:root {
    --primary: #0066cc;
    --primary-dark: #004499;
    --secondary: #6366f1;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-lg: rgba(0, 0, 0, 0.15);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--bg-primary);
    border-radius: 20px;
    box-shadow: 0 20px 60px var(--shadow-lg);
    overflow: hidden;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 60px 40px;
    text-align: center;
}

.hero-content h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 16px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.25rem;
    opacity: 0.95;
    margin-bottom: 24px;
}

.badges {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
}

.badge {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* Main Content */
main {
    padding: 40px;
}

section {
    margin-bottom: 48px;
}

h2 {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: 12px;
    font-weight: 700;
}

.section-subtitle {
    color: var(--text-secondary);
    margin-bottom: 32px;
    font-size: 1.1rem;
}

.intro p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.8;
}

.intro a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    border-bottom: 2px solid transparent;
    transition: border-color 0.3s;
}

.intro a:hover {
    border-bottom-color: var(--primary);
}

/* Version Grid */
.version-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-top: 32px;
}

.version-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: 16px;
    padding: 24px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.version-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

.version-card:hover::before {
    transform: scaleX(1);
}

.version-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 32px var(--shadow-lg);
    border-color: var(--primary);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 16px;
}

.version-icon {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    font-weight: 800;
    color: white;
    flex-shrink: 0;
}

.beta .version-icon {
    background: linear-gradient(135deg, #f59e0b, #d97706);
}

.v3 .version-icon {
    background: linear-gradient(135deg, #10b981, #059669);
}

.v4 .version-icon {
    background: linear-gradient(135deg, #6366f1, #4f46e5);
}

.card-title h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.version-label {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 12px;
    border-radius: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.beta .version-label {
    background: #fef3c7;
    color: #92400e;
}

.v3 .version-label {
    background: #d1fae5;
    color: #065f46;
}

.v4 .version-label {
    background: #e0e7ff;
    color: #3730a3;
}

.card-description {
    color: var(--text-secondary);
    line-height: 1.6;
    flex-grow: 1;
    margin-bottom: 16px;
}

.card-footer {
    display: flex;
    align-items: center;
    justify-content: flex-end;
}

.view-report {
    color: var(--primary);
    font-weight: 600;
    font-size: 0.95rem;
    transition: transform 0.3s;
}

.version-card:hover .view-report {
    transform: translateX(4px);
}

/* Tech Info */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 24px;
}

.info-card {
    background: var(--bg-tertiary);
    padding: 24px;
    border-radius: 12px;
    border-left: 4px solid var(--primary);
}

.info-card h4 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.info-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Footer */
footer {
    background: var(--bg-tertiary);
    padding: 32px 40px;
    text-align: center;
    color: var(--text-secondary);
    border-top: 1px solid var(--border);
}

footer p {
    margin-bottom: 8px;
}

footer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
}

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

.last-updated {
    font-size: 0.875rem;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

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

    .subtitle {
        font-size: 1rem;
    }

    main {
        padding: 24px;
    }

    h2 {
        font-size: 1.5rem;
    }

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

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

/* Dark mode friendly */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #1e293b;
        --bg-secondary: #0f172a;
        --bg-tertiary: #334155;
        --text-primary: #f1f5f9;
        --text-secondary: #cbd5e1;
        --border: #334155;
    }

    .version-card {
        background: var(--bg-secondary);
    }

    .info-card {
        background: var(--bg-tertiary);
    }
}