/* Modern AP Statistics Learning App Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

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

/* Hero Section */
.hero {
    text-align: center;
    color: white;
    margin-bottom: 30px;
    padding: 40px 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 15px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Navigation Tabs */
.nav-tabs {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
    gap: 10px;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 15px 25px;
    border: none;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.tab-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.tab-btn.active {
    background: rgba(255, 255, 255, 0.9);
    color: #333;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

/* Tab Content */
.tab-content {
    display: none;
    animation: fadeIn 0.5s ease-in;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Concept Cards */
.concept-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.concept-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.concept-card h3 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.concept-card p {
    margin-bottom: 20px;
    color: #666;
    font-size: 1.1rem;
}

/* Chart Containers */
.chart-container {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
    border: 2px solid #e9ecef;
    min-height: 400px;
    /* Make charts bigger */
}

/* Interactive Controls */
.interactive-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    align-items: center;
    margin-top: 20px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 15px;
}

.interactive-controls label {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    color: #495057;
}

.interactive-controls input[type="range"] {
    width: 150px;
    height: 6px;
    border-radius: 3px;
    background: #dee2e6;
    outline: none;
    -webkit-appearance: none;
}

.interactive-controls input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #667eea;
    cursor: pointer;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.interactive-controls span {
    background: #667eea;
    color: white;
    padding: 5px 12px;
    border-radius: 20px;
    font-weight: 600;
    min-width: 40px;
    text-align: center;
}

/* Buttons */
button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

button:active {
    transform: translateY(0);
}

/* Data Visualization */
.visualization {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
}

.data-points {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 20px 0;
    justify-content: center;
}

.data-point {
    background: #667eea;
    color: white;
    padding: 8px 12px;
    border-radius: 20px;
    font-weight: 600;
    animation: popIn 0.3s ease;
}

@keyframes popIn {
    from {
        transform: scale(0);
        opacity: 0;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}

.stats {
    display: flex;
    gap: 30px;
    justify-content: center;
    margin-top: 20px;
    flex-wrap: wrap;
}

.stats p {
    background: white;
    padding: 10px 20px;
    border-radius: 15px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    font-weight: 600;
}

/* SRS Demo */
.srs-demo {
    text-align: center;
}

.population {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
    margin: 20px 0;
    padding: 20px;
    background: #e3f2fd;
    border-radius: 15px;
    border: 2px dashed #2196f3;
}

.population-item {
    background: #2196f3;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.population-item:hover {
    transform: scale(1.1);
}

.population-item.selected {
    background: #ff5722;
    transform: scale(1.2);
}

.sample {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin: 20px 0;
    padding: 20px;
    background: #fff3e0;
    border-radius: 15px;
    border: 2px solid #ff9800;
    min-height: 60px;
}

/* Z-Score Calculator */
.zscore-calculator {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
}

.input-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.input-group label {
    display: flex;
    flex-direction: column;
    gap: 5px;
    font-weight: 600;
    color: #495057;
}

.input-group input {
    padding: 10px;
    border: 2px solid #dee2e6;
    border-radius: 10px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.input-group input:focus {
    outline: none;
    border-color: #667eea;
}

.result {
    background: white;
    padding: 20px;
    border-radius: 15px;
    margin-top: 20px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.result p {
    margin-bottom: 10px;
    font-weight: 600;
}

.result span {
    color: #667eea;
    font-weight: 700;
}

/* Plot Description */
.plot-description {
    margin-top: 20px;
}

.description-section {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 15px;
    margin-bottom: 20px;
}

.description-section h4 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.description-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.desc-item {
    background: white;
    padding: 15px;
    border-radius: 10px;
    border-left: 3px solid #667eea;
}

.desc-item strong {
    color: #495057;
    display: block;
    margin-bottom: 8px;
    font-size: 1rem;
}

