css
selector
.moose
element with class
<div class = "moose"></div> // selected
<div class = "bar"></div> // NOT selected
.moose.bar
element with multiple classes
<div class = "moose bar"></div> // selected
<div class = "bar"></div> // NOT selected
.moose .bar
descendant element with classes
<div class = "moose">
<div class = "bar"></div> // selected
</div>
<div class = "bar"></div> // NOT selected
p
specific element
<p></p> // selected
<div></div> // NOT selected
p.bar
specific element with class
<p class = "bar"></p> // selected
<p class = "foo"></p> // NOT selected
p,div
any element
<p></p> // selected
<div></div> // selected
<a></a> // NOT selected
div p
descendant element of other element
<div><p></p></div> // selected
<div><ul><p></p></ul></div> // NOT selected
div > o
direct descendant element of other element
<div><p></p></div> // selected
<div><ul><p></p></ul></div> // NOT selected