:root {
     --primary-color: #5E56E5;
     --primary-light: #7B73FF;
     --primary-dark: #4A42CC;
     --text-primary: #2D3748;
     --text-secondary: #718096;
     --bg-primary: #FFFFFF;
     --bg-secondary: #F7FAFC;
     --bg-card: #FFFFFF;
     --border-color: #E2E8F0;
     --border-radius: 12px;
     --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
     --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
     --transition: all 0.3s ease;
     --gradient-primary: linear-gradient(135deg, var(--primary-color), var(--primary-light));
 }

 .dark-theme {
     --text-primary: #F7FAFC;
     --text-secondary: #CBD5E0;
     --bg-primary: #1A202C;
     --bg-secondary: #2D3748;
     --bg-card: #2D3748;
     --border-color: #4A5568;
     --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.3);
     --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.4);
 }

 * {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
 }

 html {
     scroll-behavior: smooth;
 }

 body {
     font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
     background-color: var(--bg-primary);
     color: var(--text-primary);
     line-height: 1.6;
     transition: var(--transition);
 }

 .container {
     max-width: 1200px;
     margin: 0 auto;
     padding: 0 20px;
 }

 .header {
     background: var(--bg-primary);
     border-bottom: 1px solid var(--border-color);
     position: sticky;
     top: 0;
     z-index: 1000;
     backdrop-filter: blur(10px);
 }

 .header-content {
     display: flex;
     align-items: center;
     justify-content: space-between;
     padding: 12px 0;
 }

 .logo {
     display: flex;
     align-items: center;
     gap: 10px;
 }

 .logo-icon {
     font-size: 28px;
     color: var(--primary-color);
 }

 .logo-text h1 {
     font-size: 22px;
     font-weight: 800;
     background: var(--gradient-primary);
     -webkit-background-clip: text;
     background-clip: text;
     color: transparent;
     margin: 0;
 }

 .header-nav {
     display: flex;
     gap: 6px;
     margin-left: 20px;
 }

 .nav-btn {
     padding: 8px 16px;
     background: var(--bg-secondary);
     color: var(--text-secondary);
     border-radius: 8px;
     font-weight: 600;
     font-size: 13px;
     border: none;
     cursor: pointer;
     transition: var(--transition);
     text-decoration: none;
     display: inline-flex;
     align-items: center;
     gap: 6px;
     border: 1px solid transparent;
 }

 .nav-btn:hover,
 .nav-btn.active {
     background: var(--primary-color);
     color: white;
     transform: translateY(-2px);
     border-color: var(--primary-color);
     box-shadow: 0 4px 12px rgba(94, 86, 229, 0.2);
 }

 .nav-btn i {
     font-size: 14px;
 }

 .theme-toggle {
     background: var(--bg-secondary);
     border: 1px solid var(--border-color);
     width: 40px;
     height: 40px;
     border-radius: 50%;
     display: flex;
     align-items: center;
     justify-content: center;
     cursor: pointer;
     color: var(--text-secondary);
     transition: var(--transition);
     margin-left: 10px;
 }

 .theme-toggle:hover {
     background: var(--primary-color);
     color: white;
     transform: rotate(30deg);
 }

 .hero-section {
     padding: 60px 0 30px;
     min-height: 80vh;
     display: flex;
     align-items: center;
 }

 .hero-content {
     display: grid;
     grid-template-columns: 1fr 1fr;
     gap: 50px;
     align-items: center;
 }

 .hero-badge {
     display: inline-block;
     background: var(--gradient-primary);
     color: white;
     padding: 6px 14px;
     border-radius: 16px;
     font-weight: 600;
     font-size: 13px;
     margin-bottom: 20px;
 }

 .hero-title {
     font-size: 40px;
     line-height: 1.1;
     margin-bottom: 16px;
 }

 .highlight {
     background: var(--gradient-primary);
     -webkit-background-clip: text;
     background-clip: text;
     color: transparent;
 }

 .hero-subtitle {
     font-size: 16px;
     color: var(--text-secondary);
     margin-bottom: 28px;
     max-width: 500px;
 }

