*{margin:0;padding:0;box-sizing:border-box}:root{--primary: #2563eb;--primary-dark: #1d4ed8;--green: #16a34a;--green-bg: #dcfce7;--red: #dc2626;--red-bg: #fee2e2;--orange: #ea580c;--orange-bg: #fff7ed;--gray-50: #f9fafb;--gray-100: #f3f4f6;--gray-200: #e5e7eb;--gray-300: #d1d5db;--gray-500: #6b7280;--gray-700: #374151;--gray-900: #111827;--radius: 12px;--shadow: 0 1px 3px rgba(0,0,0,.1), 0 1px 2px rgba(0,0,0,.06);--shadow-lg: 0 10px 15px -3px rgba(0,0,0,.1), 0 4px 6px -2px rgba(0,0,0,.05)}body{font-family:Inter,system-ui,-apple-system,sans-serif;background:var(--gray-50);color:var(--gray-900);line-height:1.6}.navbar{background:#fff;border-bottom:1px solid var(--gray-200);padding:0 2rem;display:flex;align-items:center;justify-content:space-between;height:64px;position:sticky;top:0;z-index:100;box-shadow:var(--shadow)}.navbar-brand{font-size:1.25rem;font-weight:700;color:var(--primary);display:flex;align-items:center;gap:.5rem}.navbar-icon{font-size:1.5rem}.navbar-links{display:flex;gap:.5rem}.nav-btn{background:none;border:2px solid transparent;padding:.5rem 1.25rem;border-radius:8px;font-size:.95rem;font-weight:500;cursor:pointer;color:var(--gray-500);transition:all .2s}.nav-btn:hover{color:var(--primary);background:var(--gray-50)}.nav-btn.active{color:var(--primary);background:#eff6ff;border-color:var(--primary)}.main-content{max-width:960px;margin:0 auto;padding:2rem 1rem}.study-header{text-align:center;margin-bottom:2rem}.study-header h1{font-size:2rem;font-weight:700;color:var(--gray-900)}.subtitle{color:var(--gray-500);margin-top:.25rem}.filters{background:#fff;padding:1.25rem;border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:1.5rem}.filter-row{display:flex;gap:1rem}.category-select,.search-input{padding:.75rem 1rem;border:1px solid var(--gray-300);border-radius:8px;font-size:.95rem;font-family:inherit;outline:none;transition:border-color .2s}.category-select:focus,.search-input:focus{border-color:var(--primary);box-shadow:0 0 0 3px #2563eb1a}.category-select{flex:0 0 auto;min-width:240px}.search-input{flex:1}.filter-actions{display:flex;gap:.5rem;margin-top:.75rem}.btn-small{padding:.4rem .9rem;font-size:.85rem;border:1px solid var(--gray-300);background:#fff;border-radius:6px;cursor:pointer;color:var(--gray-700);transition:all .2s}.btn-small:hover{background:var(--gray-100)}.question-card{background:#fff;border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:.75rem;overflow:hidden;border:1px solid var(--gray-200);transition:box-shadow .2s}.question-card:hover{box-shadow:var(--shadow-lg)}.question-card.expanded{border-color:var(--primary)}.question-header{padding:1rem 1.25rem;cursor:pointer;display:flex;align-items:flex-start;gap:.75rem}.question-meta{display:flex;flex-direction:column;gap:.25rem;min-width:0}.question-number{font-size:.8rem;font-weight:600;color:var(--gray-500)}.question-category-badge{font-size:.7rem;padding:.15rem .5rem;background:#eff6ff;color:var(--primary);border-radius:4px;white-space:nowrap;font-weight:500}.question-text{flex:1;font-size:.95rem;font-weight:500;line-height:1.5}.expand-icon{font-size:1.5rem;color:var(--gray-500);flex-shrink:0;line-height:1}.question-body{padding:0 1.25rem 1.25rem;animation:slideDown .2s ease-out}@keyframes slideDown{0%{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}.options-list{display:flex;flex-direction:column;gap:.5rem}.option-item{display:flex;align-items:flex-start;gap:.75rem;padding:.75rem 