Hi rahulsurana,
You can either put a ‘border-right:1px solid #82CFFD’ onto the secondary <div> on line 1177 of style.css (that will put a line whose length will be the same as the secondary container.) You will also need to adjust the width of the container to 31.00%
Otherwise you can put a left border with the same color on the primary <div>, line 1011 of the style.css in the format ‘border-left: 1px solid #82CFFD’. You may need to also adjust the width.
Hope that helps.
Cheers
Bryan