MediaWiki:Collapse.css

/* Collapsible blocks styling (MediaWiki-native style) */
.mw-collapsible {
    margin: 0.3em 0;
    border: 1px solid #a2a9b1;
    background-color: #f8f9fa;
    border-radius: 2px;
}

.mw-collapsible-toggle {
    font-weight: bold;
    padding: 0.4em 0.6em;
    cursor: pointer;
    color: #202122;
    background-color: #eaecf0;
    border-bottom: 1px solid #c8ccd1;
}

.mw-collapsible-toggle:hover {
    background-color: #e0e2e6;
}

.mw-collapsible-toggle:after {
    content: " ▼";
    font-size: 0.85em;
    color: #54595d;
}

.mw-collapsed .mw-collapsible-toggle:after {
    content: " ▲";
}

.mw-collapsible-content {
    padding: 0.6em 0.8em;
    background-color: #ffffff;
}

.mw-collapsed .mw-collapsible-content {
    display: none;
}

/* For mobile devices */
@media screen and (max-width: 768px) {
    .mw-collapsible-toggle {
        padding: 0.5em;
    }
    .mw-collapsible-content {
        padding: 0.5em;
    }
}