CSS

The Cascade

Things are applied in the order you define them. The last AND most specific declaration wins. The specificity works on a point system.

an element is worth 1 point

a class is worth 10 points
an id is worth 100 points


p a {} = 2 points
p.intro a {} = 12 points
#about p.intro a {} = 112 points

Inheritance

Text-related properties are inherited while layout-related properties are not inherited.

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 42.5px Helvetica}
p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 32.0px Helvetica; color: #ffffff}

Margin

margin: 1em;

all margins = 1em

margin: 1em 2em;

Top & bottom = 1em. Left & right = 2em

margin: 1em 2em 3em 4em;

Top = 1em, Right = 2em, Bottom = 3em, Left = 4em

Display

Inline boxes flow left to right

Block boxes flow top to bottom