Change Calendar style

[ghost]

Closes #1728

@Canialon @smk762

[smk762]

no overflows or weird animation detected here on linux. Is it possible to change colors to match the rest of the app?

[Canialon]

@SylEze could you apply these changes to the simple mod as well? ^^

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Also, there are a few small fixes:

• change the color of arrows for a light theme
  

• fix alignment for shower effect

tested on macOS, later will recheck on Windows

[ghost]

^ @Canialon @smk762

[smk762]

I like the new colors - couple of quirks tho:

• no hover effect on lite mode over dates or top arrows.
• no hover effect on dark mode over dates.
• no "current date" tooltip

[ghost]

* no "current date" tooltip

Let's not add it for the moment, I think it was not there before ?

[ghost]

I like the new colors - couple of quirks tho:

* no hover effect on lite mode over dates or top arrows.

* no hover effect on dark mode over dates.

Fixed! @Canialon @smk762