modify main.css: fix logo size for smaller screens

static/css/main.css

@@ -201,8 +201,8 @@ img {
   -moz-transition: visibility 0.5s, opacity 0.5s ease-in-out;
   transition: visibility 0.5s, opacity 0.5s ease-in-out;
   left: 50%;
-  width: 130px;
-  margin-top: -55px;
+  width: 50px;
+  margin-top: -25px;
 }
 .navbar-custom .avatar-container  .avatar-img-border {
   width: 100%;