:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --accent: #f59e0b;
    --accent-light: #fbbf24;
    --dark: #0f172a;
    --glass: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.15);
    --text-primary: #f8fafc;
    --text-secondary: rgba(255, 255, 255, 0.7);
}

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

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
    background: var(--dark);
    min-height: 100vh;
    overflow-x: hidden;
    color: var(--text-primary);
}

/* Animated Background */
.bg-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.bg-animation::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(99, 102, 241, 0.4) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(139, 92, 246, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(245, 158, 11, 0.2) 0%, transparent 40%),
        radial-gradient(circle at 90% 90%, rgba(59, 130, 246, 0.3) 0%, transparent 50%);
    animation: bgMove 20s ease-in-out infinite;
}

@keyframes bgMove {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    25% { transform: translate(-5%, 5%) rotate(5deg); }
    50% { transform: translate(5%, -5%) rotate(-5deg); }
    75% { transform: translate(-3%, -3%) rotate(3deg); }
}

/* Floating Orbs */
.orb {
    position: fixed;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 15s ease-in-out infinite;
}

.orb-1 {
    width: 400px;
    height: 400px;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    top: -100px;
    right: -100px;
    animation-delay: 0s;
}

.orb-2 {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    bottom: -50px;
    left: -50px;
    animation-delay: -5s;
}

.orb-3 {
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, #10b981, #3b82f6);
    top: 50%;
    left: 50%;
    animation-delay: -10s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -30px) scale(1.1); }
    66% { transform: translate(-20px, 20px) scale(0.9); }
}

/* Grid Pattern Overlay */
.grid-pattern {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    z-index: -1;
}

/* 
   Note: Header and Footer styles have been moved to header.php 
   with stjy- prefix to avoid conflicts with course content.
*/