diff --git a/docs/docset.yml b/docs/docset.yml
index 635e68457..b7bb07219 100644
--- a/docs/docset.yml
+++ b/docs/docset.yml
@@ -117,6 +117,7 @@ toc:
       - file: req.md
       - folder: nested
       - file: cross-links.md
+      - file: custom-highlighters.md
       - folder: mover
         children:
           - file: first-page.md
diff --git a/docs/testing/custom-highlighters.md b/docs/testing/custom-highlighters.md
new file mode 100644
index 000000000..cde141e91
--- /dev/null
+++ b/docs/testing/custom-highlighters.md
@@ -0,0 +1,71 @@
+# Additional syntax highlighters
+
+
+## Console / REST API documentation
+
+::::{tab-set}
+
+:::{tab-item} Output
+
+```console
+GET /mydocuments/_search
+{
+    "from": 1,
+    "query": {
+        "match_all" {}
+    }
+}
+```
+
+:::
+
+:::{tab-item} Markdown
+
+````markdown
+```console
+GET /mydocuments/_search
+{
+    "from": 1,
+    "query": {
+        "match_all" {}
+    }
+}
+```
+````
+
+## EQL
+
+sequence
+```eql
+sequence
+  [ file where file.extension == "exe" ]
+  [ process where true ]
+```
+
+sequence until
+
+```eql
+sequence by ID
+  A
+  B
+until C
+```
+sample
+
+```eql
+sample by host
+  [ file where file.extension == "exe" ]
+  [ process where true ]
+```
+head (pipes)
+```eql
+process where process.name == "svchost.exe"
+| tail 5
+```
+function calls
+
+```eql
+modulo(10, 6)
+modulo(10, 5)
+modulo(10, 0.5)
+```
\ No newline at end of file
diff --git a/src/Elastic.Markdown/Assets/hljs.ts b/src/Elastic.Markdown/Assets/hljs.ts
index 7e4c9c4da..f00895a79 100644
--- a/src/Elastic.Markdown/Assets/hljs.ts
+++ b/src/Elastic.Markdown/Assets/hljs.ts
@@ -14,8 +14,63 @@ hljs.registerLanguage('apiheader', function() {
 		],		}
 })
 
-hljs.addPlugin(mergeHTMLPlugin);
+// https://tc39.es/ecma262/#sec-literals-numeric-literals
+const decimalDigits = '[0-9](_?[0-9])*';
+const frac = `\\.(${decimalDigits})`;
+// DecimalIntegerLiteral, including Annex B NonOctalDecimalIntegerLiteral
+// https://tc39.es/ecma262/#sec-additional-syntax-numeric-literals
+const decimalInteger = `0|[1-9](_?[0-9])*|0[0-7]*[89][0-9]*`;
+const NUMBER = {
+	className: 'number',
+	variants: [
+		// DecimalLiteral
+		{ begin: `(\\b(${decimalInteger})((${frac})|\\.)?|(${frac}))` +
+				`[eE][+-]?(${decimalDigits})\\b` },
+		{ begin: `\\b(${decimalInteger})\\b((${frac})\\b|\\.)?|(${frac})\\b` },
+
+		// DecimalBigIntegerLiteral
+		{ begin: `\\b(0|[1-9](_?[0-9])*)n\\b` },
+
+		// NonDecimalIntegerLiteral
+		{ begin: "\\b0[xX][0-9a-fA-F](_?[0-9a-fA-F])*n?\\b" },
+		{ begin: "\\b0[bB][0-1](_?[0-1])*n?\\b" },
+		{ begin: "\\b0[oO][0-7](_?[0-7])*n?\\b" },
+
+		// LegacyOctalIntegerLiteral (does not include underscore separators)
+		// https://tc39.es/ecma262/#sec-additional-syntax-numeric-literals
+		{ begin: "\\b0[0-7]+n?\\b" },
+	],
+	relevance: 0
+};
 
