modify: add color variable for note-detail component

Author: sota1235

browser/styles/index.styl

@@ -16,6 +16,7 @@ $ui-inactive-text-color = #939395
 $ui-borderColor = #D1D1D1
 $ui-backgroundColor = #FFFFFF
 $ui-noteList-backgroundColor = #F3F3F3
+$ui-noteDetail-backgroundColor = #F4F4F4
 $ui-border = solid 1px $ui-borderColor
 $ui-active-color = #6AA5E9
 $ui-tag-backgroundColor = rgba(0, 0, 0, 0.3)
@@ -142,6 +143,7 @@ modal()
 $ui-dark-borderColor = lighten(#21252B, 20%)
 $ui-dark-backgroundColor = #333333
 $ui-dark-noteList-backgroundColor = #171717
+$ui-dark-noteDetail-backgroundColor = #0D0D0D
 $ui-dark-tag-backgroundColor = rgba(255, 255, 255, 0.3)
 $dark-background-color = lighten($ui-dark-backgroundColor, 10%)
 $ui-dark-text-color = #DDDDDD