diff --git a/src/Languages/Base/Injections/AdditionInjection.php b/src/Languages/Base/Injections/AdditionInjection.php
index a3496ab..8ef5ba0 100644
--- a/src/Languages/Base/Injections/AdditionInjection.php
+++ b/src/Languages/Base/Injections/AdditionInjection.php
@@ -20,6 +20,8 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
 
         preg_match_all('/(\{\+)((.|\n)*?)(\+})/', $content, $matches, PREG_OFFSET_CAPTURE);
 
+        $parsedOffset = 0;
+
         foreach ($matches[0] as $match) {
             $matchedContent = $match[0];
             $offset = $match[1];
@@ -42,20 +44,22 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
                 $startingLineNumber = substr_count(
                     haystack: $content,
                     needle: PHP_EOL,
-                    length: $offset,
+                    length: $offset + $parsedOffset,
                 ) + 1;
 
                 $totalAmountOfLines = substr_count(
                     haystack: $parsedMatchedContent,
                     needle: PHP_EOL,
-                ) + 1;
+                );
 
-                for ($lineNumber = $startingLineNumber; $lineNumber < $startingLineNumber + $totalAmountOfLines; $lineNumber++) {
+                for ($lineNumber = $startingLineNumber; $lineNumber <= $startingLineNumber + $totalAmountOfLines; $lineNumber++) {
                     $gutter
                         ->addIcon($lineNumber, '+')
                         ->addClass($lineNumber, 'hl-gutter-addition');
                 }
             }
+
+            $parsedOffset += strlen($open) + strlen($close);
         }
 
         return new ParsedInjection($content);
diff --git a/src/Languages/Base/Injections/DeletionInjection.php b/src/Languages/Base/Injections/DeletionInjection.php
index 6b5d20f..355a49f 100644
--- a/src/Languages/Base/Injections/DeletionInjection.php
+++ b/src/Languages/Base/Injections/DeletionInjection.php
@@ -20,6 +20,8 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
 
         preg_match_all('/(\{-)((.|\n)*?)(-})/', $content, $matches, PREG_OFFSET_CAPTURE);
 
+        $parsedOffset = 0;
+
         foreach ($matches[0] as $match) {
             $matchedContent = $match[0];
             $offset = $match[1];
@@ -42,7 +44,7 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
                 $startingLineNumber = substr_count(
                     haystack: $content,
                     needle: PHP_EOL,
-                    length: $offset,
+                    length: $offset + $parsedOffset,
                 ) + 1;
 
                 $totalAmountOfLines = substr_count(
@@ -56,6 +58,8 @@ public function parse(string $content, Highlighter $highlighter): ParsedInjectio
                         ->addClass($lineNumber, 'hl-gutter-deletion');
                 }
             }
+
+            $parsedOffset += strlen($open) + strlen($close);
         }
 
         return new ParsedInjection($content);
diff --git a/src/Languages/Base/Patterns/AdditionEndTokenPattern.php b/src/Languages/Base/Patterns/AdditionEndTokenPattern.php
index 35e4896..5807a49 100644
--- a/src/Languages/Base/Patterns/AdditionEndTokenPattern.php
+++ b/src/Languages/Base/Patterns/AdditionEndTokenPattern.php
@@ -1,11 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tempest\Highlight\Languages\Base\Patterns;
 
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
 use Tempest\Highlight\PatternTest;
-use Tempest\Highlight\Tokens\DynamicTokenType;
 use Tempest\Highlight\Tokens\IgnoreTokenType;
 use Tempest\Highlight\Tokens\TokenType;
 
@@ -23,4 +24,4 @@ public function getTokenType(): TokenType
     {
         return new IgnoreTokenType();
     }
-}
\ No newline at end of file
+}
diff --git a/src/Languages/Base/Patterns/AdditionStartTokenPattern.php b/src/Languages/Base/Patterns/AdditionStartTokenPattern.php
index d31c565..8355b1a 100644
--- a/src/Languages/Base/Patterns/AdditionStartTokenPattern.php
+++ b/src/Languages/Base/Patterns/AdditionStartTokenPattern.php
@@ -1,11 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tempest\Highlight\Languages\Base\Patterns;
 
 use Tempest\Highlight\IsPattern;
 use Tempest\Highlight\Pattern;
 use Tempest\Highlight\PatternTest;
-use Tempest\Highlight\Tokens\DynamicTokenType;
 use Tempest\Highlight\Tokens\IgnoreTokenType;
 use Tempest\Highlight\Tokens\TokenType;
 
