Unify link colors for visited and hover effects.

Fixes #4274

static/css/devhub/new-landing/base.less

@@ -65,6 +65,23 @@ img {
   max-width: 100%;
 }
 
+.link(@color, @decoration: none) {
+  color: @color;
+  text-decoration: @decoration;
+
+  &:visited {
+    color: fadeOut(@color, 10%);
+  }
+
+  &:hover {
+    color: fadeOut(@color, 20%);
+  }
+}
+
+a {
+  .link(@color-text);
+}
+
 body {
   margin: 0;
   padding: 0;

static/css/devhub/new-landing/button.less

@@ -1,13 +1,13 @@
 .Button {
+  .link(@color-items);
+
   background-color: @color-button-default;
   border-radius: 2px;
   box-shadow: 0 2px 3px 0 rgba(0, 0, 0, 0.3);
-  color: @color-items;
   display: inline-block;
   padding: 10px 30px;
   margin: 10px 0;
   text-align: center;
-  text-decoration: none;
   width: 100%;
 
   @media @small {

static/css/devhub/new-landing/footer.less

@@ -3,8 +3,7 @@
   margin: 60px 0 0;
 
   a {
-    color: @color-button-default;
-    text-decoration: none;
+    .link(@color-button-default);
   }
 
   &.scheme-light {

static/css/devhub/new-landing/navigation.less

@@ -57,8 +57,7 @@
       }
 
       a {
-        color: @color-text;
-        text-decoration: none;
+        .link(@color-text);
       }
     }
   }
@@ -68,13 +67,13 @@
     min-width: @grid-max;
 
     ul li a {
-      color: @color-scheme-light-text;
+      .link(@color-scheme-light-text);
     }
   }
 
   &.scheme-medium {
     ul li a {
-      color: @color-scheme-medium-text;
+      .link(@color-scheme-medium-text);
     }
   }
 }

static/css/devhub/new-landing/sections/more-information.less

@@ -18,19 +18,21 @@
   h2,
   h2 a {
     color: @color-scheme-dark-text;
-    text-decoration: none;
     font-size: 32px;
     margin: 0;
   }
 
+  h2 a {
+    .link(@color-scheme-dark-text);
+  }
+
   ul {
     list-style: none;
     padding: 0;
 
     li {
       a {
-        color: @color-scheme-dark-items;
-        text-decoration: none;
+        .link(@color-scheme-dark-items);
       }
 
       p {
@@ -42,9 +44,9 @@
 
 .DevHub-BlogPosts {
   .read-more {
-    color: @color-scheme-dark-items;
+    .link(@color-scheme-dark-items);
+
     font-weight: 600;
-    text-decoration: none;
   }
 }
 

static/css/devhub/new-landing/sections/my-addons.less

@@ -33,9 +33,9 @@
 
   a,
   .DevHub-MyAddons-VersionStatus {
+    .link(@color-button-default);
+
     font-size: 15px;
-    text-decoration: none;
-    color: @color-button-default;
     margin: 0 5px;
 
     &.DevHub-MyAddons-version-status-incomplete,
@@ -120,9 +120,10 @@
 }
 
 .DevHub-MyAddons-item-buttons-all-submissions {
+  .link(@color-button-default);
+
   font-size: 15px;
   text-decoration: none;
-  color: @color-button-default;
 }
 
 .DevHub-MyAddons-item-buttons-submit {

static/css/devhub/new-landing/sections/overview.less

@@ -1,5 +1,4 @@
 .DevHub-Overview {
-
   @media @medium {
     > div {
       background-image: url(../../../img/developers/new-landing/header-background.svg);
@@ -25,7 +24,7 @@
     max-width: 560px;
 
     > a {
-      color: @color-scheme-medium-text;
+      .link(@color-scheme-medium-text, @decoration: underline);
     }
 
     @media @small {