#min-width
Defines the minimum width of the element.
默认属性
min-width: 0;
The element has no minimum width.
min-width: 300px;
You can use numeric values like pixels, (r)em, percentages...
If the minimum width is larger than the element's actual width, the min width will be applied.
min-width: 5px;
If the minimum width is smaller than the element's actual width, the min width has no effect.