Minimise Icon

Minimise Icon

Hello,

I'd like to change the "minimise" icon to a cross, but cannot get it to work.

I've tried:

.siq-minimize-icon:before {
color: black !important;
content: "\e2716" !important;
}

.sqico-min::before {
    content: "\e2716" !important;
    color: black !important;
}

Any ideas please?