diff --git a/app/src/main/res/drawable-v21/ratingbar.xml b/app/src/main/res/drawable-v21/ratingbar.xml
index 5c66e0e..fe14f96 100644
--- a/app/src/main/res/drawable-v21/ratingbar.xml
+++ b/app/src/main/res/drawable-v21/ratingbar.xml
@@ -18,17 +18,17 @@
     <item android:id="@android:id/background">
         <bitmap
             android:src="@drawable/ic_star_black_48dp"
-            android:tint="@color/middlegrey" />
+            android:tint="?attr/rankingStarNotSelected" />
     </item>
     <item android:id="@android:id/secondaryProgress">
         <bitmap
             android:src="@drawable/ic_star_half_black_48dp"
-            android:tint="@color/middlegrey" />
+            android:tint="?attr/rankingStarNotSelected" />
     </item>
     <item android:id="@android:id/progress">
         <bitmap
             android:src="@drawable/ic_star_black_48dp"
-            android:tint="@color/colorAccent" />
+            android:tint="?attr/colorAccent" />
     </item>
 </layer-list>
 
diff --git a/app/src/main/res/drawable/ic_school_black_24dp.xml b/app/src/main/res/drawable/ic_school_black_24dp.xml
index f8d18b2..7b73270 100644
--- a/app/src/main/res/drawable/ic_school_black_24dp.xml
+++ b/app/src/main/res/drawable/ic_school_black_24dp.xml
@@ -5,6 +5,6 @@
     android:viewportWidth="24.0"
     android:viewportHeight="24.0">
     <path
-        android:fillColor="#FF000000"
+        android:fillColor="?attr/standardVectorGraphic"
         android:pathData="M5,13.18v4L12,21l7,-3.82v-4L12,17l-7,-3.82zM12,3L1,9l11,6 9,-4.91V17h2V9L12,3z"/>
 </vector>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/ic_star_black_48dp.xml b/app/src/main/res/drawable/ic_star_black_48dp.xml
index 2e05e5a..810c836 100644
--- a/app/src/main/res/drawable/ic_star_black_48dp.xml
+++ b/app/src/main/res/drawable/ic_star_black_48dp.xml
@@ -4,7 +4,7 @@
     android:viewportWidth="72"
     android:viewportHeight="72">
     <path
-        android:fillColor="#000"
+        android:fillColor="?attr/standardVectorGraphic"
         android:name="Color Fill 1"
         android:pathData="m36 8 8 18 21 2 -16 14 5 20 -18 -10 -18 10 5 -20 -16 -14 21 -2 8 -18z" />
 </vector>
diff --git a/app/src/main/res/drawable/ic_star_blue_36dp.xml b/app/src/main/res/drawable/ic_star_blue_36dp.xml
index bfe4ce8..06703cd 100644
--- a/app/src/main/res/drawable/ic_star_blue_36dp.xml
+++ b/app/src/main/res/drawable/ic_star_blue_36dp.xml
@@ -4,7 +4,7 @@
     android:viewportWidth="54"
     android:viewportHeight="54">
     <path
-        android:fillColor="#0274b2"
+        android:fillColor="?attr/rankingStarSelected"
         android:name="Color Fill 1"
         android:pathData="m27 7 6 13 15 1 -11 10 3 15 -13 -7 -13 7 3 -15 -11 -10 15 -1 6 -13z" />
 </vector>
diff --git a/app/src/main/res/drawable/ic_star_grey_36dp.xml b/app/src/main/res/drawable/ic_star_grey_36dp.xml
index 669fdd5..456adf1 100644
--- a/app/src/main/res/drawable/ic_star_grey_36dp.xml
+++ b/app/src/main/res/drawable/ic_star_grey_36dp.xml
@@ -4,7 +4,7 @@
     android:viewportWidth="54"
     android:viewportHeight="54">
     <path
-        android:fillColor="#aaa"
+        android:fillColor="?attr/rankingStarNotSelected"
         android:name="Color Fill 1"
