Buttons
Accessibility and semantic
Alway wrap your label into a span.mc-button__label tag
Use aria-label="button purpose"
using only an icon without text.
<button type="button" class="mc-button mc-button--icon-only mc-button--icon-medium-m" aria-label="my button purpose"> <!-- Your icon html tag --></button>
Use the right tag for the right purpose :
<a> for links
<button type="submit" form="form_id"> to submit a form (you
should prefer it to input type submit)
<button> for any other actions