:root{--primary-color:#4f46e5;--primary-hover:#4338ca;--bg-color:#f3f4f6;--card-bg:#fff;--text-main:#1f2937;--text-muted:#6b7280;--correct-color:#10b981;--wrong-color:#ef4444;--border-color:#e5e7eb;--font-family:"Inter", system-ui, -apple-system, sans-serif}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-family);background-color:var(--bg-color);color:var(--text-main);-webkit-font-smoothing:antialiased;line-height:1.5}.app-container{flex-direction:column;max-width:600px;min-height:100vh;margin:0 auto;padding:20px;display:flex}.app-header{justify-content:space-between;align-items:center;margin-bottom:24px;display:flex}.app-header h1{color:var(--primary-color);font-size:1.5rem;font-weight:700}.progress{color:var(--text-muted);background:#fff;border-radius:20px;padding:6px 12px;font-size:.9rem;font-weight:600;box-shadow:0 1px 3px #0000001a}.quiz-card{background:var(--card-bg);border-radius:16px;padding:24px;transition:transform .2s ease-in-out;box-shadow:0 10px 25px -5px #0000001a,0 8px 10px -6px #0000001a}.card-header{justify-content:space-between;align-items:center;margin-bottom:16px;display:flex}.badge{color:var(--primary-color);letter-spacing:.05em;background-color:#eef2ff;border-radius:6px;padding:4px 10px;font-size:.8rem;font-weight:600}.translate-toggle{border:1px solid var(--border-color);cursor:pointer;color:var(--text-main);background:0 0;border-radius:20px;padding:6px 12px;font-size:.85rem;font-weight:600;transition:all .2s}.translate-toggle:hover{background:var(--bg-color);border-color:var(--text-muted)}.instruction{color:var(--text-muted);margin-bottom:12px;font-size:.9rem;font-weight:500}.question-text{margin-bottom:24px;font-size:1.25rem;font-weight:700;line-height:1.4}.options-container{flex-direction:column;gap:12px;display:flex}.option-btn{text-align:left;border:2px solid var(--border-color);cursor:pointer;width:100%;color:var(--text-main);background:#fff;border-radius:12px;align-items:center;padding:16px;font-size:1.05rem;font-weight:500;transition:all .2s;display:flex}.option-btn:not(:disabled):hover{border-color:var(--primary-color);background-color:#f8fafc}.option-btn:disabled{cursor:default}.option-btn.correct{border-color:var(--correct-color);color:#065f46;background-color:#ecfdf5}.option-btn.wrong{border-color:var(--wrong-color);color:#991b1b;background-color:#fef2f2}.play-audio-btn{color:#059669;cursor:pointer;background-color:#ecfdf5;border:2px solid #34d399;border-radius:12px;justify-content:center;align-items:center;gap:8px;width:100%;margin-bottom:20px;padding:12px;font-size:1.1rem;font-weight:700;transition:all .2s;display:flex}.play-audio-btn:hover{background-color:#d1fae5;transform:translateY(-2px)}.play-audio-btn:active{transform:translateY(0)}.lecture-btn{color:#d97706;cursor:pointer;background-color:#fef3c7;border:1px solid #fcd34d;border-radius:8px;width:100%;margin-bottom:12px;padding:10px;font-size:1rem;font-weight:600;transition:all .2s}.lecture-btn:hover{background-color:#fde68a}.opt-number{margin-right:12px;font-size:1.1rem;font-weight:700}.feedback-section{border-radius:12px;margin-top:24px;padding:16px;animation:.4s ease-out fadeIn}.correct-bg{background-color:#ecfdf5;border:1px solid #a7f3d0}.wrong-bg{background-color:#fef2f2;border:1px solid #fecaca}.feedback-section h3{margin-bottom:8px;font-size:1.1rem}.correct-bg h3{color:#059669}.wrong-bg h3{color:#dc2626}.explanation{color:var(--text-main);margin-bottom:16px;font-size:.95rem;line-height:1.5}.next-btn{background-color:var(--primary-color);color:#fff;cursor:pointer;border:none;border-radius:8px;width:100%;padding:12px;font-size:1rem;font-weight:600;transition:background-color .2s}.next-btn:hover{background-color:var(--primary-hover)}.result-screen{text-align:center;justify-content:center;align-items:center}.result-screen h2{color:var(--primary-color);margin-bottom:16px;font-size:2rem}.score-board{background:#fff;border-radius:12px;width:100%;margin-bottom:24px;padding:20px;font-size:1.25rem;font-weight:600;box-shadow:0 4px 6px -1px #0000001a}.restart-btn{background-color:var(--primary-color);color:#fff;cursor:pointer;border:none;border-radius:8px;padding:14px 28px;font-size:1.1rem;font-weight:600;transition:background-color .2s}.restart-btn:hover{background-color:var(--primary-hover)}@keyframes fadeIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.admin-container{max-width:800px;min-height:100vh;font-family:var(--font-family);margin:0 auto;padding:40px 