*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--blue:#1a56db;--blue-dark:#1e40af;--blue-light:#eff6ff;--blue-mid:#dbeafe;--green:#16a34a;--green-light:#dcfce7;--red:#dc2626;--red-light:#fef2f2;--orange:#d97706;--orange-light:#fffbeb;--gray-50:#f9fafb;--gray-100:#f3f4f6;--gray-200:#e5e7eb;--gray-300:#d1d5db;--gray-400:#9ca3af;--gray-500:#6b7280;--gray-600:#4b5563;--gray-700:#374151;--gray-800:#1f2937;--gray-900:#111827;--shadow-sm:0 1px 2px #00000014;--shadow:0 4px 12px #0000001a;--shadow-lg:0 10px 30px #00000026;--radius:10px;--radius-sm:6px;--radius-lg:16px;--bg-page:var(--gray-50);--bg-card:#fff;--bg-card-alt:var(--gray-50);--bg-input:var(--gray-50);--text-primary:var(--gray-800);--text-secondary:var(--gray-600);--text-muted:var(--gray-400);--border:var(--gray-200);--border-strong:var(--gray-300);--topbar-bg:var(--gray-900);--topbar-text:#fff;--topbar-brand:#93c5fd}[data-theme=dark]{--blue:#60a5fa;--blue-dark:#93c5fd;--blue-light:#1e3a5f;--blue-mid:#1e3a5f;--green:#4ade80;--green-light:#14532d;--red:#f87171;--red-light:#450a0a;--orange:#fbbf24;--orange-light:#451a03;--gray-50:#0f172a;--gray-100:#1e293b;--gray-200:#334155;--gray-300:#475569;--gray-400:#64748b;--gray-500:#94a3b8;--gray-600:#cbd5e1;--gray-700:#e2e8f0;--gray-800:#f1f5f9;--gray-900:#f8fafc;--shadow-sm:0 1px 2px #0006;--shadow:0 4px 12px #00000080;--shadow-lg:0 10px 30px #0009;--bg-page:#0f172a;--bg-card:#1e293b;--bg-card-alt:#162032;--bg-input:#162032;--text-primary:#f1f5f9;--text-secondary:#cbd5e1;--text-muted:#64748b;--border:#334155;--border-strong:#475569;--topbar-bg:#020617;--topbar-text:#f1f5f9;--topbar-brand:#93c5fd}html{font-size:16px}body{background:var(--bg-page);color:var(--text-primary);min-height:100vh;font-family:Segoe UI,-apple-system,BlinkMacSystemFont,Helvetica Neue,Arial,sans-serif;font-size:1rem;line-height:1.65;transition:background .25s,color .25s}.dark-toggle{color:#fff;cursor:pointer;white-space:nowrap;background:#ffffff1a;border:1px solid #fff3;border-radius:6px;padding:6px 14px;font-size:13px;font-weight:600;transition:background .2s}.dark-toggle:hover{background:#fff3}.start-dark-toggle{z-index:200;position:fixed;top:16px;right:16px}.start-dark-toggle .dark-toggle{background:#00000059;border:1px solid #ffffff40}.start-dark-toggle .dark-toggle:hover{background:#0000008c}.result-header{position:relative}.result-header-toggle{position:absolute;top:50%;right:20px;transform:translateY(-50%)}.app{min-height:100vh}.start-screen{background:linear-gradient(135deg,#0f2157 0%,#1a56db 50%,#2563eb 100%);justify-content:center;align-items:center;min-height:100vh;padding:32px 16px;display:flex}[data-theme=dark] .start-screen{background:linear-gradient(135deg,#020617 0%,#0f172a 60%,#1e293b 100%)}.start-card{background:var(--bg-card);border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);border:1px solid var(--border);width:100%;max-width:760px;padding:48px 48px 40px}.start-header{text-align:center;margin-bottom:36px}.istqb-logo{margin-bottom:16px}.logo-text{color:var(--blue);letter-spacing:-.5px;font-size:32px;font-weight:800}.logo-text sup{font-size:16px}.start-title{color:var(--text-primary);margin-bottom:8px;font-size:30px;font-weight:700;line-height:1.3}.start-subtitle{color:var(--text-muted);font-size:17px;font-weight:500}.exam-info-grid{grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:28px;display:grid}.info-item{background:var(--blue-light);border:1px solid var(--blue-mid);border-radius:var(--radius);align-items:center;gap:10px;padding:16px 12px;transition:background .25s,border-color .25s;display:flex}.info-icon{font-size:22px}.info-value{color:var(--blue-dark);font-size:22px;font-weight:700}.info-label{color:var(--gray-500);text-transform:uppercase;letter-spacing:.5px;font-size:13px;font-weight:500}.instructions-box{background:var(--bg-card-alt);border:1px solid