Focus bar items display vertically instead of horizontally

[akarki2005]

When clicking the focuses tab on the graph page, the focus tabs stack vertically instead of appearing as a horizontal row of tabs along the bottom of the screen.

Expected behavior: Tabs appear horizontally along the bottom of the screen, styled like browser tabs.

Actual behavior: Focus tabs appear in a vertical list.

focustabbug.mov

EDIT: this looks to be a safari only issue.