chore(a11y): improving a11y score to 100% for home and doc pages

[StephNathai]

Details

• Improves accessibility score to 100% for home and doc pages
• used Deque color contrast tool to determine closest accessible color to current color in production
• Closes issue 1405

Screenshots (before/after fix)

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[timdeschryver]

@all-contributors please add @StephNathai for a11y

[allcontributors[bot]]

@timdeschryver

I've put up a pull request to add @StephNathai! :tada: