body {
    font-family: 'Open Sans', sans-serif;
    margin: 0;
    padding: 0;
    background: linear-gradient(to bottom, #0F4C81, #3EB489);
    color: #ffffff;
    line-height: 1.6;
}

header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(15, 76, 129, 0.9);
    color: #fff;
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

header h1 {
    font-family: 'Roboto', sans-serif;
    font-size: 24px;
    font-weight: bold;
    margin: 0;
}

nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 20px;
}

nav ul li a {
    text-decoration: none;
    color: #ffffff;
    font-weight: bold;
    transition: color 0.3s ease;
}

nav ul li a:hover {
    color: #FFA500;
}

.container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    padding: 80px 20px 20px;
    max-width: 1440px;
    margin: 0 auto;
}

.hero {
    grid-column: span 2;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat center center / cover;
    height: 400px;
    position: relative;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, rgba(15, 76, 129, 0.8), rgba(62, 180, 137, 0.8));
    z-index: 1;
}

.hero h2 {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-family: 'Roboto', sans-serif;
    font-size: 36px;
    font-weight: bold;
    color: #fff;
    z-index: 2;
}

.card {
    background: #ffffff;
    color: #333333;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.card img {
    width: 100%;
    border-radius: 10px;
    margin-bottom: 10px;
}

.card h3 {
    font-family: 'Roboto', sans-serif;
    font-size: 20px;
    font-weight: bold;
    margin: 0 0 10px;
}

.card p {
    font-size: 14px;
    line-height: 1.6;
}

.button {
    display: inline-block;
    padding: 10px 20px;
    background: linear-gradient(to right, #3EB489, #FFA500);
    color: #fff;
    font-family: 'Roboto', sans-serif;
    font-weight: bold;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.button:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.code-block {
    background: #333333;
    color: #ffffff;
    padding: 15px;
    border-radius: 5px;
    font-family: 'Courier New', monospace;
    font-size: 14px;
    overflow-x: auto;
}

footer {
    background: #0F4C81;
    color: #fff;
    text-align: center;
    padding: 20px;
    margin-top: 40px;
}

@media (max-width: 768px) {
    header {
        flex-direction: column;
        align-items: flex-start;
    }

    .hero {
        height: 300px;
    }

    .hero h2 {
        font-size: 28px;
    }
}

@media (max-width: 480px) {
    .hero {
        height: 250px;
    }

    .hero h2 {
        font-size: 24px;
    }
}