The border-width property sets the width of the border simultaneously on all sides of an element or individually for each side.
border-width: value;
This property is not convenient for programming, since the same value can be set using the border
property, which is already used.
The example below shows 2 options with the same result.
<div class="example1">solid</div>
<div class="example2">solid</div>
.example1 {
border: solid blue;
border-width: 10px;
}
.example2 {
border: 10px solid blue;
}