IAB site accessibility

[holloway]

The accessibility of the site is pretty good. I ran an automated accessibility check on the homepage of www.iab.org and it scored 92-95 out of 100. Most pages achieve 100/100 but not the homepage.

Automated a11y testing can be unreliable but the specific issues it found seem correct. Devs can check accessibility themselves in Chrome's devtools by selecting the Lighthouse tab and then running an accessibility check.

The main issue is colour contrast which needs be improved slightly to achieve a higher score (ie changing link colour from #0A77B0 to #075E8D would fix it).