 .hero-actions {
     display: flex;
     gap: 12px;
     align-items: center;
 }

 .mascot-container {
     position: relative;
     display: flex;
     flex-direction: column;
     align-items: center;
 }

 .mascot-img {
     width: 280px;
     height: 280px;
     object-fit: scale-down;
     animation: bounce 3s ease-in-out infinite;
     transition: var(--transition);
     cursor: pointer;
    
 }

 @keyframes bounce {

     0%,
     100% {
         transform: translateY(0) scale(1);
     }

     50% {
         transform: translateY(-10px) scale(1.03);
     }
 }

 .tests-section {
     padding: 60px 0;
 }

 .section-header {
     text-align: center;
     margin-bottom: 40px;
 }

 .section-title {
     font-size: 36px;
     background: var(--gradient-primary);
     -webkit-background-clip: text;
     background-clip: text;
     color: transparent;
     margin-bottom: 12px;
 }

 .section-subtitle {
     font-size: 16px;
     color: var(--text-secondary);
     max-width: 600px;
     margin: 0 auto 24px;
 }

 .section-controls {
     display: flex;
     justify-content: space-between;
     align-items: center;
     flex-wrap: wrap;
     gap: 16px;
     margin-top: 24px;
 }

 .section-filters {
     display: flex;
     gap: 8px;
     flex-wrap: wrap;
 }

 .filter-btn {
     padding: 8px 20px;
     background: var(--bg-secondary);
     color: var(--text-secondary);
     border-radius: 16px;
     font-weight: 600;
     font-size: 13px;
     display: flex;
     align-items: center;
     gap: 6px;
     transition: var(--transition);
     border: none;
     cursor: pointer;
     border: 1px solid transparent;
 }

 .filter-btn.active {
     background: var(--primary-color);
     color: white;
     border-color: var(--primary-color);
 }

 .search-box {
     display: flex;
     align-items: center;
     gap: 10px;
     background: var(--bg-secondary);
     padding: 10px 16px;
     border-radius: 16px;
     color: var(--text-secondary);
     border: 1px solid transparent;
     transition: var(--transition);
 }

 .search-box:focus-within {
     border-color: var(--primary-color);
     box-shadow: 0 0 0 3px rgba(94, 86, 229, 0.1);
 }

 .search-input {
     border: none;
     background: transparent;
     color: var(--text-primary);
     font-size: 13px;
     width: 180px;
     outline: none;
 }

 .search-input::placeholder {
     color: var(--text-secondary);
 }

 .tests-grid {
     display: grid;
     grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
     gap: 20px;
     margin-bottom: 40px;
 }

 .test-card {
     background: var(--bg-card);
     border-radius: var(--border-radius);
     border: 1px solid var(--border-color);
     padding: 20px;
     transition: var(--transition);
     display: flex;
     flex-direction: column;
     height: 100%;
     min-height: 360px;
 }

 .test-card:hover {
     transform: translateY(-4px);
     box-shadow: var(--shadow-lg);
     border-color: var(--primary-color);
 }

 .test-badge {
     display: flex;
     gap: 6px;
     margin-bottom: 14px;
 }

 .badge-difficulty {
     padding: 4px 10px;
     border-radius: 10px;
     font-size: 11px;
     font-weight: 600;
 }

 .badge-difficulty.easy {
     background: #E8F5E9;
     color: #2E7D32;
 }

 .badge-difficulty.medium {
     background: #FFF3E0;
     color: #F57C00;
 }

 .badge-difficulty.hard {
     background: #FFEBEE;
     color: #C62828;
 }

 .card-header {
     margin-bottom: 14px;
 }

 .test-category {
     display: inline-flex;
     align-items: center;
     gap: 6px;
     padding: 5px 10px;
     border-radius: 16px;
     font-size: 11px;
     font-weight: 600;
     color: white;
     background: var(--primary-color);
 }

 .test-body {
     flex: 1;
     margin-bottom: 16px;
 }

 .test-title {
     font-size: 18px;
     margin-bottom: 10px;
     line-height: 1.4;
 }

