.monaco-workbench .debug-action.collapse-repl {
    background: url('collapse-all.svg') center center no-repeat;
}
 
.vs-dark .monaco-workbench .debug-action.collapse-repl,
.hc-black .monaco-workbench .debug-action.collapse-repl {
   background: url('collapse-inverse.svg') center center no-repeat;
}