* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Inter', 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
            line-height: 1.6;
            color: #1e293b;
            background: #f8fafc;
        }
        
        
        /* Hero Section */
        .hero-section {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: 20px 0 60px;
            position: relative;
            overflow: hidden;
        }
        
        .hero-section::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M 40 0 L 0 0 0 40" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
            opacity: 0.3;
        }
        
        .hero-content {
            position: relative;
            z-index: 1;
        }
        
        .hero-section .badge {
            display: inline-block;
            padding: 8px 16px;
            background: rgba(255, 255, 255, 0.2);
            backdrop-filter: blur(10px);
            border-radius: 50px;
            font-size: 14px;
            font-weight: 500;
            margin-bottom: 20px;
        }
        
        .hero-section h1 {
            font-size: 3rem;
            font-weight: 700;
            margin-bottom: 20px;
            line-height: 1.2;
        }
        
        .hero-section .lead {
            font-size: 1.25rem;
            opacity: 0.95;
            margin-bottom: 30px;
        }
        
        .hero-image img {
              display: block;
              position: relative;
              animation: float 6s ease-in-out infinite;
          }
        
        .btn {
            padding: 12px 28px;
            border-radius: 50px;
            font-weight: 600;
            transition: all 0.3s ease;
            border: none;
            text-decoration: none;
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }
        
        .btn-primary {
            background: white;
            color: #667eea;
        }
        
        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 30px rgba(255, 255, 255, 0.3);
            color: #667eea;
        }
        
        .btn-outline-primary {
            background: transparent;
            border: 2px solid white;
            color: white;
        }
        
        .btn-outline-primary:hover {
            background: white;
            color: #667eea;
            transform: translateY(-2px);
        }
        
        .btn-outline-light {
            background: transparent;
            border: 2px solid rgba(255, 255, 255, 0.5);
            color: white;
        }
        
        .btn-outline-light:hover {
            background: white;
            color: #667eea;
            border-color: white;
        }
        
        /* Key Concepts Section */
        .key-concepts-section {
            padding: 80px 0;
        }
        
        .section-header {
            margin-bottom: 50px;
        }
        
        .section-header h2 {
            font-size: 2.5rem;
            font-weight: 700;
            color: #1e293b;
            margin-bottom: 10px;
        }
        
        .section-header .text-muted {
            font-size: 1.1rem;
            color: #64748b;
        }
        
        .concept-card {
            background: white;
            border-radius: 16px;
            padding: 35px;
            height: 100%;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
            transition: all 0.3s ease;
            border: 1px solid #e2e8f0;
        }
        
        .concept-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 12px 24px rgba(102, 126, 234, 0.15);
        }
        
        .concept-icon {
            width: 70px;
            height: 70px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 16px;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 20px;
            font-size: 32px;
            color: white;
        }
        
        .concept-card h3 {
            font-size: 1.5rem;
            font-weight: 600;
            margin-bottom: 15px;
            color: #1e293b;
        }
        
        .concept-card p {
            color: #64748b;
            margin-bottom: 20px;
            line-height: 1.7;
        }
        
        .example-box {
            background: #f1f5f9;
            padding: 15px;
            border-radius: 10px;
            border-left: 4px solid #667eea;
            font-size: 0.95rem;
        }
        
        .example-box strong {
            color: #667eea;
            display: block;
            margin-bottom: 5px;
        }
        
        /* Rules Section */
        .rules-section {
            padding: 80px 0;
            background: #f8fafc;
        }
        
        .rules-card {
            background: white;
            border-radius: 20px;
            padding: 40px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
        }
        
        .rule-step {
            display: flex;
            gap: 25px;
            margin-bottom: 35px;
            align-items: flex-start;
        }
        
        .rule-step:last-child {
            margin-bottom: 0;
        }
        
        .step-number {
            width: 50px;
            height: 50px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            font-weight: 700;
            flex-shrink: 0;
        }
        
        .step-content {
            flex: 1;
        }
        
        .step-content h4 {
            font-size: 1.3rem;
            font-weight: 600;
            margin-bottom: 10px;
            color: #1e293b;
        }
        
        .step-content p {
            color: #64748b;
            margin-bottom: 8px;
            line-height: 1.7;
        }
        
        .step-content ul {
            list-style: none;
            padding-left: 0;
            margin-top: 15px;
        }
        
        .step-content ul li {
            padding: 10px 0;
            color: #64748b;
            border-bottom: 1px solid #e2e8f0;
        }
        
        .step-content ul li:last-child {
            border-bottom: none;
        }
        
        .step-content ul li strong {
            color: #667eea;
        }
        
        /* Examples Section */
        .examples-section {
            padding: 80px 0;
        }
        
        .example-group {
            background: white;
            padding: 30px;
            border-radius: 16px;
            height: 100%;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
            border: 1px solid #e2e8f0;
        }
        
        .example-group h4 {
            font-size: 1.3rem;
            font-weight: 600;
            margin-bottom: 20px;
            color: #1e293b;
        }
        
        .example-list {
            list-style: none;
            padding: 0;
        }
        
        .example-list li {
            padding: 12px 0;
            color: #64748b;
            font-size: 1.05rem;
            border-bottom: 1px solid #e2e8f0;
        }
        
        .example-list li:last-child {
            border-bottom: none;
        }
        
        .example-list li strong {
            color: #667eea;
            font-weight: 600;
        }
        
        /* Interactive Mind Map */
        .mindmap-section {
            padding: 60px 0;
            background: white;
        }
        
        .header {
            text-align: center;
            margin-bottom: 40px;
            padding: 30px 20px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 20px;
            color: white;
        }
        
