Auto-update forced me to use Opera One. But there are deal-breakers which I need to address otherwise no more Opera for me. Specifically I need to:

• make the sidebar not shove features down to the bottom and instead separate them by a simple line
• get rid of the super-rounded corners (I thought we were over this trend back in 2015)
• reduce margins to previous size - especially on the sidebar and top bar - so that they neatly stick to the main window
• absolute dealbreaker: get rid of the workspace switching animation

To put it suscintly: I want control over the theme.
How do I do it?

Auto-update forced me to use Opera One. But there are deal-breakers which I need to address otherwise no more Opera for me. Specifically I need to:

• make the sidebar not shove features down to the bottom and instead separate them by a simple line
• get rid of the super-rounded corners (I thought we were over this trend back in 2015)
• reduce margins to previous size - especially on the sidebar and top bar - so that they neatly stick to the main window
• absolute dealbreaker: get rid of the workspace switching animation

To put it suscintly: I want control over the theme.
How do I do it?