:root{--exam-bg: #f4f5f7;--exam-panel: #ffffff;--exam-text: #1b2230;--exam-muted: #647084;--exam-muted-border: #d8dde6;--exam-accent: #2563eb;--exam-accent-emphasis: #1d4ed8;--exam-danger: #dc2626;--exam-danger-bg: #fef2f2;--exam-warn-bg: #fffbeb;--exam-warn-text: #92400e;--exam-success: #15803d;--exam-success-bg: #f0fdf4;--exam-focus-ring: #93c5fd;--exam-editor-bg: #fbfcfe;--exam-editor-text: #1b2230;--exam-editor-gutter-bg: #f1f4f9;--exam-editor-gutter-text: #8a94a6;--exam-editor-active-line: #eef3fb;--exam-editor-selection: #dbeafe;--exam-editor-match: #fde68a}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;background:var(--exam-bg);color:var(--exam-text);font-size:15px;line-height:1.6}h1{font-size:22px;margin:0 0 8px}h2{font-size:17px;margin:0 0 8px}p{margin:8px 0}.muted{color:var(--exam-muted)}.boot-splash{display:flex;min-height:60vh;align-items:center;justify-content:center;color:var(--exam-muted);font-size:16px}.btn{appearance:none;border:1px solid var(--exam-muted-border);background:var(--exam-panel);color:var(--exam-text);border-radius:6px;padding:6px 14px;font-size:14px;cursor:pointer;text-decoration:none;display:inline-block}.btn:hover:not(:disabled){border-color:var(--exam-accent);color:var(--exam-accent)}.btn:disabled{opacity:.55;cursor:not-allowed}.btn-primary{background:var(--exam-accent);border-color:var(--exam-accent);color:#fff}.btn-primary:hover:not(:disabled){background:var(--exam-accent-emphasis);color:#fff}.btn-danger{color:var(--exam-danger);border-color:var(--exam-danger)}.btn-danger:hover:not(:disabled){color:#fff;background:var(--exam-danger);border-color:var(--exam-danger)}.btn-large{font-size:17px;padding:12px 36px}.text-input,textarea,select{width:100%;border:1px solid var(--exam-muted-border);border-radius:6px;padding:7px 10px;font-size:14px;font-family:inherit;background:var(--exam-panel);color:var(--exam-text)}textarea{min-height:72px;resize:vertical;font-family:ui-monospace,SFMono-Regular,Consolas,monospace}.text-input:focus,textarea:focus,select:focus{outline:2px solid var(--exam-focus-ring);outline-offset:1px;border-color:var(--exam-accent)}.form-field{display:flex;flex-direction:column;gap:4px;margin:10px 0}.form-field>span{font-size:13px;color:var(--exam-muted)}.checkbox-line{display:flex;align-items:center;gap:6px;margin:6px 0;cursor:pointer}.flash-danger,.flash-warn,.flash-success{border-radius:6px;padding:10px 14px;margin:10px 0}.flash-danger{background:var(--exam-danger-bg);color:var(--exam-danger)}.flash-warn{background:var(--exam-warn-bg);color:var(--exam-warn-text)}.flash-success{background:var(--exam-success-bg);color:var(--exam-success)}.card{background:var(--exam-panel);border:1px solid var(--exam-muted-border);border-radius:8px;padding:14px 16px;margin:12px 0}.pill{display:inline-block;border-radius:999px;padding:1px 10px;font-size:12px;background:#eef1f6;color:var(--exam-muted);margin-left:6px}.pill-success{background:var(--exam-success-bg);color:var(--exam-success)}.pill-danger{background:var(--exam-danger-bg);color:var(--exam-danger)}.markdown p{margin:6px 0}.markdown pre{background:#f6f8fa;border:1px solid var(--exam-muted-border);border-radius:6px;padding:10px 12px;overflow-x:auto}.markdown code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:13px}.markdown table{border-collapse:collapse}.markdown th,.markdown td{border:1px solid var(--exam-muted-border);padding:4px 10px}.exam-stage{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px}.exam-panel{background:var(--exam-panel);border:1px solid var(--exam-muted-border);border-radius:12px;padding:36px 40px;max-width:640px;width:100%;box-shadow:0 8px 30px #0f172a0f;text-align:center}.countdown-display{font-size:56px;font-weight:700;font-variant-numeric:tabular-nums;letter-spacing:2px;margin:20px 0;color:var(--exam-accent-emphasis)}.exam-facts{display:grid;grid-template-columns:1fr 1fr;gap:10px 24px;text-align:left;margin:18px 0}.exam-facts dt{font-size:12px;color:var(--exam-muted)}.exam-facts