diff --git a/Backends/RmlUi_Backend_GLFW_VK.cpp b/Backends/RmlUi_Backend_GLFW_VK.cpp
index c1cf80f..7d45299 100644
--- a/Backends/RmlUi_Backend_GLFW_VK.cpp
+++ b/Backends/RmlUi_Backend_GLFW_VK.cpp
@@ -35,7 +35,7 @@
 #include <RmlUi/Core/Core.h>
 #include <RmlUi/Core/FileInterface.h>
 #include <GLFW/glfw3.h>
-#include <cstdint>
+#include <stdint.h>
 #include <thread>
 
 static void SetupCallbacks(GLFWwindow* window);
diff --git a/Include/RmlUi/Core/Types.h b/Include/RmlUi/Core/Types.h
index 28e5ad7..39a5e8a 100644
--- a/Include/RmlUi/Core/Types.h
+++ b/Include/RmlUi/Core/Types.h
@@ -32,6 +32,7 @@
 #include "../Config/Config.h"
 
 #include <cstdlib>
+#include <stdint.h>
 #include <memory>
 
 #include "Traits.h"
diff --git a/Samples/basic/bitmapfont/src/FontEngineBitmap.cpp b/Samples/basic/bitmapfont/src/FontEngineBitmap.cpp
index bcc6f13..da487b0 100644
--- a/Samples/basic/bitmapfont/src/FontEngineBitmap.cpp
+++ b/Samples/basic/bitmapfont/src/FontEngineBitmap.cpp
@@ -219,7 +219,7 @@ int FontFaceBitmap::GenerateString(const String& string, const Vector2f& string_
 
 int FontFaceBitmap::GetKerning(Character left, Character right) const
 {
-	std::uint64_t key = (((std::uint64_t)left << 32) | (std::uint64_t)right);
+	uint64_t key = (((uint64_t)left << 32) | (uint64_t)right);
 
 	auto it = kerning.find(key);
 	if (it != kerning.end())
@@ -291,13 +291,13 @@ void FontParserBitmap::HandleElementStart(const String& name, const Rml::XMLAttr
 	}
 	else if (name == "kerning")
 	{
-		std::uint64_t first = (std::uint64_t)Get(attributes, "first", 0);
-		std::uint64_t second = (std::uint64_t)Get(attributes, "second", 0);
+		uint64_t first = (uint64_t)Get(attributes, "first", 0);
+		uint64_t second = (uint64_t)Get(attributes, "second", 0);
 		int amount = Get(attributes, "amount", 0);
 
 		if (first != 0 && second != 0 && amount != 0)
 		{
-			std::uint64_t key = ((first << 32) | second);
+			uint64_t key = ((first << 32) | second);
 			kerning[key] = amount;
 		}
 	}
diff --git a/Samples/basic/bitmapfont/src/FontEngineBitmap.h b/Samples/basic/bitmapfont/src/FontEngineBitmap.h
index f9fef43..41256c9 100644
--- a/Samples/basic/bitmapfont/src/FontEngineBitmap.h
+++ b/Samples/basic/bitmapfont/src/FontEngineBitmap.h
@@ -29,7 +29,6 @@
 #ifndef FONTENGINEBITMAP_H
 #define FONTENGINEBITMAP_H
 
-#include <cstdint>
 #include <RmlUi/Core/Types.h>
 #include "FontEngineInterfaceBitmap.h"
 
@@ -63,7 +62,7 @@ struct FontMetrics {
 using FontGlyphs = Rml::UnorderedMap<Character, BitmapGlyph>;
 
 // Mapping of combined (left, right) character to kerning in pixels.
-using FontKerning = Rml::UnorderedMap<std::uint64_t, int>;
+using FontKerning = Rml::UnorderedMap<uint64_t, int>;
 
 
 class FontFaceBitmap {
diff --git a/Source/Core/ElementStyle.h b/Source/Core/ElementStyle.h
index a89eb7e..8f62fb7 100644
--- a/Source/Core/ElementStyle.h
+++ b/Source/Core/ElementStyle.h
@@ -40,7 +40,7 @@ class ElementDefinition;
 class PropertiesIterator;
 enum class RelativeTarget;
 
-enum class PseudoClassState : std::uint8_t { Clear = 0, Set = 1, Override = 2 };
+enum class PseudoClassState : uint8_t { Clear = 0, Set = 1, Override = 2 };
 using PseudoClassMap = SmallUnorderedMap< String, PseudoClassState >;
 
 
diff --git a/Source/Core/FontEngineDefault/FontFaceHandleDefault.h b/Source/Core/FontEngineDefault/FontFaceHandleDefault.h
index 4e6c4d7..5e92d7b 100644
--- a/Source/Core/FontEngineDefault/FontFaceHandleDefault.h
+++ b/Source/Core/FontEngineDefault/FontFaceHandleDefault.h
@@ -143,8 +143,8 @@ private:
 	FontLayerCache layer_cache;
 
 	// Pre-cache kerning pairs for some ascii subset of all characters.
-	using AsciiPair = std::uint16_t;
-	using KerningIntType = std::int16_t;
+	using AsciiPair = uint16_t;
+	using KerningIntType = int16_t;
 	using KerningPairs = UnorderedMap< AsciiPair, KerningIntType >;
 	KerningPairs kerning_pair_cache;
 
diff --git a/Source/Core/LayoutFlex.cpp b/Source/Core/LayoutFlex.cpp
index b51aa93..074376d 100644
--- a/Source/Core/LayoutFlex.cpp
+++ b/Source/Core/LayoutFlex.cpp
@@ -110,7 +110,7 @@ struct FlexItem {
 	float hypothetical_main_size; // Outer size
 
 	// Used for resolving flexible length
-	enum class Violation : std::uint8_t { None = 0, Min, Max };
+	enum class Violation : uint8_t { None = 0, Min, Max };
 	bool frozen;
 	Violation violation;
 	float target_main_size; // Outer size
diff --git a/Source/Lottie/ElementLottie.cpp b/Source/Lottie/ElementLottie.cpp
index 91f4a0e..b5e36a4 100644
--- a/Source/Lottie/ElementLottie.cpp
+++ b/Source/Lottie/ElementLottie.cpp
@@ -228,7 +228,7 @@ void ElementLottie::UpdateTexture()
 
 		byte* p_data = new byte[total_bytes];
 
-		rlottie::Surface surface(reinterpret_cast<std::uint32_t*>(p_data), render_dimensions.x, render_dimensions.y, bytes_per_line);
+		rlottie::Surface surface(reinterpret_cast<uint32_t*>(p_data), render_dimensions.x, render_dimensions.y, bytes_per_line);
 		animation->renderSync(next_frame, surface);
 
 		// Swizzle the channel order from rlottie's BGRA to RmlUi's RGBA, and change pre-multiplied to post-multiplied alpha.