:root{
  /* palette - paper, ink, one restrained accent */
  --paper:#f7f5f0;
  --paper-2:#f0eee7;
  --ink:#1a1815;
  --ink-soft:#3f3c36;
  --ink-faint:#6f6a60;
  --rule:#d9d5ca;
  --accent:#b33c12;
  --accent-soft:rgba(179,60,18,.07);

  /* typography - local system stacks, no webfonts */
  --serif:"Iowan Old Style","Palatino Linotype",Palatino,Georgia,"Times New Roman",serif;
  --sans:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --mono:ui-monospace,"SF Mono","Cascadia Mono",Consolas,"Courier New",monospace;

  /* scale */
  --step--1:clamp(.8rem,.77rem + .15vw,.88rem);
  --step-0:clamp(1.02rem,.97rem + .25vw,1.15rem);
  --step-1:clamp(1.28rem,1.12rem + .7vw,1.65rem);
  --step-2:clamp(1.65rem,1.35rem + 1.4vw,2.5rem);
  --step-3:clamp(2.2rem,1.65rem + 2.6vw,3.8rem);
  --step-4:clamp(2.9rem,2rem + 4.5vw,5.8rem);
  --step-mega:clamp(3.6rem,2.2rem + 8vw,9.5rem);

  /* layout */
  --measure:34rem;          /* 60-75 chars at body size */
  --wide:78rem;
  --gutter:clamp(1.25rem,4vw,3rem);
  --section:clamp(4.5rem,10vw,9rem);

  /* diagram grammar colors */
  --dg-line:var(--ink);
}