[A11y] Accessibility low-hanging fruits

[Cheukting]

I use this tool (https://accessibilityinsights.io/) to run quick checks for simple issues, here is a list of them (not explicit):

[Main page]

• Color contracts are not enough for most of the buttons
• Quicklinks at the bottom - Ensures <li> elements are used semantically
• Logo on the top left and "Power by Vercel" btn at the bottom right missing link description

[Schedule]

• Date selection - Ensures select element has an accessible name
• The colour contrast at the "Advance" label is not enough

[List of speakers]

• Ensures that lists are structured correctly

If you would like to work on any of those, I recommend installing the same tool (https://accessibilityinsights.io/), it is a browser extension, that will guide you on how to fix them.

In general, there are not many issues that the tool found on our website. Of course, this is just a very simple tool and there maybe more we can do but these are low-hanging fruits.