         android:pathData="m27 39 13 7 -3 -15 11 -10 -15 -1 -6 -13 -6 13 -15 1 11 10 -3 15 13 -7z" />
 </vector>
diff --git a/app/src/main/res/drawable/ic_star_half_black_48dp.xml b/app/src/main/res/drawable/ic_star_half_black_48dp.xml
index ec694fb..1a29044 100644
--- a/app/src/main/res/drawable/ic_star_half_black_48dp.xml
+++ b/app/src/main/res/drawable/ic_star_half_black_48dp.xml
@@ -4,7 +4,7 @@
     android:viewportWidth="72"
     android:viewportHeight="72">
     <path
-        android:fillColor="#000"
+        android:fillColor="?attr/standardVectorGraphic"
         android:name="Color Fill 1"
         android:pathData="m36 53v-43l-8 18l-21 1l16 15l-5 20l18 -11z" />
 </vector>
diff --git a/app/src/main/res/drawable/ic_trophy_award_black_48dp.xml b/app/src/main/res/drawable/ic_trophy_award_black_48dp.xml
index 74a9a54..8dfe2b4 100644
--- a/app/src/main/res/drawable/ic_trophy_award_black_48dp.xml
+++ b/app/src/main/res/drawable/ic_trophy_award_black_48dp.xml
@@ -4,7 +4,7 @@
     android:viewportWidth="192"
     android:viewportHeight="192">
     <path
-        android:fillColor="#000"
+        android:fillColor="?attr/standardVectorGraphic"
         android:name="Color Fill 1"
         android:pathData="m96 18 -15 38 -42 3 32 27 -11 41 36 -29 36 29 -11 -41 32 -27 -42 -3 -15 -38zm0 103 -8 7v25h-11l-3 1l-2 1l-2 1l-1 1l-1 1l-1 1l-1 2l-1 2l-1 4v10h64v-10l-1 -4l-1 -2l-1 -2l-1 -1l-1 -1l-1 -1l-2 -1l-2 -1l-3 -1h-11v-25l-8 -7z" />
 </vector>
diff --git a/app/src/main/res/drawable/ic_trophy_black_48dp.xml b/app/src/main/res/drawable/ic_trophy_black_48dp.xml
index a9ae9d0..844b657 100644
--- a/app/src/main/res/drawable/ic_trophy_black_48dp.xml
+++ b/app/src/main/res/drawable/ic_trophy_black_48dp.xml
@@ -4,7 +4,7 @@
     android:viewportWidth="192"
     android:viewportHeight="192">
     <path
-        android:fillColor="#000"
+        android:fillColor="?attr/standardVectorGraphic"
         android:name="Shape 1"
         android:pathData="m48 32v56h-16v-56zm112 0v56h-16v-56zm-144 -16c0 0 0 1.52 0 4.13c0 15.29 0 67.88 0 67.88c0.06 0.25 0.13 0.25 0.13 0.25c0 7.53 8.9 13.72 14.75 15.45c0.1 0.03 0.2 0.06 0.3 0.09c0.11 0.03 0.22 0.06 0.32 0.08l0.5 0.12l18.22 0.02c0.01 0.07 0.02 0.14 0.03 0.21c2.48 19.1 19.25 29.53 37.76 31.8c0 4.69 0 15.96 0 16.91h-0c-12.93 2.24 -24 9.94 -24 23.06h64c-0 -13.22 -11.07 -20.9 -24 -23.09h-0v-16.92c0.05 -0.01 0.1 -0.01 0.14 -0.02c18.93 -2.45 35.9 -13.31 37.45 -32.03c0.01 -0.08 3.5 -0.1 7.48 -0.1c5.28 0 11.42 0.04 11.42 0.04c0.11 -0.03 0.21 -0.05 0.32 -0.08c5.84 -1.6 15.05 -7.88 15.05 -15.54l0.13 0.75c0 0 0 -63.25 0 -72c0 -0.65 0 -1 0 -1l-32.5 0.13c-0.11 0.03 -0.21 0.05 -0.32 0.08c-0.12 0.03 -0.25 0.07 -0.37 0.11c-5.85 1.76 -14.68 7.93 -14.68 15.43h-64.25c0 -7.66 -9.21 -13.94 -15.05 -15.54c-0.11 -0.03 -0.22 -0.06 -0.32 -0.08l-32.5 -0.13z" />
 </vector>
diff --git a/app/src/main/res/drawable/ic_undo_black_48dp.xml b/app/src/main/res/drawable/ic_undo_black_48dp.xml
index 43df107..cd95195 100644
--- a/app/src/main/res/drawable/ic_undo_black_48dp.xml
+++ b/app/src/main/res/drawable/ic_undo_black_48dp.xml
@@ -5,6 +5,6 @@
     android:viewportHeight="192">
   <path
