Reduce Harlowe's default margin

Hey folks, sorry if this question has been asked elsewhere, Twine Forum search isn't helping.
Is it possible to alter Harlowe's margin (margin, not alignment) to the extreme left end of the screen like Snowman ? Harlowe's Default margin takes a lot of empty space in mobile screens. I deleted the sidebar with the 'display:none' CSS alteration, but the margin isn't reducing. Please help.