The priority level of the selector is decided by importance of selectors:
- style attribute = a
- number of ID attributes (# id=) in the selector = b
- number of other attributes and pseudo-classes (. class=) in the selector = c
- number of element names and pseudo-elements (<article>, <p>, <span>, etc.) in the selector = d
For example:
[index.html]
<body> <article> <p>This is <span id="red">paragraph</span>.</p> </article> </body>
[style.css]
article p span{ color: blue; } #red{ color: red; }
“article p span” are “a=0, b=0, c=0, d=3 (0003)“.
“#red” is “a=0, b=1, c=0, d=0 (0100)“.
In this instance, paragraph becomes a red character. Because “#red(0100)” is bigger than “article p span(0003)”.
Examples
In order of highest priority first:
a {color: red;}
#wrapper #content a {color: red;}
#content a {color: red;}
.content a {color:red}