       android:pathData="M16,91.8l0,36.2 36.2,-0 36.3,-0 -14.4,-14.4 -14.3,-14.3 3.3,-2.6c5.2,-3.9 14.9,-8.4 22,-10.2 4.8,-1.3 9.2,-1.6 17.9,-1.3 9.9,0.4 12.6,0.9 19.5,3.6 14.8,5.9 27.7,17.9 34.6,32.3 1.8,3.8 3.8,6.9 4.4,6.9 0.6,-0 4.9,-1.3 9.5,-2.9 10.1,-3.4 10.1,-3.4 3.9,-15.7 -10.7,-21.5 -31.5,-37.8 -55.4,-43.5 -7.6,-1.8 -11.1,-2 -23,-1.7 -11.8,0.4 -15.2,0.9 -21.8,3.2 -10,3.4 -17.8,7.3 -24.7,12.5l-5.5,4.1 -14.2,-14.2 -14.3,-14.3 0,36.3z"
-      android:fillColor="#000000"
-      android:strokeColor="#00000000"/>
+      android:fillColor="?attr/standardVectorGraphic"
+      android:strokeColor="?attr/standardVectorGraphic"/>
 </vector>
diff --git a/app/src/main/res/drawable/inactive_button.xml b/app/src/main/res/drawable/inactive_button.xml
index 523ab80..959e81a 100644
--- a/app/src/main/res/drawable/inactive_button.xml
+++ b/app/src/main/res/drawable/inactive_button.xml
@@ -4,7 +4,7 @@
 <item>
     <shape >
         <solid
-            android:color="@color/middlegrey" />
+            android:color="?attr/inactiveButtonColor" />
         <corners android:radius="6dp" />
     </shape>
 </item>
diff --git a/app/src/main/res/drawable/mnenomic_numpad_button.xml b/app/src/main/res/drawable/mnenomic_numpad_button.xml
index 12c4d14..af4c22e 100644
--- a/app/src/main/res/drawable/mnenomic_numpad_button.xml
+++ b/app/src/main/res/drawable/mnenomic_numpad_button.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
     <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
-        <gradient android:endColor="@color/lightblue" android:startColor="@color/lightblue" />
+        <gradient android:endColor="?attr/activeButtonColor" android:startColor="?attr/activeButtonColor" />
         <corners android:radius="6dp" />
     </shape>
diff --git a/app/src/main/res/drawable/numpad_highlighted.xml b/app/src/main/res/drawable/numpad_highlighted.xml
index 7af2c1a..2c00338 100644
--- a/app/src/main/res/drawable/numpad_highlighted.xml
+++ b/app/src/main/res/drawable/numpad_highlighted.xml
@@ -2,10 +2,10 @@
 <shape xmlns:android="http://schemas.android.com/apk/res/android"
     android:shape="rectangle">
     <gradient
-        android:endColor="@color/lightblue"
-        android:startColor="@color/lightblue" />
+        android:endColor="?attr/activeButtonColor"
+        android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
         android:width="10px"
-        android:color="@color/colorPrimaryDark" />
+        android:color="?attr/colorPrimaryDark" />
 </shape>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/numpad_highlighted_four.xml b/app/src/main/res/drawable/numpad_highlighted_four.xml
index 8b8e766..87ce8d9 100644
--- a/app/src/main/res/drawable/numpad_highlighted_four.xml
+++ b/app/src/main/res/drawable/numpad_highlighted_four.xml
@@ -2,10 +2,10 @@
 <shape xmlns:android="http://schemas.android.com/apk/res/android"
     android:shape="rectangle">
     <gradient
-        android:endColor="@color/lightblue"
-        android:startColor="@color/lightblue" />
+        android:endColor="?attr/activeButtonColor"
+        android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
         android:width="10px"
-        android:color="@color/black" />
+        android:color="?attr/standardVectorGraphic" />
 </shape>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/numpad_highlighted_three.xml b/app/src/main/res/drawable/numpad_highlighted_three.xml
