Custom border image template
Specify the location of the image to be used as the template for a custom border.
Despite its name, this property can be used to define a border image source from more than just image files.
|<url>||The URL of a bitmap image file|
|linear-gradient()||Colors that gradually transition from top to bottom|
|radial-gradient()||Colors that gradually transition from the center to the edges|
|conic-gradient()||Colors that gradually transition around a point|
|repeating-linear-gradient()||A pattern made up from linear gradients|
|repeating-radial-gradient()||A pattern made up from radial gradients|
|repeating-conic-gradient()||A pattern made up from conical gradients|