Color

I would like to set a color for particular sections of text in my post. The intended use would be something like: Shall I compare thee to a summer’s day? Thou art more lovely and more temperate: Rough winds do shake the darling buds of May, And summer’s lease hath all too short a date; I want to make the bolded text red, and the italicized text blue. I am currently using the stock Blog template and uploading my posts as .docx files. (My bold/italics/underline and embedded images upload this way, but not text colors.) Where do I change my process to let me apply color to particular passages of text? Should I be uploading in a different file format, or modifying style.css in the Blog template?