30px;font-weight:700;display:grid}.selected .option-label{color:#fff;border-color:var(--accent);background:var(--accent)}.sync-state{min-height:20px;color:var(--muted);text-align:right;margin:18px 0 0;font-size:12px}.attempt-actions{z-index:4;border-top:1px solid var(--line);background:#fffffff5;justify-content:flex-end;align-items:center;gap:12px;width:100%;height:72px;padding:0 max(24px,50vw - 590px);display:flex;position:fixed;bottom:0;left:0}.result-pending{text-align:center;place-content:center;justify-items:center;min-height:380px;display:grid}.result-pending h2{margin:18px 0 8px}.result-pending p{color:var(--muted)}.result-pending strong{color:var(--accent)}.success-mark{color:#fff;background:var(--accent);border-radius:50%;place-items:center;width:58px;height:58px;font-size:28px;display:grid}.score-summary{border-block:1px solid var(--line);background:#fff;grid-template-columns:repeat(3,1fr);min-height:150px;display:grid}.score-summary>div{text-align:center;border-right:1px solid var(--line);place-content:center;gap:9px;display:grid}.score-summary>div:last-child{border-right:0}.score-summary span{color:var(--muted);font-size:13px}.score-summary strong{font-size:28px}.score-summary small{color:var(--muted);font-size:14px}.passed{color:var(--accent)}.failed{color:var(--danger)}.score-details{margin-top:34px}.score-details h2{font-size:20px}.score-details article{border-top:1px solid var(--line);padding:22px 4px}.score-item-heading{justify-content:space-between;margin-bottom:14px;display:flex}.score-details p{color:var(--muted);margin:7px 0;font-size:14px}.score-details .analysis{color:var(--ink);border-left:2px solid #9ebdb8;margin-top:13px;padding-left:12px;line-height:1.65}@media (width<=700px){.app-header{height:56px;padding:0 16px}.student-account span{display:none}.workspace{width:calc(100% - 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