Use a fullstop "." at the beginning of a line to add a class. When using Tailwind in your client site this can add useful styling:
e.g. to center a heading instead of using the default for your stylesheet:
.text-center ## This is a centralised heading
.text-blue-600 This text is blue
Classes can be combined, to give e.g. to get 1/3 width centered:
.text-center .w-1/3 .font-bold This content is centrally aligned and taking up a 1/3rd of the available width