Hi Michel,
You can change the header text, color and the size of the font via customizer. Login to your WP admin dashboard and go to Appearance > Customize > Ambition Theme Option There you can see the font family/size/color option.
And to disposition of the text on two lines please go to Appearance > Customize > Ambition Theme Options > Custom CSS and paste the below CSS code then click on Save & Publish button.
#site-description {
border-left: 0 none;
padding-left: 0;
clear: left;
}
Thank you for using our theme. Happy New Year 2016 and Happy Holidays! 🙂