MediaWiki:Vector.css

/* Hide all sidebar content blocks for anonymous users */
body:not(.mw-user-loggedin) #mw-panel .portal {
    display: none !important;
}

/* Keep the logo visible */
body:not(.mw-user-loggedin) #p-logo {
    display: block !important;
}

/* Ensure logo and image are visible */
body:not(.mw-user-loggedin) #p-logo a,
body:not(.mw-user-loggedin) #p-logo a img {
    display: block !important;
    visibility: visible !important;
}

/* Keep personal tools (login link) */
body:not(.mw-user-loggedin) #p-personal {
    display: block !important;
}

/* 🆕 Preserve an empty sidebar block for layout balance */
body:not(.mw-user-loggedin) #mw-panel::after {
    content: '';
    display: block;
    height: 400px;  /* Adjust this height if needed */
    background: transparent;
}

/* Optional: tweak appearance */
body:not(.mw-user-loggedin) #mw-panel {
    padding-top: 0;
    background: none;
}