[Light theme] Pop-ups on Epiphany have a titlebar with white text over a light gray background

[junrrein]

Note: Before submitting an issue, please check whether it also occurs with other themes.

The issue doesn't happen in the Flat-Plat dark variant.

• Distribution (and version)
• Desktop environment (and version)
• GTK+ 3 version (You can check it with pkg-config --modversion gtk+-3.0)
• Flat-Plat version
• Related application version

Same environent as in issue #75.

• Steps to reproduce

1 - Set the Flat-Plat light variant as your application theme.
2 - Trigger a pop-up in Epiphany. For example, in this page, on the "Build Results" panel, click on any "blocked" label.

• Screenshot(s)

Flat-Plat, dark variant

Flat-Plat, light variant

[junrrein]

Thank you!

[nana-4]

Thank you for the report. :)