.header-nav .sub-menu .menu-item a {
    display: flex;
    flex-direction: column;
    align-items: flex-start; /* prevents both lines from stretching full width */
    font-weight: bold;
}

.header-nav .sub-menu .menu-item-description {
    display: block;
    font-weight: normal;
    color: #767676; /* muted secondary text */
    white-space: normal; /* let it wrap in a narrow dropdown */
}

@media only screen and (min-width: 960px) {
    .header-nav .sub-menu {
        padding-top: 6px;
        padding-bottom: 6px;
    }

    .header-nav .sub-menu .menu-item a {
        font-size: 1.5em;
        margin-top: 30px;
        margin-bottom: 30px;
        padding-right: 20px;
        padding-left: 20px;
    }

    .header-nav .sub-menu .menu-item-description {
        margin-top: 4px;
        font-size: .8em;
        line-height: .8em;
    }
}