zulip/web/styles/lightbox.css

#lightbox_overlay {
    background-color: hsl(227deg 40% 16%);
    display: flex;
    flex-direction: column;
    height: 100dvh;

    .image-preview {
        flex: 1;
        display: flex;
        align-items: center;
        justify-content: center;
        position: relative;
        width: 100%;
        margin: 0;
        overflow: hidden;

        background-size: contain;
        background-repeat: no-repeat;
        background-position: center center;

        & img {
            cursor: move;
            max-height: 100%;
            max-width: 100%;
            object-fit: contain;
        }

        .zoom-element {
            width: 100%;
            height: 100%;
            display: flex;
            align-items: center;
            justify-content: center;
        }
    }

    .video-player {
        flex: 1;
        display: flex;
        width: 100%;
        align-items: center;
        justify-content: center;
        margin: 0;
        overflow: hidden;

        & video {
            max-width: 100%;
            max-height: 100%;
        }
    }

    .exit {
        flex-shrink: 0;

        color: hsl(0deg 0% 100% / 80%);
        font-size: 2rem;
        line-height: 1.8rem;

        transform: scaleY(0.75);
        font-weight: 300;

        opacity: 0;
        pointer-events: none;
        cursor: pointer;
        transition: opacity 0.2s ease;
    }

    &.show .exit {
        pointer-events: auto;
        opacity: 1;
    }

    .media-info-wrapper {
        display: flex;
        justify-content: end;
        align-items: start;
        gap: 20px;
        padding: 20px;

        background-color: transparent;
    }

    .media-actions {
        display: flex;
        flex-shrink: 0;
        gap: 10px;

        .button {
            font-size: 0.9rem;
            min-width: inherit;
            padding: 4px 10px;
            border: 1px solid hsl(0deg 0% 100% / 60%);
            background-color: transparent;
            color: hsl(0deg 0% 100%);
            border-radius: 4px;
            text-decoration: none;
            display: inline-block;

            &:hover {
                background-color: hsl(0deg 0% 100%);
                border-color: hsl(0deg 0% 100%);
                color: hsl(227deg 40% 16%);
            }
        }

        .disabled {
            opacity: 0.7;
            cursor: default;

            &:hover {
                background-color: transparent;
                color: hsl(0deg 0% 100%);
                border: 1px solid hsl(0deg 0% 100% / 60%);
            }
        }
    }

    .media-description {
        container: media-description / inline-size;

        flex: 1;
        /* setting min-width to an absolute value will make
           sure the text gets truncated in case of overflow */
        min-width: 0;

        font-size: 1.1rem;
        color: hsl(0deg 0% 100%);

        .title {
            vertical-align: top;
            font-weight: 400;
            line-height: normal;

            /* Required for text-overflow */
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .user {
            font-weight: 300;
            line-height: normal;
            text-overflow: ellipsis;
            overflow: hidden;
            white-space: pre;

            &::before {
                margin-right: 5px;
                content: "\2014";
            }
        }
    }

    .player-container {
        flex: 1;
        display: flex;
        justify-content: center;
        align-items: center;

        & iframe {
            aspect-ratio: 16/9;
            /* for screen_width<=lg_min aspect-ratio will be
               maintained given portrait mode is used */
            /* in landscape max-height will prevent overflow,
               however user will benefit more from using
               youtube fullscreen at that point */
            width: 100%;
            /* maintains the aspect ratio for screen_width>=lg_min. */
            max-width: $lg_min;
            /* height(media_info_container) + height(center) < 200px */
            max-height: calc(100dvh - 200px);
        }
    }

    .center {
        display: flex;
        justify-content: center;
        align-items: center;
        gap: 2px;
        padding: 12px 20px;

        .arrow {
            padding: 0 10px;
            color: hsl(0deg 0% 100%);
            font-size: 1.8rem;
            line-height: 1.6rem;
            font-weight: 200;

            transform: scaleY(2);
            cursor: pointer;

            opacity: 0.5;
            transition: opacity 0.3s ease;

            &:hover {
                opacity: 1;
            }
        }

        .image-list {
            position: relative;
            display: inline-block;
            font-size: 0;

            max-width: 40vw;
            overflow: hidden;
            white-space: nowrap;

            .image {
                display: inline-block;
                vertical-align: top;
                width: 50px;
                height: 50px;
                margin: 0 2px;

                background-color: hsl(0deg 0% 94% / 20%);
                opacity: 0.5;

                background-size: cover;
                background-position: center;
                cursor: pointer;

                &.selected {
                    opacity: 1;
                }
            }

            .lightbox_video video {
                width: 50px;
                height: 50px;
            }
        }
    }
}

/* hide media-description if it has width less than 100px  */
@container media-description (max-width: 100px) {
    .media-description {
        .title {
            display: none;
        }

        .user {
            display: none;
        }
    }
}