need a code to change the language icon

@nassim try adding this to your custom CSS: 

.header-actions .language-picker-desktop .language-picker-content {
	opacity: 1;
	background: transparent;
	display: flex;
	position: relative;
}
.header-actions .language-picker-desktop .language-picker-content .language-item:first-of-type {
	padding-right: 10px;
	margin-right: 10px;
	border-right: 2px solid;
}
.header-actions .language-picker-desktop .current-language {
	display: none;
}

If that doesn't work, trying playing around with adding !important to certain properties to override the existing styles, like this:

.header-actions .language-picker-desktop .language-picker-content {
	opacity: 1 !important;
	background: transparent !important;
	display: flex;
	position: relative !important;
}
.header-actions .language-picker-desktop .language-picker-content .language-item:first-of-type {
	padding-right: 10px;
	margin-right: 10px;
	border-right: 2px solid;
}
.header-actions .language-picker-desktop .current-language {
	display: none;
}