1rem;border-radius:8px;background:var(--gray-50);border:1px solid var(--gray-200);font-size:.9rem}.option-item.correct{background:var(--green-bg);border-color:var(--green)}.option-letter{font-weight:700;color:var(--gray-500);min-width:24px;height:24px;display:flex;align-items:center;justify-content:center;border-radius:50%;background:var(--gray-200);font-size:.8rem;flex-shrink:0}.option-item.correct .option-letter{background:var(--green);color:#fff}.option-text{flex:1}.correct-badge{font-size:.75rem;padding:.15rem .5rem;background:var(--green);color:#fff;border-radius:4px;font-weight:600;white-space:nowrap;align-self:center}.explanation-box{margin-top:1rem;padding:1rem;background:#fefce8;border:1px solid #fde68a;border-radius:8px;font-size:.88rem;line-height:1.6;color:#92400e}.exam-page{max-width:800px;margin:0 auto}.exam-start-card{background:#fff;border-radius:var(--radius);padding:3rem 2rem;text-align:center;box-shadow:var(--shadow-lg)}.exam-start-card h1{font-size:2rem;color:var(--primary);margin-bottom:.25rem}.exam-start-card h2{font-size:1.25rem;color:var(--gray-500);font-weight:400;margin-bottom:2rem}.exam-info{display:flex;justify-content:center;gap:2rem;margin-bottom:2rem}.info-item{display:flex;flex-direction:column;align-items:center;padding:1rem 1.5rem;background:var(--gray-50);border-radius:12px;min-width:120px}.info-label{font-size:.85rem;color:var(--gray-500)}.info-value{font-size:1.5rem;font-weight:700;color:var(--gray-900)}.exam-desc{max-width:500px;margin:0 auto 2rem;color:var(--gray-500);font-size:.9rem}.btn-start{padding:1rem 3rem;font-size:1.1rem;font-weight:600;background:var(--primary);color:#fff;border:none;border-radius:12px;cursor:pointer;transition:all .2s}.btn-start:hover{background:var(--primary-dark);transform:translateY(-1px)}.btn-secondary{padding:1rem 2rem;font-size:1rem;font-weight:500;background:#fff;color:var(--gray-700);border:1px solid var(--gray-300);border-radius:12px;cursor:pointer}.btn-secondary:hover{background:var(--gray-50)}.exam-toolbar{display:flex;align-items:center;justify-content:space-between;background:#fff;padding:.75rem 1.25rem;border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:1rem;position:sticky;top:72px;z-index:50}.timer{font-size:1.5rem;font-weight:700;font-variant-numeric:tabular-nums;color:var(--gray-900)}.timer.warning{color:var(--orange)}.timer.danger{color:var(--red);animation:pulse 1s infinite}@keyframes pulse{50%{opacity:.5}}.progress-info{font-size:.9rem;color:var(--gray-500)}.btn-end{padding:.5rem 1rem;background:var(--red);color:#fff;border:none;border-radius:8px;cursor:pointer;font-weight:500;font-size:.9rem}.btn-end:hover{background:#b91c1c}.question-nav-dots{display:flex;flex-wrap:wrap;gap:4px;margin-bottom:1rem;padding:.75rem;background:#fff;border-radius:var(--radius);box-shadow:var(--shadow)}.dot{width:32px;height:32px;border:1px solid var(--gray-300);border-radius:6px;background:#fff;font-size:.75rem;font-weight:500;cursor:pointer;transition:all .15s;color:var(--gray-500)}.dot.current{border-color:var(--primary);background:var(--primary);color:#fff}.dot.answered{background:#dbeafe;border-color:#93c5fd;color:var(--primary)}.dot:hover{transform:scale(1.1)}.exam-question-card{background:#fff;border-radius:var(--radius);padding:2rem;box-shadow:var(--shadow);margin-bottom:1rem}.exam-q-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:1rem}.exam-q-number{font-weight:700;color:var(--primary);font-size:.9rem}.exam-q-category{font-size:.8rem;padding:.2rem .6rem;background:var(--gray-100);border-radius:4px;color:var(--gray-500)}.exam-q-text{font-size:1.1rem;font-weight:500;margin-bottom:1.5rem;line-height:1.5}.exam-options{display:flex;flex-direction:column;gap:.6rem}.exam-option{display:flex;align-items:flex-start;gap:.75rem;padding:1rem;border:2px solid var(--gray-200);border-radius:10px;background:#fff;cursor:pointer;text-align:left;font-size:.95rem;font-family:inherit;transition:all .15s}.exam-option:hover{border-color:var(--primary);background:#f0f7ff}.exam-option.selected{border-color:var(--primary);background:#eff6ff}.exam-option.selected .option-letter{background:var(--primary);color:#fff}.exam-nav-buttons{display:flex;justify-content:space-between}.btn-nav{padding:.75rem 2rem;border:1px solid var(--gray-300);background:#fff;border-radius:8px;font-size:.95rem;cursor:pointer;font-weight:500;transition:all .2s}.btn-nav:hover:not(:disabled){background:var(--gray-100)}.btn-nav:disabled{opacity:.4;cursor:not-allowed}.results-header{text-align:center;margin-bottom:2rem;padding:2rem;background:#fff;border-radius:var(--radius);box-shadow:var(--shadow)}.score-circle{width:160px;height:160px;border-radius:50%;display:flex;flex-direction:column;align-items:center;justify-content:center;margin:1.5rem auto;border:6px solid}.score-circle.passed{border-color:var(--green);background:var(--green-bg)}.score-circle.failed{border-color:var(--red);background:var(--red-bg)}.score-number{font-size:2rem;font-weight:700}.score-percent{font-size:1rem;color:var(--gray-500)}.result-text{font-size:1.5rem;font-weight:700;margin:.5rem 0 1rem}.result-text.passed{color:var(--green)}.result-text.failed{color:var(--red)}.result-detail{color:var(--gray-500);margin-bottom:1.5rem}.results-review h2{margin-bottom:1rem}.result-card{background:#fff;border-radius:var(--radius);padding:1.25rem;margin-bottom:.75rem;border-left:4px solid;box-shadow:var(--shadow)}.result-card.correct{border-left-color:var(--green)}.result-card.wrong{border-left-color:var(--red)}.result-card.skipped{border-left-color:var(--orange)}.result-card-header{display:flex;align-items:center;gap:.5rem;margin-bottom:.5rem}.result-number{font-weight:700;color:var(--gray-500)}.result-badge{font-size:.75rem;padding:.15rem .5rem;border-radius:4px;font-weight:600;color:#fff}.result-badge.correct{background:var(--green)}.result-badge.wrong{background:var(--red)}.result-badge.skipped{background:var(--orange)}.result-card h4{margin-bottom:.75rem;font-size:.95rem}.result-options{display:flex;flex-direction:column;gap:.4rem}.result-option{display:flex;align-items:center;gap:.5rem;padding:.5rem .75rem;border-radius:6px;font-size:.88rem;background:var(--gray-50)}.result-option.is-correct{background:var(--green-bg);font-weight:500}.result-option.is-wrong{background:var(--red-bg)}.tag-correct{font-size:.7rem;padding:.1rem .4rem;background:var(--green);color:#fff;border-radius:3px;margin-left:auto}.tag-wrong{font-size:.7rem;padding:.1rem .4rem;background:var(--red);color:#fff;border-radius:3px;margin-left:auto}@media(max-width:768px){.navbar{padding:0 1rem}.navbar-brand span:last-child{display:none}.main-content{padding:1rem .75rem}.filter-row{flex-direction:column}.category-select{min-width:auto}.exam-info{flex-direction:column;gap:.75rem}.exam-toolbar{flex-wrap:wrap;gap:.5rem;top:64px}.timer{font-size:1.25rem}.exam-question-card{padding:1.25rem}}