border

As with all shorthand properties, any omitted sub-values will be set to their initial value. Importantly, border cannot be used to specify a custom value for border-image, but instead sets it to its initial value, i.e., none.

The border shorthand is especially useful when you want all four borders to be the same. To make them different from each other, however, you can use the longhand border-width, border-style, and border-color properties, which accept different values for each side. Alternatively, you can target one border at a time with the physical (e.g., border-top ) and logical (e.g., border-block-start) border properties.