.wp-block-firebox-heading,
.wp-block-firebox-heading>* {
    margin: 0;
    font-weight: 500
}

.wp-block-firebox-heading:not(.block-full-width)>* {
    display: inline-block
}

.wp-block-firebox-heading.block-full-width {
    -ms-flex-item-align: normal;
    align-self: normal
}

.wp-block-firebox-heading.block-full-width>* {
    display: block
}