:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --text-color: #333;
    --light-gray: #f5f5f5;
    --border-color: #ddd;
}

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

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

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

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

.btn {
    display: inline-block;
    padding: 10px 20px;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

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