Here are some great styled search forms in html5, if you are looking for the CSS code for your project, here are some really cool search forms for you to choose from, just grab the code and use it on your sites.
Basic html code:
Small Brown Search – by Fabian Pecher
All the way Round – by Amol Mandhane
Natureful Search Form – by Jordan Foreman
Glowing Pulse – by Jack Rugile
SpaceCat – by John Jack
Blur – by Josh Allen
Blue Search – by Ernesto Camacho
Here are more search forms for you to choose from.