:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-card: #ffffff;
    --text-primary: #1a1a1a;
    --text-secondary: #666666;
    --text-muted: #999999;
    --border-color: #e0e0e0;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    --border-color: #334155;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.3);
}

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

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

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

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    background: var(--bg-card);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

.theme-toggle .sun {
    display: block;
}

.theme-toggle .moon {
    display: none;
}

[data-theme="dark"] .theme-toggle .sun {
    display: none;
}

[data-theme="dark"] .theme-toggle .moon {
    display: block;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--accent-color) 0%, #1d4ed8 100%);
    color: white;
    padding: 100px 0 80px;
    text-align: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 1rem;
    opacity: 0.95;
}

.hero-meta {
    font-size: 1rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.separator {
    margin: 0 10px;
}

.hero-description {
    font-size: 1.125rem;
    max-width: 800px;
    margin: 0 auto;
    opacity: 0.9;
    line-height: 1.7;
}

/* Navigation */
.nav {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.nav .container {
    display: flex;
    gap: 2rem;
    padding: 1.5rem 20px;
    overflow-x: auto;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    white-space: nowrap;
    transition: color 0.2s ease;
    font-size: 1rem;
}

.nav-link:hover {
    color: var(--accent-color);
}

/* Main Content */
.main {
    padding: 60px 0;
}

.section {
    margin-bottom: 80px;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-weight: 700;
}

.section-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    max-width: 800px;
    line-height: 1.7;
}

/* Cards */
.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

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

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

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

.card-list {
    list-style: none;
    margin-bottom: 1.5rem;
}

.card-list li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: 1.5rem;
}

.card-list li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

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

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

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

.btn-outline {
    background: transparent;
    color: var(--accent-color);
    border: 2px solid var(--accent-color);
}

.btn-outline:hover {
    background: var(--accent-color);
    color: white;
}

/* Highlight Box */
.highlight-box {
    background: var(--bg-secondary);
    border-left: 4px solid var(--accent-color);
    padding: 1.5rem;
    border-radius: 8px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.highlight-box strong {
    color: var(--text-primary);
}

/* Task Grid */
.task-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.task-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 1.5rem;
    transition: all 0.3s ease;
}

.task-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.task-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 1rem;
}

.task-badge.critical {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
}

.task-badge.high {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
}

.task-badge.medium {
    background: rgba(37, 99, 235, 0.1);
    color: var(--accent-color);
}

.task-card h4 {
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.task-card p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 0.9rem;
    line-height: 1.5;
}

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

.doc-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
}

.doc-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

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

.doc-card h4 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

/* Video Section */
.video-container {
    max-width: 900px;
    margin: 0 auto;
}

.video-placeholder {
    background: var(--bg-secondary);
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 4rem 2rem;
    text-align: center;
}

.video-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.video-placeholder p {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

.video-note {
    font-size: 0.9rem !important;
    color: var(--text-muted) !important;
    margin-top: 0.5rem;
}

/* Value Section */
.value-section {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 3rem 2rem;
    text-align: center;
    margin-top: 4rem;
}

.value-section h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

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

.value-card {
    padding: 1.5rem;
}

.value-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.value-card p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0;
    text-align: center;
    margin-top: 4rem;
}

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

.footer-links a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
}

.footer-links a:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

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

    .nav .container {
        gap: 1rem;
    }

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

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

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

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

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Selection */
::selection {
    background: var(--accent-color);
    color: white;
}