01. Inline style (don't promotion use, can't reuse) : at the start of the interior of the tag can set a call style properties, properties of double quotes to deposit the element code CSS styles,
Example: & lt; Div style="to store the elements of CSS code" & gt;
02. Internal style (can only be used in the current document, using practice) : the head the way add style tags
Example: 1 & gt; Simple

<style>
H3 {
Color: color;
H3} (boby of all into the color you want)
2 & gt; One class selector: if [h2_h6] want to have different

<style>
. Color {color: color; } (as long as in the previous one. It is ok to)

3 & gt;> The id selector
<style> # username {color: color; }

03. External style (used in the project, strong reusability) : in the head by introducing cases: the link tag & lt; head>