Your biggest headline is probably too small.

What the study measured

The taste-skill study, from an MIT-licensed project that publishes its research, had a panel score a set of sites and then measured their typography at 1440 by 900px. Of the 235 usable sites, 202 had enough text to measure. It calls sites scoring 7.5 or more top, and those under 6.5 weak.

The clearest gap is in the largest text on the page:

• Top-site median: 8.4vw. About 121px at 1440.
• Weak-site median: 5.0vw. About 72px.
• The upper quarter of top sites starts at 12.5vw; for weak sites, at 6.7vw.
• The headline-to-body ratio shifts too, though less: 4.7 times the body size on top sites, 4.0 on weak ones.

One finding runs against intuition: line count doesn't separate them. Weak sites are actually more likely to keep the headline to two lines or fewer (83% against 71%). The problem isn't a long headline. It's a flat one.

The CSS

To let the size grow with the screen without breaking on a phone, use clamp(): a floor for narrow screens, the vw value in between, and a ceiling for very wide monitors.

h1 {
  /* 44px on a phone, 8.4vw in between, never above 136px */
  font-size: clamp(2.75rem, 8.4vw, 8.5rem);
  line-height: 0.95;
  letter-spacing: -0.04em;
  text-wrap: balance;
}

.hero {
  /* don't let the container force it onto five lines */
  max-inline-size: none;
}

The tight leading and negative tracking are my call, not the study's: at that size, body-text line height leaves gaps and the letters drift apart. Test it with your real sentence. If it runs past three lines on a phone, shorten the sentence before you shrink the type.

If you already have your own scale, this is its top step. You don't need a new size; you need the top one to sit far from everything else.

A big headline asks for few words

A paragraph won't fit at 120px. That's the point: it forces you to say in a few words what the visitor gets, which is the headline's only job. Whatever doesn't fit goes in the line below, at body size. And keep it to one text at that size: if every section opens with a giant heading, you're back to a page where everything shouts equally.

The prompt

Models drift back to the safe size the moment you change something else. Give it the number and the rule:

The homepage headline is the only large text on the page: font-size: clamp(2.75rem, 8.4vw, 8.5rem), line-height 0.95, letter-spacing -0.04em, text-wrap: balance. Don't put it in a narrow container and don't shrink it to fit one line. Section headings are much smaller, half its size at most. If the headline runs past three lines on a 390px phone, tell me so I can shorten the sentence; don't reduce the size.

Then run your page through the Slop Score and compare it with before. More steps like this, one change at a time, are in the guide to fixing an AI-built site.