.desc-item ul {
    margin: 0;
    padding-left: 20px;
}

.desc-item li {
    margin-bottom: 5px;
    color: #666;
    font-size: 0.95rem;
}

/* Takeaways */
.takeaways {
    margin-top: 20px;
}

.takeaway-item {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 15px;
    margin-bottom: 15px;
    border-left: 4px solid #28a745;
}

.takeaway-item h4 {
    color: #28a745;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.takeaway-item p {
    color: #495057;
    margin: 0;
    line-height: 1.6;
}

/* irl Explanations */
.irl-explanation {
    margin-top: 25px;
    padding: 20px;
    background: linear-gradient(135deg, #e3f2fd 0%, #f3e5f5 100%);
    border-radius: 15px;
    border: 2px solid #2196f3;
}

.irl-explanation h5 {
    color: #1976d2;
    margin-bottom: 20px;
    font-size: 1.3rem;
    text-align: center;
}

.explanation-table {
    margin-bottom: 20px;
}

.explanation-table table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.explanation-table th {
    background: #2196f3;
    color: white;
    padding: 12px;
    text-align: left;
    font-weight: 600;
}

.explanation-table td {
    padding: 12px;
    border-bottom: 1px solid #e0e0e0;
    vertical-align: top;
}

.explanation-table tr:nth-child(even) {
    background: #f8f9fa;
}

.bottom-line {
    background: #fff3cd;
    padding: 15px;
    border-radius: 10px;
    border-left: 4px solid #ffc107;
    margin-top: 20px;
}

.bottom-line p {
    margin: 0;
    font-weight: 600;
    color: #856404;
}

.explanation-steps {
    margin-bottom: 20px;
}

.step {
    background: white;
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 15px;
    border-left: 4px solid #4caf50;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.step h6 {
    color: #2e7d32;
    margin-bottom: 8px;
    font-size: 1.1rem;
}

.step p {
    margin: 0;
    color: #495057;
    line-height: 1.5;
}

.real-world-example {
    background: #e8f5e8;
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 20px;
    border-left: 4px solid #4caf50;
}

.real-world-example h6 {
    color: #2e7d32;
    margin-bottom: 8px;
    font-size: 1.1rem;
}

.real-world-example p {
    margin: 0;
    color: #2e7d32;
    line-height: 1.5;
}

.visuals {
    background: #fff3e0;
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 20px;
    border-left: 4px solid #ff9800;
}

.visuals h6 {
    color: #e65100;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.visuals ul {
    margin: 0;
    padding-left: 20px;
}

.visuals li {
    margin-bottom: 8px;
    color: #e65100;
    line-height: 1.4;
}

.one-sentence-wrapup {
    background: #f3e5f5;
    padding: 15px;
    border-radius: 10px;
    border-left: 4px solid #9c27b0;
}

.one-sentence-wrapup h6 {
    color: #6a1b9a;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.one-sentence-wrapup ul {
    margin: 0;
    padding-left: 20px;
}

.one-sentence-wrapup li {
    margin-bottom: 8px;
    color: #6a1b9a;
    line-height: 1.4;
}

/* Tooltip Styling */
.underline.decoration-dotted.cursor-help {
    border-bottom: 1px dotted #667eea;
    cursor: help;
    transition: all 0.2s ease;
}

.underline.decoration-dotted.cursor-help:hover {
    background: rgba(102, 126, 234, 0.1);
    border-radius: 3px;
    padding: 2px 4px;
}

/* You Try Section */
.you-try-section {
    background: #f0f9ff;
    padding: 20px;
    border-radius: 15px;
    margin-top: 20px;
    border-left: 4px solid #0ea5e9;
}

.you-try-section h6 {
    color: #0ea5e9;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.input-feedback {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-top: 15px;
    flex-wrap: wrap;
}

.feedback-input {
    flex: 1;
    min-width: 200px;
    padding: 10px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.feedback-input:focus {
    outline: none;
    border-color: #0ea5e9;
}

