footer {
    background-color: #f1f1f1;
    padding: 1em 0;
    width: 100%;
    bottom: 0;
    text-align: center; /* 确保内容居中显示 */
}

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

.footer-ad {
    flex: 2.5;
    text-align: center;
    overflow: hidden; /* 确保多出的部分隐藏 */
}

.footer-content {
    flex: 5;
    text-align: center;
}