var(--border);border-radius:var(--radius);margin-bottom:24px;padding:20px 24px}.instructions-box h3{color:var(--text-secondary);text-transform:uppercase;letter-spacing:.5px;margin-bottom:12px;font-size:15px;font-weight:700}.instructions-box ul{flex-direction:column;gap:8px;list-style:none;display:flex}.instructions-box li{color:var(--text-secondary);padding-left:20px;font-size:15px;position:relative}.instructions-box li:before{content:"•";color:var(--blue);font-weight:700;position:absolute;left:6px}.topics-section{margin-bottom:28px}.topics-section h3{color:var(--gray-600);text-transform:uppercase;letter-spacing:.5px;margin-bottom:10px;font-size:15px;font-weight:700}.topics-grid{flex-wrap:wrap;gap:8px;display:flex}.topic-chip{background:var(--blue-mid);color:var(--blue-dark);border-radius:20px;padding:6px 14px;font-size:14px;font-weight:600}.btn-start{background:var(--blue);color:#fff;border-radius:var(--radius);cursor:pointer;letter-spacing:.3px;border:none;width:100%;padding:18px;font-size:20px;font-weight:700;transition:background .2s,transform .1s;display:block}.btn-start:hover{background:var(--blue-dark);transform:translateY(-1px)}.btn-start:active{transform:translateY(0)}.mode-selector{margin-bottom:24px}.mode-selector-label{color:var(--text-secondary);text-transform:uppercase;letter-spacing:.5px;margin-bottom:10px;font-size:15px;font-weight:700}.mode-options{grid-template-columns:1fr 1fr;gap:10px;display:grid}.mode-option{background:var(--bg-card-alt);border:2px solid var(--border);border-radius:var(--radius);cursor:pointer;text-align:left;align-items:center;gap:12px;padding:14px 16px;transition:all .2s;display:flex;position:relative}.mode-option:hover{border-color:var(--blue)}.mode-active{border-color:var(--blue)!important}.mode-exam-active{background:var(--blue-light);border-color:var(--blue)!important}.mode-study-active{background:#f0fdf4;border-color:var(--green)!important}[data-theme=dark] .mode-study-active{background:#14532d;border-color:var(--green)!important}.mode-icon{flex-shrink:0;font-size:24px}.mode-info{flex:1}.mode-name{color:var(--text-primary);margin-bottom:2px;font-size:15px;font-weight:700}.mode-desc{color:var(--text-muted);font-size:12px;line-height:1.4}.mode-check{color:var(--blue);flex-shrink:0;font-size:16px;font-weight:800}.mode-study-active .mode-check{color:var(--green)}.start-disclaimer{text-align:center;color:var(--text-muted);margin-top:16px;font-size:13px}.exam-screen{background:var(--bg-page);flex-direction:column;min-height:100vh;display:flex}.exam-topbar{background:var(--topbar-bg);color:var(--topbar-text);z-index:100;justify-content:space-between;align-items:center;gap:16px;padding:10px 24px;display:flex;position:sticky;top:0;box-shadow:0 2px 8px #0000004d}.topbar-left{flex-shrink:0;align-items:center;gap:10px;display:flex}.exam-brand{color:var(--topbar-brand);white-space:nowrap;font-size:15px;font-weight:600}.mode-pill{cursor:pointer;white-space:nowrap;border:none;border-radius:20px;align-items:center;gap:5px;padding:4px 12px;font-size:12px;font-weight:700;transition:all .2s;display:inline-flex}.mode-pill-exam{color:#93c5fd;background:#ffffff1f}.mode-pill-exam:hover{background:#ffffff38}.mode-pill-study{color:#4ade80;background:#4ade802e}.mode-pill-study:hover{background:#4ade8047}.topbar-right{flex-shrink:0;align-items:center;gap:8px;display:flex}.topbar-center{flex:1;max-width:400px}.progress-info{flex-direction:column;align-items:center;gap:4px;display:flex}.answered-count{color:#fff9;font-size:13px}.progress-bar-wrap{background:#ffffff26;border-radius:3px;width:100%;height:6px;overflow:hidden}.progress-bar-fill{background:#22c55e;border-radius:3px;height:100%;transition:width .3s}.timer{white-space:nowrap;background:#ffffff14;border:1px solid #ffffff26;border-radius:8px;align-items:center;gap:6px;padding:6px 14px;display:flex}.timer-icon{font-size:15px}.timer-display{color:#86efac;font-family:Courier