.check-btn {
    background: #0ea5e9;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
}

.check-btn:hover {
    background: #0284c7;
    transform: translateY(-1px);
}

.feedback-result {
    margin-top: 10px;
    padding: 10px;
    border-radius: 8px;
    font-weight: 600;
    min-height: 20px;
}

.feedback-result.correct {
    background: #dcfce7;
    color: #166534;
    border: 1px solid #22c55e;
}

.feedback-result.incorrect {
    background: #fef2f2;
    color: #dc2626;
    border: 1px solid #ef4444;
}

/* Probability Grid */
.probability-visual {
    background: #f8fafc;
    padding: 20px;
    border-radius: 15px;
    margin-top: 20px;
    border-left: 4px solid #6366f1;
}

.probability-visual h6 {
    color: #6366f1;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.prob-grid {
    display: grid;
    grid-template-columns: repeat(10, 1fr);
    gap: 2px;
    margin: 15px 0;
    max-width: 300px;
}

.square {
    width: 25px;
    height: 25px;
    background: #e2e8f0;
    border-radius: 3px;
    transition: all 0.3s ease;
}

.square.shaded {
    background: #60a5fa;
    transform: scale(1.1);
}

.prob-caption {
    font-size: 0.9rem;
    color: #64748b;
    font-style: italic;
    margin-top: 10px;
}

/* About Me Page Styling */
.about-me-hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px;
    border-radius: 20px;
    margin-bottom: 30px;
    box-shadow: 0 20px 40px rgba(102, 126, 234, 0.3);
}

.profile-section {
    display: flex;
    align-items: center;
    gap: 30px;
    flex-wrap: wrap;
}

.profile-avatar {
    position: relative;
}

.avatar-circle {
    width: 120px;
    height: 120px;
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    font-weight: bold;
    color: white;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    animation: pulse 2s infinite;
}

@keyframes pulse {

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

    50% {
        transform: scale(1.05);
    }
}

.status-badge {
    position: absolute;
    bottom: 5px;
    right: 5px;
    background: #10b981;
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    animation: blink 2s infinite;
}

@keyframes blink {

    0%,
    50% {
        opacity: 1;
    }

    51%,
    100% {
        opacity: 0.7;
    }
}

.profile-info h2 {
    margin: 0 0 10px 0;
    font-size: 2.5rem;
    font-weight: 700;
}

.tagline {
    font-size: 1.2rem;
    margin: 0 0 20px 0;
    opacity: 0.9;
}

.quick-stats {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
    background: rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 15px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
    display: block;
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.8;
}

.about-content {
    display: grid;
    gap: 30px;
}

.story-card,
.interests-card,
.teaching-philosophy,
.fun-facts {
    background: white;
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border-left: 5px solid #667eea;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.story-card:hover,
.interests-card:hover,
.teaching-philosophy:hover,
.fun-facts:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.journey-timeline {
    display: grid;
    gap: 20px;
    margin-top: 20px;
}

.timeline-item {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 20px;
    background: #f8fafc;
    border-radius: 15px;
    border-left: 4px solid #667eea;
}

.timeline-icon {
    font-size: 2rem;
    background: linear-gradient(45deg, #667eea, #764ba2);
    color: white;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.timeline-content h4 {
    margin: 0 0 8px 0;
    color: #1e293b;
    font-size: 1.2rem;
}

.timeline-content p {
    margin: 0;
    color: #64748b;
    line-height: 1.6;
}

.interests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.interest-item {
    text-align: center;
    padding: 25px;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    border-radius: 15px;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.interest-item:hover {
    border-color: #667eea;
    transform: translateY(-3px);
}

.interest-icon {
    font-size: 3rem;
    margin-bottom: 15px;
    display: block;
}

.interest-item h4 {
    margin: 0 0 10px 0;
    color: #1e293b;
    font-size: 1.3rem;
}

.interest-item p {
    margin: 0;
    color: #64748b;
    line-height: 1.5;
}

.philosophy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.philosophy-item {
    text-align: center;
    padding: 25px;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    border-radius: 15px;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.philosophy-item:hover {
    border-color: #0ea5e9;
    transform: translateY(-3px);
}

.philosophy-icon {
    font-size: 2.5rem;
    margin-bottom: 15px;
    display: block;
}

.philosophy-item h4 {
    margin: 0 0 10px 0;
    color: #0c4a6e;
    font-size: 1.2rem;
}

.philosophy-item p {
    margin: 0;
    color: #0369a1;
    line-height: 1.5;
}

.facts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.fact-item {
    text-align: center;
    padding: 20px;
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    border-radius: 15px;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.fact-item:hover {
    border-color: #f59e0b;
    transform: translateY(-3px);
}

.fact-number {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 10px;
}

.fact-item p {
    margin: 0;
    color: #92400e;
    font-weight: 500;
    line-height: 1.4;
}

/* Section Headers and Export Buttons */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 20px;
}

.section-header h2 {
    margin: 0;
}

.export-btn {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
    display: flex;
    align-items: center;
    gap: 8px;
}

.export-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(16, 185, 129, 0.4);
    background: linear-gradient(135deg, #059669 0%, #047857 100%);
}

.export-btn:active {
    transform: translateY(0);
}

.export-btn:disabled {
    background: #9ca3af;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* PDF Export Modal */
.pdf-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.pdf-modal.show {
    display: flex;
}

.pdf-modal-content {
    background: white;
    padding: 30px;
    border-radius: 20px;
    max-width: 500px;
    width: 90%;
    text-align: center;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.pdf-modal h3 {
    color: #1e293b;
    margin: 0 0 20px 0;
    font-size: 1.5rem;
}

.pdf-modal p {
    color: #64748b;
    margin: 0 0 25px 0;
    line-height: 1.6;
}

.pdf-modal-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.pdf-modal-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.pdf-modal-btn.primary {
    background: #10b981;
    color: white;
}

.pdf-modal-btn.primary:hover {
    background: #059669;
}

.pdf-modal-btn.secondary {
    background: #e2e8f0;
    color: #475569;
}

.pdf-modal-btn.secondary:hover {
    background: #cbd5e1;
}

/* Responsive Design */
@media (max-width: 768px) {
    .profile-section {
        flex-direction: column;
        text-align: center;
    }

    .quick-stats {
        justify-content: center;
    }

    .timeline-item {
        flex-direction: column;
        text-align: center;
    }

    .interests-grid,
    .philosophy-grid,
    .facts-grid {
        grid-template-columns: 1fr;
    }

    .section-header {
        flex-direction: column;
        text-align: center;
    }

    .export-btn {
        width: 100%;
        justify-content: center;
    }
}

/* Road to Mastery Page Styling */
.progress-rocket {
    background: linear-gradient(135deg, #1e293b 0%, #334155 100%);
    padding: 30px;
    border-radius: 20px;
    margin-bottom: 30px;
    color: white;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.rocket-container {
    position: relative;
    margin-bottom: 20px;
}

.rocket {
    font-size: 3rem;
    display: inline-block;
    transition: transform 0.5s ease;
    animation: rocketFloat 3s ease-in-out infinite;
}

@keyframes rocketFloat {

    0%,
    100% {
        transform: translateY(0px) rotate(0deg);
    }

    50% {
        transform: translateY(-10px) rotate(5deg);
    }
}

.rocket-trail {
    position: absolute;
    bottom: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 40px;
    background: linear-gradient(to bottom, #fbbf24, transparent);
    border-radius: 2px;
    animation: trailFlicker 2s ease-in-out infinite;
}

