List of steps to reproduce (step by step, including full links if applicable):

• enable new-vector
• https://en.wikipedia.org/wiki/Special:SpecialPages

What happens?:

What should have happened instead?:

I think this looks better.

Software version (if not a Wikimedia wiki), browser information, screenshots, other information, etc:

This should fix this (part of the selector is the same as for an article body):

@media screen {
    .skin-vector-disable-max-width .mw-article-toolbar-container {
        max-width: none;
    }
    .skin-vector-disable-max-width .mw-checkbox-hack-checkbox:checked ~ .mw-workspace-container .mw-article-toolbar-container {
        margin-left: 11.5em;
    }
}