Have you tried adding left padding to the widget areas? (on the sidebars and layout tab for each widget area)
This may not work as you expected or require since padding is not the same as a margin.
Tweaking left/right margins in content/widget areas cannot be done with the free version of Weaver Xtreme, but is a Weaver Xtreme Plus option.
Because Weaver Xtreme uses a modified “grid” layout model used by many responsive themes, anything that adjusts horizontal spacing must be very carefully accounted for in the overall styling. What seems like a simple thing to do – add a little margin – requires that the entire horizontal layout be adjusted.
This automatic adjustment is called the “Smart Margin Width”, and that can be changed on the Fonts & Custom tab in Weaver Xtreme Plus.