@keyframes trailFlicker {

    0%,
    100% {
        opacity: 0.8;
    }

    50% {
        opacity: 0.4;
    }
}

.progress-bar {
    background: rgba(255, 255, 255, 0.1);
    height: 20px;
    border-radius: 10px;
    overflow: hidden;
    position: relative;
    margin-bottom: 15px;
}

.progress-fill {
    background: linear-gradient(90deg, #10b981 0%, #34d399 100%);
    height: 100%;
    width: 0%;
    transition: width 1s ease;
    border-radius: 10px;
}

.progress-text {
    font-size: 1.1rem;
    font-weight: 600;
}

.roadmap-container {
    background: white;
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
    position: relative;
}

.roadmap-path {
    width: 100%;
    height: 200px;
    margin-bottom: 30px;
}

.road-path {
    filter: drop-shadow(0 2px 4px rgba(102, 126, 234, 0.3));
}

.station-marker {
    fill: #e2e8f0;
    stroke: #667eea;
    stroke-width: 3;
    cursor: pointer;
    transition: all 0.3s ease;
}

.station-marker:hover {
    fill: #667eea;
    transform: scale(1.2);
}

.station-marker.completed {
    fill: #10b981;
    stroke: #059669;
}

.station-marker.current {
    fill: #fbbf24;
    stroke: #f59e0b;
    animation: pulse 2s infinite;
}

.station-number {
    font-size: 12px;
    font-weight: bold;
    fill: #374151;
}

.station-labels {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 20px;
    margin-top: 20px;
}

.station-label {
    text-align: center;
    padding: 15px;
    background: #f8fafc;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.station-label:hover {
    background: #e2e8f0;
    transform: translateY(-3px);
    border-color: #667eea;
}

.station-label.completed {
    background: #dcfce7;
    border-color: #10b981;
}

.station-label.current {
    background: #fef3c7;
    border-color: #f59e0b;
}

.station-icon {
    font-size: 2rem;
    display: block;
    margin-bottom: 8px;
}

.station-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: #374151;
    line-height: 1.3;
}

.mastery-footer {
    text-align: center;
    margin-top: 30px;
}

.xp-badge {
    display: inline-flex;
    align-items: center;
    gap: 15px;
    background: linear-gradient(135deg, #8b5cf6 0%, #a855f7 100%);
    color: white;
    padding: 20px 30px;
    border-radius: 25px;
    box-shadow: 0 10px 30px rgba(139, 92, 246, 0.3);
    animation: badgeGlow 2s ease-in-out infinite;
}

@keyframes badgeGlow {

    0%,
    100% {
        box-shadow: 0 10px 30px rgba(139, 92, 246, 0.3);
    }

    50% {
        box-shadow: 0 15px 40px rgba(139, 92, 246, 0.5);
    }
}

.xp-icon {
    font-size: 2rem;
}

.xp-text {
    font-size: 1.1rem;
    font-weight: 600;
}

.xp-count {
    background: rgba(255, 255, 255, 0.2);
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: bold;
    font-size: 1.2rem;
}

/* Station Modal Styling */
.station-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.station-modal.show {
    display: flex;
}

.station-modal-content {
    background: white;
    border-radius: 20px;
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: modalSlideIn 0.3s ease;
}

.station-modal-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 25px;
    border-radius: 20px 20px 0 0;
    display: flex;
    align-items: center;
    gap: 15px;
    position: relative;
}

.station-modal-icon {
    font-size: 2.5rem;
}

.station-modal-header h3 {
    margin: 0;
    flex: 1;
}

.close-station-modal {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.close-station-modal:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

.station-modal-body {
    padding: 25px;
}

.station-goals,
.station-tools,
.station-practice {
    margin-bottom: 25px;
}

.station-goals h4,
.station-tools h4,
.station-practice h4 {
    color: #1e293b;
    margin: 0 0 15px 0;
    font-size: 1.2rem;
}

.station-goals ul {
    margin: 0;
    padding-left: 20px;
}

.station-goals li {
    margin-bottom: 8px;
    color: #374151;
    line-height: 1.5;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
}

