Hey there,
I am really sorry for the delay of this reply as it is a weekend for us here.
I already applied some css block of code into your template custom css file ->
JoomlaFolder/templates/ja_teline_v/css/custom.css
Now those button show green color now, but I am not really sure which color you want, you can modify it anytime.
/* customize the Easysocial button color */
div#fd.es .btn-es-primary, div#fd.es .btn-es-primary:focus {
border: 1px solid #A8CF45 !important;
background-image: -webkit-linear-gradient(top,#A8CF45 0,#A8CF45 100%) !important;
background-image: linear-gradient(to bottom,#A8CF45 0,#A8CF45 100%) !important;
}
div#fd.es .es-story-privacy .es-privacy .es-privacy-toggle, div#fd.es .es-story-privacy .es-privacy .es-privacy-toggle:hover, div#fd.es .es-story-privacy .es-privacy .es-privacy-toggle:focus, div#fd.es .es-story-privacy .es-privacy .es-privacy-toggle:active {
background-image: -webkit-linear-gradient(top,#A8CF45 0,#A8CF45 100%) !important;
background-image: linear-gradient(to bottom,#A8CF45 0,#A8CF45 100%) !important;
border-color: #A8CF45 !important;
}