@@ -23,4 +24,4 @@ public function getTokenType(): TokenType
     {
         return new IgnoreTokenType();
     }
-}
\ No newline at end of file
+}
diff --git a/src/Languages/Base/Patterns/DeletionEndTokenPattern.php b/src/Languages/Base/Patterns/DeletionEndTokenPattern.php
index 07dc29a..eba69c8 100644
--- a/src/Languages/Base/Patterns/DeletionEndTokenPattern.php
+++ b/src/Languages/Base/Patterns/DeletionEndTokenPattern.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tempest\Highlight\Languages\Base\Patterns;
 
 use Tempest\Highlight\IsPattern;
@@ -22,4 +24,4 @@ public function getTokenType(): TokenType
     {
         return new IgnoreTokenType();
     }
-}
\ No newline at end of file
+}
diff --git a/src/Languages/Base/Patterns/DeletionStartTokenPattern.php b/src/Languages/Base/Patterns/DeletionStartTokenPattern.php
index 4262b21..bc7acfa 100644
--- a/src/Languages/Base/Patterns/DeletionStartTokenPattern.php
+++ b/src/Languages/Base/Patterns/DeletionStartTokenPattern.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tempest\Highlight\Languages\Base\Patterns;
 
 use Tempest\Highlight\IsPattern;
@@ -22,4 +24,4 @@ public function getTokenType(): TokenType
     {
         return new IgnoreTokenType();
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Languages/Base/Injections/GutterInjectionTest.php b/tests/Languages/Base/Injections/GutterInjectionTest.php
index 19010e0..2724790 100644
--- a/tests/Languages/Base/Injections/GutterInjectionTest.php
+++ b/tests/Languages/Base/Injections/GutterInjectionTest.php
@@ -54,6 +54,58 @@ public function test_gutter_injection(): void
         $this->assertSame($expected, $highlighter->parse($input, 'php'));
     }
 
+    public function test_gutter_injection_one_single_line(): void
+    {
+        $input = <<<'TXT'
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+{+ pull_request_target: +}
+other: foo
+TXT;
+
+        $expected = <<<'TXT'
+<span class="hl-gutter ">  10</span> <span class="hl-property">on</span>:
+<span class="hl-gutter ">  11</span>   <span class="hl-property">pull_request</span>:
+<span class="hl-gutter ">  12</span>     <span class="hl-property">types</span>: [opened, synchronize, reopened, ready_for_review]
+<span class="hl-gutter hl-gutter-addition">13 +</span> <span class="hl-addition"> <span class="hl-property">pull_request_target</span>: </span>
+<span class="hl-gutter ">  14</span> <span class="hl-property">other</span>: foo
+TXT;
+
+        $highlighter = (new Highlighter())->withGutter(10);
+
+        $this->assertSame($expected, $highlighter->parse($input, 'php'));
+    }
+
+    public function test_gutter_injection_many_single_lines(): void
+    {
+        $input = <<<'TXT'
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+{+ pull_request_target: +}
+{+   types: [opened, synchronize, reopened, ready_for_review] +}
+{+   types: [opened, synchronize, reopened, ready_for_review] +}
+{+   types: [opened, synchronize, reopened, ready_for_review] +}
+other: foo
+TXT;
+
+        $expected = <<<'TXT'
+<span class="hl-gutter ">  10</span> <span class="hl-property">on</span>:
+<span class="hl-gutter ">  11</span>   <span class="hl-property">pull_request</span>:
+<span class="hl-gutter ">  12</span>     <span class="hl-property">types</span>: [opened, synchronize, reopened, ready_for_review]
+<span class="hl-gutter hl-gutter-addition">13 +</span> <span class="hl-addition"> <span class="hl-property">pull_request_target</span>: </span>
+<span class="hl-gutter hl-gutter-addition">14 +</span> <span class="hl-addition">   <span class="hl-property">types</span>: [opened, synchronize, reopened, ready_for_review] </span>
+<span class="hl-gutter hl-gutter-addition">15 +</span> <span class="hl-addition">   <span class="hl-property">types</span>: [opened, synchronize, reopened, ready_for_review] </span>
+<span class="hl-gutter hl-gutter-addition">16 +</span> <span class="hl-addition">   <span class="hl-property">types</span>: [opened, synchronize, reopened, ready_for_review] </span>
+<span class="hl-gutter ">  17</span> <span class="hl-property">other</span>: foo
+TXT;
+
+        $highlighter = (new Highlighter())->withGutter(10);
+
+        $this->assertSame($expected, $highlighter->parse($input, 'php'));
+    }
+
     public function test_gutter_injection_terminal(): void
     {
         $input = <<<'TXT'
@@ -76,7 +128,7 @@ public function test_gutter_injection_terminal(): void
 TXT;
 
         $expected = <<<'TXT'
-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
 TXT;
 
         $highlighter = (new Highlighter(new LightTerminalTheme()))->withGutter(10);
diff --git a/tests/index.php b/tests/index.php
index 246ecb2..9901430 100644
--- a/tests/index.php
+++ b/tests/index.php
@@ -11,7 +11,6 @@
 use Tempest\Highlight\CommonMark\InlineCodeBlockRenderer;
 use Tempest\Highlight\Highlighter;
 use Tempest\Highlight\Themes\CssTheme;
-use Tempest\Highlight\Themes\InlineTheme;
 
 $environment = new Environment();
 
diff --git a/tests/targets/test.md b/tests/targets/test.md
index 16d519a..16a567b 100644
--- a/tests/targets/test.md
+++ b/tests/targets/test.md
@@ -2,6 +2,9 @@
 on:
   pull_request:
     types: [opened, synchronize, reopened, ready_for_review]
-{- pull_request_target: -}
-{-   types: [opened, synchronize, reopened, ready_for_review] -}
+{+ pull_request_target: +}
+{+   types: [opened, synchronize, reopened, ready_for_review] +}
+{+   types: [opened, synchronize, reopened, ready_for_review] +}
+{+   types: [opened, synchronize, reopened, ready_for_review] +}
+other: foo
 ```
\ No newline at end of file