There are really lots of free and premium themes for WordPress. Hueman is a free theme which can be used for WP blogs. Premium version is also available.
The Hueman theme loads fast and is 100% mobile-friendly according to Google. This theme is activated in more than 70K+ websites around the world.
You can change the background color of the head in Hueman when using a basic version.
To change the head background color of this theme, please add the following CSS code:
#header {
background: #33408a; // Change the color code as you wish
}You can add the above code under Appearance > Customize > Additional CSS. Or you can create a child theme (which is a good way to modify or customize your theme.)
Personally, I love this theme and use one of my personal blogs.
For simple blogs or magazine sites, Hueman might be a good choice. If you site grows, you may want to consider Newspaper or other blog or magazine WordPress themes. Newspaper is the best-selling blog theme.
If you are not good at coding, you can consider Avada, the best-selling WordPress theme for 6 consecutive years. Avada is a multi-purpose theme which is good for most websites.