:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --accent-color: #ec4899;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #111827;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

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

html {
    scroll-behavior: smooth;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-primary);
    text-decoration: none;
}

.logo-img {
    width: 32px;
    height: 32px;
}

.logo-text {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-links a:hover {
    color: var(--primary-color);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all 0.3s ease;
}

/* Header Section */
.header-section {
    padding: 6rem 0 3rem;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    margin-top: 60px;
}

.header-content {
    text-align: center;
}

.logo-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.header-logo {
    width: 64px;
    height: 64px;
    object-fit: contain;
}

.header-title {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
    max-width: 900px;
    margin: 0 auto;
}

.authors {
    margin: 25px 0;
    font-size: 15px;
    line-height: 1.8;
}

.author-list {
    margin-bottom: 10px;
}

.author {
    color: var(--text-primary);
}

.supervisor {
    color: var(--text-secondary);
    font-size: 14px;
}

.affiliation {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.6;
}

.supervisor-note {
    display: block;
    margin-top: 5px;
    font-size: 13px;
    font-style: italic;
}

.header-links {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 25px;
    flex-wrap: wrap;
}

.link-btn {
    display: inline-block;
    padding: 10px 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: #fff;
    text-decoration: none;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.link-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--bg-primary);
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-secondary:hover {
    background: var(--primary-color);
    color: white;
}

.btn-outline {
    background: transparent;
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-outline:hover {
    background: var(--bg-secondary);
    border-color: var(--text-secondary);
}

/* Section Styles */
section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

/* Overview Section */
.overview {
    background: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Demo Section */
.demo {
    background: var(--bg-primary);
}

.demo-content {
    max-width: 900px;
    margin: 0 auto;
}

.video-container {
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    background: var(--bg-dark);
}

.video-container video {
    display: block;
    width: 100%;
    height: auto;
}

/* Updates Section */
.updates {
    background: var(--bg-secondary);
}

.updates-list {
    list-style: none;
    padding: 0;
    max-width: 800px;
    margin: 0 auto;
}

.update-item {
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    gap: 15px;
    align-items: flex-start;
}

.update-item:last-child {
    border-bottom: none;
}

.update-date {
    font-weight: 700;
    color: var(--primary-color);
    min-width: 100px;
    flex-shrink: 0;
}

.update-text {
    color: var(--text-primary);
    line-height: 1.6;
}

/* Resources Section */
.resources {
    background: var(--bg-secondary);
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.resource-card {
    background: var(--bg-primary);
    padding: 2.5rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.resource-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.resource-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.resource-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.resource-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.resource-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: gap 0.3s ease;
}

.resource-link:hover {
    gap: 0.75rem;
}

/* Visualizations Section */
.visualizations {
    background: var(--bg-primary);
}

.viz-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.viz-tab {
    padding: 0.75rem 1.5rem;
    border: 2px solid var(--border-color);
    background: var(--bg-primary);
    color: var(--text-secondary);
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s ease;
}

.viz-tab:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.viz-tab.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
}

.viz-content {
    position: relative;
    min-height: 400px;
}

.viz-panel {
    display: none;
    animation: fadeIn 0.5s ease;
}

.viz-panel.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.stat-card {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 2rem;
    border-radius: 1rem;
    text-align: center;
    color: white;
    box-shadow: var(--shadow-lg);
}

.stat-value {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 1rem;
    opacity: 0.9;
}

.chart-container {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    position: relative;
    height: 400px;
}

/* Heatmap tooltip */
.heatmap-tooltip {
    z-index: 1000;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

/* Installation Section */
.installation {
    background: var(--bg-secondary);
}

.install-steps {
    max-width: 800px;
    margin: 0 auto;
}

.step {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
}

.step-number {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
}

.step-content h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.step-content p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.step-content pre {
    background: var(--bg-dark);
    color: #f3f4f6;
    padding: 1rem;
    border-radius: 0.5rem;
    overflow-x: auto;
    margin-top: 0.5rem;
}

.step-content code {
    font-family: 'Monaco', 'Courier New', monospace;
    font-size: 0.875rem;
}

.step-content ol {
    margin-left: 1.5rem;
    margin-top: 0.5rem;
    color: var(--text-secondary);
}

.step-content ol li {
    margin-bottom: 0.5rem;
}

/* BibTeX Section */
.bibtex {
    background: var(--bg-secondary);
}

.bibtex-container {
    max-width: 900px;
    margin: 0 auto;
}

.bibtex-code {
    background-color: var(--bg-dark);
    color: #f0f0f0;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    font-family: 'Courier New', Courier, monospace;
    font-size: 13px;
    line-height: 1.6;
    margin: 0;
    box-shadow: var(--shadow-md);
}

.bibtex-code code {
    color: inherit;
    font-family: inherit;
    font-size: inherit;
}

/* Footer */
.footer {
    background: var(--bg-dark);
    color: #f3f4f6;
    padding: 3rem 0 1.5rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    color: white;
}

.footer-section p {
    color: #9ca3af;
    line-height: 1.6;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #374151;
    color: #6b7280;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .header-title {
        font-size: 22px;
    }

    .logo-section {
        flex-direction: column;
        gap: 10px;
    }

    .header-logo {
        width: 48px;
        height: 48px;
    }

    .header-links {
        flex-direction: column;
        align-items: center;
    }

    .link-btn {
        width: 100%;
        max-width: 200px;
        text-align: center;
    }

    .update-item {
        flex-direction: column;
        gap: 5px;
    }

    .update-date {
        min-width: auto;
    }

    .section-title {
        font-size: 2rem;
    }

    .container {
        padding: 0 1rem;
    }

    .step {
        flex-direction: column;
    }

    .step-number {
        align-self: flex-start;
    }

    .bibtex-code {
        font-size: 11px;
        padding: 15px;
    }
}

@media (max-width: 480px) {
    .header-title {
        font-size: 18px;
    }

    .authors {
        font-size: 14px;
    }

    .header-links {
        flex-direction: column;
    }

    .link-btn {
        width: 100%;
        max-width: 200px;
    }

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