:root {
    --primary-color: #0078d4;
    --secondary-color: #f3f2f1;
    --text-color: #323130;
    --bg-color: #ffffff;
    --hover-color: #005a9e;
}

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

body {
    font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

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

header {
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

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

.nav-links li {
    margin-left: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
}

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

.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #0078d4 0%, #00bcf2 100%);
    color: #fff;
    text-align: center;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
}

.hero p {
    font-size: 20px;
    margin-bottom: 30px;
    opacity: 0.9;
}

.btn-download {
    display: inline-block;
    padding: 15px 40px;
    background-color: #fff;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 20px;
    font-weight: bold;
    border-radius: 30px;
    transition: transform 0.3s, box-shadow 0.3s;
}

.btn-download:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

.section {
    padding: 60px 0;
}

.section h2 {
    font-size: 32px;
    margin-bottom: 40px;
    text-align: center;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-card {
    padding: 30px;
    background-color: var(--secondary-color);
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-card i {
    font-size: 40px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.content-area {
    line-height: 1.8;
}

.content-area h3 {
    margin: 30px 0 15px;
}

.footer {
    background-color: #333;
    color: #fff;
    padding: 40px 0;
    text-align: center;
}

.footer-links {
    margin-bottom: 20px;
}

.footer-links a {
    color: #ccc;
    text-decoration: none;
    margin: 0 15px;
}

@media (max-width: 768px) {
    .hero h1 { font-size: 32px; }
    .nav-links { display: none; }
}