:root{--primary-bg: #2c2a4a;--secondary-bg: #4f4a72;--accent-color: #fdb924;--text-color: #f0f0f0;--correct-color: #28a745;--incorrect-color: #dc3545;--light-bg: #6a6494}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background-color:var(--primary-bg);color:var(--text-color);margin:0;padding:20px;box-sizing:border-box}#root{width:100%;display:flex;justify-content:center;align-items:flex-start;min-height:100vh}.container{width:100%;max-width:800px;text-align:center}header{margin-bottom:40px}header h1{color:var(--accent-color);font-size:2.5rem;margin-bottom:.5rem}header p{font-size:1.1rem;opacity:.9}.menu-box,.notification-box{background-color:var(--secondary-bg);padding:25px;border-radius:12px;box-shadow:0 4px 15px #0003;margin-bottom:20px}.notification-box{background-color:var(--incorrect-color);color:#fff;font-weight:700;display:none}.menu-box h2{margin-top:0;color:var(--accent-color)}.form-group{margin:20px 0;text-align:left}.form-group label{display:block;margin-bottom:8px;font-weight:700}select{width:100%;padding:12px;border-radius:8px;border:2px solid var(--accent-color);background-color:var(--primary-bg);color:var(--text-color);font-size:1rem;cursor:pointer;-webkit-appearance:none;-moz-appearance:none;appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%23fdb924' class='bi bi-chevron-down' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 1rem center}button{background-color:var(--accent-color);color:#000;border:none;padding:14px 28px;border-radius:8px;font-size:1.1rem;font-weight:700;cursor:pointer;transition:transform .2s,box-shadow .2s;width:100%;margin-top:10px}button:hover{transform:translateY(-2px);box-shadow:0 4px 8px #0000004d}button:disabled{background-color:#aaa;cursor:not-allowed;transform:none;box-shadow:none}.special-button{background:linear-gradient(45deg,#ff6b6b,#fdb924)}.start-flashcards-button{background-color:var(--accent-color)!important;background-image:none!important;background:var(--accent-color)!important}#quiz-box,#flashcard-box{background-color:var(--secondary-bg);padding:30px;border-radius:12px;min-height:350px;display:flex;flex-direction:column}.quiz-header{display:flex;justify-content:space-between;margin-bottom:20px;font-weight:700;font-size:1.1rem}#question-text{font-size:1.6rem;margin-bottom:25px;flex-grow:1;display:flex;flex-direction:column;align-items:center;justify-content:center}#question-text img{max-width:100%;max-height:150px;border-radius:8px;margin-top:15px;border:2px solid var(--light-bg)}input[type=text]{width:90%;padding:14px;font-size:1.2rem;text-align:center;border:2px solid var(--accent-color);background-color:var(--primary-bg);color:var(--text-color);border-radius:8px}#feedback{margin-top:20px;font-size:1.2rem;font-weight:700;min-height:30px}.correct{color:var(--correct-color)}.incorrect{color:var(--incorrect-color)}.flashcard{width:100%;height:300px;position:relative;transform-style:preserve-3d;transition:transform .6s;cursor:pointer;margin-bottom:20px}.flashcard.is-flipped{transform:rotateY(180deg)}.card-face{position:absolute;width:100%;height:100%;-webkit-backface-visibility:hidden;backface-visibility:hidden;background-color:var(--light-bg);border-radius:12px;display:flex;justify-content:center;align-items:center;padding:20px;box-sizing:border-box;font-size:1.5rem;text-align:center}.card-back{transform:rotateY(180deg);color:var(--accent-color);font-weight:700}.flashcard-nav{margin-top:auto;display:flex;justify-content:center;align-items:center;gap:15px}.back-link{display:inline-block;margin-bottom:15px;color:var(--accent-color);text-decoration:none;font-weight:700;cursor:pointer}.timer-options{display:flex;flex-direction:column;gap:15px;margin-bottom:30px}.timer-option{width:100%}.timer-button{width:100%;background-color:var(--secondary-bg);border:2px solid var(--light-bg);border-radius:12px;padding:20px;color:var(--text-color);cursor:pointer;transition:all .3s ease;text-align:left}.timer-button:hover{background-color:var(--light-bg);border-color:var(--accent-color);transform:translateY(-2px);box-shadow:0 4px 12px #0003}.timer-label{font-size:1.4rem;font-weight:700;color:var(--accent-color);margin-bottom:8px}.timer-description{font-size:1rem;opacity:.9;line-height:1.4}.timer-info{background-color:var(--light-bg);border-radius:8px;padding:15px;margin-top:20px;font-size:.9rem;opacity:.8}.quiz-timer{position:absolute;top:10px;right:10px;background-color:var(--accent-color);color:var(--primary-bg);padding:8px 12px;border-radius:20px;font-weight:700;font-size:1.1rem}.quiz-timer.warning{background-color:var(--incorrect-color);color:#fff;animation:pulse 1s infinite}@keyframes pulse{0%{opacity:1}50%{opacity:.7}to{opacity:1}}.category-selection{text-align:left;margin-bottom:25px}.category-item{margin-bottom:12px}.category-item.select-all{border-bottom:2px solid var(--light-bg);padding-bottom:15px;margin-bottom:20px}.category-label{display:flex;align-items:center;cursor:pointer;padding:8px 12px;border-radius:8px;transition:background-color .2s;position:relative}.category-label:hover{background-color:var(--light-bg)}.category-label input[type=checkbox]{opacity:0;position:absolute;cursor:pointer}.checkmark{width:20px;height:20px;border:2px solid var(--accent-color);border-radius:4px;margin-right:12px;position:relative;transition:all .2s;flex-shrink:0}.category-label input[type=checkbox]:checked+.checkmark{background-color:var(--accent-color)}.category-label input[type=checkbox]:checked+.checkmark:after{content:"";position:absolute;left:6px;top:2px;width:5px;height:10px;border:solid var(--primary-bg);border-width:0 2px 2px 0;transform:rotate(45deg)}.category-name{font-weight:500;font-size:1.1rem}.select-all .category-name{font-weight:700;color:var(--accent-color)}.category-count{margin-left:auto;opacity:.7;font-size:.9rem}.categories-list{max-height:300px;overflow-y:auto;border:1px solid var(--light-bg);border-radius:8px;padding:10px}.selection-summary{background-color:var(--light-bg);border-radius:8px;padding:15px;margin:20px 0;font-size:.95rem}.selection-summary p{margin:5px 0}.loading-container{margin:20px 0;text-align:center}.loading-text{margin-bottom:10px;font-weight:700;color:var(--accent-color)}.progress-bar{width:100%;height:8px;background-color:var(--light-bg);border-radius:4px;overflow:hidden}.progress-fill{height:100%;background-color:var(--accent-color);transition:width .3s ease}.start-flashcards-button{background:linear-gradient(45deg,#4f4a72,var(--accent-color));font-size:1.2rem;padding:16px 32px}