fix(graph): Fixed issue with light theme text color issue in tooltip, fixes #4702

CHANGELOG.md

-# 3.0.0-beta4 (unreleased)
+# 3.0.0-beta5 ()
+
+### Bug fixes
+* **Graph**: Fixed issue with light theme text color issue in tooltip, fixes [#4702](https://github.com/grafana/grafana/issues/4702)
+
+# 3.0.0-beta4 (2016-04-13)
 
 ### Bug fixes
 * **Home dashboard**: Fixed issue with permission denied error on home dashboard, fixes [#4686](https://github.com/grafana/grafana/issues/4686)

public/sass/_variables.light.scss

@@ -281,7 +281,7 @@ $tooltipColor:            $popover-help-color;
 $tooltipBackground:       $popover-help-bg;
 $tooltipArrowWidth:       5px;
 $tooltipArrowColor:       $tooltipBackground;
-$tooltipLinkColor:        $link-color;
+$tooltipLinkColor:        lighten($popover-help-color, 5%);
 $graph-tooltip-bg:        $gray-5;
 
 // images

public/sass/components/_panel_graph.scss

@@ -236,6 +236,7 @@
   white-space: nowrap;
   font-size: $font-size-sm;
   background-color: $graph-tooltip-bg;
+  color: $text-color;
 
   .graph-tooltip-time {
     text-align: center;
@@ -248,7 +249,7 @@
     display: table-row;
 
     &--highlight {
-      color: $link-color;
+      color: $text-color-emphasis;
       font-weight: bold;
     }
   }