Banner won't resize into mobile

Site URL: http://www.achacunsonpain.ca

Hello, I want to make my banner responsive for mobile and tablets, and every piece of code I try doesn't work...

Thank you.

18 hours ago, helenechicoine said:

Site URL: http://www.achacunsonpain.ca

Hello, I want to make my banner responsive for mobile and tablets, and every piece of code I try doesn't work...

Thank you.

Add to Design > Custom CSS > Then save & reload your site

/* resize mobile banner */
@media screen and (max-width:640px) {
section#commandeenligne figure img {
    width: 100% !important;
    height: auto !important;
    left: 0 !important;
}
section#commandeenligne {
    min-height: unset !important;
    height: 200px !important;
}
}