Postcard 1

Desktop: The text is a bit close to her face. The next line is capitalized, even though gramatically it should not be. I think the two hypens should be an em dash. Maybe differ the font weights for visual interest.

Mobile: Same feedback as Desktop. The white is easier to read here than the black on desktop.

Postcard 2

There is no punctuation for the quote. Add an em dash or en dash instead of two hypens. Also vary font weights.

Postcard 3

Same feedback as Postcard 2, besides the punctuation. White on color looks good since there is a decent amount of contrast!