/* Base Styles & CSS Variables */
:root {
    --primary-color: #e74c3c;
    --secondary-color: #c0392b;
    --accent-color: #ff6b6b;
    --dark-color: #2c3e50;
    --light-color: #ecf0f1;
    --text-color: #34495e;
    --border-color: #bdc3c7;
    --white: #ffffff;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

header {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    transition: var(--transition);
}

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

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
}

.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    text-align: center;
}

.hero-content h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

.btn {
    display: inline-block;
    padding: 1rem 2rem;
    background: var(--white);
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    transition: var(--transition);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.features {
    padding: 4rem 0;
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--dark-color);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.content-section {
    padding: 4rem 0;
    background: var(--light-color);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--dark-color);
}

footer {
    background: var(--dark-color);
    color: var(--white);
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.contact-info p {
    margin-bottom: 0.5rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Responsive Design */
@media (max-width: 768px) {
    nav ul {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }
}