New,monospace;font-size:20px;font-weight:700}.timer.timer-warning .timer-display{color:#fcd34d}.timer.timer-critical .timer-display{color:#f87171;animation:1s infinite pulse}@keyframes pulse{0%,to{opacity:1}50%{opacity:.5}}.exam-body{flex:1;gap:20px;width:100%;max-width:1300px;margin:0 auto;padding:24px;display:flex}.question-panel{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);flex-direction:column;flex:1;gap:20px;padding:32px;display:flex}.question-meta{flex-wrap:wrap;align-items:center;gap:8px;display:flex}.question-number{color:var(--text-secondary);margin-right:4px;font-size:16px;font-weight:700}.difficulty-badge{text-transform:uppercase;border-radius:4px;padding:4px 10px;font-size:12px;font-weight:700}.diff-K1{background:var(--green-light);color:#15803d}.diff-K2{color:#92400e;background:#fef3c7}.diff-K3{color:#991b1b;background:#fee2e2}.topic-badge{background:var(--blue-light);color:var(--blue-dark);border-radius:4px;padding:4px 10px;font-size:13px;font-weight:600}.flag-btn{border:1.5px solid var(--border-strong);cursor:pointer;color:var(--text-muted);background:0 0;border-radius:6px;margin-left:auto;padding:6px 14px;font-size:14px;font-weight:600;transition:all .2s}.flag-btn:hover{border-color:var(--orange);color:var(--orange)}.flag-btn.flagged{background:var(--orange-light);border-color:var(--orange);color:var(--orange)}.question-text p{color:var(--text-primary);font-size:20px;font-weight:500;line-height:1.7}.options-list{flex-direction:column;gap:10px;display:flex}.option-btn{background:var(--bg-input);border:2px solid var(--border);border-radius:var(--radius);cursor:pointer;text-align:left;align-items:flex-start;gap:14px;width:100%;padding:14px 16px;transition:all .15s;display:flex}.option-btn:hover{border-color:var(--blue);background:var(--blue-light)}.option-btn.selected{border-color:var(--blue);background:var(--blue-light);box-shadow:0 0 0 3px #1a56db1f}.option-letter{background:var(--border);min-width:34px;height:34px;color:var(--text-secondary);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;font-size:15px;font-weight:700;display:inline-flex}.option-btn.selected .option-letter{background:var(--blue);color:#fff}.option-text{color:var(--text-secondary);flex:1;padding-top:2px;font-size:18px;line-height:1.55}.option-btn.option-correct{border-color:var(--green);background:var(--green-light);cursor:default}.option-btn.option-correct .option-letter{background:var(--green);color:#fff}.option-btn.option-correct .option-text{color:var(--text-primary)}.option-btn.option-wrong{border-color:var(--red);background:var(--red-light);cursor:default}.option-btn.option-wrong .option-letter{background:var(--red);color:#fff}.option-btn.option-wrong .option-text{color:var(--text-primary)}.option-btn.option-neutral{opacity:.55;cursor:default}.option-btn:disabled{cursor:default}.option-indicator{flex-shrink:0;margin-left:auto;font-size:17px;font-weight:800}.indicator-correct{color:var(--green)}.indicator-wrong{color:var(--red)}.inline-feedback{border-radius:var(--radius);border-left:5px solid;flex-direction:column;gap:8px;padding:16px 20px;animation:.2s slideIn;display:flex}@keyframes slideIn{0%{opacity:0;transform:translateY(-6px)}to{opacity:1;transform:translateY(0)}}.feedback-correct{background:var(--green-light);border-color:var(--green)}.feedback-wrong{background:var(--red-light);border-color:var(--red)}.feedback-verdict{font-size:18px;font-weight:700;line-height:1.5}.feedback-correct .feedback-verdict{color:var(--green)}.feedback-wrong .feedback-verdict{color:var(--red)}.feedback-explanation{color:var(--text-secondary);font-size:17px;line-height:1.65}.status-correct-ans{color:var(--green);font-weight:700}.status-wrong-ans{color:var(--red);font-weight:700}.nav-btn.nav-correct{background:var(--green);border-color:var(--green);color:#fff}.nav-btn.nav-wrong{background:var(--red);border-color:var(--red);color:#fff}.nav-correct-dot{background:var(--green)}.nav-wrong-dot{background:var(--red)}.option-check{color:var(--blue);flex-shrink:0;margin-left:auto;font-weight:700}.question-nav-arrows{border-top:1px