CSS: reducing line spacing of text?

Add display:block & remove height.

<span style="font-size: 75%; line-height: 16px; display:block">blog posts & occasional updates (updates max 1 every 14 days)</span>

You learn more about display:block property here.

You have a line-height: 21px; In the body. Remove this, and it should work.

Inline elements don't honour properties such as line-height; they take on the line height of the nearest block parent.

See Fiddle

Solution: remove the line-height from the body, or turn the span into a block (i.e. make it a div; don't give display:block to the span).