div css website layout basics_html/css_WEB-ITnose

Tag basics

meta tag tells the browser that the document is text/html
tag selector
group selector: reduce the amount of code and improve the css code structure.
Inclusion selector: Sub-objects in the object can also be subtracted and included.
: Before the link a link is visited
: The style of the hover object when it is on the mouse
: The style of the active object when it is clicked by the user and released by the click
: After the visited a object is clicked The style of
:fater sets the content after a certain object.text:after{content:url(../a.jpg)}
em is relative to the font size of the text in the current object