alfresco-ng2-components/lib/core/viewer/components/pdf-viewer-thumbnails.theme.scss

@mixin adf-pdf-thumbnails-theme($theme) {
    $background: map-get($theme, background);

    .adf-pdf-thumbnails {
        display: block;
        overflow: hidden;
        overflow-y: auto;
        height: 100%;
        position: relative;

        &__content {
            top: 5px;
            left: 50%;
            height: 0;
            position: absolute;
        }

        &__thumb {
            cursor: pointer;
            display: block;
            width: 91px;
            background: mat-color($background, background);
            margin-bottom: 15px;
        }

        &__thumb:hover {
            box-shadow: 0 0 5px 0 $black-87-opacity;
        }

        &__thumb--selected {
            border: 2px solid mat-color($alfresco-ecm-blue, A200);
        }
    }
}