 .test-description {
     color: var(--text-secondary);
     font-size: 13px;
     margin-bottom: 16px;
     line-height: 1.5;
 }

 .test-meta {
     display: flex;
     gap: 16px;
     margin-bottom: 16px;
 }

 .meta-item {
     display: flex;
     align-items: center;
     gap: 5px;
     color: var(--text-secondary);
     font-size: 12px;
 }

 .card-progress {
     margin-top: auto;
 }

 .progress-label {
     display: flex;
     justify-content: space-between;
     font-size: 12px;
     color: var(--text-secondary);
     margin-bottom: 6px;
 }

 .progress-bar {
     width: 100%;
     height: 4px;
     background: var(--border-color);
     border-radius: 2px;
     overflow: hidden;
 }

 .progress-fill {
     height: 100%;
     border-radius: 2px;
 }

 .progress-fill.easy {
     width: 33%;
     background: #4CAF50;
 }

 .progress-fill.medium {
     width: 66%;
     background: #FF9800;
 }

 .progress-fill.hard {
     width: 100%;
     background: #F44336;
 }

 .cta-btn,
 .test-btn {
     background: var(--primary-color);
     color: white;
     border: none;
     cursor: pointer;
     transition: var(--transition);
     font-weight: 600;
     border-radius: 8px;
     border: 1px solid transparent;
 }

 .cta-btn:hover,
 .test-btn:hover {
     background: var(--primary-dark);
     transform: translateY(-2px);
     box-shadow: 0 4px 12px rgba(94, 86, 229, 0.2);
 }

 .cta-btn {
     padding: 14px 28px;
     font-size: 14px;
     display: inline-flex;
     align-items: center;
     gap: 8px;
 }

 .cta-btn.primary {
     background: var(--gradient-primary);
     box-shadow: 0 4px 20px rgba(94, 86, 229, 0.2);
 }

 .test-btn {
     width: 100%;
     padding: 10px;
     font-size: 13px;
     display: flex;
     align-items: center;
     justify-content: center;
     gap: 6px;
 }

 .test-interface {
     display: none;
     position: fixed;
     top: 0;
     left: 0;
     right: 0;
     bottom: 0;
     background: var(--bg-primary);
     z-index: 10000;
     overflow-y: auto;
 }

 .test-interface.active {
     display: block;
 }

 .interface-header {
     padding: 16px 20px;
     border-bottom: 1px solid var(--border-color);
     display: flex;
     justify-content: space-between;
     align-items: center;
     background: var(--bg-secondary);
     position: sticky;
     top: 0;
     z-index: 10;
 }

 .test-back-btn {
     display: flex;
     align-items: center;
     gap: 10px;
     color: var(--text-secondary);
     background: none;
     border: none;
     font-size: 14px;
     cursor: pointer;
     padding: 8px 14px;
     border-radius: 8px;
     transition: var(--transition);
 }

 .test-back-btn:hover {
     background: var(--bg-card);
 }

 .interface-progress {
     flex: 1;
     margin: 0 20px;
 }

 .test-progress-bar {
     height: 4px;
     background: var(--border-color);
     border-radius: 2px;
     overflow: hidden;
     margin-bottom: 6px;
 }

 .test-progress-fill {
     height: 100%;
     background: var(--primary-color);
     transition: width 0.3s ease;
     width: 0%;
 }

 .test-progress-text {
     display: flex;
     justify-content: space-between;
     font-size: 13px;
     color: var(--text-secondary);
 }

 .test-timer {
     display: flex;
     align-items: center;
     gap: 6px;
     color: var(--text-secondary);
     font-weight: 600;
 }

 .test-content {
     max-width: 700px;
     margin: 0 auto;
     padding: 30px 16px;
 }

 .test-question {
     margin-bottom: 30px;
 }

 .question-number {
     display: inline-flex;
     align-items: center;
     justify-content: center;
     width: 28px;
     height: 28px;
     background: var(--primary-color);
     color: white;
     border-radius: 50%;
     font-weight: 600;
     margin-right: 10px;
     font-size: 13px;
 }