solid var(--border);justify-content:space-between;align-items:center;margin-top:auto;padding-top:8px;display:flex}.btn-nav-arrow{background:var(--bg-card-alt);border:1px solid var(--border);border-radius:var(--radius-sm);cursor:pointer;color:var(--text-secondary);padding:10px 22px;font-size:15px;font-weight:600;transition:all .15s}.btn-nav-arrow:hover:not(:disabled){background:var(--blue);border-color:var(--blue);color:#fff}.btn-nav-arrow:disabled{opacity:.4;cursor:not-allowed}.btn-review-submit{background:var(--blue);border-color:var(--blue);color:#fff}.btn-review-submit:hover{background:var(--blue-dark)!important}.question-status{align-items:center;gap:8px;font-size:14px;display:flex}.status-answered{color:var(--green);font-weight:600}.status-unanswered{color:var(--text-muted)}.status-flagged{color:var(--orange);font-size:12px;font-weight:600}.sidebar{flex-direction:column;flex-shrink:0;gap:12px;width:240px;max-height:calc(100vh - 88px);display:flex;position:sticky;top:68px;overflow-y:auto}.sidebar-header{background:var(--topbar-bg);color:var(--topbar-text);border-radius:var(--radius-sm);text-align:center;letter-spacing:.3px;padding:11px 16px;font-size:14px;font-weight:700}.nav-grid{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-sm);grid-template-columns:repeat(5,1fr);gap:5px;padding:12px;display:grid}.nav-btn{aspect-ratio:1;border:1.5px solid var(--border);background:var(--bg-card);cursor:pointer;width:100%;color:var(--text-secondary);border-radius:5px;justify-content:center;align-items:center;font-size:13px;font-weight:600;transition:all .1s;display:flex}.nav-btn:hover{border-color:var(--blue);color:var(--blue)}.nav-btn.answered{background:var(--green);border-color:var(--green);color:#fff}.nav-btn.flagged{background:var(--orange);border-color:var(--orange);color:#fff}.nav-btn.current{background:var(--blue);border-color:var(--blue);color:#fff;box-shadow:0 0 0 2px #1a56db4d}.nav-legend{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-sm);flex-direction:column;gap:6px;padding:10px 12px;display:flex}.legend-item{color:var(--text-secondary);align-items:center;gap:8px;font-size:13px;display:flex}.legend-dot{border-radius:3px;flex-shrink:0;width:12px;height:12px}.answered-dot{background:var(--green)}.flagged-dot{background:var(--orange)}.current-dot{background:var(--blue)}.unanswered-dot{background:var(--gray-200);border:1.5px solid var(--gray-300)}.sidebar-stats{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-sm);flex-direction:column;gap:8px;padding:12px 14px;display:flex}.stat-row{color:var(--text-secondary);justify-content:space-between;align-items:center;font-size:14px;display:flex}.stat-green{color:var(--green)}.stat-red{color:var(--red)}.stat-orange{color:var(--orange)}.btn-review{background:var(--blue);color:#fff;border-radius:var(--radius);cursor:pointer;border:none;padding:13px;font-size:15px;font-weight:700;transition:background .2s}.btn-review:hover{background:var(--blue-dark)}.review-screen{background:var(--bg-page);min-height:100vh}.review-topbar{background:var(--topbar-bg);color:var(--topbar-text);z-index:100;justify-content:space-between;align-items:center;gap:12px;padding:12px 32px;display:flex;position:sticky;top:0}.review-body{max-width:960px;margin:0 auto;padding:32px 24px 48px}.review-header{margin-bottom:24px}.review-header h2{color:var(--text-primary);margin-bottom:4px;font-size:26px;font-weight:700}.review-subtitle{color:var(--text-muted);font-size:15px}.review-summary-cards{grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:20px;display:grid}.summary-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);text-align:center;box-shadow:var(--shadow-sm);border-top:3px