        .header .icon {
            font-size: 3rem;
            margin-bottom: 15px;
        }
        
        .header h3 {
            font-size: 2rem;
            font-weight: 700;
            margin: 0;
        }
        
        .control-panel {
            margin-bottom: 30px;
        }
        
        .btn-control {
            padding: 12px 24px;
            border-radius: 50px;
            font-weight: 600;
            transition: all 0.3s ease;
        }
        
        .btn-expand {
            background: #10b981;
            color: white;
            border: none;
        }
        
        .btn-expand:hover {
            background: #059669;
            transform: translateY(-2px);
        }
        
        .btn-collapse {
            background: #f59e0b;
            color: white;
            border: none;
        }
        
        .btn-collapse:hover {
            background: #d97706;
            transform: translateY(-2px);
        }
        
        .btn-reset {
            background: #6366f1;
            color: white;
            border: none;
        }
        
        .btn-reset:hover {
            background: #4f46e5;
            transform: translateY(-2px);
        }
        
        .mindmap-container {
            background: white;
            border-radius: 20px;
            padding: 40px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
            overflow-x: auto;
        }
        
        .mindmap {
            min-width: 800px;
        }
        
        .node {
            background: white;
            padding: 15px 20px;
            border-radius: 10px;
            margin: 10px;
            display: inline-block;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
            border: 2px solid #e2e8f0;
            transition: all 0.3s ease;
            cursor: default;
            position: relative;
        }
        
        .node i {
            margin-right: 8px;
            color: #667eea;
        }
        
        .node.root {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            font-size: 1.3rem;
            font-weight: 700;
            padding: 20px 30px;
            margin: 20px auto;
            display: block;
            text-align: center;
            max-width: 500px;
        }
        
        .node.root i {
            color: white;
        }
        
        .node.clickable {
            cursor: pointer;
            background: #f8fafc;
            border-color: #667eea;
        }
        
        .node.clickable:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(102, 126, 234, 0.3);
            background: #667eea;
            color: white;
        }
        
        .node.clickable:hover i {
            color: white;
        }
        
        .node.clickable.expanded {
            background: #667eea;
            color: white;
        }
        
        .node.clickable.expanded i {
            color: white;
        }
        
        .children {
            margin-left: 40px;
            margin-top: 15px;
            padding-left: 20px;
            border-left: 3px solid #e2e8f0;
        }
        
        .children.root-level {
            margin-left: 0;
            padding-left: 0;
            border-left: none;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        
        /* Quiz Section */
        .quiz-section {
            padding: 80px 0;
            background: #f8fafc;
        }
        
        .quiz-container {
            background: white;
            padding: 40px;
            border-radius: 20px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
        }
        
        .quiz-question {
            margin-bottom: 35px;
            padding-bottom: 30px;
            border-bottom: 2px solid #e2e8f0;
        }
        
        .quiz-question:last-of-type {
            border-bottom: none;
        }
        
        .quiz-question h4 {
            color: #667eea;
            font-weight: 600;
            margin-bottom: 15px;
        }
        
        .question-text {
            font-size: 1.1rem;
            color: #1e293b;
            font-weight: 500;
            margin-bottom: 20px;
        }
        
        .form-check {
            padding: 12px 15px;
            margin-bottom: 10px;
            border-radius: 10px;
            transition: all 0.2s ease;
        }
        
        .form-check:hover {
            background: #f8fafc;
        }
        
        .form-check-input {
            margin-top: 0.4em;
            cursor: pointer;
        }
        
        .form-check-label {
            cursor: pointer;
            font-size: 1.05rem;
            color: #475569;
        }
        
        .results-container {
            background: #f8fafc;
            padding: 30px;
            border-radius: 15px;
            margin-top: 30px;
        }
        
        /* FAQ Section */
        .faq-section {
            padding: 80px 0;
        }
        
        .accordion-item {
            border: none;
            margin-bottom: 15px;
            border-radius: 12px;
            overflow: hidden;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
        }
        
        .accordion-button {
            background: white;
            color: #1e293b;
            font-weight: 600;
            font-size: 1.1rem;
            padding: 20px 25px;
            border: none;
            box-shadow: none;
        }
        
        .accordion-button:not(.collapsed) {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
        }
        
        .accordion-button:focus {
            box-shadow: none;
            border: none;
        }
        
        .accordion-body {
            padding: 25px;
            background: white;
            color: #64748b;
            line-height: 1.8;
            font-size: 1.05rem;
        }
        
        /* CTA Section */
        .bg-primary {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important;
        }
        
        /* Video Section */
        .ratio {
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
            border-radius: 16px;
            overflow: hidden;
        }
        
        /* Responsive Design */
        @media (max-width: 768px) {
            .hero-section h1 {
                font-size: 2rem;
            }
            
            .hero-section .lead {
                font-size: 1rem;
            }
            
            .section-header h2 {
                font-size: 2rem;
            }
            
            .concept-card,
            .rules-card,
            .quiz-container {
                padding: 25px;
            }
            
            .mindmap {
                min-width: 100%;
            }
            
            .children {
                margin-left: 20px;
                padding-left: 10px;
            }
        }
        
        /* Loading Animation */
        .btn.loading {
            pointer-events: none;
            opacity: 0.7;
        }
        
        /* Smooth Transitions */
        * {
            transition: background-color 0.3s ease, color 0.3s ease;
        }
        
      @keyframes float {
          0%, 100% {
              transform: translateY(0);
          }
          50% {
              transform: translateY(-20px);
          }
      }