Atom is a theme framework from Romanian designer M. Popovici. The framework has a professional and clean design and would be perfect base for designing your own custom design.
It boasts a range of options which allow you to easily change the structure of your site and what pages are displayed. Atom also boasts a large amount of custom widgets.
Below is a screenshot of the default design followed by two simply colour customisations of the default design. As you can see, the overall appearance of the framework can be changed easily just by changing a few colours.
Atom isn’t the most advanced framework available for WordPress but I recommend downloading it and trying it out if you like the design :)
Atom Framework: Info & Download | Demo