/* 全局重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

/* 容器样式 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部样式 */
header {
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo {
    font-size: 24px;
    font-weight: bold;
    color: #0066cc;
    text-decoration: none;
}

/* 导航样式 */
nav ul {
    display: flex;
    list-style: none;
}

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

nav ul li a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: #0066cc;
}

/* 主按钮样式 */
.btn {
    display: inline-block;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background-color: #0066cc;
    color: white;
}

.btn-primary:hover {
    background-color: #0052a3;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 102, 204, 0.3);
}

.btn-secondary {
    background-color: #f0f0f0;
    color: #333;
}

.btn-secondary:hover {
    background-color: #e0e0e0;
}

/* 表单样式 */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #333;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: #0066cc;
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

/* 卡片样式 */
.card {
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    padding: 24px;
    margin-bottom: 24px;
}

/* 页脚样式 */
footer {
    background-color: #333;
    color: white;
    padding: 40px 0 20px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    margin-bottom: 30px;
}

.footer-column {
    flex: 1;
    min-width: 200px;
    margin-bottom: 20px;
}

.footer-column h3 {
    font-size: 18px;
    margin-bottom: 16px;
}

.footer-column ul {
    list-style: none;
}

.footer-column ul li {
    margin-bottom: 10px;
}

.footer-column ul li a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-column ul li a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #555;
    color: #ccc;
    font-size: 14px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 15px;
    }
    
    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    nav ul li {
        margin: 5px 10px;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 20px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

/* 工具类 */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }