Sections can also be used to create more complex layouts based on flexbox. They can contain any kind of block and even other sections.
First column, one row.
Second column, first row ...
... and a second row.
Third column, first row ...
... a second ...
... and a third row.
You are in full control over flex properties such as the minimum block width, the gap size and the alignment of items.
Cards are basically not more than styled sections. They are a bunch of blocks combined in one section that maybe has a border, a shadow, padding and even rounded corners.
Styling Other Blocks
Aside from being a card, sections can also be used to control the appearance of just one single block such as a gallery. The gallery block below has rounded corners, a white border and drops a shadow — all those styles are actually applied to the wrapping section.