Selector Type	Example	Note
Universal selector	* { color:#555; }	/
Type selectors	b { color:red; }	div,p select all <div> elements and all <p> elements.
Class selectors	.classname { color:blue; }	/
ID selectors	#idname { background:cyan; }	/
Descendant selectors	span em { color:green }	Select all <em> elements who have a parent element of <span>.
Child selectors	div > em { background:lime; }	Select all <em> elements who have a direct parent element of <div>
Adjacent sibling selectors	i + b { color:gray; }	Select the <b> element who is directly after the <i> element, and meanwhile both the <i> and <b> elements should be within a same parent element.
Attribute selectors	a[href=’info.htm’] { color:red; }	/
Pseudoclasses	a:hover { font-weight:bold; }	/
Pseudoelements	p::first-letter { font-size:300% }	/