solid var(--border);padding:20px}.summary-answered{border-top-color:var(--green)}.summary-unanswered{border-top-color:var(--red)}.summary-flagged{border-top-color:var(--orange)}.summary-total{border-top-color:var(--blue)}.summary-number{color:var(--text-primary);font-size:36px;font-weight:800}.summary-label{color:var(--text-muted);text-transform:uppercase;letter-spacing:.5px;margin-top:2px;font-size:13px;font-weight:600}.review-warning{border-radius:var(--radius-sm);color:#92400e;background:#fffbeb;border:1px solid #fcd34d;margin-bottom:20px;padding:13px 18px;font-size:15px}.review-table-wrap{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:24px;overflow:hidden}.review-table{border-collapse:collapse;table-layout:fixed;width:100%}.review-table th{background:var(--bg-card-alt);text-align:left;color:var(--text-secondary);text-transform:uppercase;letter-spacing:.5px;border-bottom:1px solid var(--border);vertical-align:middle;padding:13px 18px;font-size:13px;font-weight:700}.review-table td{border-bottom:1px solid var(--border);color:var(--text-primary);vertical-align:middle;padding:12px 18px;font-size:14px}.review-table th:first-child,.review-table td:first-child{text-align:center;width:56px;padding-left:12px;padding-right:12px}.review-table th:nth-child(3),.review-table td:nth-child(3){width:34%}.review-table th:nth-child(4),.review-table td:nth-child(4){width:120px}.review-table th:nth-child(5),.review-table td:nth-child(5){width:110px}.review-table tr:last-child td{border-bottom:none}.review-row.row-unanswered{background:var(--red-light)}.review-row.row-flagged{background:var(--orange-light)}.review-row:hover{background:var(--bg-card-alt)}.review-num{color:var(--text-secondary);text-align:center;white-space:nowrap;font-weight:700}.review-num .flag-indicator{margin-top:2px;font-size:11px;line-height:1;display:block}.flag-indicator{font-size:12px}.review-topic{max-width:200px}.topic-short{color:var(--blue);font-size:12px;font-weight:700;display:block}.topic-name{color:var(--text-muted);font-size:13px}.review-answer{max-width:280px}.answer-text{color:var(--text-secondary);font-size:14px}.no-answer{color:var(--red);font-size:14px;font-style:italic}.status-pill{border-radius:12px;padding:3px 10px;font-size:11px;font-weight:700}.pill-answered{background:var(--green-light);color:#15803d}.pill-unanswered{background:var(--red-light);color:#dc2626}.btn-review-goto{background:var(--blue-light);border:1px solid var(--blue-mid);color:var(--blue-dark);cursor:pointer;white-space:nowrap;border-radius:4px;padding:6px 14px;font-size:13px;font-weight:600;display:inline-block}.btn-review-goto:hover{background:var(--blue);color:#fff;border-color:var(--blue)}.review-actions{justify-content:flex-end;gap:12px;display:flex}.btn-back-exam{background:var(--bg-card-alt);border:1px solid var(--border);border-radius:var(--radius-sm);cursor:pointer;color:var(--text-secondary);padding:13px 26px;font-size:15px;font-weight:600}.btn-back-exam:hover{background:var(--border)}.btn-submit{background:var(--green);border-radius:var(--radius-sm);color:#fff;cursor:pointer;border:none;padding:13px 34px;font-size:16px;font-weight:700}.btn-submit:hover{background:#15803d}.result-screen{background:var(--bg-page);min-height:100vh;padding-bottom:60px}.result-header{background:var(--topbar-bg);color:var(--topbar-text);text-align:center;padding:20px 32px}.result-logo{color:var(--topbar-brand);margin-bottom:4px;font-size:14px;font-weight:600}.result-title{font-size:24px;font-weight:700}.score-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-lg);max-width:800px;box-shadow:var(--shadow-lg);border-top:6px solid var(--border);flex-wrap:wrap;justify-content:center;align-items:center;gap:28px;margin:28px