:root {
    --primary: #2563eb;
    --secondary: #64748b;
    --success: #10b981;
    --info: #06b6d4;
    --warning: #f59e0b;
    --danger: #ef4444;
    --light: #f8fafc;
    --dark: #0f172a;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --card-bg: #1e293b;
}

[data-theme="light"],
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --card-bg: #ffffff;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
    line-height: 1.6;
}

.navbar {
    transition: background-color 0.3s ease;
}

[data-theme="dark"] .navbar {
    background-color: var(--bg-secondary) !important;
    border-bottom: 1px solid var(--border-color);
}

[data-theme="dark"] .navbar-light .navbar-nav .nav-link {
    color: var(--text-secondary);
}

[data-theme="dark"] .navbar-light .navbar-nav .nav-link.active,
[data-theme="dark"] .navbar-light .navbar-nav .nav-link:hover {
    color: var(--text-primary);
}

.brand-gradient {
    background: linear-gradient(135deg, var(--primary), var(--info));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.5rem;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.5rem;
}

.nav-link {
    font-weight: 500;
    padding: 0.5rem 1rem !important;
    transition: color 0.3s ease;
}

.hero-section {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    position: relative;
    overflow: hidden;
}

[data-theme="dark"] .hero-section {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

.min-vh-75 {
    min-height: 75vh;
}

.display-3 {
    font-weight: 800;
    letter-spacing: -0.02em;
}

.lead {
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text-secondary);
}

.btn {
    font-weight: 600;
    padding: 0.75rem 2rem;
    border-radius: 0.5rem;
    transition: all 0.3s ease;
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
    border-color: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(37, 99, 235, 0.3);
}

.btn-outline-primary {
    border-width: 2px;
}

.btn-outline-primary:hover {
    background-color: var(--primary);
    border-color: var(--primary);
    transform: translateY(-2px);
}

.hero-visual {
    position: relative;
    height: 400px;
}

.floating-card {
    position: absolute;
    width: 200px;
    height: 200px;
    border-radius: 1rem;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    animation: float 6s ease-in-out infinite;
}

.card-1 {
    background: linear-gradient(135deg, var(--primary), var(--info));
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    animation-delay: 0s;
}

.card-2 {
    background: linear-gradient(135deg, var(--success), var(--info));
    top: 100px;
    left: 10%;
    animation-delay: 2s;
}

.card-3 {
    background: linear-gradient(135deg, var(--info), var(--primary));
    top: 100px;
    right: 10%;
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-20px);
    }
}

.feature-card {
    transition: all 0.3s ease;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color) !important;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15) !important;
}

[data-theme="dark"] .feature-card:hover {
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4) !important;
}

.icon-circle {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
}

.stat-card {
    text-align: center;
    padding: 2rem;
    background-color: var(--card-bg);
    border-radius: 1rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .stat-card {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.cta-section {
    background: linear-gradient(135deg, var(--primary), var(--info));
}

[data-theme="dark"] .bg-light {
    background-color: var(--bg-secondary) !important;
}

[data-theme="dark"] .text-muted {
    color: var(--text-muted) !important;
}

.content-section {
    padding: 80px 0;
}

.section-title {
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 3rem;
}

.content-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
}

.content-card:hover {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transform: translateY(-5px);
}

[data-theme="dark"] .content-card:hover {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.content-card h3 {
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 1rem;
}

.key-concept {
    background-color: var(--bg-tertiary);
    border-left: 4px solid var(--primary);
    padding: 1.5rem;
    margin: 2rem 0;
    border-radius: 0.5rem;
}

.key-concept h4 {
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.benefits-list {
    list-style: none;
    padding: 0;
}

.benefits-list li {
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: flex-start;
}

.benefits-list li:last-child {
    border-bottom: none;
}

.benefits-list li::before {
    content: "✓";
    color: var(--success);
    font-weight: bold;
    font-size: 1.5rem;
    margin-right: 1rem;
    flex-shrink: 0;
}

.info-box {
    background: linear-gradient(135deg, var(--info), var(--primary));
    color: white;
    padding: 2rem;
    border-radius: 1rem;
    margin: 2rem 0;
}

.info-box h4 {
    color: white;
    margin-bottom: 1rem;
}

.timeline {
    position: relative;
    padding: 2rem 0;
}

.timeline-item {
    position: relative;
    padding-left: 3rem;
    margin-bottom: 2rem;
}

.timeline-item::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--info));
}

.timeline-item::after {
    content: "";
    position: absolute;
    left: 0.9rem;
    top: 2rem;
    width: 2px;
    height: calc(100% + 2rem);
    background-color: var(--border-color);
}

.timeline-item:last-child::after {
    display: none;
}

#themeToggle {
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

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

[data-theme="dark"] #themeToggle .theme-icon::before {
    content: "🌙";
}

[data-theme="light"] #themeToggle .theme-icon::before {
    content: "☀️";
}

.form-select {
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-primary);
}

[data-theme="dark"] .form-select {
    background-color: var(--bg-tertiary);
}

footer {
    background-color: var(--dark) !important;
}

.text-white-50 {
    color: rgba(255, 255, 255, 0.6) !important;
}

.text-white-50:hover {
    color: rgba(255, 255, 255, 0.9) !important;
}

@media (max-width: 768px) {
    .display-3 {
        font-size: 2.5rem;
    }
    
    .hero-section {
        padding: 60px 0;
    }
    
    .hero-visual {
        height: 300px;
    }
    
    .floating-card {
        width: 150px;
        height: 150px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .content-section {
        padding: 60px 0;
    }
}

@media (max-width: 576px) {
    .btn-lg {
        padding: 0.75rem 1.5rem;
        font-size: 1rem;
    }
    
    .display-3 {
        font-size: 2rem;
    }
    
    .display-5 {
        font-size: 1.75rem;
    }
}

.shadow-sm {
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075) !important;
}

[data-theme="dark"] .shadow-sm {
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.3) !important;
}

.card {
    background-color: var(--card-bg);
    color: var(--text-primary);
}

[data-theme="dark"] .bg-white {
    background-color: var(--bg-secondary) !important;
}

.sticky-top {
    position: sticky;
    top: 0;
    z-index: 1020;
}