I don't understand how "<div class="Card" data-size="big"></div>" is better than just <div class="Card big">, then using a .card.big selector?
The article just says "but this can cause specificity issues, which can create problems further down the line" to move the same thing into attributes rather than just use the thing for what it was designed for there has to be a good reason.
The article just says "but this can cause specificity issues, which can create problems further down the line" to move the same thing into attributes rather than just use the thing for what it was designed for there has to be a good reason.