+
+hljs.registerLanguage('eql', function() {
+	return {
+		case_insensitive: true, // language is case-insensitive
+		keywords: {
+			keyword: 'where sequence sample untill and or not in in~',
+			literal: ['false','true','null'],
+			'subst': 'add between cidrMatch concat divide endsWith indexOf length modulo multiply number startsWith string stringContains substring subtract'
+		},
+		contains: [
+			hljs.QUOTE_STRING_MODE,
+			hljs.C_LINE_COMMENT_MODE,
+			{
+				scope: "operator", // (pathname: path1/path2/dothis) color #ab5656
+				match: /(?:<|<=|==|:|!=|>=|>|like~?|regex~?)/,
+			},
+			{
+				scope: "punctuation", // (pathname: path1/path2/dothis) color #ab5656
+				match: /(?:!?\[|\]|\|)/,
+			},
+			NUMBER,
+
+		]
+	}
+})
+
+hljs.addPlugin(mergeHTMLPlugin);
 export function initHighlight() {
+
 	hljs.highlightAll();
 }
diff --git a/src/Elastic.Markdown/Assets/toc-nav.ts b/src/Elastic.Markdown/Assets/toc-nav.ts
index 20b55fa09..95ee4f238 100644
--- a/src/Elastic.Markdown/Assets/toc-nav.ts
+++ b/src/Elastic.Markdown/Assets/toc-nav.ts
@@ -128,8 +128,10 @@ function setupSmoothScrolling(elements: TocElements) {
 
 export function initTocNav() {
 	const elements = initializeTocElements();
-	elements.progressIndicator.style.height = '0';
-	elements.progressIndicator.style.top = '0';
+	if (elements.progressIndicator != null) {
+		elements.progressIndicator.style.height = '0';
+		elements.progressIndicator.style.top = '0';
+	}
 	const update = () => updateIndicator(elements)
 	update();
 	window.addEventListener('scroll', update);
diff --git a/src/Elastic.Markdown/Myst/CodeBlocks/SupportedLanguages.cs b/src/Elastic.Markdown/Myst/CodeBlocks/SupportedLanguages.cs
index 68d7ca45e..38e3ff95f 100644
--- a/src/Elastic.Markdown/Myst/CodeBlocks/SupportedLanguages.cs
+++ b/src/Elastic.Markdown/Myst/CodeBlocks/SupportedLanguages.cs
@@ -179,6 +179,9 @@ public static class CodeBlock
 		{ "xquery", "xpath, xq, xqm" }, // XQuery
 		{ "yml", "yaml" }, // YAML
 		{ "zephir", "zep" }, // Zephir
+
+		//CUSTOM, Elastic language we wrote highlighters for
+		{ "eql", "" }
 	};
 
 
diff --git a/src/Elastic.Markdown/Slices/Layout/_Scripts.cshtml b/src/Elastic.Markdown/Slices/Layout/_Scripts.cshtml
index a37818726..1d625db25 100644
--- a/src/Elastic.Markdown/Slices/Layout/_Scripts.cshtml
+++ b/src/Elastic.Markdown/Slices/Layout/_Scripts.cshtml
@@ -18,5 +18,4 @@
 <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/languages/go.min.js"></script>
 
 <script src="@Model.Static("hljs.js")"></script>
-<script src="@Model.Static("custom.js")"></script>
 <script src="https://unpkg.com/mermaid@10.2.0/dist/mermaid.min.js"></script>
diff --git a/src/Elastic.Markdown/_static/custom.js b/src/Elastic.Markdown/_static/custom.js
deleted file mode 100644
index 17388341c..000000000
--- a/src/Elastic.Markdown/_static/custom.js
+++ /dev/null
@@ -1,12 +0,0 @@
-hljs.registerLanguage('apiheader', function() {
-  return {
-    case_insensitive: true, // language is case-insensitive
-    keywords: 'GET POST PUT DELETE HEAD OPTIONS PATCH',
-    contains: [
-      hljs.HASH_COMMENT_MODE,
-      {
-        className: "subst", // (pathname: path1/path2/dothis) color #ab5656
-        begin: /(?<=(?:\/|GET |POST |PUT |DELETE |HEAD |OPTIONS |PATH))[^?\n\r\/]+/,
-      }
-    ],		}
-})