.linguise_switcher_dropdown li.linguise_current { 
    border: none! important; 
}
/* To remove the background color */
.linguise_switcher{
    background: transparent !important;
}

/* To remove the additional border to make it clear */
.linguise_current_lang{
    border: none !important;
}

/* To remove the background on the child (other language when it's dropdown) */
.linguise_switcher_dropdown ul{
    background-color: transparent !important;
}

.linguise_switcher_dropdown li{
    border-bottom: none !important;
}