 .question-text {
     font-size: 18px;
     font-weight: 600;
     margin-bottom: 20px;
     line-height: 1.4;
 }

 .answers-container {
     display: flex;
     flex-direction: column;
     gap: 10px;
 }

 .answer-option {
     background: var(--bg-card);
     border: 2px solid var(--border-color);
     border-radius: 10px;
     padding: 14px 16px;
     cursor: pointer;
     transition: var(--transition);
     display: flex;
     align-items: center;
     gap: 10px;
 }

 .answer-option.selected {
     border-color: var(--primary-color);
     background: rgba(94, 86, 229, 0.05);
 }

 .answer-radio {
     width: 18px;
     height: 18px;
     border: 2px solid var(--border-color);
     border-radius: 50%;
     display: flex;
     align-items: center;
     justify-content: center;
     transition: var(--transition);
 }

 .answer-option.selected .answer-radio {
     border-color: var(--primary-color);
 }

 .answer-radio-inner {
     width: 8px;
     height: 8px;
     background: var(--primary-color);
     border-radius: 50%;
     display: none;
 }

 .answer-option.selected .answer-radio-inner {
     display: block;
 }

 .answer-text {
     flex: 1;
     color: var(--text-primary);
     font-size: 14px;
     line-height: 1.4;
 }

 .test-navigation {
     display: flex;
     justify-content: space-between;
     gap: 12px;
     margin-top: 30px;
 }

 .test-navigation .nav-btn {
     padding: 12px 24px;
     border-radius: 8px;
     font-size: 14px;
     display: flex;
     align-items: center;
     gap: 8px;
     border: none;
     cursor: pointer;
     font-weight: 600;
 }

 .test-navigation .nav-btn.prev {
     background: var(--bg-secondary);
     color: var(--text-secondary);
 }

 .test-navigation .nav-btn.next,
 .test-navigation .nav-btn.submit {
     background: var(--primary-color);
     color: white;
 }

 .test-navigation .nav-btn:disabled {
     opacity: 0.5;
     cursor: not-allowed;
 }

 .test-results {
     text-align: center;
     padding: 30px 0;
 }

 .results-score {
     font-size: 60px;
     font-weight: 800;
     background: var(--gradient-primary);
     -webkit-background-clip: text;
     background-clip: text;
     margin: 16px 0;
 }

 .results-stats {
     display: grid;
     grid-template-columns: repeat(3, 1fr);
     gap: 16px;
     margin: 30px 0;
 }

 .stat-item {
     background: var(--bg-card);
     padding: 20px;
     border-radius: var(--border-radius);
     text-align: center;
 }

 .stat-value {
     font-size: 28px;
     font-weight: 800;
     color: var(--primary-color);
     margin-bottom: 6px;
 }

 .stat-label {
     color: var(--text-secondary);
     font-size: 13px;
 }

 .results-actions {
     display: flex;
     gap: 12px;
     justify-content: center;
     margin-top: 30px;
 }

 .results-actions .cta-btn.secondary {
     background: var(--bg-secondary);
     color: var(--text-secondary);
 }

 .results-actions .cta-btn.secondary:hover {
     background: var(--text-secondary);
     color: var(--bg-secondary);
 }

 .answers-review {
     text-align: left;
     margin: 30px 0;
 }

 .review-title {
     font-size: 24px;
     margin-bottom: 20px;
     color: var(--primary-color);
 }

 .review-question {
     background: var(--bg-card);
     border-radius: var(--border-radius);
     padding: 20px;
     margin-bottom: 16px;
     border: 1px solid var(--border-color);
 }

 .review-question.correct {
     border-left: 4px solid #4CAF50;
 }

 .review-question.incorrect {
     border-left: 4px solid #F44336;
 }

 .review-question.unanswered {
     border-left: 4px solid #FF9800;
 }

 .review-question-text {
     font-weight: 600;
     margin-bottom: 12px;
 }

 .review-user-answer {
     margin: 8px 0;
     padding: 8px 12px;
     background: var(--bg-secondary);
     border-radius: 6px;
     font-size: 14px;
 }

