CSS – Outline
A CSS outline is a line that is drawn around elements, outside the borders, prior to the margin, to give the element additional visibility for the user.
CSS – outline Property
The outline property is a shorthand property for outline-width, outline-style, and outline-color. It draws a line around elements outside any borders.
CSS – outline-color Property
The outline-color property specifies the color of an outline, a drawn line around elements outside any borders.
CSS – outline-offset Property
The outline-color property specifies the color of an outline, a drawn line around elements outside any borders.
CSS – outline-style Property
The outline-style property specifies the style of an outline drawn around an element.
CSS – outline-width Property
The outline-width specifies the width of an outline drawn around an element.