Change loading background colour 7.1

Site URL: https://sealion-aqua-6cgh.squarespace.com

Password: PartTwoDesign

Is there a way within the Site Styles to change the loading background colour of each page?

For a split second, when clicking through my site's pages, it seems to load the darker grey (part of my colour palette)... why is this? 

TIA,

Anna

Thank you @rebeccagracedesigns!!! I'd never have found this. How bizarre that you can only do this via the mobile app - Squarespace really need to add this to desktop too 🤯

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