adjust colors

resource/styles/scss/_layout_crowi.scss

@@ -22,7 +22,7 @@
       border-radius: 0 5px;
       padding: 3px 11px;
       font-weight: bold;
-      background: $gray-light;
+      background: $gray-lighter;
       margin-left: 5px;
       margin-bottom: 5px;
 

resource/styles/scss/_login.scss

@@ -163,7 +163,7 @@
     }
   }
   .link-switch {
-    color: $gray;
+    color: $gray-lighter;
     &:hover {
       color: white;
     }

resource/styles/scss/_override-bootstrap-variables.scss

@@ -8,11 +8,11 @@
 //## Gray and brand colors for use across Bootstrap.
 
 $gray-base:              #000 !default;
-$gray-darker:            lighten($gray-base, 13.5%) !default; // #222
-$gray-dark:              lighten($gray-base, 20%) !default;   // #333
-$gray:                   #f0f0f0;
-$gray-light:             #f5f5f5;
-$gray-lighter:           #fafafa;
+$gray-darker:            lighten($gray-base, 13.5%); // #222
+$gray-dark:              lighten($gray-base, 20%);   // #333
+$gray:                   lighten($gray-base, 33.5%); // #555
+$gray-light:             lighten($gray-base, 46.7%); // #777
+$gray-lighter:           lighten($gray-base, 93.5%); // #eee
 $gray-extralight:        #fafafa; // Growi original
 
 $brand-primary:         $primary;