amal66 makes the Word add-in prove it matches the product

A small design fix becomes a useful guardrail against a Word workspace quietly drifting from the main application.

The Word add-in had begun showing slightly different light-mode surfaces from the web product it mirrors. amal66's proposed change corrects those differences and makes future mismatches fail during ordinary build checks, rather than relying on someone noticing them by eye.

It also brings the add-in's tab controls back in line with the shared visual treatment and gives keyboard users a clearly visible focus indicator as they move between tabs. The add-in remains its own implementation for now, but its styling is being tied more closely to the same shared rules used elsewhere in the product.

For legal teams using Word as a primary drafting environment, consistency and accessible navigation matter: this is unglamorous work that makes the embedded experience feel less like a second-class product.