You can pass style or class properties for the whole slide by annotating it:
<!-- .slide: style="background-color: coral;" -->
# Header with coral background color
Paragraph has coral background color, too!
---
<!-- .slide: style="background-color: green;" -->
- All Bullet points
- have green
- background color
# Header with coral background color
Paragraph has coral background color, too!
---
- All Bullet points
- have green
- background color