NoSquint is a Firefox add-on that allows you to adjust the text-only and full-page zoom levels as well as color settings both globally (for all sites) and per site.
The standard Firefox' buttons + / - are better looking than Nosquint's, but are bound together in (like) a wrong order – to the left, + to the right, and unseparatable. Maybe this can be solved with custom icons anyhow, but maybe Nosquint could do something here, like making the standard buttons separatable, or let choose the icons for itself, or using the Firefox's icons for its buttons.
The standard Firefox' buttons + / - are better looking than Nosquint's, but are bound together in (like) a wrong order – to the left, + to the right, and unseparatable. Maybe this can be solved with custom icons anyhow, but maybe Nosquint could do something here, like making the standard buttons separatable, or let choose the icons for itself, or using the Firefox's icons for its buttons.