Hello,
You can change anything in a Template with some basic CSS and PHP knowledge. We can't have too many highlight colors or it becomes confusing to people what highlights target which elements.
This would be the coding from the index.php that affects the highlight color chosen in the Template Manager with a PHP echo. You can see there are many elements that take on this highlight. If you remove a class name from the code block and re-add it in the custom.css file then you can have any color you want.
.jdGallery .carousel .carouselInner .active, .button, .readmore a, .readon, button, .S5_submenu_item:hover, .S5_grouped_child_item .S5_submenu_item:hover, .readon.dark:hover, .success_area_number, .s5_tab_show_slide_button_active, .progress_bar2, #s5_pos_custom_6, .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, .readmore a, .s5_masonry_inactive, #s5_footer_area1, #s5_accordion_menu h3:hover, #s5_accordion_menu h3.s5_am_open, #s5_register, #s5_login, .module_round_box-highlight1, .module_round_box-highlight1_dark_title, .s5_pricetable_column.recommended .s5_title {
background: #e8374d none repeat scroll 0 0 !important;
}
Regards,