If you would like a divider line in a different color or width from the standard one in Weebly, you can easily code one by dropping in a Custom HTML section where you want it.
Below, is a 5 pixel thick solid purple line (hex code #441468) that runs 100% of the width of the column (any column):
Below, is a 5 pixel thick solid purple line (hex code #441468) that runs 100% of the width of the column (any column):