Implement responsive design

See https://mibew.org/forums/index.php/topic,191515.msg199759.html for details

src/mibew/styles/chats/default/chat.css

@@ -26,7 +26,7 @@ body {
     font-size: 11px;
     font-family: Tahoma, sans-serif;
     line-height: 1;
-    min-width: 500px;
+    min-width: auto;
     background-color: #f1f2f2;
 }
 body.rtl {
@@ -83,7 +83,7 @@ img {
     background: #ffffff url("images/bottombg.gif") scroll repeat-x 0 0;
 }
 #footer {
-    width: 400px;
+    max-width: 100%;
     margin: 0 auto;
     padding-top: 5px;
     padding-bottom: 5px;
@@ -387,6 +387,7 @@ a:hover .image-close-window {
 /* leavy message */
 #message-leave {
     resize: none;
+    width: 100%;
 }
 
 /* error page (error.tpl) */
@@ -559,3 +560,10 @@ ul li {
     float: none;
     display: inline-block;
 }
+
+.username {
+    width: 100%;
+}
+#logo img {
+    max-width: 100%;
+}

src/mibew/styles/chats/default/iframe.css

@@ -21,6 +21,8 @@ div.mibew-chat-wrapper {
     position: fixed !important;
     bottom: 5px !important;
     right: 5px !important;
+    -webkit-overflow-scrolling: touch !important;
+    overflow-y: scroll !important;
 }
 
 iframe.mibew-chat-frame {