sharepoint server – Increase the width and height of the cell / grid in the calendar

Please help me with this urgent task.

I want to know how to increase the size of the grid / cell in the calendar. The current cell / grid / block are two small for my needs. I want to develop them every day and light them every month.

Will I make these changes in .css or javascript?

Please check the link.

calendar grid / cell / block

Thank you guys.