:root {
    --primary-color: #0074D9;
    --secondary-color: #FFFFFF;
    --accent-color: #2ECC40;
    --dark-blue: #003366;
    --light-blue: #E6F7FF;
    --gradient-bg: linear-gradient(135deg, #003366, #0074D9, #2ECC40);
    --font-stack: 'Montserrat', sans-serif;
}

body {
    margin: 0;
    font-family: var(--font-stack);
    background: var(--gradient-bg);
    color: var(--secondary-color);
    line-height: 1.6;
}

header {
    position: relative;
    height: 100vh;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat center center/cover, var(--gradient-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

header h1 {
    font-size: 4rem;
    font-weight: bold;
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.5);
}

header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 200%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
    transform: rotate(30deg);
    animation: moveBackground 20s infinite alternate;
}

@keyframes moveBackground {
    from { transform: translateX(-25%) rotate(30deg); }
    to { transform: translateX(25%) rotate(30deg); }
}

nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
}

nav li {
    margin: 0 1rem;
}

nav a {
    text-decoration: none;
    color: var(--secondary-color);
    font-size: 1.2rem;
    padding: 1rem;
    transition: all 0.3s ease;
}

nav a:hover {
    background: var(--accent-color);
    color: var(--dark-blue);
    border-radius: 4px;
}

section {
    padding: 4rem 2rem;
    background: var(--light-blue);
    margin: 2rem auto;
    border-radius: 12px;
    max-width: 1200px;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
    position: relative;
}

section:nth-child(even) {
    background: var(--secondary-color);
    color: var(--dark-blue);
}

section img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin-bottom: 1rem;
}

h2, h3 {
    color: var(--primary-color);
}

pre {
    background: var(--dark-blue);
    color: var(--secondary-color);
    padding: 1rem;
    border-radius: 8px;
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    background: var(--secondary-color);
    color: var(--dark-blue);
}

th, td {
    padding: 1rem;
    text-align: left;
    border: 1px solid var(--accent-color);
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2.5rem;
    }

    nav a {
        font-size: 1rem;
        padding: 0.75rem;
    }

    section {
        padding: 2rem 1rem;
    }

    pre {
        font-size: 0.9rem;
    }
}

footer {
    text-align: center;
    padding: 2rem;
    background: var(--gradient-bg);
    color: var(--secondary-color);
    font-size: 0.9rem;
}