You can always check out dark mode add ons since it’s a browser based ide. Chrome webstore has plenty.
I use dark reader and with the shortcut alt-shift-d you can toggle to dark mode.
I found a few colours were off so I adapted them using stylus which allows some edits of to the css of a page
/* adjusted highlighting for dark reader */
.CodeMirror-focused .CodeMirror-selected { background: #3aa3fe40 !important; }
.CodeMirror-activeline-background{background-color: #5a9bff47 !important;}
.cm-matchhighlight{border-bottom: 2px solid rgba(143, 180, 238, 0.9);background: #008dff66;}
