A super simple monochromatic theme.
Colorful variants with the "One" theme:
(One Blue: https://themes.vivaldi.net/themes/bKXlYP37O6Z)
(One Green: https://themes.vivaldi.net/themes/nV6vp3mldN2)
(One - Cyan Edition: https://themes.vivaldi.net/themes/x3WlOPRvGYa)
(One - Orange Edition: https://themes.vivaldi.net/themes/ZQDJnV2JLBz)
(One - Purple Edition: https://themes.vivaldi.net/themes/ayRlXg070MG)