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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f7fafc;
}

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

/* 头部样式 */
header {
    background: white;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    padding: 1rem 0;
    margin-bottom: 2rem;
}

header h1 {
    color: #667eea;
    text-align: center;
    margin-bottom: 1rem;
}

nav {
    display: flex;
    justify-content: center;
    gap: 2rem;
}

nav a {
    text-decoration: none;
    color: #4a5568;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: all 0.3s ease;
}

nav a:hover {
    background-color: #edf2f7;
    color: #667eea;
}

/* 主体内容 */
main {
    min-height: calc(100vh - 200px);
    padding-bottom: 2rem;
}

/* 表单样式 */
.auth-form {
    max-width: 400px;
    margin: 2rem auto;
    padding: 2rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.auth-form h2 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2d3748;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: #4a5568;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e2e8f0;
    border-radius: 5px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    border-color: #667eea;
    outline: none;
}

.form-group small {
    display: block;
    margin-top: 0.25rem;
    color: #a0aec0;
    font-size: 0.875rem;
}

.auth-link {
    text-align: center;
    margin-top: 1rem;
    color: #718096;
}

.auth-link a {
    color: #667eea;
    text-decoration: none;
}

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

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    text-align: center;
    transition: all 0.3s ease;
}

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

.btn-primary:hover {
    background: #5a67d8;
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.btn-secondary {
    background: #a0aec0;
    color: white;
}

.btn-secondary:hover {
    background: #718096;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

/* 警告框 */
.alert {
    padding: 1rem;
    border-radius: 5px;
    margin-bottom: 1rem;
}

.alert-error {
    background-color: #fed7d7;
    border: 1px solid #fc8181;
    color: #c53030;
}

.alert-success {
    background-color: #c6f6d5;
    border: 1px solid #9ae6b4;
    color: #22543d;
}

.alert-warning {
    background-color: #feebc8;
    border: 1px solid #fbd38d;
    color: #744210;
}

/* 页脚 */
footer {
    text-align: center;
    padding: 2rem 0;
    margin-top: 2rem;
    border-top: 1px solid #e2e8f0;
    color: #718096;
}

/* 页面标题 */
.page-header {
    text-align: center;
    margin-bottom: 2rem;
}

.page-header h2 {
    color: #2d3748;
    margin-bottom: 0.5rem;
}

.page-header p {
    color: #718096;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 10px;
    }
    
    nav {
        flex-direction: column;
        align-items: center;
        gap: 0.5rem;
    }
    
    nav a {
        display: block;
        width: 100%;
        text-align: center;
    }
    
    .auth-form {
        padding: 1rem;
        margin: 1rem;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .stats, .actions {
        grid-template-columns: 1fr;
    }
}

/* 打印样式 */
@media print {
    nav, footer, .btn {
        display: none;
    }
    
    body {
        font-size: 12pt;
    }
}