You can make as many class types as you want
body.fm to set the body for the Front matter pages
<body class="fm">
or a paragraph class with a different font size
K.I.S.S. in style sheets is good Many IMHO do it backwards.
Set the most used style attributes in the Body (font size, face.
Set the paragraph most used( Margins, indent justification...)
Now set the exceptions (bold, italic, no-indent...)
if done right, most paragraphs would be a simple <p>
A first Paragraph would be an exception <p class="first">
.first style simply sets the margin-left to 0. all the rest is inherited from the p settings