border-top-width

border-top-width 该属性是用于规定元素的上边框的宽度。

border-top-width: 3em;
border-top-width: 4vmax;
border-top-width: 3px;
border-top-width: medium;
border-top-width: thick;
border-top-width: thin;
border-top-width: inherit;

HTML

<div id="red">
</div>

CSS

#red {
     width: 200px;
     height: 200px;
     border: 2px dashed red;
     border-top-width: 10px;
     }
   

执行结果

相关链接

• border-top-color
• border-top-style

外部链接

• border-top-width-MDN