Module:Mbox/styles.css

.mbox {
    position: relative;
    display: flex;
    flex-direction: column;
    margin-top: var( --space-xs );
    margin-bottom: var( --space-md );
    background-color: var( --color-surface-2 );
    border: 1px solid var( --border-color-base );
    border-radius: var( --border-radius--medium );
    color: var( --color-base--subtle );
    font-size: var( --font-size-small );
    line-height: var( --line-height-xs );
}

.mbox.mbox-high {
    background-color: var( --background-color-destructive-subtle );
}

.mbox.mbox-med {
    background-color: var( --background-color-warning-subtle );
}

.mbox-title {
    display: flex;
    align-items: center;
    padding: var( --space-sm ) var( --space-md );
}

.mbox-icon img {
    display: block;
    width: var( --font-size-small );
    height: auto;
    margin-right: var( --space-xs );
    opacity: var( --opacity-icon-base );
    filter: var( --filter-invert );
}

.mbox-text {
    position: absolute;
    top: 100%;
    z-index: 10;
    padding: var( --space-md );
    width: 100%;
    box-sizing: border-box;
    background-color: var( --color-surface-1 );
    border-bottom-left-radius: var( --border-radius--medium );
    border-bottom-right-radius: var( --border-radius--medium );
    box-shadow: var( --box-shadow-dialog );
    opacity: 0;
    visibility: hidden;
}

.mbox:hover {
    /* Merge with popup */
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    box-shadow: var( --box-shadow-dialog );
}

.mbox:hover .mbox-text {
    opacity: 1;
    visibility: visible;
}