:root {
    --primary-color: #1890ff;
    --text-color: #333;
    --bg-gray: #f5f5f5;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
}

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

/* Header */
.header {
    background: #fff;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
    font-size: 22px;
    letter-spacing: 2px;
}

.logo img {
    height: 80px;
}

.nav ul {
    display: flex;
    list-style: none;
}

.nav a {
    color: var(--text-color);
    text-decoration: none;
    padding: 10px 20px;
    font-size: 16px;
    transition: color 0.3s;
}

.nav a:hover,
.nav a.active {
    color: var(--primary-color);
}

/* Banner */
.banner {
    margin-top: 80px;
    height: 500px;
    overflow: hidden;
    position: relative;
}

.banner-slider {
    height: 100%;
}

.banner-slider img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Sections */
.section {
    padding: 80px 0;
}

.section-gray {
    background: var(--bg-gray);
}

.section-title {
    text-align: center;
    font-size: 32px;
    margin-bottom: 40px;
}

/* Course Grid */
.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

/* VIP Features */
.vip-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: #fff;
    padding: 30px;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 2px 12px rgba(0,0,0,0.1);
}

.feature-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

.feature-card img {
    width: 100px;
    height: 100px;
    margin-bottom: 15px;
}

/* Footer */
.footer {
    background: #333;
    color: #fff;
    padding: 20px 0;
    text-align: center;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .banner {
        height: 300px;
    }
    
    .section {
        padding: 40px 0;
    }
}