How to make a page background?

Question

css

Tell me how to make such a wave so that it stretches in width and height to the full screen?
Layout for mobile gadgets.
So it runs down

-moz-background-size: 100%; /* Firefox 3.6+ */
    -webkit-background-size: 100%; /* Safari 3.1+ и Chrome 4.0+ */
    -o-background-size: 100%; /* Opera 9.6+ */
    background-size: 100%; /* Современные браузеры */

Answer 1

just make a picture