Is a mobile website still HTML and usual PHP?
 

Is it as I was wondering?

Yes it is. Just you have a smaller screen to display on and different ways that people will interact with your page.

Hi masters,

Do we need a different css and design? How do we know the users machine specification? Do we need to apply some API from smart phone system suppliers?

There are a couple of device/user agent detection scripts on the internet but for simple layout issues the best is to use CSS media queries. Also do a search with the keywords “responsive web design”.

1. You'll want to design the site so it works on smaller screens, so yes, you'll need to rethink your page so they appear correctly and are not squeezed into a small screen. Googling "responsive web design" will give you a start.

2. You don't really need to know the user's phone screen size.

3. You don't need to apply any APIs from smartphone suppliers if you are just redesigning your web site to fit smaller screens.