 .review-user-answer.correct {
     background: #E8F5E9;
     color: #2E7D32;
 }

 .review-user-answer.incorrect {
     background: #FFEBEE;
     color: #C62828;
 }

 .review-correct-answer {
     margin-top: 8px;
     padding: 8px 12px;
     background: #E3F2FD;
     border-radius: 6px;
     color: #1565C0;
     font-size: 14px;
 }

 .help-modal {
     display: none;
     position: fixed;
     top: 0;
     left: 0;
     right: 0;
     bottom: 0;
     background: rgba(0, 0, 0, 0.5);
     z-index: 11000;
     align-items: center;
     justify-content: center;
     padding: 20px;
 }

 .help-modal.active {
     display: flex;
 }

 .help-content {
     background: var(--bg-card);
     border-radius: var(--border-radius);
     max-width: 500px;
     width: 100%;
     max-height: 80vh;
     overflow-y: auto;
     box-shadow: var(--shadow-lg);
 }

 .help-header {
     display: flex;
     justify-content: space-between;
     align-items: center;
     padding: 20px;
     border-bottom: 1px solid var(--border-color);
 }

 .help-title {
     font-size: 20px;
     font-weight: 700;
     color: var(--text-primary);
 }

 .help-close {
     background: none;
     border: none;
     color: var(--text-secondary);
     font-size: 20px;
     cursor: pointer;
     width: 36px;
     height: 36px;
     border-radius: 50%;
     display: flex;
     align-items: center;
     justify-content: center;
     transition: var(--transition);
 }

 .help-close:hover {
     background: var(--bg-secondary);
 }

 .help-body {
     padding: 20px;
 }

 .help-section {
     margin-bottom: 20px;
 }

 .help-section:last-child {
     margin-bottom: 0;
 }

 .help-section h3 {
     font-size: 16px;
     margin-bottom: 10px;
     color: var(--primary-color);
 }

 .help-section p {
     font-size: 14px;
     color: var(--text-secondary);
     line-height: 1.5;
     margin-bottom: 8px;
 }

 .help-section ul {
     list-style: none;
     padding-left: 0;
 }

 .help-section li {
     font-size: 14px;
     color: var(--text-secondary);
     margin-bottom: 6px;
     padding-left: 20px;
     position: relative;
 }

 .help-section li:before {
     content: "•";
     color: var(--primary-color);
     position: absolute;
     left: 0;
 }

 .tests-library {
     position: fixed;
     top: 0;
     left: -400px;
     width: 380px;
     height: 100vh;
     background: var(--bg-primary);
     border-right: 1px solid var(--border-color);
     z-index: 9999;
     transition: transform 0.3s ease;
     display: flex;
     flex-direction: column;
 }

 .tests-library.open {
     transform: translateX(400px);
 }

 .library-header {
     display: flex;
     justify-content: space-between;
     align-items: center;
     padding: 16px 20px;
     border-bottom: 1px solid var(--border-color);
     background: var(--bg-secondary);
 }

 .library-title {
     display: flex;
     align-items: center;
     gap: 10px;
 }

 .library-close {
     width: 36px;
     height: 36px;
     border-radius: 50%;
     background: var(--bg-secondary);
     color: var(--text-secondary);
     display: flex;
     align-items: center;
     justify-content: center;
     font-size: 18px;
     border: none;
     cursor: pointer;
     transition: var(--transition);
 }

 .library-close:hover {
     background: var(--primary-color);
     color: white;
 }

 .library-search {
     padding: 16px 20px;
     border-bottom: 1px solid var(--border-color);
 }

 .search-container {
     display: flex;
     align-items: center;
     gap: 10px;
     background: var(--bg-secondary);
     padding: 10px 14px;
     border-radius: 10px;
 }

 .library-search-input {
     flex: 1;
     border: none;
     background: transparent;
     color: var(--text-primary);
     font-size: 13px;
     outline: none;
 }

