CSS is a technique for develop web pages with hyper text markup language. When i create a new html file, for create a web page. For increse your web page quialty you can use a technique called cascading style sheet. you can make a new file for special css. and after then connect to each other html and css. now i will tell you, you can use css coding in html file also. For this you can use online css. it’s very easy and compatible for us.
If you want to apply css coding on any html file then you can. like if you apply css on a h1 or h2. There is two simple way to define h1 or h2. The first one is you create a html file a tag h1 apply css. then if you want to change this h1 color. you can create a css file and connect with html file. and the other one is using css codes in html file. You can mention it in html head section.like you can see a image for this:
This is a good way to declare a short web page and you can say those people create web page for other and after done this online css you can send only one file to other user and this is html file. otherwise if you create a two file like one html and another css. then this is very difficult to sending and time consuming.