body {
    margin: 0;
    padding: 0;
    font-family: 'Helvetica', sans-serif;
    background-color: #f3f4f6;
    color: #2d3748;
    line-height: 1.6;
    overflow-x: hidden;
}
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: linear-gradient(135deg, rgba(224, 247, 250, 0.9), rgba(237, 231, 246, 0.9));
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    transition: all 0.3s ease;
}
header.scrolled {
    background: linear-gradient(135deg, rgba(224, 247, 250, 0.8), rgba(237, 231, 246, 0.8));
}
header nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}
header nav .logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: #4a5568;
    text-transform: uppercase;
    letter-spacing: 2px;
}
header nav ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
}
header nav ul li a {
    text-decoration: none;
    color: #4a5568;
    font-size: 1rem;
    transition: color 0.3s ease, transform 0.3s ease;
}
header nav ul li a:hover {
    color: #2b6cb0;
    transform: translateY(-2px);
}
.hero-section {
    position: relative;
    height: 100vh;
    background: url('https://images.gptkong.com/demo/sample1.png'), linear-gradient(135deg, #e0f7fa, #ede7f6);
    background-size: cover;
    background-position: center;
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: #fff;
    overflow: hidden;
}
.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
}
.hero-section h1 {
    font-size: 3rem;
    font-weight: bold;
    z-index: 1;
    position: relative;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}
.hero-section p {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 1rem auto 0;
    z-index: 1;
    position: relative;
}
.features-section {
    padding: 4rem 2rem;
    background: #ffffff;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}
.feature-card {
    background: #f7fafc;
    border-radius: 10px;
    padding: 2rem;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.2);
}
.feature-card img {
    width: 100px;
    height: 100px;
    object-fit: cover;
    border-radius: 50%;
    margin-bottom: 1rem;
    border: 2px solid #cbd5e0;
    transition: border-color 0.3s ease;
}
.feature-card:hover img {
    border-color: #2b6cb0;
}
.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: #2d3748;
}
.feature-card p {
    font-size: 1rem;
    color: #718096;
}
.article-section {
    padding: 4rem 2rem;
    background: #edf2f7;
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}
.article-section h2 {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 2rem;
    color: #2d3748;
}
.article-section article {
    background: #fff;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    max-width: 800px;
    margin: 0 auto;
}
.article-section h3 {
    font-size: 1.5rem;
    margin-top: 2rem;
    color: #2b6cb0;
}
.article-section pre {
    background: #f7fafc;
    padding: 1rem;
    border-radius: 5px;
    overflow-x: auto;
    font-size: 0.9rem;
    color: #4a5568;
}
footer {
    background: #2d3748;
    color: #f7fafc;
    padding: 2rem;
    text-align: center;
    font-size: 0.9rem;
}
@media (max-width: 768px) {
    header nav {
        flex-direction: column;
        gap: 1rem;
    }
    header nav ul {
        flex-direction: column;
        gap: 0.5rem;
    }
    .hero-section h1 {
        font-size: 2rem;
    }
    .features-section {
        grid-template-columns: 1fr;
    }
}