Index: openacs-4/packages/chat/tcl/chat-ajax-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/chat/tcl/chat-ajax-procs.tcl,v
diff -u -r1.24 -r1.25
--- openacs-4/packages/chat/tcl/chat-ajax-procs.tcl	19 Nov 2018 14:32:29 -0000	1.24
+++ openacs-4/packages/chat/tcl/chat-ajax-procs.tcl	19 Nov 2018 16:35:12 -0000	1.25
@@ -21,7 +21,6 @@
 
   chat_room instproc render {} {
       :get_parameters
-      template::head::add_css -href /chat/resources/chat.css
       return [::chat::Chat login \
                   -chat_id $chat_id \
                   -mode    $mode \
Index: openacs-4/packages/chat/www/chat.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/chat/www/chat.tcl,v
diff -u -r1.21 -r1.22
--- openacs-4/packages/chat/www/chat.tcl	19 Nov 2018 14:32:29 -0000	1.21
+++ openacs-4/packages/chat/www/chat.tcl	19 Nov 2018 16:35:12 -0000	1.22
@@ -53,8 +53,6 @@
     ad_script_abort
 }
 
-template::head::add_css -href resources/chat.css
-
 set chat_frame [::chat::Chat login \
                     -chat_id $room_id]
 
Index: openacs-4/packages/xowiki/tcl/chat-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/chat-procs.tcl,v
diff -u -r1.39 -r1.40
--- openacs-4/packages/xowiki/tcl/chat-procs.tcl	19 Nov 2018 14:12:17 -0000	1.39
+++ openacs-4/packages/xowiki/tcl/chat-procs.tcl	19 Nov 2018 16:35:12 -0000	1.40
@@ -387,6 +387,11 @@
     set context id=$chat_id&s=$session_id
     set base_url ${path}ajax/chat?${context}
 
+    # This will point to chat/resources/chat.css for a chat instance
+    # and to <xowiki_mountpoint>/resources.chat.css for a plain xowiki
+    # chat
+    template::head::add_css -href ${path}resources/chat.css
+
     if {$mode eq ""} {
       #
       # The parameter "mode" was not specified, we try to guess the
Index: openacs-4/packages/xowiki/www/resources/chat.css
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/www/resources/Attic/chat.css,v
diff -u
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ openacs-4/packages/xowiki/www/resources/chat.css	19 Nov 2018 16:35:12 -0000	1.1
@@ -0,0 +1,202 @@
+* {
+    box-sizing: border-box;
+}
+
+/* Chat container */
+#xowiki-chat-container {
+    height: 70vh;
+    width: 100%;
+    position: relative;
+}
+
+/* Users and messages container */
+#xowiki-chat {
+    height: 100%;
+    width: 100%;
+    margin-bottom: 1%;
+    overflow: hidden;
+    display: flex;
+    background-color: white;
+}
+
+#xowiki-chat-fs {
+    height: 100vh;
+    width: 100%;
+    overflow: hidden;
+    display: flex;
+    background-color: white;
+    position: fixed;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    left: 0;
+    z-index: 1031;
+}
+
+/* Users block */
+#xowiki-chat-users {
+    border: 1px solid #ddd;
+    border-left: none;
+    overflow: auto;
+    order: 2;
+    display: flex;
+    flex-direction: column;
+    min-width: 240px;
+}
+
+#xowiki-chat-users .xowiki-chat-user-link {
+    text-decoration: none;
+}
+
+#xowiki-chat-users .xowiki-chat-user-block {
+    padding: 18px 10px 18px 16px;
+    border-bottom: 1px solid #ddd;
+}
+
+#xowiki-chat-users .xowiki-chat-user-block:hover {
+    background-color: rgb(235,235,235);
+}
+
+#xowiki-chat-users .xowiki-chat-user-pic {
+    width: 45px;
+    height: 45px;
+    border-radius: 50%;
+    border: 2px solid;
+    padding: 3px;
+    margin-right: 15px;
+}
+
+#xowiki-chat-users .xowiki-chat-user-pic-wrap {
+    float: left;
+}
+
+#xowiki-chat-users .xowiki-chat-user {
+    font-weight: bold;
+}
+
+#xowiki-chat-users .xowiki-chat-timestamp {
+    color: rgb(152,152,152);
+}
+
+/* Messages block */
+#xowiki-chat-messages-and-form {
+    width: 100%;
+    border: 1px solid #ddd;
+    display: flex;
+    flex-direction: column;
+    order: 1;
+    justify-content: flex-end;
+}
+
+#xowiki-chat-messages {
+    padding: 10px;
+    height: 100%;
+    overflow: auto;
+    order: 1;
+}
+
+#xowiki-chat-messages .xowiki-chat-user-block {
+    float: left;
+}
+
+#xowiki-chat-messages .xowiki-chat-user-block-me {
+    float: left;
+}
+
+#xowiki-chat-messages .xowiki-chat-user {
+    white-space: nowrap;
+}
+
+#xowiki-chat-messages .xowiki-chat-message {
+    padding: 10px;
+}
+
+#xowiki-chat-messages .xowiki-chat-message-me {
+    padding: 10px;
+}
+
+#xowiki-chat-messages .xowiki-chat-timestamp {
+    color: rgb(152,152,152);
+    float: right;
+}
+
+#xowiki-chat-messages .xowiki-chat-timestamp-me {
+    /* color: yellow; */
+    color: rgb(152,152,152);
+    float: right;
+    /* font-size: 65%; */
+}
+
+/* Send form */
+#xowiki-chat-messages-form-block {
+    margin-left: 20px;
+    margin-right: 20px;
+    margin-top: 5px;
+    border-top: 1px solid #ddd;
+    padding: 10px 10px 10px 10px;
+    min-height: 80px;
+    display: flex;
+    align-items: center;
+    order: 2;
+}
+
+#xowiki-chat-messages-form {
+    width: 100%;
+}
+
+#xowiki-chat-send {
+    /* font-size: 24px; */
+    height: 48px;
+    width: 100%;
+    padding-left: 10px;
+    border: 0;
+    outline: none;
+    background-color: #eceff1;
+    border-radius: 8px;
+}
+
+/* Full screen trigger */
+.xowiki-chat-trigger-fs-block {
+    padding: 10px;
+}
+
+.xowiki-chat-trigger-fs-link {
+    text-decoration: none;
+}
+
+.xowiki-chat-trigger-fs-link:hover {
+    text-decoration: none !important;
+}
+
+.xowiki-chat-trigger-fs-pic:hover {
+    background-color: white;
+    border: 1px solid white;
+}
+
+/* Responsive design */
+@media (max-width: 1000px) {
+    #xowiki-chat {
+        flex-direction: column;
+    }
+    #xowiki-chat-fs {
+        flex-direction: column;
+        height: 100%;
+    }
+    #xowiki-chat-users {
+        order: 1;
+        border-left: 1px solid #ddd;
+        border-bottom: none;
+        flex-direction: row;
+        overflow-x: auto;
+    }
+    #xowiki-chat-users .xowiki-chat-user-block {
+        border-right: 1px solid #ddd;
+        border-bottom: none;
+        min-width: 240px;
+    }
+    #xowiki-chat-messages-and-form {
+        width: 100%;
+        order: 2;
+        flex: 1 1 auto;
+    }
+}