Why should we use html with css ?

In html, suppose we have to give a particular font family, color and size. Then we have to write all the codes again and again in html.
            But by the help of css, we define that code once in the beginning and use all over the webpage without writing again and again. It saves our time and also reduces the complexity of coding.  

linking two html pages

Say, ur first html page is webpage.html and other is web.html.

If u want to go from webpage.html page to other page

Just write the following code-

<form action="web.html">

/* comments */

<input type="submit" value="SEND">

</form>

when u click on SEND button, u will be directed to web.html.