body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    text-align: center;
    background-color: #f4f4f4;
}

header {
    background: #4CAF50;
    color: white;
    padding: 15px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 40px;
}

header .logo {
    display: flex;
    align-items: center;
}

header .logo img {
    width: 50px;
    height: 50px;
    margin-right: 10px;
}

header .logo span {
    font-size: 22px;
    font-weight: bold;
}

nav ul {
    list-style: none;
    padding: 0;
    display: flex;
    margin: 0;
}

nav ul li {
    flex: 1;
    padding: 15px 25px;
    min-width: 120px;  /* 增加菜单宽度，避免四字换行 */
}

nav ul li a {
    color: white;
    text-decoration: none;
    font-size: 18px;
    display: block;
    padding: 15px 20px;
    transition: background 0.3s;
}

nav ul li:hover {
    background: rgba(255, 255, 255, 0.2);
    cursor: pointer;
}

/* 当前选中菜单项保持悬浮状态样式 */
nav ul li.active {
    background: rgba(255, 255, 255, 0.2);
}

.content {
    padding: 40px 15%;
    text-align: left;
    background: white;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    border-radius: 10px;
    margin: 20px auto;
}

.content h2 {
    color: #333;
    border-left: 5px solid #4CAF50;
    padding-left: 10px;
}

.content img {
    width: 100%;
    border-radius: 10px;
    margin: 20px 0;
}

footer {
    background: #333;
    color: white;
    padding: 15px;
    margin-top: 40px;
}

footer div a {
    color: #fcd300;
    text-decoration: none;
    outline: none;
}