154. Amazing Alert Buttons With Only HTML and CSS

1. 用<a>製作button效果，需要設置text-decoration padding display

.btn{
    text-decoration: none;
    padding: 14px 20px;
    display: inline-block;
    
    text-align: center;
    color:white;
    font-size: 20px;
    font-family: sans-serif;
}

2. 鼠標hover到button上面會高亮的效果。是調整了opacity

.btn:hover{
    opacity: 0.5;
}