:root {
    --primary: #ff7e21; /* Orange theme for "快橙" */
    --primary-hover: #e66a1a;
    --dark: #1a1a1a;
    --light: #f4f4f4;
    --white: #ffffff;
    --text: #333333;
    --gray: #666666;
}

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

body {
    font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text);
    background-color: var(--white);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 15px 0;
}

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

.logo {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary);
}

nav ul {
    display: flex;
    list-style: none;
}

nav ul li {
    margin-left: 20px;
}

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

nav ul li a:hover, nav ul li a.active {
    color: var(--primary);
}

.hero {
    padding: 100px 0;
    background: linear-gradient(135deg, #fff5eb 0%, #ffffff 100%);
    text-align: center;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
    color: var(--dark);
}

.hero p {
    font-size: 20px;
    color: var(--gray);
    margin-bottom: 40px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: bold;
    transition: all 0.3s;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary);
    color: var(--white);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
}

.btn-secondary {
    border: 2px solid var(--primary);
    color: var(--primary);
    margin-left: 15px;
}

.btn-secondary:hover {
    background: var(--primary);
    color: var(--white);
}

.download-section {
    padding: 80px 0;
    background: var(--light);
}

.download-section h2 {
    text-align: center;
    margin-bottom: 50px;
    font-size: 32px;
}

.platforms {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
}

.platform-card {
    background: var(--white);
    padding: 40px 20px;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    transition: transform 0.3s;
}

.platform-card:hover {
    transform: translateY(-10px);
}

.platform-card img {
    width: 60px;
    margin-bottom: 20px;
}

.platform-card h3 {
    margin-bottom: 10px;
}

.platform-card p {
    color: var(--gray);
    margin-bottom: 20px;
}

.features {
    padding: 80px 0;
}

.features h2 {
    text-align: center;
    margin-bottom: 50px;
    font-size: 32px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.feature-item h3 {
    color: var(--primary);
    margin-bottom: 15px;
}

footer {
    background: var(--dark);
    color: #999;
    padding: 60px 0;
    text-align: center;
}

footer p {
    margin-bottom: 20px;
}

.footer-links a {
    color: #999;
    text-decoration: none;
    margin: 0 10px;
}

.footer-links a:hover {
    color: var(--white);
}

@media (max-width: 768px) {
    .hero h1 { font-size: 32px; }
    nav ul { display: none; }
    .btn-secondary { margin-left: 0; margin-top: 15px; display: block; }
}