Hi

Use this custom css

.com-content-adminForm .tab-pane .post-formats label, .btn, .sppb-btn, .btn.btn-info:hover, .sppb-btn.btn-info:hover, .btn.sppb-btn-info:hover, .sppb-btn.sppb-btn-info:hover, .btn.btn-info:focus, .sppb-btn.btn-info:focus, .btn.sppb-btn-info:focus, .sppb-btn.sppb-btn-info:focus, .sp-megamenu-parent > li > a:before, body .pagination >li:nth-child(2) a, body .pagination >li:nth-last-child(2) a, .view-article article.item .published-date-wrap .published-date, .educon-notice-board article.item .educon-notice .published-date, .educon-topics-wrapper .common-topics li a:hover:before, .educon-topics-wrapper .common-topics li a:focus:before, .educon-topics-wrapper .sppb-addon-accordion .sppb-panel-default .sppb-panel-heading:before, .event-details-section .sppb-addon-single-image .sppb-addon-title, .splms-readmore.btn-primary, .splms.view-splms-course.course-details .btn.btn-primary, .splms.splms-view-event .splms-event-image .event-date, .event-details-bottom .btn.btn-primary, #sp-top-bar, .view-registration #sp-main-body, .view-login #sp-main-body, article.item .content-wrap .published-date, .helix-social-share .helix-social-share-icon ul li div a:hover, .helix-social-share .helix-social-share-icon ul li div a:focus, .view-splms-quiz-list .quiz-item-wrapper .quiz-description .btn.btn-primary, .view-quizquestion .splms.view-splms-quiz .btn.btn-primary, .view-quizquestion .splms.view-splms-quiz .btn.btn-default, .splms.splms-view-events .splms-event-details .btn.btn-primary, .scrollup, .splms-course-categories .splms-row.splms-course-category-wrapper .splms-course-category .splms-coursescategory-wrapper:hover, .mod-splms-course-categoies .lms-single-category:hover, .search .page-title, .view-category .page-header, .border-heading-style.sppb-addon-text-block .sppb-addon-title:before, .border-heading-style.sppb-addon-header .sppb-addon-title:before, .carousel-controller.splms-course-carousel .splms-course-title:before, .addon-splms-courses .splms-course-title:before, .owl-carousel .owl-controls .owl-dots .owl-dot.active span, .educon-latest-news-wrap .educon-latest-news .sppb-addon-title, .sppb-addon-tweet .sppb-tweet-slider .sppb-carousel-indicators li:before, .speasyimagegallery-albums .speasyimagegallery-album:hover .speasyimagegallery-album-info{
  background: unset !important;
}

Path towards custom CSS: Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.

-Regards