How to shorten product description text width – Baseline Theme

This is the final answer / solution (thank you for your original help below folks!):

To adjust / shorten product description width on desktop view only, while keeping width on mobile view full-width and responsive, use this code in the product page custom CSS for that section:

.js-enabled.accordian.mt-8 .rte {
width: 50%; /* Desktop width /
}
@media (max-width: 768px) {
/
Adjust the breakpoint as needed /
.js-enabled.accordian.mt-8 .rte {
width: 100%; /
Full width on mobile */
}
}