una/modules/boonex/messenger/template/css/filepond-custom.css

.bx-messenger-uploading-placeholder .filepond--root,
.bx-messenger-attachment-group .filepond--root {
    max-height: 240px;
    font-family:inherit !important;
    overflow: hidden;
    margin-bottom:0 !important;
}

.bx-messenger-uploading-placeholder .filepond--item,
.bx-messenger-attachment-group .filepond--item {
    width: calc(50% - .5em);
    padding-left:0;
}

.bx-messenger-uploading-placeholder .filepond--drop-label,
.bx-messenger-attachment-group .filepond--drop-label {
    display: none !important;
}

.bx-messenger-uploading-placeholder .filepond--list,
.bx-messenger-attachment-group .filepond--list{
    left: 0;
}

.bx-messenger-uploading-placeholder .filepond--panel-root,
.bx-messenger-attachment-group .filepond--panel-root {
    background-color: rgba(0,0,0,0) !important;
    border-radius: 0 !important;
}

.bx-messenger-uploading-placeholder .filepond--image-preview-overlay-success,
.bx-messenger-attachment-group .filepond--image-preview-overlay-success{
    color: rgba(68, 136, 255, 0.7) !important;
}

@media (min-width: 30em) {
    .bx-messenger-uploading-placeholder .filepond--item,
    .bx-messenger-attachment-group .filepond--item {
        width: calc(50% - .5em);
    }
    .bx-messenger-uploading-placeholder .filepond--root,
    .bx-messenger-attachment-group .filepond--root {
        max-height: 120px;
    }
}
.bx-messenger-uploading-placeholder .filepond--file-wrapper,
.bx-messenger-attachment-group .filepond--file-wrapper {
    overflow: hidden;
}

@media (min-width: 50em) {
    .bx-messenger-uploading-placeholder .filepond--item,
    .bx-messenger-attachment-group .filepond--item {
        width: calc(33.33% - .5em);
    }

    .bx-messenger-uploading-placeholder .filepond--root,
    .bx-messenger-attachment-group .filepond--root {
        max-height: 240px;
    }
}