In this case, there is no way to override so I decide to remove the button element in the above style:
root/templates/business_line/index.php
and remove the 'button' element in line 69:
.readon, .button, .s5_ls_readmore, .dropdown-menu li > a:hover, .dropdown-menu li > a:focus, .dropdown-submenu:hover > a, .dropdown-menu .active > a, .dropdown-menu .active > a:hover, .nav-list > .active > a, .nav-list > .active > a:hover, .nav-pills > .active > a, .nav-pills > .active > a:hover, .btn-group.open .btn-primary.dropdown-toggle, .btn-primary, .item-page .dropdown-menu li > a:hover, .blog .dropdown-menu li > a:hover, .item .dropdown-menu li > a:hover, .btn, .pagenav a, .ac-container label:hover, .ac-container2 label:hover, .jdGallery .carousel .carouselInner .active, p.readmore a:hover, .s5_is_css_10 .s5_is_slide_css_plus_circle:hover, .progress_bar3, .s5_tab_show_slide_button_active, .steps_boxes_highlight1, .module_round_box.highlight1 {
background:#<?php echo $s5_highlightcolor1; ?> !important;
}