How do I change the body text size in Squarespace?

Body text size is set globally on the body or .sqs-block-content selector. Setting it on body affects everything, so target .sqs-block-content p for just paragraph text in content blocks.

For readability, body text should be 16-18px on desktop and 15-16px on mobile. Pair it with a line-height of 1.6-1.8 for comfortable reading.

/* Global body text */
.sqs-block-content p {
  font-size: 17px !important;
  line-height: 1.75 !important;
  color: #333333;
}

/* Slightly smaller on mobile */
@media screen and (max-width: 767px) {
  .sqs-block-content p {
    font-size: 16px !important;
    line-height: 1.65 !important;
  }
}