dd{margin:0;font-weight:600}.exam-panel .instructions{text-align:left}.ready-panel .btn-large,.finished-panel .btn,.error-panel .btn{margin-top:16px}.exam-running{min-height:100vh;display:flex;flex-direction:column}.exam-topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;gap:18px;background:var(--exam-panel);border-bottom:1px solid var(--exam-muted-border);padding:10px 20px}.exam-topbar-title{font-size:16px}.exam-countdown{font-variant-numeric:tabular-nums;font-weight:700;font-size:16px}.exam-countdown.is-urgent{color:var(--exam-danger)}.exam-topbar .muted{margin-left:auto}.violation-banner{background:var(--exam-danger);color:#fff;text-align:center;font-weight:600;padding:8px 16px}.exam-session-layout{display:grid;grid-template-columns:minmax(0,1fr) 220px;gap:20px;padding:20px;max-width:1200px;width:100%;margin:0 auto;align-items:start}.exam-question-list{display:flex;flex-direction:column;gap:18px;min-width:0}.exam-question{background:var(--exam-panel);border:1px solid var(--exam-muted-border);border-radius:10px;padding:18px 20px}.exam-question-heading{display:flex;justify-content:space-between;align-items:baseline;border-bottom:1px solid var(--exam-muted-border);padding-bottom:8px;margin-bottom:12px;font-weight:600}.save-status{font-size:12px;font-weight:400;color:var(--exam-muted)}.save-status--saving{color:var(--exam-accent)}.save-status--conflict{color:var(--exam-danger)}.save-status--unsaved{color:var(--exam-warn-text)}.copy-protected{user-select:none;-webkit-user-select:none}.copy-protected input,.copy-protected textarea,.copy-protected .code-editor{user-select:text;-webkit-user-select:text}.choice-group{display:flex;flex-direction:column;gap:8px;margin-top:10px}.choice-group .checkbox-line{align-items:flex-start}.choice-group .option-label{flex:1}.choice-group .option-label p{margin:0}.exam-answer-sheet{position:fixed;z-index:20;top:76px;right:max(20px,calc((100vw - 1200px)/2 + 20px));width:220px;box-sizing:border-box;background:var(--exam-panel);border:1px solid var(--exam-muted-border);border-radius:10px;box-shadow:0 4px 16px #0f172a1f;padding:14px}.exam-answer-sheet header{display:flex;justify-content:space-between;margin-bottom:10px}.exam-answer-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:6px}.exam-answer-link{display:flex;align-items:center;justify-content:center;height:32px;border:1px solid var(--exam-muted-border);border-radius:6px;text-decoration:none;color:var(--exam-text);font-size:13px}.exam-answer-link.is-complete{background:var(--exam-accent);border-color:var(--exam-accent);color:#fff}.exam-answer-legend{display:flex;gap:14px;margin-top:10px;font-size:12px;color:var(--exam-muted)}.exam-answer-legend i{display:inline-block;width:10px;height:10px;border-radius:3px;border:1px solid var(--exam-muted-border);margin-right:4px}.exam-answer-legend i.is-complete{background:var(--exam-accent);border-color:var(--exam-accent)}.fullscreen-overlay{position:fixed;inset:0;z-index:100;background:#0f172ab8;display:flex;align-items:center;justify-content:center}.fullscreen-overlay-panel{background:var(--exam-panel);border-radius:12px;padding:32px 40px;text-align:center;max-width:420px}.public-samples-heading{margin:14px 0 8px}.public-sample-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:12px}.public-sample-card{border:1px solid var(--exam-muted-border);border-radius:8px;padding:12px;display:flex;flex-direction:column;gap:8px}.public-sample-actions{display:flex;gap:8px}.output-block{background:#f6f8fa;border:1px solid var(--exam-muted-border);border-radius:6px;padding:8px 10px;overflow-x:auto;white-space:pre-wrap;word-break:break-all;font-size:13px}.ide-language{max-width:240px}.code-editor-shell{margin:10px 0}.code-editor{height:340px;border:1px solid var(--exam-muted-border);border-radius:6px;overflow:hidden;background:var(--exam-editor-bg)}.editor-toolbar{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin:8px 0 