Incorrect text styles in post card

**Page:** Home

## Description
The card in "What's happening" section has two incorrect styles:
1. The post author and post date should use `small caption` and `$color-dark-slate-gray` styles.
2. The dot separating both fields mentioned above should be smaller. I tried changing the rem definition and `0.4 rem` works to replicate the mockup.

## Observation and featured request
Since this section has three links below, is it possible to define a fixed height for all three cards? The risk is that long titles might break the card, but I think we don't have posts three-line length. And to balance the white space, we should bottom fix the author and date section.

## Screenshot
### Current implementation

### Proposal