Slide Margin - yihui/xaringan GitHub Wiki
Using the .css file, you can change some characteristics of slides using .remark-slide-content.
For example, the following lines will drastically reduce the margin of your slides.
.remark-slide-content {
padding-top: 10px;
padding-left: 10px;
padding-right: 10px;
padding-bottom: 10px;
}
To specify the margin of the first title h1, you can add to your .css file:
.remark-slide-content > h1:first-of-type {
margin-top: 0px;
}