Google Sheets Dark Mode

dark_sheets.css

/* invert the table, formula bar, cell editor, and navbar
   and dim transparency to soften */
#waffle-grid-container,
#formula-bar-name-box-wrapper,
div[role="navigation"],
.cell-input.editable {
  filter: invert();
  opacity: 0.9;
}

/* re-invert colors inside inverted parents to restore them */
.overlay-container-ltr,
.formula-content > span:not(.default-formula-text-color),
.docs-gm .docs-sheet-active-tab .docs-sheet-tab-name,
.docs-gm .docs-sheet-active-tab .docs-icon {
  filter: invert();
}

/* invert selection color manually */
::selection {
  background-color: #e58c17 !important;
}

/* Misc artifacts */
.autofill-handle {
  border-color: #333;
}
.input-box {
  background: #000 !important;
}
.cell-input {
  background: #DDD !important;
}
.docs-gm .docs-menubar .goog-control-disabled {
  background-color: transparent !important;
  opacity: 0.5;
}

Added to Google Docs Dark Mode to make this work for Google Sheets.