General design
The first feeling Nucleare brings me is a sense of peaceful and relaxed. To avoid all the disturbing factors, the author uses very few decorative tools. He just needs some thin lines or small cute icons and symbols to embellish the appearance. That answer why it's so clean and harmonic like this.
The decorative element
Other elements
The color scheme plays the most essential part of giving the tranquility of this theme. The green elements throughout the theme make me think of nature and energy. It is also associated with freshness and safety. Besides, the light grey background color can ease my eyes so that I'm very willing to read the post all day. This combination makes me feel extremely healing and comfortable.
The Play-fair Display family font is artistic while the Archivo Narrow is readable for the body texts. I believe that it's a perfect combination.
The header is simple. All the elements are arranged in one line. But thanks to the icons and symbol, it can be less boring.
Header and social icons
The list of posts on the archive page is prominent. The large featured image, together with the hovering-effect enhance the impressive look of this page. That is also the only default layout of the free version.
Featured image on the archive page
The footer in the demo is also straightforward without any widget. You can't add footer widget columns here so I suppose that it may be quite emptry.
Overall, the design doesn't have many special things to say other than the slim design and the sense of tranquility and safety.
Responsive
It's a good new that when you use this free WordPress theme by different devices, the design is still okay. I don't see any mistake of it on my laptop, PC, tablet or even smartphone at all.
The responsive design checked by ami.responsivedesign.is