Twenty Eleven Menu Bar Icons Will Not Remain Static

Create a child theme.
https://codex.www.ads-software.com/Child_Themes

When parent theme stylesheet is directly edtied, it’s hard to figure things out. Only make changes using child theme.

the ‘current’ menu item is styled with a larger font-size:

/* Line 633 */

#access .current-menu-item > a,
#access .current-menu-ancestor > a,
#access .current_page_item > a,
#access .current_page_ancestor > a {
	font-weight: bold;
	font-size: 1.1em;
}

btw:
maybe a bit late for you, but it is not recommended to edit the default theme Twenty Eleven directly; a better way would be to work with a child theme or at least use a custom css plugin;
https://codex.www.ads-software.com/Child_Themes
https://www.ads-software.com/plugins/search.php?q=custom+css

make sure to have backup copies in case you accidentally update the theme.

Yeah, I backed up everything before I started fiddling with the code. If the next update messes anything up I’ll look into Child Themes. For now it’s on to making some content.

Thanks for all the help.