在自定义主题-额外CSS处填入如下代码

.button {
    border-radius: 5px;
    color: #ffffff!important;
    display: inline-block;
    margin-right: 10px;
	  margin-bottom: 10px;
    padding: 7px 10px;
	background-color: #3bc492;
	text-decoration: none!important;
	text-indent: 0!important;
}
.button2 {
    border-radius: 5px;
    color: #ffffff!important;
    display: inline-block;
    margin-right: 10px;
	  margin-bottom: 10px;
    padding: 7px 10px;
	background-color: #CC00CC;
	text-decoration: none!important;
	text-indent: 0!important;
}

在编辑器中使用如下格式调用：

<p style="text-align: center;"><a class="button" href="https://google.com" target="_blank" rel="noopener">MediaFire</a></p>

<p style="text-align: center;"><a class="button2" href="https://www.baidu.com" target="_blank" rel="noopener">77File</a></p>