if html is used for coding web and html5 is too used? than why we use CSS ? i think CSS play same role of HTML & HTML5

Question

is this advanced or any other reason.

Answer 1

Html - is markup language I.e., structure.
CSS - stylesheet I.e., used to style the markup.

Answer 2

As @P R already stated, they dont play the same role, but rather have different functionalities.
HTML is used to insert the content and structure it in the way you want.
Then you use CSS to style this content to make it look good and professional - nobody likes bad-designed websites. You just need it to make your website visually attractive for visitors.
Last but not least there is Javascript for the behaviour, e.g. getting user input and performing actions with/on it.
In short, usually all three languages come and work together to form a proper website.

Answer 3

If you want to design a professional website in a comfortable way you have to use CSS.