Resize form with CSS

hey, i am trying to resize the contact us form as it’s being made too wide due to a custom CSS applied to a twenty twenty theme
which is…

.entry-content > *:not(.alignwide):not(.alignfull):not(.alignleft):not(.alignright):not(.is-style-wide)
{
max-width: 90rem;
width: calc(100% – 8rem);
}`

I have tried the below and it’s not overriding the above CSS. I’m very new to web and CSS so please go easy on me and i’m using the standard free ninja forms plugin 🙂

#nf-form-2-cont {
color:#fff;
padding: 15px;
border-radius: 9px;
{
max-width: 40rem;
width: calc(100% – 8rem);
}

The page I need help with: [log in to see the link]