/* ======== RESET & BASE STYLES ======== */
 
 * {
     box-sizing: border-box;
     margin: 0;
     padding: 0;
     font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
 }
 
 body {
     background: linear-gradient(135deg, #FF8080 0%, #B30000 100%);
     min-height: 100vh;
     display: flex;
     justify-content: center;
     align-items: center;
     padding: 20px;
     color: #333;
     line-height: 1.5;
 }
 /* ======== CONTAINERS & LAYOUT ======== */
 
 .container,
 .info-form-container,
 .exam-type-container {
     background-color: white;
     border-radius: 15px;
     box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
     width: 100%;
     max-width: 900px;
     overflow: hidden;
     padding: 30px;
     margin: 20px auto;
 }
 
 .content {
     display: flex;
     gap: 25px;
 }
 /* ======== HEADER & TYPOGRAPHY ======== */
 
 header {
     text-align: center;
     margin-bottom: 25px;
     padding-bottom: 20px;
     border-bottom: 2px solid #f0f0f0;
 }
 
 h1,
 h2 {
     color: #2c3e50;
     font-size: 2.2rem;
     margin-bottom: 10px;
 }
 
 .description {
     color: #7f8c8d;
     font-size: 1.1rem;
     max-width: 700px;
     margin: 0 auto;
 }
 
 .title {
     font-size: 2rem;
 }
 
 .sidebar-title {
     font-size: 1.2rem;
     margin-bottom: 15px;
     color: #2c3e50;
     text-align: center;
     font-weight: 600;
 }
 
 .question-title {
     font-size: 1.5rem;
     color: #2c3e50;
     font-weight: 600;
 }
 
 .result-title {
     font-size: 2rem;
     color: #2c3e50;
     margin-bottom: 20px;
 }
 /* ======== QUESTION SIDEBAR ======== */
 
 .questions-sidebar {
     width: 250px;
     background: #f8f9fa;
     border-radius: 10px;
     padding: 20px;
     box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.05);
 }
 
 .questions-grid {
     display: grid;
     grid-template-columns: repeat(5, 1fr);
     gap: 10px;
 }
 
 .question-number {
     width: 35px;
     height: 35px;
     display: flex;
     align-items: center;
     justify-content: center;
     border-radius: 50%;
     background: #e0e0e0;
     cursor: pointer;
     font-weight: 500;
     transition: all 0.3s ease;
 }
 
 .question-number:hover {
     background: #B30000;
     color: white;
 }
 
 .question-number.active {
     background: #B30000;
     color: white;
     transform: scale(1.1);
     box-shadow: 0 0 10px rgba(219, 52, 52, 0.5);
 }
 
 .question-number.answered {
     background: #67a9ff;
     box-shadow: 0 0 10px rgba(52, 124, 219, 0.5);
     color: white;
 }
 /* ======== QUESTION CONTENT ======== */
 
 .question-container {
     flex: 1;
     padding: 20px;
 }
 
 .question-header {
     display: flex;
     justify-content: space-between;
     align-items: center;
     margin-bottom: 20px;
     padding-bottom: 15px;
     border-bottom: 1px solid #eee;
 }
 
 .question-text {
     font-size: 1.2rem;
     line-height: 1.6;
     margin-bottom: 25px;
     color: #34495e;
     background: #f8f9fa;
     padding: 20px;
     border-radius: 10px;
     border-left: 4px solid #B30000;
 }
 
 .question-text p {
     margin-bottom: 15px;
 }
 /* ======== QUESTION IMAGE FIX ======== */
 
 .question-image {
     max-width: 100%;
     max-height: 500px;
     /* Tăng kích thước tối đa */
     height: auto;
     margin: 15px auto;
     border: 1px solid #ddd;
     border-radius: 6px;
     /* Bo tròn hơn */
     padding: 8px;
     /* Tăng padding */
     background-color: white;
     object-fit: contain;
     box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
     /* Thêm bóng đổ */
     cursor: zoom-in;
     /* Hiển thị biểu tượng phóng to */
     transition: all 0.3s ease;
     /* Hiệu ứng mượt mà */
 }
 
