Added styling to Raven components of Budgie panel

src/gtk-3.20/scss/_widgets.scss

@@ -37,3 +37,4 @@
 @import "apps/xfce";
 @import "apps/unity";
 @import "apps/lightdm";
+@import "apps/budgie";

src/gtk-3.20/scss/apps/_budgie.scss

@@ -0,0 +1,24 @@
+/******************
+ ! Budgie Desktop *
+*******************/
+.budgie-container {
+    background-color: transparent;
+}
+
+.raven {
+    background-color: transparentize($bg_color, .07);
+
+    .raven-header {
+        background-color: $bg_color;
+        border: solid $borders_color;
+        border-width: 1px 0;
+    }
+
+    .raven-background {
+        background-color: transparentize($bg_color, .07);
+    }
+}
+
+.raven-mpris {
+    background-color: transparentize($bg_color, .3);
+}