The border-top-width property in CSS is used to set a specific width to the top border of an element. The border-top-style or border-style property is used for the element before using the border-top-width property.
The border-top-width property sets the width of an element's top border.
Syntax:
border-top-width: length|thin|medium|thick|initial|inherit;
Property Values: The border-top-width property values are listed below:
Note: Always declare the border-style or the
border-top-style property before the border-top-width
property. An element must have borders before you can change the width.