 .question-image:hover {
     transform: scale(1.02);
     /* Hiệu ứng phóng nhẹ khi hover */
     box-shadow: 0 6px 15px rgba(0, 0, 0, 0.2);
     /* Tăng bóng khi hover */
 }
 
 .image-error {
     background: #ffebee;
     border: 1px solid #e74c3c;
     padding: 15px;
     border-radius: 8px;
     color: #e74c3c;
     margin: 15px 0;
     text-align: center;
     font-size: 0.9rem;
 }
 /* ======== OPTIONS & FEEDBACK ======== */
 
 .options-container {
     margin-bottom: 25px;
 }
 
 .option {
     display: flex;
     align-items: center;
     padding: 15px;
     margin-bottom: 12px;
     border-radius: 8px;
     background: #f8f9fa;
     cursor: pointer;
     transition: all 0.2s ease;
     border: 2px solid transparent;
 }
 
 .option:hover {
     background: #e3f2fd;
     transform: translateY(-2px);
 }
 
 .option.selected {
     border-color: #B30000;
     background: #e3f2fd;
 }
 
 .option.correct {
     border-color: #2ecc71;
     background: #e8f5e9;
 }
 
 .option.incorrect {
     border-color: #e95949;
     background: #ffebee;
 }
 
 .option-letter {
     width: 30px;
     height: 30px;
     display: flex;
     align-items: center;
     justify-content: center;
     border-radius: 50%;
     background: #B30000;
     color: white;
     font-weight: bold;
     margin-right: 15px;
     flex-shrink: 0;
 }
 
 .option-text {
     flex: 1;
 }
 
 .feedback {
     padding: 20px;
     border-radius: 10px;
     margin-top: 20px;
     display: none;
     animation: fadeIn 0.5s ease;
 }
 
 .feedback.show {
     display: block;
 }
 
 .feedback.correct {
     background: #e8f5e9;
     border: 1px solid #2ecc71;
     color: #2ecc71;
 }
 
 .feedback.incorrect {
     background: #ffebee;
     border: 1px solid #e74c3c;
     color: #e74c3c;
 }
 /* ======== NAVIGATION & BUTTONS ======== */
 
 .navigation {
     display: flex;
     gap: 10px;
     justify-content: space-between;
     margin-top: 20px;
     flex-wrap: wrap;
     margin-bottom: 20px;
 }
 
 button {
     padding: 12px 25px;
     border: none;
     border-radius: 8px;
     font-size: 1rem;
     font-weight: 600;
     cursor: pointer;
     transition: all 0.3s ease;
 }
 
 .btn-prev {
     background: #7f8c8d;
     color: white;
     width: 100%;
 }
 
 .btn-next {
     background: #B30000;
     color: white;
     width: 100%;
 }
 
 button:disabled {
     opacity: 0.6;
     cursor: not-allowed;
 }
 
 .btn-prev:hover:not(:disabled) {
     background: #95a5a6;
     transform: translateX(-3px);
 }
 
 .btn-next:hover:not(:disabled) {
     background: #5c0000;
     transform: translateX(3px);
 }
 
 .btn-start {
     background: #B30000;
     color: white;
     padding: 12px 25px;
     border: none;
     border-radius: 8px;
     font-size: 1.1rem;
     font-weight: 600;
     cursor: pointer;
     transition: all 0.3s ease;
     display: block;
     width: 100%;
     margin-top: 20px;
 }
 
 .btn-prev,
 .btn-next,
 #submit-btn {
     flex: 1;
     min-width: 120px;
 }
 
 .btn-start:hover {
     background: #FF8080;
     transform: translateY(-2px);
 }
 
 .btn-start:disabled {
     background: #7f8c8d;
     cursor: not-allowed;
 }
 
 .restart-btn {
     background: #2ecc71;
     color: white;
     padding: 10px;
     font-size: 1.1rem;
     margin-top: 20px;
 }
 
 .restart-btn:hover {
     background: #27ae60;
     transform: scale(1.05);
 }
 
 .button-group {
     display: flex;
     flex-wrap: wrap;
     gap: 10px;
     justify-content: center;
     margin-top: 20px;
 }
 
 .btn {
     padding: 12px 20px;
     font-size: 16px;
     border: none;
     border-radius: 6px;
     color: white;
     cursor: pointer;
     transition: background 0.3s ease;
     text-decoration: none;
 }
 /* Style từng nút */
 
 .retry {
     background-color: #2863a7;
     /* xanh lá */
 }
 
 .retry:hover {
     background-color: #214e88;
 }
 
 .home {
     background-color: #B30000;
     /* đỏ */
 }
 
 .home:hover {
     background-color: #e93042;
 }
 /* Responsive: màn nhỏ thì full width */
 
 @media (max-width: 600px) {
     .btn {
         width: 100%;
         text-align: center;
     }
     .navigation {
         justify-content: space-between;
         width: 100%;
     }
 }
 /* ======== RESULTS SECTION ======== */
 
 .result-container {
     text-align: center;
     padding: 30px;
     display: none;
 }
 
 .score {
     font-size: 3rem;
     font-weight: bold;
     color: #B30000;
     margin: 20px 0;
 }
 /* ======== FORM STYLES ======== */
 
 .form-group {
     margin-bottom: 20px;
 }
 
 .form-group label {
     display: block;
     margin-bottom: 8px;
     font-weight: 600;
     color: #2c3e50;
 }
 
 .form-group input {
     width: 100%;
     padding: 12px;
     border: 1px solid #ddd;
     border-radius: 8px;
     font-size: 1rem;
     transition: border-color 0.3s;
 }
 
 .form-group input:focus {
     border-color: #B30000;
     outline: none;
     box-shadow: 0 0 0 3px rgba(179, 0, 0, 0.2);
 }
 /* ======== PROGRESS & UTILITY CLASSES ======== */
 
 .progress-container {
     margin-top: 20px;
 }
 
 .progress-bar {
     height: 10px;
     background: #ecf0f1;
     border-radius: 5px;
     overflow: hidden;
 }
 
 .progress {
     height: 100%;
     background: #2ecc71;
     width: 0%;
     transition: width 0.5s ease;
 }
 
 .progress-text {
     text-align: right;
     margin-top: 5px;
     font-size: 0.9rem;
     color: #7f8c8d;
 }
 
 .hidden {
     display: none;
 }
 
 .success-message {
     background: #e8f5e9;
     border: 1px solid #2ecc71;
     color: #2ecc71;
     padding: 15px;
     border-radius: 8px;
     margin-bottom: 20px;
     text-align: center;
     display: none;
 }
 
 .success-message.show {
     display: block;
     animation: fadeIn 0.5s ease;
 }
 /* ======== ANIMATIONS ======== */
 
 @keyframes fadeIn {
     from {
         opacity: 0;
     }
     to {
         opacity: 1;
     }
 }
 /* ======== RESPONSIVE DESIGN ======== */
 
 @media (max-width: 768px) {
     .content {
         flex-direction: column;
     }
     .questions-sidebar {
         width: 100%;
         margin-bottom: 20px;
     }
     .questions-grid {
         grid-template-columns: repeat(6, 1fr);
     }
     .container,
     .info-form-container,
     .exam-type-container {
         padding: 20px;
     }
     .exam-types {
         flex-direction: column;
         align-items: center;
     }
     .exam-type-btn {
         width: 100%;
         max-width: 300px;
         margin-bottom: 10px;
     }
     .question-image {
         max-height: 400px;
         /* Giảm nhẹ cho màn hình tablet */
     }
 }
 
