Readable text needs space and contrast. A unitless line height scales with the font size, while a reasonable text measure prevents very long lines on a wide screen. Color is only useful when the foreground remains readable against the background. Keyboard focus needs the same care: someone must be able to see which action is active. You'll set text spacing, check contrast, and preserve an explicit focus outline. One task hides a helper visually while keeping it in the document for assistive technology. That is a different operation from display none, which removes the helper from both visual and accessibility output.