/* UNDRSCR_ color. Four colors. Nothing else. No fifth hue, ever — not even for a highlight.
   Emphasis comes from contrast and weight: dark box against light page, bold ink against pale grey. */
:root{
  --ink:#1D1919;
  --grey-light:#D3D3D3;
  --grey-mid:#656666;
  --white:#FFFFFF;

  /* text */
  --text-primary:var(--ink);
  --text-secondary:var(--grey-mid);
  --text-on-ink:var(--white);
  --text-on-ink-muted:var(--grey-light);
  --text-label:var(--grey-mid);
  --text-label-on-ink:var(--grey-light);

  /* surfaces */
  --surface-page:var(--white);
  --surface-muted:var(--grey-light);
  --surface-ink:var(--ink);
  --surface-mid:var(--grey-mid);

  /* lines and edges */
  --border-hairline:var(--grey-light);
  --border-strong:var(--ink);
  --border-on-ink:var(--grey-mid);
  --rule:var(--grey-light);

  /* the one permitted decoration */
  --bar-on-light:var(--ink);
  --bar-on-dark:var(--white);

  /* image placeholder region (visible, obviously unfinished, never a finished-looking block) */
  --placeholder-fill:var(--grey-light);
  --placeholder-ink:var(--grey-mid);
}