.tool-item {
    text-align: center;
    padding: 15px;
    background: #f8fafc;
    border-radius: 10px;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.tool-item:hover {
    border-color: #667eea;
    transform: translateY(-2px);
}

.tool-icon {
    font-size: 1.5rem;
    display: block;
    margin-bottom: 8px;
}

.tool-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: #374151;
}

.practice-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.practice-btn {
    background: linear-gradient(135deg, #10b981 0%, #34d399 100%);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 25px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.practice-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(16, 185, 129, 0.4);
}

.practice-icon {
    font-size: 1.2rem;
}

.xp-display {
    display: flex;
    align-items: center;
    gap: 8px;
    background: #f3f4f6;
    padding: 10px 15px;
    border-radius: 20px;
}

.xp-label {
    font-weight: 600;
    color: #374151;
}

.xp-progress {
    background: #10b981;
    color: white;
    padding: 4px 12px;
    border-radius: 15px;
    font-weight: bold;
    font-size: 0.9rem;
}

/* Quiz Modal Styling */
.quiz-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1100;
    backdrop-filter: blur(5px);
}

.quiz-modal.show {
    display: flex;
}

.quiz-modal-content {
    background: white;
    border-radius: 20px;
    max-width: 500px;
    width: 90%;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: modalSlideIn 0.3s ease;
}

.quiz-header {
    background: linear-gradient(135deg, #f59e0b 0%, #fbbf24 100%);
    color: white;
    padding: 20px;
    border-radius: 20px 20px 0 0;
    text-align: center;
}

.quiz-header h3 {
    margin: 0 0 10px 0;
}

.quiz-progress {
    font-size: 0.9rem;
    opacity: 0.9;
}

.quiz-body {
    padding: 25px;
}

.question-container {
    margin-bottom: 20px;
}

#quizQuestion {
    font-size: 1.1rem;
    color: #1e293b;
    margin-bottom: 20px;
    line-height: 1.6;
}

.answer-options {
    display: grid;
    gap: 10px;
}

.answer-option {
    padding: 15px;
    background: #f8fafc;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: left;
}

.answer-option:hover {
    background: #e2e8f0;
    border-color: #667eea;
}

.answer-option.selected {
    background: #667eea;
    color: white;
    border-color: #667eea;
}

.quiz-footer {
    padding: 20px;
    display: flex;
    gap: 15px;
    justify-content: center;
}

.quiz-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.quiz-btn.primary {
    background: #10b981;
    color: white;
}

.quiz-btn.primary:hover {
    background: #059669;
}

.quiz-btn.secondary {
    background: #e2e8f0;
    color: #475569;
}

.quiz-btn.secondary:hover {
    background: #cbd5e1;
}



/* Progress Analytics Styling */
.progress-analytics {
    margin: 40px 0;
    padding: 30px;
    background: #ffffff;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.progress-analytics h3 {
    text-align: center;
    margin-bottom: 30px;
    color: #1e293b;
    font-size: 1.8rem;
}

.analytics-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin-bottom: 20px;
}

.analytics-card {
    background: #ffffff;
    border: 2px solid #e2e8f0;
    border-radius: 15px;
    padding: 25px;
    transition: all 0.3s ease;
    min-height: 350px;
}

.analytics-card canvas {
    min-height: 250px !important;
    height: 250px !important;
}

.analytics-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

.analytics-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
}

.analytics-icon {
    font-size: 1.5rem;
}

.analytics-header h4 {
    margin: 0;
    color: #1e293b;
    font-size: 1.1rem;
}

.study-stats-card {
    margin-top: 25px;
    min-height: auto !important;
}

.study-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.stat-item {
    text-align: center;
    padding: 15px;
    background: #ffffff;
    border-radius: 10px;
    border: 1px solid #e2e8f0;
}

