fix dropzone color and position

packages/rocketchat-theme/assets/stylesheets/base.less

@@ -3998,12 +3998,10 @@ body:not(.is-cordova) {
 		bottom: 0;
 		right: 0;
 		z-index: 1000000;
-		display: block;
 		font-size: 42px;
 		display: flex;
 		align-items: center;
 		justify-content: center;
-		margin: 0 51px 0 12px;
 		> div {
 			padding: 40px;
 			border-radius: 10px;
@@ -4014,11 +4012,11 @@ body:not(.is-cordova) {
 	}
 }
 
-@media (min-width: 780px) {
-	.dropzone.over .dropzone-overlay {
-		margin: 0 51px 0 270px;
-	}
-}
+// @media (min-width: 780px) {
+// 	.dropzone.over .dropzone-overlay {
+// 		margin: 0 51px 0 270px;
+// 	}
+// }
 
 .is-cordova {
 	.flex-tab {

packages/rocketchat-theme/assets/stylesheets/utils/_colors.import.less

@@ -196,10 +196,10 @@ blockquote:before {
 }
 
 .dropzone.over .dropzone-overlay {
-	background-color: @transparent-darker;
+	background-color: @transparent-darkest;
 	color: @content-background-color;
 	> div {
-		background-color: @transparent-darker;
+		background-color: @transparent-darkest;
 	}
 }
 

packages/rocketchat-theme/server/variables.coffee

@@ -9,6 +9,7 @@
 # New colors, used for shades on solid backgrounds
 # Defined range of transparencies reduces random colour variances
 alphaColors=
+  'transparent-darkest': 'rgba(0,0,0,0.5)' 
   'transparent-darker': 'rgba(0,0,0,0.15)'
   'transparent-dark': 'rgba(0,0,0,0.05)'
   'transparent-light': 'rgba(255,255,255,0.10)'