chat client: css optimization

public/assets/chat/chat.css

@@ -302,7 +302,10 @@
   background: white; }
 
 .zammad-chat-input {
+  margin: 0;
+  padding: 0;
   float: left;
+  width: auto;
   height: auto;
   font-family: inherit;
   line-height: inherit;
@@ -310,7 +313,7 @@
   -webkit-appearance: none;
   -moz-appearance: none;
   appearance: none;
-  border: none;
+  border: none !important;
   background: none;
   box-shadow: none;
   padding: 1em 2em;
@@ -319,7 +322,8 @@
   -webkit-flex: 1;
   -ms-flex: 1;
   flex: 1;
-  max-height: 6em; }
+  max-height: 6em;
+  box-shadow: none !important; }
 
 .zammad-chat-input::-webkit-input-placeholder {
   color: #d9d9d9; }
@@ -330,6 +334,7 @@
   appearance: none;
   font-family: inherit;
   font-size: inherit;
+  line-height: initial;
   background: #379ad7;
   color: white;
   padding: 0.6em 1.2em;

public/assets/chat/chat.scss

@@ -303,13 +303,16 @@
 }
 
 .zammad-chat-input {
+  margin: 0;
+  padding: 0;
   float: left;
+  width: auto;
   height: auto;
   font-family: inherit;
   line-height: inherit;
   font-size: inherit;
   appearance: none;
-  border: none;
+  border: none !important;
   background: none;
   box-shadow: none;
   padding: 1em 2em;
@@ -317,6 +320,7 @@
   resize: none;
   flex: 1;
   max-height: 6em;
+  box-shadow: none !important;
 }
 
 .zammad-chat-input::-webkit-input-placeholder {
@@ -327,6 +331,7 @@
   appearance: none;
   font-family: inherit;
   font-size: inherit;
+  line-height: initial;
   background: hsl(203,67%,53%);
   color: white;
   padding: 0.6em 1.2em;