4px}.editor-toolbar-field{display:flex;gap:6px;align-items:center;font-size:13px;color:var(--exam-muted);white-space:nowrap}.editor-toolbar-hint{margin-left:auto;font-size:12px}.programming-item.focus-mode{position:fixed;inset:0;z-index:60;background:var(--exam-bg);overflow:auto;padding:16px;margin:0}.programming-item.focus-mode .code-editor{height:calc(100vh - 420px);min-height:300px}.manual-run-result .manual-run-summary{display:flex;gap:14px;align-items:baseline}.code-template{background:#f6f8fa;border-radius:6px;padding:10px;overflow-x:auto}.admin-shell{min-height:100vh;display:flex;flex-direction:column}.admin-topbar{display:flex;align-items:center;justify-content:space-between;background:var(--exam-panel);border-bottom:1px solid var(--exam-muted-border);padding:10px 20px}.admin-brand{appearance:none;border:none;background:none;font-size:17px;font-weight:700;cursor:pointer;color:var(--exam-text);padding:4px 0}.admin-topbar>.btn{margin-left:8px;margin-right:auto}.admin-main{flex:1;padding:20px;max-width:1280px;width:100%;margin:0 auto}.stack{display:flex;flex-direction:column;gap:4px}.page-heading{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:12px}.row-actions{display:flex;gap:8px;flex-wrap:wrap}.table-wrap{overflow-x:auto;background:var(--exam-panel);border:1px solid var(--exam-muted-border);border-radius:8px}.data-table{width:100%;border-collapse:collapse;font-size:14px}.data-table th,.data-table td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--exam-muted-border);vertical-align:middle}.data-table th{font-size:12px;color:var(--exam-muted);font-weight:600;white-space:nowrap}.data-table tbody tr:last-child td{border-bottom:none}.row-warning{background:#fff7f7}.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:4px 24px;max-width:860px}.form-field-wide{grid-column:1 / -1}.form-grid .checkbox-line{align-self:end}.form-actions{grid-column:1 / -1;margin-top:8px;display:flex;gap:10px}.items-editor-layout{display:grid;grid-template-columns:minmax(0,5fr) minmax(0,7fr);gap:16px;align-items:start}.bank-panel,.selected-panel{margin:0}.tab-bar{display:flex;gap:6px;margin-bottom:10px}.tab{appearance:none;border:1px solid var(--exam-muted-border);background:var(--exam-panel);border-radius:6px;padding:5px 12px;cursor:pointer;font-size:13px}.tab.is-active{background:var(--exam-accent);border-color:var(--exam-accent);color:#fff}.bank-list,.selected-list{list-style:none;margin:12px 0 0;padding:0;display:flex;flex-direction:column;gap:8px}.bank-row{display:flex;align-items:center;justify-content:space-between;gap:10px;border:1px solid var(--exam-muted-border);border-radius:8px;padding:8px 12px}.bank-row .btn{flex-shrink:0}.panel-heading{display:flex;justify-content:space-between;align-items:baseline}.selected-row{display:flex;align-items:center;gap:10px;border:1px solid var(--exam-muted-border);border-radius:8px;padding:8px 12px}.selected-index{font-weight:700;width:28px;flex-shrink:0}.selected-main{flex:1;min-width:0}.points-field{display:flex;align-items:center;gap:6px}.points-field .text-input{width:72px}.violation-badge{color:var(--exam-danger);font-weight:700;display:inline-flex;align-items:center;gap:5px}.violation-dot{display:inline-block;width:9px;height:9px;border-radius:50%;background:var(--exam-danger);box-shadow:0 0 0 3px #dc26262e}.drawer-backdrop{position:fixed;inset:0;z-index:50;background:#0f172a73;display:flex;justify-content:flex-end}.drawer{background:var(--exam-panel);width:min(480px,92vw);height:100%;overflow-y:auto;padding:18px 20px;box-shadow:-8px 0 30px #0f172a2e}.modal-backdrop{justify-content:center;align-items:center}.modal{background:var(--exam-panel);width:min(1080px,96vw);height:min(880px,94vh);padding:18px 20px;border-radius:8px;box-shadow:0 12px 40px #0f172a4d;display:flex;flex-direction:column;gap:10px}.modal-editor-wrap{flex:1;display:flex}.modal-editor-wrap .scratch-editor-frame{height:100%;min-height:0}.drawer-heading{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}.event-timeline{list-style:none;margin:0;padding:0;display:flex;flex-direction:column}.event-row{display:flex;align-items:baseline;gap:10px;padding:8px 