.stat-value {
    display: block;
    font-size: 1.8rem;
    font-weight: bold;
    color: #667eea;
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.9rem;
    color: #1e293b;
    opacity: 0.8;
}

/* Responsive Analytics */
@media (max-width: 1024px) {
    .analytics-grid {
        grid-template-columns: 1fr;
    }

    .study-stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .analytics-card canvas {
        min-height: 200px !important;
        height: 200px !important;
    }
}

@media (max-width: 768px) {
    .study-stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .analytics-card {
        padding: 15px;
        min-height: 280px;
    }

    .analytics-card canvas {
        min-height: 180px !important;
        height: 180px !important;
    }
}

@media (max-width: 480px) {
    .study-stats {
        grid-template-columns: 1fr;
    }
}

/* Responsive Design for Roadmap */
@media (max-width: 768px) {
    .station-labels {
        grid-template-columns: repeat(2, 1fr);
    }

    .roadmap-path {
        height: 150px;
    }

    .station-modal-content {
        width: 95%;
        margin: 20px;
    }

    .practice-options {
        flex-direction: column;
        align-items: stretch;
    }

    .practice-btn {
        justify-content: center;
    }
}

/* Problem Statement */
.problem-statement {
    background: white;
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border-left: 5px solid #667eea;
}

.problem-statement h3 {
    color: #667eea;
    margin-bottom: 15px;
}

.problem-statement p {
    margin-bottom: 15px;
    line-height: 1.8;
}

/* Problem Parts */
.part {
    background: white;
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 25px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    border-left: 4px solid #28a745;
}

.part h4 {
    color: #28a745;
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.solution {
    margin-top: 20px;
}

.show-solution {
    background: #28a745;
    margin-bottom: 15px;
}

.solution-content {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 15px;
    border-left: 4px solid #28a745;
}

.solution-content.hidden {
    display: none;
}

.hypothesis-table table {
    width: 100%;
    border-collapse: collapse;
    margin: 15px 0;
}

.hypothesis-table td {
    padding: 12px;
    border-bottom: 1px solid #dee2e6;
    vertical-align: top;
}

.hypothesis-table td:first-child {
    font-weight: 600;
    color: #495057;
    width: 30%;
}

/* Tool Cards */
.tool-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.tool-card h3 {
    color: #667eea;
    margin-bottom: 20px;
    font-size: 1.4rem;
}

.inputs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.inputs label {
    display: flex;
    flex-direction: column;
    gap: 5px;
    font-weight: 600;
    color: #495057;
}

.inputs input,
.inputs select {
    padding: 10px;
    border: 2px solid #dee2e6;
    border-radius: 10px;
    font-size: 1rem;
}

/* Practice Problems */
.problem-generator {
    background: white;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.problem-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 30px;
    align-items: center;
}

.problem-controls label {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    color: #495057;
}

.problem-controls select {
    padding: 8px 15px;
    border: 2px solid #dee2e6;
    border-radius: 10px;
    font-size: 1rem;
}

.practice-problem {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 15px;
    margin-bottom: 25px;
    border-left: 4px solid #ff9800;
}

.problem-actions {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.problem-actions button {
    flex: 1;
    min-width: 150px;
}

.hidden {
    display: none;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .nav-tabs {
        flex-direction: column;
        align-items: center;
    }

    .tab-btn {
        width: 100%;
        max-width: 300px;
    }

    .significance-demo {
        grid-template-columns: 1fr;
    }

    .input-group {
        grid-template-columns: 1fr;
    }

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

    .problem-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .problem-controls label {
        flex-direction: column;
        align-items: stretch;
    }
}

/* Animations */
.concept-card,
.tool-card,
.part {
    animation: slideInUp 0.6s ease-out;
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

/* Success States */
.success {
    border-color: #28a745;
    background: #d4edda;
}

/* Error States */
.error {
    border-color: #dc3545;
    background: #f8d7da;
}