auto;padding:32px;display:flex}.score-pass{border-top-color:var(--green)}.score-fail{border-top-color:var(--red)}.score-circle{background:var(--bg-card-alt);border:6px solid var(--border);border-radius:50%;flex-direction:column;flex-shrink:0;justify-content:center;align-items:center;width:120px;height:120px;display:flex}.score-pass .score-circle{background:var(--green-light);border-color:var(--green)}.score-fail .score-circle{background:var(--red-light);border-color:var(--red)}.score-percent{color:var(--text-primary);font-size:30px;font-weight:800}.score-fraction{color:var(--text-muted);font-size:15px;font-weight:600}.score-verdict{text-align:center}.verdict-label{margin-bottom:4px;font-size:28px;font-weight:800}.verdict-pass{color:var(--green)}.verdict-fail{color:var(--red)}.verdict-detail{color:var(--text-secondary);max-width:260px;font-size:15px}.score-stats{flex-wrap:wrap;justify-content:center;gap:20px;display:flex}.score-stat{text-align:center}.stat-val{color:var(--text-primary);font-size:24px;font-weight:800;display:block}.stat-correct{color:var(--green)}.stat-wrong{color:var(--red)}.stat-time{color:var(--blue)}.stat-label{color:var(--gray-400);text-transform:uppercase;letter-spacing:.4px;font-size:12px;font-weight:600}.chapter-breakdown{max-width:800px;margin:0 auto 28px;padding:0 16px}.chapter-breakdown h2{color:var(--text-primary);margin-bottom:14px;font-size:20px;font-weight:700}.chapter-grid{grid-template-columns:repeat(3,1fr);gap:12px;display:grid}.chapter-card{background:var(--bg-card);border-radius:var(--radius);box-shadow:var(--shadow-sm);border:1px solid var(--border);padding:16px}.ch-header{justify-content:space-between;align-items:center;margin-bottom:4px;display:flex}.ch-number{color:var(--text-muted);font-size:13px;font-weight:700}.ch-pct{font-size:18px;font-weight:800}.pct-pass{color:var(--green)}.pct-fail{color:var(--red)}.ch-topic{color:var(--text-muted);margin-bottom:8px;font-size:13px;line-height:1.3}.ch-bar-wrap{background:var(--border);border-radius:3px;height:6px;margin-bottom:4px;overflow:hidden}.ch-bar-fill{border-radius:3px;height:100%;transition:width .5s}.bar-pass{background:var(--green)}.bar-fail{background:var(--red)}.ch-score{color:var(--text-muted);font-size:13px;font-weight:600}.answer-review{max-width:800px;margin:0 auto;padding:0 16px}.review-controls{flex-wrap:wrap;align-items:center;gap:10px;margin-bottom:16px;display:flex}.review-controls h2{color:var(--text-primary);margin-right:auto;font-size:20px;font-weight:700}.filter-buttons{gap:6px;display:flex}.filter-btn{border:1.5px solid var(--border);background:var(--bg-card);cursor:pointer;color:var(--text-secondary);border-radius:20px;padding:6px 16px;font-size:13px;font-weight:600;transition:all .15s}.filter-btn.active,.filter-btn:hover{border-color:var(--blue);background:var(--blue);color:#fff}.filter-btn.filter-correct.active{background:var(--green);border-color:var(--green)}.filter-btn.filter-incorrect.active{background:var(--red);border-color:var(--red)}.btn-toggle-explanations{background:var(--bg-card-alt);border:1px solid var(--border);cursor:pointer;color:var(--text-secondary);border-radius:6px;padding:7px 16px;font-size:13px;font-weight:600}.btn-toggle-explanations:hover{background:var(--border)}.answer-list{flex-direction:column;gap:12px;display:flex}.answer-item{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-sm);border-left:4px solid var(--border);overflow:hidden}.answer-correct{border-left-color:var(--green)}.answer-wrong{border-left-color:var(--red)}.answer-item-header{background:var(--bg-card-alt);border-bottom:1px solid var(--border);flex-wrap:wrap;align-items:center;gap:8px;padding:10px 16px;display:flex}.answer-qnum{color:var(--text-secondary);font-size:14px;font-weight:800}.answer-result{border-radius:12px;padding:3px 