对父盒子设置边框后,会与子盒子之间有空隙(上面和左边)这是为什么,该如何解决?
代码:
```css
*{
margin: 0;
padding: 0;
}
.box{
width: 300px;
height: 200px;
border: 5px solid sienna;
margin: 50px;
font-size: 0;
}
.box .box1{
width: 100%;
height: 100%;
background-color: red;
position: relative;
}
```html
<div class="box">
<div class="box1"></div>
</div>