20px}.login-screen{flex-direction:column;justify-content:center;align-items:center;display:flex}.login-form{background:#fff;border-radius:12px;flex-direction:column;gap:16px;width:100%;max-width:360px;margin-top:24px;padding:32px;display:flex;box-shadow:0 10px 15px -3px #0000001a}.login-form input{border:1px solid var(--border-color);border-radius:6px;padding:12px;font-size:1rem}.login-form button{background-color:var(--primary-color);color:#fff;cursor:pointer;border:none;border-radius:6px;padding:12px;font-size:1rem;font-weight:700}.admin-header{justify-content:space-between;align-items:center;margin-bottom:32px;display:flex}.admin-header h2{color:var(--primary-color)}.back-link{color:var(--text-muted);font-weight:600;text-decoration:none}.admin-layout{grid-template-columns:1fr 1fr;gap:24px;display:grid}@media (width<=768px){.admin-layout{grid-template-columns:1fr}}.admin-form{background:#fff;border-radius:12px;flex-direction:column;gap:16px;padding:24px;display:flex;box-shadow:0 4px 6px -1px #0000001a}.form-group{flex-direction:column;gap:8px;display:flex}.form-group label{color:var(--text-main);font-size:.9rem;font-weight:600}.form-group input,.form-group textarea{border:1px solid var(--border-color);border-radius:6px;padding:10px;font-family:inherit}.generate-btn{color:#fff;cursor:pointer;background-color:#10b981;border:none;border-radius:8px;margin-top:10px;padding:12px;font-size:1.05rem;font-weight:700}.admin-output{color:#fff;background:#1f2937;border-radius:12px;flex-direction:column;padding:24px;display:flex}.admin-output h3{margin-bottom:8px}.help-text{color:#9ca3af;margin-bottom:16px;font-size:.85rem}.json-box{color:#a7f3d0;white-space:pre-wrap;word-break:break-all;background:#111827;border-radius:8px;flex-grow:1;margin-bottom:16px;padding:16px;font-size:.85rem;overflow-x:auto}.copy-btn{color:#fff;cursor:pointer;background-color:#3b82f6;border:none;border-radius:6px;padding:10px;font-weight:700}.modal-overlay{z-index:1000;background-color:#00000080;justify-content:center;align-items:center;width:100vw;height:100vh;padding:20px;display:flex;position:fixed;top:0;left:0}.modal-content{background:#fff;border-radius:16px;width:100%;max-width:500px;max-height:90vh;padding:24px;animation:.3s ease-out slideUp;position:relative;overflow-y:auto;box-shadow:0 20px 25px -5px #0000001a}.modal-content.loading{min-height:200px;color:var(--text-muted);justify-content:center;align-items:center;font-size:1.2rem;display:flex}.close-btn{color:var(--text-muted);cursor:pointer;background:0 0;border:none;font-size:1.5rem;transition:color .2s;position:absolute;top:16px;right:16px}.close-btn:hover{color:var(--text-main)}.lecture-badge{color:#d97706;background-color:#fef3c7;border-radius:6px;margin-bottom:12px;padding:4px 10px;font-size:.8rem;font-weight:700;display:inline-block}.lecture-section h2{color:var(--primary-color);margin-bottom:16px;font-size:1.4rem;line-height:1.3}.lecture-body{color:var(--text-main);border-bottom:1px solid var(--border-color);margin-bottom:24px;padding-bottom:24px;font-size:1rem;line-height:1.6}.lecture-body p{margin-bottom:12px}.comments-section h3{color:var(--text-main);margin-bottom:16px;font-size:1.1rem}.comment-input-area{flex-direction:column;gap:12px;margin-bottom:24px;display:flex}.comment-input-area textarea{border:1px solid var(--border-color);resize:vertical;border-radius:8px;width:100%;min-height:80px;padding:12px;font-family:inherit;font-size:.95rem}.comment-input-area textarea:focus{border-color:var(--primary-color);outline:none;box-shadow:0 0 0 2px #4f46e533}.comment-input-area button{background-color:var(--primary-color);color:#fff;cursor:pointer;border:none;border-radius:6px;align-self:flex-end;padding:8px 16px;font-weight:600;transition:background-color .2s}.comment-input-area button:hover{background-color:var(--primary-hover)}.no-comments{color:var(--text-muted);text-align:center;padding:20px 0;font-style:italic}.comments-list{flex-direction:column;gap:12px;display:flex}.comment-item{border:1px solid var(--border-color);background-color:#f9fafb;border-radius:8px;padding:12px}.comment-text{color:var(--text-main);white-space:pre-wrap;margin-bottom:8px;font-size:.95rem}.comment-footer{justify-content:space-between;align-items:center;display:flex}.comment-date{color:var(--text-muted);font-size:.75rem}.delete-comment-btn{color:var(--wrong-color);cursor:pointer;background:0 0;border:none;font-size:.8rem}.delete-comment-btn:hover{text-decoration:underline}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}