0 8px 14px;border-left:3px solid var(--exam-muted-border)}.event-row--violation{border-left-color:var(--exam-danger)}.event-kind{font-weight:600}.event-detail{font-size:12px;color:var(--exam-muted);word-break:break-all}@media(max-width:900px){.exam-session-layout{grid-template-columns:1fr}.exam-answer-sheet{position:static;order:-1}.items-editor-layout,.form-grid,.exam-facts{grid-template-columns:1fr}}.face-gate-backdrop{position:fixed;inset:0;z-index:80;background:#0f172a8c;display:flex;align-items:center;justify-content:center}.face-gate{background:var(--exam-panel);border-radius:12px;padding:24px;width:min(480px,92vw);display:flex;flex-direction:column;gap:10px}.face-gate h2{margin:0}.face-gate-video{width:100%;aspect-ratio:4 / 3;border-radius:8px;background:#0f172a;object-fit:cover;transform:scaleX(-1)}.face-gate-hint{margin:0;color:var(--exam-muted);min-height:1.5em}.face-gate-hint--ok{color:var(--exam-success)}.face-gate-actions{display:flex;gap:10px;justify-content:flex-end}.face-warning-banner{background:var(--exam-warn-bg);color:var(--exam-warn-text);border:1px solid var(--exam-warn-text);border-radius:6px;padding:8px 14px;margin:8px 0}.event-row--face{border-left-color:var(--exam-warn-text)}.face-monitor-live{position:relative;width:108px;aspect-ratio:4 / 3;border-radius:6px;overflow:hidden;border:1px solid var(--exam-muted-border);background:#0f172a;flex-shrink:0}.face-monitor-live video{width:100%;height:100%;object-fit:cover;transform:scaleX(-1);display:block}.face-monitor-dot{position:absolute;left:4px;bottom:2px;font-size:10px;color:#fff;text-shadow:0 0 4px rgba(0,0,0,.8)}.face-monitor-dot:first-letter{color:var(--exam-danger)}.exam-rules{margin:18px auto 0;max-width:560px;text-align:left}.exam-rules h2{margin:0 0 8px;font-size:16px;text-align:center}.exam-rules ol{margin:0;padding-left:22px;display:flex;flex-direction:column;gap:6px}.exam-rules li{line-height:1.6}.pill-warn{background:var(--exam-warn-bg);color:var(--exam-warn-text)}.scratch-item{display:flex;flex-direction:column;gap:8px}.scratch-editor-wrap{position:relative}.scratch-editor-frame{width:100%;height:70vh;min-height:420px;border:1px solid var(--exam-muted-border);border-radius:8px;background:#fff;display:block}.scratch-editor-overlay{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:#ffffffd9;border-radius:8px;color:var(--exam-muted);pointer-events:none}.scratch-hint{margin:0;font-size:12px}.scratch-grade-cell{display:flex;flex-direction:column;gap:6px;align-items:flex-start;min-width:150px}.scratch-grade-cell .scratch-grade-row{display:flex;gap:6px;align-items:center}.scratch-grade-cell .text-input{width:72px}.programming-split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:20px;align-items:start}.programming-statement-col{min-width:0}.programming-ide-col{min-width:0;display:flex;flex-direction:column;gap:8px}.programming-ide-col .code-editor-shell{flex:1;margin:0}.programming-ide-col .code-editor{height:100%;min-height:460px}.ide-editor-heading{display:flex;justify-content:space-between;align-items:baseline;margin-top:4px}.ide-byte-count{font-size:12px;color:var(--exam-muted)}.ide-byte-count--danger{color:var(--exam-danger)}.public-samples-markdown h3{margin:14px 0 6px;font-size:15px}.public-sample-markdown-code{position:relative;border:1px solid var(--exam-muted-border);border-radius:6px;background:var(--exam-editor-bg)}.public-sample-markdown-code pre{margin:0;padding:10px 12px;overflow-x:auto;font-size:13px;white-space:pre-wrap;word-break:break-all}.public-sample-code-actions{display:flex;gap:8px;padding:6px 12px;border-top:1px solid var(--exam-muted-border)}.verdict-pill{display:inline-block;padding:2px 10px;border-radius:999px;background:var(--exam-success-bg);color:var(--exam-success);font-weight:600;font-size:13px}@media(max-width:900px){.programming-split{grid-template-columns:1fr}}.programming-item.focus-mode .programming-ide-col .code-editor{min-height:calc(100vh - 420px)}