The border-style shorthand CSS property sets the line style for all four sides of an element's border.
/* Keyword values */
border-style: none;
border-style: hidden;
border-style: dotted;
border-style: dashed;
border-style: solid;
border-style: double;
border-style: groove;
border-style: ridge;
border-style: inset;
border-style: outset;
/* top and bottom | left and right */
border-style: dotted solid;
/* top | left and right | bottom */
border-style: hidden double dashed;
/* top | right | bottom | left */
border-style: none solid dotted dashed;
/* Global values */
border-style: inherit;
border-style: initial;
border-style: unset;This property is a shorthand for the following CSS properties:
The border-style property may be specified using one, two, three, or four values.
If no border style is specified, the border does not exists. We must always declare the style of border, or the other border properties will be ignored.
Source: https://developer.mozilla.org/en-US/docs/Web/CSS/border-style