:root {
    --primary: #1A294C;
    --secondary: #6F30B7;
    --accent: #FF8C00;
    --text: #333333;
    --light: #FFFFFF;
    --dark: #111111;
    --gray: #F5F5F5;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Montserrat', 'Arial', sans-serif;
    line-height: 1.6;
    color: var(--text);
    background-color: var(--gray);
    overflow-x: hidden;
}

.header {
    position: relative;
    height: 80vh;
    min-height: 500px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: var(--light);
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
    opacity: 0.2;
    z-index: 0;
}

.header-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.header h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.header p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.notice {
    background-color: var(--accent);
    color: var(--light);
    padding: 1rem;
    border-radius: 8px;
    margin: 2rem auto;
    max-width: 800px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.main-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    position: relative;
}

.article {
    background-color: var(--light);
    border-radius: 12px;
    padding: 3rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    margin-bottom: 3rem;
}

.article h2 {
    color: var(--primary);
    font-size: 2rem;
    margin: 2rem 0 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
}

.article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100px;
    height: 4px;
    background: linear-gradient(to right, var(--accent), var(--secondary));
    border-radius: 2px;
}

.article h3 {
    color: var(--secondary);
    font-size: 1.5rem;
    margin: 1.5rem 0 1rem;
}

.article p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
}

pre {
    background-color: var(--dark);
    color: var(--light);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.5);
}

code {
    font-family: 'Courier New', monospace;
    background-color: rgba(0,0,0,0.1);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9rem;
}

.image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.image-card {
    position: relative;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: var(--transition);
}

.image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

.image-card img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    transition: var(--transition);
}

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

.nav-tabs {
    display: flex;
    flex-wrap: wrap;
    margin: 2rem 0;
    border-bottom: 1px solid rgba(0,0,0,0.1);
}

.nav-tab {
    padding: 0.8rem 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    font-weight: 600;
    color: var(--text);
    position: relative;
    transition: var(--transition);
}

.nav-tab.active {
    color: var(--accent);
}

.nav-tab.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--accent);
}

.tab-content {
    display: none;
    padding: 1.5rem 0;
    animation: fadeIn 0.5s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.footer {
    background-color: var(--primary);
    color: var(--light);
    padding: 3rem 2rem;
    text-align: center;
    margin-top: 3rem;
}

.footer p {
    opacity: 0.8;
    margin-bottom: 1rem;
}

@media (max-width: 768px) {
    .header h1 {
        font-size: 2.2rem;
    }
    
    .article {
        padding: 2rem;
    }
    
    .image-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .header {
        height: auto;
        padding: 4rem 1rem;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .article {
        padding: 1.5rem;
    }
    
    .article h2 {
        font-size: 1.6rem;
    }
}