/* ===========================
   CSS Reset & Base
   =========================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --performance-gradient: linear-gradient(135deg, #43cea2 0%, #185a9d 100%);
    --babylon-color: #667eea;
    --unity-hq-color: #764ba2;
    --unity-hp-color: #43cea2;
    
    --bg-color: #0f0f1e;
    --bg-secondary: #1a1a2e;
    --text-primary: #ffffff;
    --text-secondary: #b4b4c8;
    --border-color: rgba(255, 255, 255, 0.1);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ===========================
   Layout
   =========================== */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-md);
}

/* ===========================
   Header
   =========================== */
.header {
    text-align: center;
    padding: var(--spacing-xl) 0;
    background: var(--primary-gradient);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
}

.logo {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: var(--spacing-xs);
    background: linear-gradient(to right, #fff, #e0e0ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: rgba(255, 255, 255, 0.9);
    font-weight: 300;
    letter-spacing: 2px;
    text-transform: uppercase;
}

/* ===========================
   Main Content
   =========================== */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
}

.intro {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding: 0 var(--spacing-md);
}

.intro h2 {
    font-size: clamp(1.5rem, 4vw, 2.5rem);
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.intro p {
    font-size: clamp(1rem, 2vw, 1.125rem);
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.8;
}

/* ===========================
   Demo Grid
   =========================== */
.demo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.demo-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
    position: relative;
    display: flex;
    flex-direction: column;
}

.demo-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.demo-card.featured {
    border: 2px solid var(--unity-hq-color);
    box-shadow: 0 0 20px rgba(118, 75, 162, 0.3);
}

.demo-image {
    position: relative;
    width: 100%;
    height: 240px;
    overflow: hidden;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.2), rgba(118, 75, 162, 0.2));
}

.demo-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.demo-card:hover .demo-image img {
    transform: scale(1.05);
}

.demo-badge {
    position: absolute;
    top: var(--spacing-sm);
    left: var(--spacing-sm);
    background: rgba(0, 0, 0, 0.85);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 700;
    backdrop-filter: blur(10px);
    z-index: 10;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.demo-badge.premium {
    background: linear-gradient(135deg, #764ba2, #667eea);
}

.demo-badge.performance {
    background: linear-gradient(135deg, #43cea2, #185a9d);
}

.demo-content {
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    flex: 1;
}

.demo-content h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.demo-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.demo-features {
    list-style: none;
    margin-bottom: var(--spacing-md);
    flex: 1;
}

.demo-features li {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.demo-features .icon {
    font-size: 1.2rem;
}

.demo-button {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.demo-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(102, 126, 234, 0.4);
}

.demo-button.premium {
    background: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
}

.demo-button:active {
    transform: translateY(0);
}

/* ===========================
   Tech Info Section
   =========================== */
.tech-info {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    border: 1px solid var(--border-color);
}

.tech-info h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.tech-item {
    text-align: center;
}

.tech-item h4 {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.tech-item p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* ===========================
   Footer
   =========================== */
.footer {
    text-align: center;
    padding: var(--spacing-lg) 0;
    color: var(--text-secondary);
    font-size: 0.875rem;
    border-top: 1px solid var(--border-color);
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-sm);
    }
    
    .header {
        padding: var(--spacing-lg) var(--spacing-sm);
        margin-bottom: var(--spacing-lg);
    }
    
    .demo-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .demo-image {
        height: 200px;
    }
    
    .tech-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .tech-info {
        padding: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .demo-content {
        padding: var(--spacing-md);
    }
    
    .demo-image {
        height: 180px;
    }
}

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

.demo-card {
    animation: fadeIn 0.6s ease-out backwards;
}

.demo-card:nth-child(1) { animation-delay: 0.1s; }
.demo-card:nth-child(2) { animation-delay: 0.2s; }
.demo-card:nth-child(3) { animation-delay: 0.3s; }