Style for split-out interactive auth

For https://github.com/matrix-org/matrix-react-sdk/pull/691

src/skins/vector/css/_common.scss

@@ -152,6 +152,7 @@ textarea {
     font-size: 15px;
     position: relative;
     padding-left: 58px;
+    padding-bottom: 36px;
     width: 60%;
     max-width: 704px;
     box-shadow: 0 1px 0 0 rgba(0, 0, 0, 0.2);
@@ -184,6 +185,13 @@ textarea {
     pointer-events: none;
 }
 
+.mx_Dialog_cancelButton {
+    float: right;
+    margin-top: 5px;
+    margin-right: 5px;
+    cursor: pointer;
+}
+
 .mx_Dialog_content {
     margin: 24px 58px 68px 0;
     font-size: 14px;
@@ -191,10 +199,6 @@ textarea {
     word-wrap: break-word;
 }
 
-.mx_Dialog_buttons {
-    padding-bottom: 36px;
-}
-
 .mx_Dialog button, .mx_Dialog input[type="submit"] {
     border: 0px;
     height: 36px;
@@ -286,6 +290,10 @@ textarea {
     display: inline;
 }
 
+.mx_button_row {
+    margin-top: 69px;
+}
+
 .changelog_text {
     font-family: 'Open Sans', Arial, Helvetica, Sans-Serif;
 }