If You want to develop a WordPress theme for your client or website. Then i suggest you to use _s(underscore) theme. Which have all required files with css. This theme is developed using HTML5.
Hi. I’m a starter theme called _s, or underscores, if you like. I’m a theme meant for hacking so don’t use me as a Parent Theme. Instead try turning me into the next, most awesome, WordPress theme out there. That’s what I’m here for.
My ultra-minimal CSS might make me look like theme tartare but that means less stuff to get in your way when you’re designing your awesome theme. Here are some of the other more interesting things you’ll find here …
Learn more about me in “A 1000-Hour Head Start: Introducing The _s Theme” on ThemeShaper.
Download It from Github . Download Here