simple css cant make it work

im trying to make a simple class/button change color on page change.
When u click the link/button it should show the new colors and stay like that until another page is switched to. is it just me that is dumb?

<button class=”herre”>HERRE</button> ???

.herre {
color: #fff !important;
cursor: pointer !important;
}

.herre a {
color: #000 !important;
background: green !important;
}