margin-left for second sidebar...

I am nobody to tell if it's a bug or not;

but I'm going crazy all evening to add a margin-left to second sidebar.....

1. First, I wanted no margin-left at all or very narrow for my Content area; so:

global.base.css line 480 I removed 10px margins:

#main-content,
.block-inner,
.pane-inner,
.menu-wrapper,
.branding-elements,
.breadcrumb-wrapper,
.attribution,
.at-panel .rounded-corner,
.block-panels-mini > .block-title,
.rendered-by-ds .panel-display .region-inner,
div.messages {
  margin-right: 0px;
  margin-left: 0px;
  
}

2. Result - the same 10px got lost from Second sidebar;
3. If I try to add 10px to Second sidebar - like - :

.region-sidebar-second {padding-left: 10px;}
- Second sidebar disappears from the place and falls to the bottom of page;

4. What else I can do with this sidebar to add some margin?
5. One of the latest approaches was : trying to remove :

.block-content ul, .block-content ol {0 0 0 15px} to 5px only;

which would add extra space for other blocks in content area; but for the Second Sidebar results were like:
(the Second Sidebar Nav block crossing the Content block's right border: solid)