 @media (max-width: 480px) {
     .questions-grid {
         grid-template-columns: repeat(4, 1fr);
     }
     h1 {
         font-size: 1.8rem;
     }
     .container,
     .info-form-container,
     .exam-type-container {
         padding: 15px;
     }
     .option {
         padding: 10px;
     }
     .option-letter {
         width: 25px;
         height: 25px;
         font-size: 0.9rem;
     }
     .btn-prev,
     .btn-next {
         padding: 12px 12px;
         font-size: 0.9rem;
         width: 100%;
         text-align: center;
         flex-direction: column;
     }
     .question-image {
         max-height: 300px;
         /* Giảm hơn cho mobile */
         padding: 5px;
     }
     .exam-type-btn {
         font-size: 1rem;
         padding: 12px;
     }
 }
 /* cho ảnh câu hỏi tự động co và không tràn khung */
 
 .question-content img {
     max-width: 100%;
     height: auto;
     display: block;
     margin: 8px 0;
 }
 /* ======== EXAM TYPE SELECTION ======== */
 
 .exam-types {
     display: flex;
     flex-direction: column;
     gap: 15px;
     margin-top: 20px;
 }
 
 .exam-type-btn {
     padding: 15px;
     background: #B30000;
     color: white;
     border: none;
     border-radius: 8px;
     font-size: 1.1rem;
     font-weight: 600;
     cursor: pointer;
     transition: all 0.3s ease;
     text-align: center;
 }
 
 .exam-type-btn:hover {
     background: #FF8080;
     transform: translateY(-3px);
 }
 
 .exam-title {
     display: block;
     font-size: 1.2rem;
     font-weight: bold;
     margin-bottom: 5px;
 }
 
 .exam-details {
     display: block;
     font-size: 0.9rem;
     opacity: 0.9;
 }
 /* ======== TIMER POSITION FIX ======== */
 
 .timer-container {
     text-align: center;
     margin: 20px auto;
     padding: 15px;
     background: #f8f9fa;
     border-radius: 10px;
     box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
     max-width: 300px;
 }
 
 .timer {
     font-size: 2rem;
     font-weight: bold;
     color: #2c3e50;
     font-family: monospace;
 }
 
 .timer.warning {
     color: #e74c3c;
     animation: pulse 1s infinite;
 }
 
 .timer-label {
     font-size: 0.9rem;
     color: #7f8c8d;
     margin-top: 5px;
 }
 
 @keyframes pulse {
     0% {
         opacity: 1;
     }
     50% {
         opacity: 0.5;
     }
     100% {
         opacity: 1;
     }
 }
 
 .logo-img {
     height: 60px;
     width: auto;
     object-fit: contain;
 }
 /* CSS mới cho nút học viên taylaimoi
 
 .skip-info-container {
     text-align: center;
     padding-top: 24px;
     border-top: 1px solid #eee;
 }
 
 .skip-text {
     color: #666;
     margin-bottom: 12px;
     font-size: 15px;
 }
 
 .btn-skip-info {
     color: #1A2F51;
     border: none;
     border-radius: 5px;
     padding: 12px 24px;
     width: 100%;
     font-size: 16px;
     cursor: pointer;
     transition: background-color 0.3s;
     font-weight: 600;
 }
 
 .btn-skip-info:hover {
     background-color: #1A2F51;
     color: white;
 }
 
 .btn-skip-info:active {
     transform: scale(0.98);
 } */
 
 .sub-text {
     text-align: center;
     padding-top: 20px;
     border-top: 1px solid rgba(255, 255, 255, 0.2);
     font-size: 1rem;
     opacity: 0.8;
 }
 /* Css câu có hình ảnh*/
 
