Strip header and footer from one page

I have a non live site, on which i would like to strip out the header and the footer in the custom CSS section to create a landing page..

I have tried codes such as:

.page-id-154 .site-header,
.page-id-154 .site-footer {
display: none;
}

and substituted in my:

.page-id-4531 header-v2-container {
display: none; !important;
}

nothing really seams to work. do you have a CSS available to remove header and footer in inovado??

Ticket