ui: fix table color in dark theme (fix #915) (#968)

packages/ui-default/theme/dark.styl

@@ -221,7 +221,7 @@ $hover-background-color = #424242
     background-color: rgb(30, 30, 30)
 
   .typo table th, .typo table td, .typo table caption
-    border-color: #323232
+    border-color: #666
     color: #999
 
   body>.marker
@@ -405,3 +405,6 @@ $hover-background-color = #424242
 
   &.hasjs .collapsed #status:not([data-status="7"]) .compiler-text-mask
     background-image: linear-gradient(to bottom, transparent, #000000 25px)
+
+  .page--record_detail .subtask
+    background-color: #000 !important