Code to left align text on mobile only (York)

Hi, what's the CSS code to align all header and body text to align left for mobile, but remain centred for desktop? Thanks!

Can you share link to your site?

https://bagpipe-maracas-j3xs.squarespace.com/

13 hours ago, lines said:

https://bagpipe-maracas-j3xs.squarespace.com/

Add to Home > Design > Custom CSS

@media screen and (max-width:640px) {
.overlay-nav-wrapper {
    text-align: left;
    margin-left: 0;
    padding-left: 2vw;
}
main#page * {
    text-align: left !important;
}
}