Template:Expand/styles.css

.expandable-container {
    background-color: var( --color-surface-1 );
    border: 1px solid var( --border-color-base );
	border-radius: var( --border-radius--large );
    padding: 1rem;
}

.expandable-header {
    font-weight: bold;
}

.expandable-container + :not(.expandable-container) + .expandable-container {
    margin-top: 1rem;
}

/* NOTE: The CSS written below is repeated in MediaWiki:Common.css so that   */
/* the "[Expand]" and "[Collapse]" text that MediaWiki automatically fills in*/
/* is removed more quickly. Basically, this makes for faster page loading.   */
.mw-collapsible-toggle-default::after {
    display: none;
}

.mw-collapsible-toggle-default::before {
    font-weight: bold;
}

.mw-collapsible-toggle-default.mw-collapsible-toggle-collapsed::before {
    content: '⟩';
}

.mw-collapsible-toggle-default.mw-collapsible-toggle-expanded::before {
    content: '⟩';
}

.mw-collapsible-toggle-default.mw-collapsible-toggle-collapsed {
    transform: rotate(0deg);
    transition: 100ms;
    margin-right: 0.5em;
}

.mw-collapsible-toggle-default.mw-collapsible-toggle-collapsed:hover {
    color: var(--color-primary);
}

.mw-collapsible-toggle-default.mw-collapsible-toggle-expanded {
    transform: rotate(90deg);
    transition: 100ms;
    margin-right: 0.5em;
    color: var(--color-primary);
}

.mw-collapsible-text {
    display: none;
}