Every component in Replo can have a border, which displays around the component's box (outside of the padding/background, but inside of the margin). You can either edit the entire border, or one side at a time.
Several properties of the border can be edited:
To set the color of the border, click the color input and select a color from the color picker.
To set the width of the border, click the "Border Width" input and type in the desired width. Larger values mean a thicker border.
To adjust the border style (solid, dashed, dotted, etc.), click the "Border Style" dropdown and select the desired style.
To adjust whether the border's corners are rounded, use the "Corner Rounding" input or adjust the slider. You can even click the "Individual Corners" button to edit each corner rounding independently!