10px;font-size:13px;font-weight:700}.result-correct{background:var(--green-light);color:var(--green)}.result-wrong{background:var(--red-light);color:var(--red)}.answer-topic{color:var(--text-muted);font-size:13px}.answer-question-text{color:var(--text-primary);padding:14px 18px 10px;font-size:15px;font-weight:600;line-height:1.55}.answer-options-review{flex-direction:column;gap:5px;padding:0 16px 12px;display:flex}.review-option{background:var(--bg-card-alt);border:1.5px solid var(--border);border-radius:6px;align-items:flex-start;gap:10px;padding:10px 12px;font-size:14px;display:flex}.review-option.correct-option{background:var(--green-light);border-color:#86efac}.review-option.wrong-option{background:var(--red-light);border-color:#fca5a5}.opt-letter{color:var(--text-muted);min-width:18px;font-weight:700}.correct-option .opt-letter{color:var(--green)}.wrong-option .opt-letter{color:var(--red)}.opt-text{color:var(--text-secondary);flex:1}.opt-indicators{white-space:nowrap;gap:6px;font-size:12px;font-weight:700;display:flex}.correct-mark{color:#15803d}.wrong-mark{color:var(--red)}.your-correct-mark{color:#15803d}.not-answered-note{color:var(--red);padding:6px 0;font-size:14px;font-style:italic}.explanation-box{background:var(--blue-light);border:1px solid var(--blue-mid);color:var(--blue-dark);border-radius:6px;margin:0 16px 14px;padding:12px 16px;font-size:14px;line-height:1.65}.result-actions{justify-content:center;margin-top:32px;padding:0 16px;display:flex}.btn-retake{background:var(--blue);color:#fff;border-radius:var(--radius);cursor:pointer;border:none;padding:16px 44px;font-size:18px;font-weight:700;transition:background .2s}.btn-retake:hover{background:var(--blue-dark)}.sidebar-toggle-btn{color:#fff;cursor:pointer;background:#ffffff1a;border:1px solid #fff3;border-radius:6px;align-items:center;gap:5px;padding:5px 10px;font-size:14px;display:none}.hamburger-icon{font-size:16px}.toggle-count{opacity:.7;font-size:11px;font-weight:700}.sidebar-overlay{z-index:199;background:#00000073;display:none;position:fixed;inset:0}.sidebar-close-btn{color:#fff;cursor:pointer;background:0 0;border:none;padding:4px 8px;font-size:18px;line-height:1;display:none}.sidebar-header{justify-content:center;align-items:center;display:flex}.review-card-list{display:none}@media (width<=960px){.exam-body{flex-direction:column;padding:16px}.exam-info-grid,.chapter-grid{grid-template-columns:repeat(2,1fr)}.start-card{padding:32px 24px}.review-summary-cards{grid-template-columns:repeat(2,1fr)}.mode-options{grid-template-columns:1fr}.sidebar-toggle-btn{display:flex}.sidebar{z-index:200;background:var(--bg-card);border-left:1px solid var(--border);width:280px;height:100vh;max-height:100vh;padding:0 14px 14px;transition:right .25s;position:fixed;top:0;right:-300px;overflow-y:auto;box-shadow:-4px 0 24px #00000040}.sidebar.sidebar-open{right:0}.sidebar-overlay{display:block}.sidebar-header{background:var(--topbar-bg);z-index:1;justify-content:space-between;margin:0 -14px 12px;padding:12px 14px;position:sticky;top:0}.sidebar-close-btn{display:block}.nav-grid{grid-template-columns:repeat(5,1fr);margin-top:0}.review-table th,.review-table td{padding:10px 12px;font-size:13px}}@media (width<=640px){html{font-size:15px}.start-screen{padding:16px 10px}.start-card{border-radius:12px;padding:24px 16px}.start-title{font-size:22px}.start-subtitle{font-size:14px}.exam-info-grid{gap:8px}.info-item{gap:8px;padding:12px 10px}.info-icon,.info-value{font-size:18px}.info-label{font-size:11px}.instructions-box{padding:14px 16px}.instructions-box li{font-size:14px}.btn-start{padding:14px;font-size:17px}.mode-option{gap:10px;padding:12px}.mode-icon{font-size:20px}.mode-name{font-size:14px}.mode-desc{font-size:11px}.topic-chip{padding:4px 10px;font-size:12px}.exam-topbar{flex-wrap:wrap;gap:8px;padding:8px 10px}.topbar-left{flex:100%;order:1}.exam-brand{font-size:13px}.mode-pill{padding:3px 