Hi@dark-side#126896
All button use same style code
here is code you can override via custom.css
.joms-button__next, .joms-button--secondary, .joms-button--signup, .joms-button--invite, .joms-focus__button--message {
background: #259b24;
color: #fff !important;
}
for specific page try this code
. task-registerAvatar ..joms-button__next {
background: #259b24;
color: #fff !important;
}