[fractal] app.css: Use opacity for .direct-chat icon instead of hardcoded color

[Daniel Garcia Moreno <danigm src gnome org>]

commit f0e6e408d3e74d2e27ae0d32d968c7fed7f94ee3
Author: Alex Monday <monday15 gmx com>
Date:   Tue Nov 5 18:12:41 2019 +0000

    app.css: Use opacity for .direct-chat icon instead of hardcoded color

 fractal-gtk/res/app.css | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/fractal-gtk/res/app.css b/fractal-gtk/res/app.css
index ac9e89d6..99724eec 100644
--- a/fractal-gtk/res/app.css
+++ b/fractal-gtk/res/app.css
@@ -126,11 +126,11 @@ row:not(:selected) .member-uid {
 }
 
 .direct-chat {
-  color: alpha(@theme_fg_color, 0.5);
+  opacity: 0.4;
 }
 
 .room-list list row:selected .direct-chat {
-  color: alpha(@theme_selected_fg_color, 0.5);
+  opacity: 0.5;
 }
 
 .collapsed row:selected {