8px;font-size:11px}.topbar-center{flex:100%;order:3}.topbar-right{order:2;align-items:center;gap:6px;margin-left:auto;display:flex}.dark-toggle{padding:4px 8px;font-size:11px}.timer{padding:4px 8px}.timer-display{font-size:16px}.timer-icon{font-size:12px}.exam-body{padding:10px}.question-panel{border-radius:8px;gap:14px;padding:18px 14px}.question-meta{gap:6px}.question-number{font-size:14px}.difficulty-badge{padding:2px 6px;font-size:10px}.topic-badge{padding:3px 8px;font-size:11px}.flag-btn{padding:4px 8px;font-size:12px}.question-text p{font-size:16px;line-height:1.6}.option-btn{border-radius:8px;gap:10px;padding:12px}.option-letter{min-width:28px;height:28px;font-size:13px}.option-text{font-size:14px}.btn-nav-arrow{padding:8px 12px;font-size:13px}.question-status{font-size:12px}.inline-feedback{padding:12px 14px}.feedback-verdict{font-size:14px}.feedback-explanation{font-size:13px}.sidebar{width:260px}.review-topbar{padding:10px 14px}.review-body{padding:16px 10px 32px}.review-header h2{font-size:20px}.review-subtitle{font-size:13px}.review-summary-cards{gap:8px}.summary-card{padding:14px 10px}.summary-number{font-size:26px}.summary-label{font-size:11px}.review-table-wrap{display:none}.review-card-list{flex-direction:column;gap:8px;margin-bottom:20px;display:flex}.review-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);text-align:left;cursor:pointer;border-left:4px solid var(--green);flex-direction:column;gap:6px;width:100%;padding:12px 14px;font-family:inherit;transition:background .15s;display:flex}.review-card:active{background:var(--bg-card-alt)}.review-card.card-unanswered{border-left-color:var(--red)}.review-card.card-flagged{border-left-color:var(--orange)}.rc-top{justify-content:space-between;align-items:center;display:flex}.rc-num{color:var(--text-primary);font-size:14px;font-weight:800}.rc-topic{color:var(--text-muted);font-size:12px}.rc-topic .topic-short{color:var(--blue);margin-right:6px;font-weight:700}.rc-answer{color:var(--text-secondary);font-size:13px;line-height:1.4}.rc-no-answer{color:var(--red);font-style:italic}.review-actions{flex-direction:column;gap:10px}.btn-back-exam{text-align:center;width:100%}.btn-submit{width:100%}.review-warning{padding:10px 12px;font-size:13px}.result-header{padding:14px 16px}.result-title{font-size:20px}.result-header-toggle{right:12px}.score-card{flex-direction:column;gap:16px;margin:16px 10px;padding:20px 16px}.score-circle{border-width:5px;width:100px;height:100px}.score-percent{font-size:24px}.score-fraction{font-size:13px}.verdict-label{font-size:22px}.verdict-detail{font-size:13px}.score-stats{gap:12px}.stat-val{font-size:20px}.chapter-breakdown{margin-bottom:20px;padding:0 10px}.chapter-breakdown h2{font-size:17px}.chapter-grid{grid-template-columns:1fr 1fr;gap:8px}.chapter-card{padding:12px}.ch-pct{font-size:16px}.answer-review{padding:0 10px}.review-controls{flex-direction:column;align-items:stretch;gap:8px}.review-controls h2{font-size:17px}.filter-buttons{flex-wrap:wrap;gap:4px}.filter-btn{padding:5px 10px;font-size:12px}.btn-toggle-explanations{font-size:12px}.answer-item-header{gap:6px;padding:8px 12px}.answer-question-text{padding:10px 12px 8px;font-size:14px}.answer-options-review{padding:0 12px 10px}.review-option{gap:6px;padding:8px;font-size:13px}.opt-indicators{font-size:10px}.explanation-box{margin:0 12px 10px;padding:10px 12px;font-size:13px}.result-actions{padding:0 10px}.btn-retake{width:100%;padding:14px 24px;font-size:16px}}@media (width<=380px){html{font-size:14px}.exam-info-grid{grid-template-columns:1fr 1fr}.start-card{padding:20px 12px}.start-title{font-size:20px}.review-summary-cards{grid-template-columns:1fr 1fr}.chapter-grid{grid-template-columns:1fr}.score-stats{flex-wrap:wrap;justify-content:center;gap:8px}.sidebar{width:100%;right:-100%}.option-btn{gap:8px;padding:10px}.option-letter{min-width:24px;height:24px;font-size:12px}}