embarrassing post, if u can't do simple imgui styling, then you don't need the menu anyway because you are simply incompetent.
styling the childs is just pushing imgui styles & moving the label using setcursorpos (simplest way)
same with checkboxes
for the tabs, you can literally just use regular imgui buttons and style them to have a thick border, active color, etc. (all possible with just pushstylecolor/var) & add the current active tab color line (i promise you drawing a vertical line from point 1 to point 2 is NOT difficult)