The DRY way

Make individual selectors as rare and sparse as possible.

Why this style isn't part of a group?

Try to think like when you're working with React.js. Split elements in smaller elements. Draw boxes around every element (and its children) in the mock and give them all names accordingly to its style, not the content. Forget about classes like .profile-card or .about-page-title. Think in more reusable and simple classes like .box or .big-text. Nicole Sullivan talked about this on her article.