Today, I changed the alignment of table cells on my site from centered (the default) to top of the cell by adding the following CSS:

td {
  vertical-align: top;

I use tables extensively to summarize legal rules, so a cell can have several lines of text that I separate using two HTML breaks (<br><br>). Aligning the text to the top of the cell makes the table easier to read.

I’m using the default Jekyll theme, Minima. I added the CSS to to this file : _sass > minima > custom-styles.scss

For more using CSS to change the alignment of text in a table, see CSS Table Alignment, W3Schools.