I am sorry for being unclear.
I am trying to create a more creative box. Meaning: adding some style to it which is not possible with CSS. (AFAIK: CSS does not support 45 degree corners like I showed on this image: http://i.imgur.com/J5dVWbo.jpg .
I would love to create such thing without the need of any graphic tools /shops whatsoever.
SVG comes here in handy, but I am not 100% sure, if this is a good approach for such a project. I humbly ask you for information, or what you consider as a good method to create an unusual shaped box and still maybe have the advantages of using CSS.
Thank you in advance.