Customize account page

Hi, I am just wondering how can I get rid of the left navigation bar on the account page and only leave the content on the right side, I tried using the css code below but it does not work. (It seems weird doing this but I’m just trying to customize the account page so that I’ll make a new navigation bar other than the default one they provide)

.um_account_tabs {
display:none;
}

.um_account .um_account_content {
width: 100%;
}

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