Customising summary block to have a coloured background - spacing is off

Site URL: https://papaya-armadillo-7acs.squarespace.com/

Site password: design101

Hello, I'm customising this summary block for each piece of content to have a 'background'. I've managed to use the custom code to get to this point but I am having this issue on the right hand side where the card is cut off. 

Please help!

Add this CSS

div#block-yui_3_17_2_1_1655273166588_27464 .summary-item-list-container {
    overflow: visible !important;
}

html, body {
    overflow: hidden;
}

This section of the code:

html, body {
    overflow: hidden;
}

Disables the scrolling of the website. Can I just leave this out?