If you wish to make the lines around text wider, which property should you increase?

To make the lines around text wider, increasing the stroke width is the correct approach. The stroke width property directly affects the thickness of the lines that define the edges of text or shapes. When you increase the stroke width, you enhance the visibility and prominence of the text outlines, making them appear bolder or more pronounced. This is particularly important in graphic design, where emphasis and clarity are crucial.

The other properties listed serve different functions that do not affect the outline around the text. Fill width pertains to the interior color or pattern of the text and does not influence the thickness of the border. Kerning is related to the spacing between pairs of characters, affecting the overall readability and aesthetics of the text but not the outline's width. Leading refers to the vertical space between lines of text, which also does not influence the outlines. Thus, stroke width is the specific property to adjust for increasing the lines around text.