 #image-overlay {
     display: flex;
     position: fixed;
     top: 0;
     left: 0;
     width: 100%;
     height: 100%;
     background-color: rgba(0, 0, 0, 0.9);
     justify-content: center;
     align-items: center;
     z-index: 1000;
 }
 
 #image-overlay.hidden {
     display: none;
 }
 
 #image-overlay img {
     max-width: 90%;
     max-height: 90%;
     border: 2px solid white;
     border-radius: 5px;
     box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
 }
 
 .close-btn {
     position: absolute;
     top: 20px;
     right: 30px;
     color: white;
     font-size: 40px;
     cursor: pointer;
     transition: color 0.3s;
 }
 
 .close-btn:hover {
     color: #FF8080;
 }
 /* Thêm các style mới cho tính năng zoom */
 
 #overlay-image {
     max-width: 90%;
     max-height: 90%;
     border: 2px solid white;
     border-radius: 5px;
     box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
     cursor: zoom-in;
     /* Hiển thị cursor zoom-in */
     transition: transform 0.3s ease;
     /* Hiệu ứng zoom mượt mà */
     transform-origin: center center;
     /* Điểm bắt đầu zoom */
 }
 
 .zoomed {
     cursor: move !important;
     /* Khi zoom thì cursor thành move */
     transform: scale(1.5);
     /* Mức zoom mặc định */
 }
 
 .zoom-controls {
     position: absolute;
     bottom: 20px;
     left: 50%;
     transform: translateX(-50%);
     display: flex;
     gap: 15px;
     z-index: 1001;
 }
 
 .zoom-btn {
     width: 40px;
     height: 40px;
     border-radius: 50%;
     background: rgba(255, 255, 255, 0.7);
     color: #333;
     display: flex;
     align-items: center;
     justify-content: center;
     font-size: 24px;
     cursor: pointer;
     transition: all 0.3s ease;
 }
 
 .zoom-btn:hover {
     background: rgba(255, 255, 255, 0.9);
     transform: scale(1.1);
 }
 /* Thêm style cho nút khi disabled */
 
 .btn-prev:disabled,
 .btn-next:disabled {
     opacity: 0.5;
     cursor: not-allowed;
     transform: none !important;
 }
 /* Thêm style cho nút nộp bài */
 
 #submit-btn {
     background: #2ecc71;
     color: white;
     padding: 12px 25px;
     border: none;
     border-radius: 8px;
     font-size: 1rem;
     font-weight: 600;
     cursor: pointer;
     transition: all 0.3s ease;
     display: none;
     /* Ẩn mặc định */
     width: 100%;
 }
 
 #submit-btn:hover:not(:disabled) {
     background: #27ae60;
     transform: translateY(-2px);
 }
 /* Responsive cho nút nộp bài */
 
 @media (max-width: 768px) {
     .navigation {
         flex-direction: column;
     }
 }
 /* Modal xác nhận nộp bài */
 
 .modal {
     position: fixed;
     top: 0;
     left: 0;
     width: 100%;
     height: 100%;
     background-color: rgba(0, 0, 0, 0.7);
     display: flex;
     justify-content: center;
     align-items: center;
     z-index: 2000;
 }
 /* Đảm bảo modal hiển thị trên mọi thứ */
 
 .modal.hidden {
     display: none;
 }
 
 .modal-content {
     background-color: white;
     padding: 30px;
     border-radius: 10px;
     max-width: 500px;
     width: 90%;
     text-align: center;
     box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
 }
 
 .modal-buttons {
     display: flex;
     justify-content: center;
     gap: 15px;
     margin-top: 20px;
 }
 
 .modal-buttons button {
     padding: 10px 20px;
     border: none;
     border-radius: 5px;
     cursor: pointer;
     font-size: 16px;
     font-weight: 600;
 }
 
 #confirm-submit {
     background: #2ecc71;
     color: white;
 }
 
 #cancel-submit {
     background: #e74c3c;
     color: white;
 }