This is a gist for the FULL BLACK theme for replit. I have this also in the marketplace for reflux themes for replit. There the CSS is not included and it is just a bookmark pressing CSS thing so I have included the CSS here so you can use a CSS injector!

replit.css

.line-numbers {
  color: var(--color-primary-1) !important;
}

.replit-ui-theme-root {
  --color-background-1: #141414 !important;
  --color-background-2: #070707 !important;
  --color-background-3: #1D1E20 !important;
  --color-background-4: #141414 !important;
  --color-control-1: #1D1E20 !important;
  --color-control-2: #1D1E20 !important;
  --color-control-3: #1D1E20 !important;
  --color-border: #141414 !important;
  --color-foreground-1: #C9CBCF !important;
  --color-foreground-2: #B3B6BC !important;
  --color-foreground-3: #9FA2A8 !important;
  --color-foreground-4: #233329 !important;
  --color-primary-1: #2D07DA !important;
  --color-primary-2: #3C12F8 !important;
  --color-primary-3: #5C39F9 !important;
  --color-primary-4: #2D07DA !important;
}

.monaco-editor, .monaco-editor-background, .monaco-editor .inputarea.ime-input, .monaco-editor .margin {
  background-color: #090128 !important;
}

.monaco-editor .margin-view-overlays .current-line-margin, .current-line {
  background-color: #0D023C !important;
}

.jsx-3971054001.content, p, .jsx-4279741890 {
  background-color: var(--color-background-2) !important;
  color: #B3B6BC !important;
}

.jsx-3414412928 {
  background-color: var(--color-background-1) !important;
}

.toggle-bar {
  background-color: var(--color-foreground-2) !important;
}

a.jsx-330798097, .jsx-801033477, a.jsx-56292044 {
  color: #29339B !important;
}

.jsx-467725132 {
  background-color: var(--color-background-3) !important;
}

.jsx-2906438576, .jsx-986859180, .jsx-918008940  {
  background-color: var(--color-background-3) !important;
}

.interactive.jsx-2106077415:hover {
  border-color: var(--color-background-4) !important;
}

.jsx-3414412928.sidebar-layout-header-toggle-alert {
  background-color: var(--color-primary-1) !important;
}