 .library-content {
     flex: 1;
     overflow-y: auto;
     padding: 0;
 }

 .tests-list {
     padding: 0;
 }

 .test-list-item {
     padding: 14px 20px;
     border-bottom: 1px solid var(--border-color);
     cursor: pointer;
     display: flex;
     align-items: center;
     gap: 10px;
     transition: var(--transition);
 }

 .test-list-item:hover {
     background: var(--bg-secondary);
 }

 .test-list-icon {
     width: 36px;
     height: 36px;
     background: var(--bg-secondary);
     border-radius: 8px;
     display: flex;
     align-items: center;
     justify-content: center;
     font-size: 16px;
     color: var(--primary-color);
 }

 .test-list-content {
     flex: 1;
 }

 .test-list-title {
     font-weight: 600;
     font-size: 13px;
     margin-bottom: 4px;
 }

 .test-list-meta {
     display: flex;
     gap: 10px;
     font-size: 11px;
     color: var(--text-secondary);
 }

 .difficulty-badge {
     display: inline-block;
     padding: 2px 6px;
     border-radius: 8px;
     font-size: 10px;
     font-weight: 600;
 }

 .difficulty-badge.easy {
     background: #E8F5E9;
     color: #2E7D32;
 }

 .difficulty-badge.medium {
     background: #FFF3E0;
     color: #F57C00;
 }

 .difficulty-badge.hard {
     background: #FFEBEE;
     color: #C62828;
 }

 .open-library-btn {
     position: fixed;
     left: 16px;
     bottom: 16px;
     padding: 12px 16px;
     background: var(--primary-color);
     color: white;
     border-radius: 50px;
     box-shadow: 0 4px 16px rgba(94, 86, 229, 0.3);
     display: flex;
     align-items: center;
     gap: 8px;
     z-index: 9998;
     border: none;
     cursor: pointer;
     font-weight: 600;
     font-size: 13px;
     transition: var(--transition);
 }

 .open-library-btn:hover {
     transform: translateY(-2px);
     box-shadow: 0 6px 20px rgba(94, 86, 229, 0.4);
 }

 .notification {
     position: fixed;
     top: 16px;
     right: 16px;
     padding: 14px 20px;
     border-radius: 10px;
     box-shadow: var(--shadow-lg);
     z-index: 9999;
     max-width: 280px;
     transform: translateX(500px);
     opacity: 0;
     transition: all 0.4s ease;
     color: white;
     background: var(--primary-color);
     font-size: 14px;
 }

 @media (max-width: 768px) {
     .hero-content {
         grid-template-columns: 1fr;
         text-align: center;
         gap: 30px;
     }

     .hero-title {
         font-size: 28px;
     }

     .hero-subtitle {
         font-size: 14px;
     }

     .tests-grid {
         grid-template-columns: 1fr;
     }

     .section-controls {
         flex-direction: column;
     }

     .search-box {
         width: 100%;
     }

     .mascot-img {
         width: 220px;
         height: 220px;
     }

     .header-nav {
         margin-left: 12px;
     }

     .tests-library {
         width: 100%;
         left: -100%;
     }

     .tests-library.open {
         transform: translateX(100%);
     }

     .interface-header {
         flex-direction: column;
         gap: 12px;
         padding: 12px;
     }

     .interface-progress {
         width: 100%;
         margin: 0;
     }

     .test-navigation {
         flex-direction: column;
     }

     .test-navigation .nav-btn {
         width: 100%;
     }

     .open-library-btn {
         left: 50%;
         transform: translateX(-50%);
         bottom: 10px;
     }

     .results-stats {
         grid-template-columns: 1fr;
     }

     .results-actions {
         flex-direction: column;
     }
 }

 @media (max-width: 480px) {
     .hero-title {
         font-size: 24px;
     }

     .section-title {
         font-size: 24px;
     }

     .test-card {
         min-height: 340px;
     }

     .test-meta {
         flex-direction: column;
         gap: 8px;
     }

     .header-nav .nav-btn {
         padding: 6px 10px;
         font-size: 12px;
     }

     .logo-text h1 {
         font-size: 20px;
     }
 }