Translating error boxes? (see the picture)

Hello! I have a problem! How can i translating or modify those error boxes in the picture? Those appears when i click "send" in contact form but i haven't wrote my message or email adresses which in requrred.

I want delete the text "Your form has encountered a problem. Please scroll down to review."   Or if that can't delete, it would be translate to: "Ongelmia yhteydenotossa. Täytä vaadittavat kentät".

Next i want translate text Sähköpostiosoitteesi is required. to "Sähköpostiosoitteesi vaaditaan."

And i want translate text Viestisi is required. to "Viesti vaaditaan".

If somebody can help me, i would be thankful! 

October 2021:
See https://www.silvabokis.com/squarespace-tips/dynamic-translation-of-squarespace-form-error-messages

May 2023 Update:
Squarespace have updated the Form Block. Posts written before this date that refer to code or CSS for forms will no longer work.

Thanks for the response paul2009. Unfortunately, that doesn't work. Where should i put that code?

On 10/20/2021 at 12:28 AM, Joni86 said:

Thanks for the response paul2009. Unfortunately, that doesn't work. Where should i put that code?

Add to Settings > Advanced > Code Injection > Footer

Hello !

Is there any css code that works please? There is something missing on the link shared :s