index fe0f0cf..05aa808 100644
--- a/app/src/main/res/drawable/numpad_highlighted_three.xml
+++ b/app/src/main/res/drawable/numpad_highlighted_three.xml
@@ -2,10 +2,10 @@
 <shape xmlns:android="http://schemas.android.com/apk/res/android"
     android:shape="rectangle">
     <gradient
-        android:endColor="@color/lightblue"
-        android:startColor="@color/lightblue" />
+        android:endColor="?attr/activeButtonColor"
+        android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
         android:width="10px"
-        android:color="@color/yellow" />
+        android:color="?attr/highlightedButtonBorder" />
 </shape>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/splash_screen.xml b/app/src/main/res/drawable/splash_screen.xml
index cfb80f8..0088edb 100644
--- a/app/src/main/res/drawable/splash_screen.xml
+++ b/app/src/main/res/drawable/splash_screen.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <layer-list xmlns:android="http://schemas.android.com/apk/res/android">
     <item
-        android:drawable="@color/colorAccent"/>
+        android:drawable="?attr/colorAccent"/>
 
     <item>
         <bitmap xmlns:android="http://schemas.android.com/apk/res/android"
diff --git a/app/src/main/res/drawable/standalone_button.xml b/app/src/main/res/drawable/standalone_button.xml
index 8f125d3..f2d80f6 100644
--- a/app/src/main/res/drawable/standalone_button.xml
+++ b/app/src/main/res/drawable/standalone_button.xml
@@ -4,7 +4,7 @@
     <item>
         <shape >
             <solid
-                android:color="@color/colorPrimary" />
+                android:color="?attr/colorPrimary" />
             <corners android:radius="6dp" />
         </shape>
     </item>
diff --git a/app/src/main/res/values/attrs.xml b/app/src/main/res/values/attrs.xml
index 6dbe1d6..944bb90 100644
--- a/app/src/main/res/values/attrs.xml
+++ b/app/src/main/res/values/attrs.xml
@@ -6,5 +6,10 @@
         <attr name="standardVectorGraphic" format="color"/>
         <attr name="winScreenPedestalColor" format="color"/>
         <attr name="backgroundSurroundingDialog" format="color"/>
+        <attr name="rankingStarSelected" format="color"/>
+        <attr name="rankingStarNotSelected" format="color"/>
+        <attr name="inactiveButtonColor" format="color"/>
+        <attr name="activeButtonColor" format="color"/>
+        <attr name="highlightedButtonBorder" format="color"/>
     </declare-styleable>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
index d5042f9..327f1b0 100644
--- a/app/src/main/res/values/styles.xml
+++ b/app/src/main/res/values/styles.xml
@@ -11,6 +11,11 @@
         <item name="standardVectorGraphic">@color/black</item>
         <item name="winScreenPedestalColor">@color/middleblue</item>
         <item name="backgroundSurroundingDialog">@color/transparent</item>
+        <item name="rankingStarSelected">@color/lightblue</item>
+        <item name="rankingStarNotSelected">@color/middlegrey</item>
+        <item name="activeButtonColor">@color/lightblue</item>
+        <item name="inactiveButtonColor">@color/middlegrey</item>
+        <item name="highlightedButtonBorder">@color/yellow</item>
         <item name="actionBarTheme">@style/ToolbarStyle</item>
     </style>