Change the background of a column
To set a custom background for a particular column and component(s) within that column, simply open the edit window for the column you wish to customize.
Under the Background tab, choose a custom background color for your column:
You can add additional CSS in the CSS tab to further customize this column. For instance, you can make the column white with a border-radius of 15 to make the corners rounded:
Your column and component within that column will now appear with a white background with a border radius of 15 pixels: