Disable Reveal.js incremental/fragment scroll stops on mobile for Quarto presentations

Problem

Quarto Reveal.js presentations use .incremental lists and .fragment divs to reveal content one piece at a time during a talk. On desktop this works great — click/arrow to advance.

On mobile, Reveal.js switches to a scroll view where each fragment becomes a separate scroll stop. A slide with 5 incremental bullet points becomes 5 scroll stops instead of 1, making the presentation tedious to read on phones.

Solution

Add a single CSS media query to the custom SCSS theme:

@media (max-width: 768px) {
  .reveal .slides section .fragment {
    opacity: 1 !important;
    visibility: visible !important;
  }
}

Why it works

Reveal.js hides fragments via opacity: 0; visibility: hidden and reveals them by adding a .visible class. The media query fires on the real device viewport width (not Reveal's internal 1920×1080 coordinate system), so it correctly targets phones/small tablets while leaving desktop presentation mode untouched.

Placement

In Quarto's SCSS theme file (the one referenced in format.revealjs.theme), place it after the /*-- scss:rules --*/ section — outside any .reveal { } block so it compiles as a standalone media query.