.categories {
    width: 600px;
    margin: 25px auto;
    padding: 0;
    display: flex;
    flex-direction: row;
}
@media screen and (max-width: 768px) {
    .categories {
        width: 100%;
    }
}

.portfolio-grid {
    display: -ms-flexbox; /* IE10 */
    display: flex;
    -ms-flex-wrap: wrap; /* IE10 */
    flex-wrap: wrap;
    padding: 0;
}

.portfolio-grid:after {
    content: '';
    display: table;
    clear: both;
}

/* 4 equal columns next to each other */
.portfolio-image {
    -ms-flex: 24%; /* IE10 */
    flex: 24%;
    max-width: 24%;
    max-height: 250px;
    margin: 3px;
    overflow: hidden;
    display: block;
    text-align: center;
    cursor: pointer;
    position: relative;
}
.hide {
    display: none !important;
}
.show {
    display: block !important;
}

.portfolio-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    vertical-align: middle;
}

/* two column-layout for tablets */
@media screen and (max-width: 768px) {
    .portfolio-image {
        -ms-flex: 49%;
        flex: 49%;
        max-width: 49%;
    }
}

/* one column-layout for smartphones */
@media screen and (max-width: 480px) {
    .portfolio-image {
        -ms-flex: 99%;
        flex: 99%;
        max-width: 99%;
    }
}


/* -------------------------------- IMAGE HOVER EFFECT -------------------------------- */
/* only for desktop */
@media screen and (min-width: 769px) {
    .image-hover .portfolio-image__caption {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;

        padding: 2rem;
        color: #ffffff;
        text-transform: uppercase;
        font-size: 1.1rem;
        -webkit-backface-visibility: hidden;
        backface-visibility: hidden;
    }

    .image-hover .portfolio-image__caption p {
        color: #ffffff;
        margin: 0;
        letter-spacing: 1px;
        font-size: 1.1rem;
        padding: 20px 2.5em;
        opacity: 0;
        -webkit-transition: opacity 0.35s, -webkit-transform 0.35s;
        transition: opacity 0.35s, transform 0.35s;
        -webkit-transform: translate3d(0, 20px, 0);
        transform: translate3d(0, 20px, 0);
    }

    .image-hover:hover p {
        opacity: 1;
        -webkit-transform: translate3d(0, 0, 0);
        transform: translate3d(0, 0, 0);
    }

    .image-hover {
        background: -webkit-linear-gradient(45deg, var(--gold) 0%, var(--grey) 40%, var(--darkgrey) 100%);
        background: linear-gradient(45deg, var(--gold) 0%, var(--grey) 40%, var(--darkgrey) 100%);
    }

    .image-hover img {
        opacity: 0.9;
        -webkit-transition: opacity 0.35s;
        transition: opacity 0.35s;
    }

    .image-hover:hover img {
        opacity: 0.3;
    }

    .image-hover .portfolio-image__caption::before,
    .image-hover .portfolio-image__caption::after {
        pointer-events: none;
        position: absolute;
        top: 30px;
        right: 30px;
        bottom: 30px;
        left: 30px;
        content: '';
        opacity: 0;
        -webkit-transition: opacity 0.35s, -webkit-transform 0.35s;
        transition: opacity 0.35s, transform 0.35s;
    }

    .image-hover .portfolio-image__caption::before {
        border-top: 1px solid #fff;
        border-bottom: 1px solid #fff;
        -webkit-transform: scale(0, 1);
        transform: scale(0, 1);
    }

    .image-hover .portfolio-image__caption::after {
        border-right: 1px solid #fff;
        border-left: 1px solid #fff;
        -webkit-transform: scale(1, 0);
        transform: scale(1, 0);
    }

    .image-hover:hover .portfolio-image__caption::before,
    .image-hover:hover .portfolio-image__caption::after {
        opacity: 1;
        -webkit-transform: scale(1);
        transform: scale(1);
    }
}


/* -------------------------------- LIGHTBOX -------------------------------- */
.lightbox__text {
    display: none;
}
#lightbox {
    display: none;
    position: fixed;
    z-index: 1;
    padding-top: 2vh;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.9);
}

.lightbox__content {
    position: relative;
    background-color: transparent;
    margin: auto;
    padding: 0;
    width: 90%;
    max-width: 1200px;
    height: 100%;
}
@media screen and (max-width: 768px) {
    .lightbox__content {
        height: auto;
        width: 95%;
    }
}

.lightbox__close {
    position: absolute;
    top: 20px;
    right: 25px;
    height: 30px;
}
.lightbox__close:hover span,
.lightbox__close:focus span,
.lightbox__close span:hover {
    background: var(--lightgrey);
    cursor: pointer;
}
.lightbox__close span {
    display: block;
    width: 33px;
    height: 4px;
    margin-bottom: 5px;
    position: relative;
    background: var(--white);
    border-radius: 3px;
    z-index: 1;
    transform-origin: 0 0;
    -webkit-transform-origin: 0 0;
    transition: background 0.2s cubic-bezier(0.77,0.2,0.05,1.0);
    -webkit-transition: background 0.2s cubic-bezier(0.77,0.2,0.05,1.0);
}
.lightbox__close span:first-child {
    transform: rotate(45deg) translate(2px, -10px);
    -webkit-transform: rotate(45deg) translate(2px, -10px);
}
.lightbox__close span:nth-child(2) {
    transform: rotate(-45deg) translate(-2px, 10px);
    -webkit-transform: rotate(-45deg) translate(-2px, 10px);
}

.lightbox__image-container {
    width: 100%;
    height: 90%;
}
@media screen and (max-width: 768px) {
    .lightbox__image-container {
        height: auto;
        margin-top: 70px;
    }
}

.lightbox__image-container img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.lightbox__caption-container {
    text-align: center;
    background-color: transparent;
    padding: 2px 16px;
    color: var(--white);
}
.lightbox__caption-container p {
    color: var(--white);
}