Accessibility in software

The Web Content Accessibility Guidelines boil down to four words:

Every meaningful image needs alt text. Decorative images get alt="".

• Body text: 4.5:1 contrast minimum (WCAG AA). Large text: 3:1.
• Never use color as the only signal — pair it with text, icons, or shape. Red error? Add the word "error" and an icon.
• Check designs in grayscale and with a color-blindness simulator.

• Everything clickable must be reachable with Tab and activatable with Enter / Space.
• Focus must be visible. Don't kill the outline.
• Add a "Skip to main content" link as the first focusable thing.
• Don't trap focus (except inside an open modal — and provide Escape).

• Use <button> for actions, <a> for navigation. A <div onclick> is invisible to keyboards and screen readers.
• One <h1> per page. Don't skip heading levels.
• Form fields need real <label>s — not just placeholders.
• ARIA is a sharp tool: "No ARIA is better than bad ARIA." Reach for it only when HTML can't express the role.

• Plain language: short sentences, common words, one idea per paragraph.
• Consistent layout — nav in the same place every screen.
• Forgiving errors — let people undo, recover, and try again.
• Avoid auto-playing video, flashing content, and unexpected motion. Respect prefers-reduced-motion.