Grouping Classes in CSS

Let's say we have several classes that paint elements in different colors:

.xxx {
	color: green;
}
.yyy {
	color: red;
}

Let's say we want to make it so that these classes, in addition to color, also set the font size:

.xxx {
	color: green;
	font-size: 30px;
}
.yyy {
	color: red;
	font-size: 30px;
}

Since both classes set the same font size, let's use selector grouping like this:

.xxx {
	color: green;
}
.yyy {
	color: red;
}

.xxx, .yyy {
	font-size: 30px;
}

Simplify your code by using selector grouping:

.eee {
	font-size: 20px;
	line-height: 1.5;
	font-family: Arial;
}
.zzz {
	font-size: 30px;
	line-height: 1.5;
	font-family: Arial;
}

Simplify your code by using selector grouping:

.eee {
	font-size: 20px;
	text-align: center;
	font-family: Arial;
}
.zzz {
	font-size: 30px;
	text-align: center;
	font-family: Arial;
}
.ggg {
	font-size: 35px;
	text-align: center;
	font-family: Arial;
}