.main-menu {
    display: -webkit-box;      /* OLD - iOS 6-, Safari 3.1-6 */
    display: -moz-box;         /* OLD - Firefox 19- (buggy but mostly works) */
    display: -ms-flexbox;      /* TWEENER - IE 10 */
    display: -webkit-flex;     /* NEW - Chrome */
    display: flex;

    -ms-flex-flow: column nowrap;
    -webkit-flex-flow: column nowrap;
    flex-flow: column nowrap;
    position: absolute;
    top: 48px;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    transition: opacity 0.6s ease-in-out;
    opacity: 0;
    overflow: hidden;
    z-index: 100;
    pointer-events: none;
}

.mobile-menu-open .main-menu {
    display: block;
    flex-flow: inherit;
}

.main-menu.is-open {
    opacity: 1;
    pointer-events: auto;
    overflow-y: auto;
}

/* Main Menu Link */
.main-menu__link > button,
.main-menu__link > a{
    padding-left: 10px;
    width: 100%;
}

/* Sub menu */
.main-sub-menu {
    display: -webkit-box;      /* OLD - iOS 6-, Safari 3.1-6 */
    display: -moz-box;         /* OLD - Firefox 19- (buggy but mostly works) */
    display: -ms-flexbox;      /* TWEENER - IE 10 */
    display: -webkit-flex;     /* NEW - Chrome */
    display: flex;

    -ms-flex-flow: column nowrap;
    -webkit-flex-flow: column nowrap;
    flex-flow: column nowrap;
    transition: opacity 0.2s ease-in-out;
    height: 0;
    opacity: 0;
    padding: 20px 0;
    overflow: hidden;
    pointer-events: none;
}

.main-menu__link.is-open .main-sub-menu {
    height: auto;
    opacity: 1;
    pointer-events: auto;
}

.sub-menu__link {
    margin: 0 auto;
    max-height: 266px;
    width: 218px;
    text-align: center;
}

.sub-menu__link a{
    display: block;
}

/* thumbmail */
.sub-menu__thumbmail {
    display: none;
    height: 218px;
    width: 218px;
    overflow: hidden;
}

.main-menu__link.is-open .sub-menu__thumbmail {
    display: block;
}

@media (min-width: 769px) {
    .main-menu-block {
        flex-grow: 1;
        -webkit-flex-grow: 1;
    }

    button.mobile-menu {
        display: none;
    }

    .main-menu {
        display: -webkit-inline-flex;
        display: inline-flex;
        position: static;
        flex-flow: row nowrap;
        -webkit-flex-flow: row nowrap;
        -ms-flex-flow: row nowrap;
        justify-content: space-around;
        -webkit-justify-content: space-around;
        opacity: 1;
        pointer-events: auto;
    }

    /* Main menu link */
    .main-menu__link button,
    .main-menu__link a{
        padding-left: 0;
        width: auto;
    }

    .main-sub-menu {
        position: absolute;
        top: 48px;
        left: 0;
        right: 0;
        bottom: 0;
        overflow-y: auto;
        height: auto;
        z-index: 100;
        flex-flow: row wrap;
        -webkit-flex-flow: row wrap;
        -ms-flex-flow: row wrap;
        justify-content: space-around;
        -webkit-justify-content: space-around;
        transition-duration: 0.3s;
    }

    .sub-menu__link {
        margin: 0;
    }

    .sub-menu__link:not(:last-child) {
        margin-right: 10px;
    }
}