/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

/* 导航栏 */
.navbar {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
}

.logo {
    display: flex;
    align-items: center;
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
}

.logo i {
    margin-right: 10px;
    font-size: 2rem;
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

.nav-item {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    transition: all 0.3s ease;
}

.nav-item:hover,
.nav-item.active {
    background: rgba(255,255,255,0.2);
}

.nav-auth {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.5rem 1.5rem;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.btn-login {
    background: white;
    color: #667eea;
}

.btn-register {
    background: #ff6b6b;
    color: white;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 0.75rem 2rem;
    font-size: 1.1rem;
}

.btn-secondary {
    background: #4ecdc4;
    color: white;
    padding: 0.75rem 2rem;
    font-size: 1.1rem;
}

/* 英雄区域 */
.hero {
    padding: 8rem 2rem 4rem;
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    min-height: 100vh;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-content p {
    font-size: 1.2rem;
    color: #666;
    margin-bottom: 2rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

/* 功能特色 */
.features {
    padding: 4rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #333;
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

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

.feature-card i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 1rem;
}

.feature-card h3 {
    margin-bottom: 1rem;
    color: #333;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    z-index: 1001;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
}

.modal-content {
    background-color: white;
    margin: 10% auto;
    padding: 2rem;
    border-radius: 15px;
    width: 90%;
    max-width: 400px;
    position: relative;
}

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 1.5rem;
    cursor: pointer;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .hero {
        grid-template-columns: 1fr;
        text-align: center;
        padding-top: 6rem;
    }
    
    .hero-content h1 {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
    }
}