CSS Basics

Syntax

tag [attributes] #id .class :pseudo-class ::pseudo-element {
  property: value;
}

/* comments */

Simple Selectors

Name	Selector	Example	Example description
Class	.class	.intro	elements with class="intro"
ID	#id	#firstname	element with id="firstname"
Universal	*	*	Selects all elements
Element	element	p	<p> elements
Grouping Selector	element,element,..	div, p	<div> and <p> elements

Combinators

A CSS selector can contain more than one simple selector. Between the simple selectors, we can include a combinator.

Name	Selector	Example	Example description
Descendant	element element	div p	<p> elements inside <div> elements
Child	element > element	div > p	<p> elements where the parent is a <div> element
Adjacent Sibling	element + element	div + p	<p> elements that are placed immediately after <div> elements
General Sibling	element1 ~ element2	p ~ ul	<ul> element that are preceded by a <p> element

Pseudo-classes

Selector	Example	Example description
:active	a:active	Selects the active link
:checked	input:checked	Selects every checked <input> element
:disabled	input:disabled	Selects every disabled <input> element
:empty	p:empty	Selects every <p> element that has no children
:enabled	input:enabled	Selects every enabled <input> element
:first-child	p:first-child	Selects every <p> elements that is the first child of its parent
:first-of-type	p:first-of-type	Selects every <p> element that is the first <p> element of its parent
:focus	input:focus	Selects the <input> element that has focus
:hover	a:hover	Selects links on mouse over
:in-range	input:in-range	Selects <input> elements with a value within a specified range
:invalid	input:invalid	Selects all <input> elements with an invalid value
:lang(language)	p:lang(it)	Selects every <p> element with a lang attribute value starting with "it"
:last-child	p:last-child	Selects every <p> elements that is the last child of its parent
:last-of-type	p:last-of-type	Selects every <p> element that is the last <p> element of its parent
:link	a:link	Selects all unvisited links
:not(selector)	:not(p)	Selects every element that is not a <p> element
:nth-child(n)	p:nth-child(2)	Selects every <p> element that is the second child of its parent
:nth-last-child(n)	p:nth-last-child(2)	Selects every <p> element that is the second child of its parent, counting from the last child
:nth-last-of-type(n)	p:nth-last-of-type(2)	Selects every <p> element that is the second <p> element of its parent, counting from the last child
:nth-of-type(n)	p:nth-of-type(2)	Selects every <p> element that is the second <p> element of its parent
:only-of-type	p:only-of-type	Selects every <p> element that is the only <p> element of its parent
:only-child	p:only-child	Selects every <p> element that is the only child of its parent
:optional	input:optional	Selects <input> elements with no "required" attribute
:out-of-range	input:out-of-range	Selects <input> elements with a value outside a specified range
:read-only	input:read-only	Selects <input> elements with a "readonly" attribute specified
:read-write	input:read-write	Selects <input> elements with no "readonly" attribute
:required	input:required	Selects <input> elements with a "required" attribute specified
:root	root	Selects the document's root element
:target	#news:target	Selects the current active #news element (clicked on a URL containing that anchor name)
:valid	input:valid	Selects all <input> elements with a valid value
:visited	a:visited	Selects all visited links

Pseudo Elements

Selector	Example	Example description
::after	p::after	Insert content after every <p> element
::before	p::before	Insert content before every <p> element
::first-letter	p::first-letter	Selects the first letter of every <p> element
::first-line	p::first-line	Selects the first line of every <p> element
::selection	p::selection	Selects the portion of an element that is selected by a user

::first-line

Note: The ::first-line pseudo-element can only be applied to block-level elements.

Available properties:

• font properties
• color properties
• background properties
• word-spacing
• letter-spacing
• text-decoration
• vertical-align
• text-transform
• line-height
• clear

::first-letter

Note: ::first-letter pseudo-element can only be applied to block-level elements.

Available properties:

• font properties
• color properties
• background properties
• margin properties
• padding properties
• border properties
• text-decoration
• vertical-align (only if "float" is "none")
• text-transform
• line-height
• float
• clear

::selection

Available properties:

• color
• background
• cursor
• outline