braine-l-alleud: add active/hover bar to navigation items (#57775)

static/braine-l-alleud/_custom.scss

@@ -465,3 +465,44 @@ div.buttons .cancel-button button,
 		border-top-left-radius: 0;
 	}
 }
+
+
+div.gru-nav li > a {
+	&::after {
+		content: "";
+		display: block;
+		width: 0px;
+		height: 2px;
+		background: $orange;
+		margin: 5px auto 0 auto;
+		transition: width linear 0.2s;
+		@media screen and ($max-mobile-viewport) {
+			content: none;
+		}
+	}
+}
+
+div.gru-nav > ul li ul {
+	box-shadow: 0px 13px 24px 0px rgba(0, 0, 0, 0.34);
+	padding: 10px;
+	@media screen and ($max-mobile-viewport) {
+		padding: 0 20px;
+		box-shadow: none;
+	}
+}
+
+div.gru-nav > ul > li li a {
+	padding: 0.5rem 0.5rem 0.15rem 0.5rem;
+}
+
+div.gru-nav li li a::after {
+	margin: 0;
+}
+
+div.gru-nav li:hover > a,
+div.gru-nav li.selected > a {
+	border-bottom-color: transparent;
+	&:after {
+		width: calc(100% - 50px);
+	}
+}