diff --git a/src/ColorPair.php b/src/ColorPair.php
index 3800c03..76a0ffb 100644
--- a/src/ColorPair.php
+++ b/src/ColorPair.php
@@ -17,7 +17,7 @@ public function __construct(float $ratio = null, string $color1 = null, string $
 
     /**
      * '000' => '#000000'
-     * '000000' => '#000000'
+     * '000000' => '#000000'.
      */
 //    protected function normalize($color)
 //    {
diff --git a/src/HexColor.php b/src/HexColor.php
index f60ee33..0dd7084 100644
--- a/src/HexColor.php
+++ b/src/HexColor.php
@@ -25,22 +25,22 @@ public static function random(): self
 
     /**
      * '#abc' or 'abc' => '#aabbcc'
-     * '#abcdef' or 'abcdef' => '#abcdef'
+     * '#abcdef' or 'abcdef' => '#abcdef'.
      */
     protected function normalize(string $hexColor)
     {
         // '#abcdef' or 'abcdef'
         if (preg_match('/^\s*#?([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})\s*$/i', $hexColor, $matches)) {
-            return sprintf("#%s%s%s", $matches[1], $matches[2], $matches[3]);
+            return sprintf('#%s%s%s', $matches[1], $matches[2], $matches[3]);
         }
 
         // '#abc' or 'abc'
         if (preg_match('/^\s*#?([0-9a-f])([0-9a-f])([0-9a-f])\s*$/i', $hexColor, $matches)) {
-            return sprintf("#%s%s%s", str_repeat($matches[1], 2), str_repeat($matches[2], 2),
+            return sprintf('#%s%s%s', str_repeat($matches[1], 2), str_repeat($matches[2], 2),
                 str_repeat($matches[3], 2));
         }
 
-        return null; // TODO throw
+        // TODO throw
     }
 
     /**
@@ -48,7 +48,7 @@ protected function normalize(string $hexColor)
      */
     protected static function randomColor()
     {
-        return static::randomColorPart() . static::randomColorPart() . static::randomColorPart();
+        return static::randomColorPart().static::randomColorPart().static::randomColorPart();
     }
 
     protected static function randomColorPart()
diff --git a/src/HexColorPair.php b/src/HexColorPair.php
index ed22be3..dca71ee 100644
--- a/src/HexColorPair.php
+++ b/src/HexColorPair.php
@@ -79,8 +79,8 @@ public function getSibling(string $hexValue): HexColor
 
     protected static function calculateRatio(HexColor $fg = null, HexColor $bg = null)
     {
-        if (!$fg || !$bg) {
-            return null;
+        if (! $fg || ! $bg) {
+            return;
         }
 
         $fgLuminance = static::luminance($fg);
@@ -108,11 +108,11 @@ protected static function luminance(HexColor $color)
         $g = ($gSrgb <= 0.03928) ? $gSrgb / 12.92 : pow((($gSrgb + 0.055) / 1.055), 2.4);
         $b = ($bSrgb <= 0.03928) ? $bSrgb / 12.92 : pow((($bSrgb + 0.055) / 1.055), 2.4);
 
-        return (0.2126 * $r + 0.7152 * $g + 0.0722 * $b);
+        return 0.2126 * $r + 0.7152 * $g + 0.0722 * $b;
     }
 
     /**
-     * '#abcdef' => ['ab', 'cd', 'ef']
+     * '#abcdef' => ['ab', 'cd', 'ef'].
      */
     protected static function rgbHexChannels(HexColor $hexColor): array
     {
diff --git a/src/TailwindColor.php b/src/TailwindColor.php
index b2fbdf9..4cc59b9 100644
--- a/src/TailwindColor.php
+++ b/src/TailwindColor.php
@@ -16,7 +16,7 @@ public function __construct()
     }
 
     /**
-     * Returns all the default Tailwind colors
+     * Returns all the default Tailwind colors.
      */
     public static function colors(): array
     {
@@ -29,7 +29,7 @@ public function getColors(): array
     }
 
     /**
-     * Returns a random Tailwind color
+     * Returns a random Tailwind color.
      */
     public static function random(): HexColor
     {
@@ -69,7 +69,7 @@ public static function merge(array $customPalette): self
     }
 
     /**
-     * Returns a random pair of accessible (min. contrast 3:1) Tailwind colors
+     * Returns a random pair of accessible (min. contrast 3:1) Tailwind colors.
      */
     public static function randomPair(): HexColorPair
     {
@@ -122,6 +122,6 @@ protected function flatten(array $twColorsArr): Collection
 
     protected function parseDefaultTailwindColors()
     {
-        return json_decode(file_get_contents(__DIR__ . '/../stubs/twcolors.json'), true);
+        return json_decode(file_get_contents(__DIR__.'/../stubs/twcolors.json'), true);
     }
 }
diff --git a/tests/HexColorPairTest.php b/tests/HexColorPairTest.php
index 2e196a1..de1de29 100644
--- a/tests/HexColorPairTest.php
+++ b/tests/HexColorPairTest.php
@@ -70,23 +70,23 @@ public function provideContrastData()
     {
         yield 'maximum contrast' => [
             21,
-            ['000', 'fff',],
+            ['000', 'fff'],
         ];
         yield 'no contrast - black on black' => [
             1,
-            ['000', '000',],
+            ['000', '000'],
         ];
         yield 'no contrast - white on white' => [
             1,
-            ['fff', 'fff',],
+            ['fff', 'fff'],
         ];
         yield 'high contrast' => [
             18.4,
-            ['300', 'fff',],
+            ['300', 'fff'],
         ];
         yield 'low contrast' => [
             1.1,
-            ['300', '000',],
+            ['300', '000'],
         ];
     }
 }
diff --git a/tests/HexColorTest.php b/tests/HexColorTest.php
index ca97d5a..d8102f8 100644
--- a/tests/HexColorTest.php
+++ b/tests/HexColorTest.php
@@ -3,7 +3,6 @@
 namespace Breadthe\PhpContrast\Tests;
 
 use Breadthe\PhpContrast\HexColor;
-use Breadthe\PhpContrast\HexColorPair;
 use PHPUnit\Framework\TestCase;
 
 class HexColorTest extends TestCase
diff --git a/tests/TailwindTest.php b/tests/TailwindTest.php
index 7791d6b..49fb480 100644
--- a/tests/TailwindTest.php
+++ b/tests/TailwindTest.php
@@ -6,7 +6,6 @@
 use Breadthe\PhpContrast\HexColorPair;
 use Breadthe\PhpContrast\TailwindColor;
 use PHPUnit\Framework\TestCase;
-use Tightenco\Collect\Support\Collection;
 
 class TailwindTest extends TestCase
 {
@@ -47,7 +46,7 @@ public function it_returns_random_color_pairs_of_minimum_3_to_1_ratio()
     /** @test */
     public function it_can_merge_default_and_custom_colors()
     {
-        $customPalette = json_decode(file_get_contents(__DIR__ . '/../stubs/custom-palette.json'), true);
+        $customPalette = json_decode(file_get_contents(__DIR__.'/../stubs/custom-palette.json'), true);
 
         $colors = TailwindColor::merge($customPalette)->getColors();
         $customPalette = collect($customPalette)