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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f4f4f4;
}

/* 导航栏 */
.navbar {
    background: #2c3e50;
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-links a {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: background 0.3s;
}

.nav-links a:hover, .nav-links a.active {
    background: #34495e;
}

.welcome {
    color: #3498db;
    padding: 0.5rem 1rem;
}

/* 主横幅 */
.hero-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 4rem 2rem;
}

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

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

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* 功能卡片 */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    padding: 4rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    text-align: center;
}

.feature-card h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
}

.feature-card p {
    color: #666;
    margin-bottom: 1.5rem;
}

/* 按钮 */
.btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    background: #3498db;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    border: none;
    cursor: pointer;
    transition: background 0.3s;
}

.btn:hover {
    background: #2980b9;
}

.btn-primary {
    background: #e74c3c;
}

.btn-primary:hover {
    background: #c0392b;
}

.btn-secondary {
    background: transparent;
    border: 2px solid white;
}

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

/* 表单样式 */
.container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.form-box {
    background: white;
    padding: 3rem;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 400px;
}

.form-box h2 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2c3e50;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: #555;
}

.form-group input {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

.form-group input:focus {
    outline: none;
    border-color: #3498db;
}

.error {
    background: #fee;
    color: #c33;
    padding: 0.8rem;
    border-radius: 4px;
    margin-bottom: 1rem;
    text-align: center;
}

.success {
    background: #efe;
    color: #3c3;
    padding: 0.8rem;
    border-radius: 4px;
    margin-bottom: 1rem;
    text-align: center;
}

.link-text {
    text-align: center;
    margin-top: 1rem;
    color: #666;
}

.link-text a {
    color: #3498db;
    text-decoration: none;
}

.link-text a:hover {
    text-decoration: underline;
}

/* 页面内容 */
.page-content {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 2rem;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.page-content h1 {
    color: #2c3e50;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #3498db;
}

.page-content h2 {
    color: #34495e;
    margin: 1.5rem 0 1rem;
}

.page-content p {
    margin-bottom: 1rem;
    line-height: 1.8;
}

/* 页脚 */
footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem;
    margin-top: 4rem;
}