Once a vocabulary card carries pronunciation, meaning, and an example sentence, it's easy for every line to end up the same size, stacked one after another. Flip the card over and your eyes don't know where to start — they scan the whole thing — and the answer you actually need ends up being the last thing you notice.
The rule is simple: on any given card, make only the one thing you should see first big. Bump the answer word or meaning up to around 24–32px, and shrink secondary details like pronunciation, example sentences, or notes down to 14–16px, giving them a light gray color (like #888888) as well. The answer registers first, and secondary details only get read when you actually need them.
In ankieditor, click a field in the preview to select it, then change Font size (slider or number box) and Text color under Text Style. Each field can be selected separately and given its own values.
Two or three size tiers are plenty. Go past four and the sense of priority disappears again — you're effectively back to the original "everything the same size" problem.