diff --git a/.editorconfig b/.editorconfig
index 60b15f5..767f78c 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -49,8 +49,10 @@ csharp_style_expression_bodied_local_functions = true:refactoring
 dotnet_style_readonly_field = true:suggestion
 dotnet_code_quality_unused_parameters = non_public:suggestion
 
+csharp_style_namespace_declarations = file_scoped:warning
+
 # Naming: PascalCase for constants
-dotnet_naming_rule.constant_fields_should_be_pascal_case.severity = suggestion
+dotnet_naming_rule.constant_fields_should_be_pascal_case.severity = warning
 dotnet_naming_rule.constant_fields_should_be_pascal_case.symbols = constant_fields
 dotnet_naming_rule.constant_fields_should_be_pascal_case.style = pascal_case_style
 dotnet_naming_symbols.constant_fields.applicable_kinds = field
diff --git a/JsonApiToolkit/Extensions/ServiceCollectionExtensions.cs b/JsonApiToolkit/Extensions/ServiceCollectionExtensions.cs
index 38e3141..c237f09 100644
--- a/JsonApiToolkit/Extensions/ServiceCollectionExtensions.cs
+++ b/JsonApiToolkit/Extensions/ServiceCollectionExtensions.cs
@@ -10,83 +10,82 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 
-namespace JsonApiToolkit.Extensions
+namespace JsonApiToolkit.Extensions;
+
+/// <summary>
+/// Extension methods for registering JsonApiToolkit services.
+/// </summary>
+public static class ServiceCollectionExtensions
 {
     /// <summary>
-    /// Extension methods for registering JsonApiToolkit services.
+    /// Registers JsonApiToolkit services with default options.
+    /// </summary>
+    public static IServiceCollection AddJsonApiToolkit(this IServiceCollection services) =>
+        AddJsonApiToolkit(services, _ => { });
+
+    /// <summary>
+    /// Registers JsonApiToolkit services with custom options configuration.
     /// </summary>
-    public static class ServiceCollectionExtensions
+    /// <param name="services">The service collection.</param>
+    /// <param name="configure">Action to configure JsonApiOptions.</param>
+    public static IServiceCollection AddJsonApiToolkit(
+        this IServiceCollection services,
+        Action<JsonApiOptions> configure
+    )
     {
-        /// <summary>
-        /// Registers JsonApiToolkit services with default options.
-        /// </summary>
-        public static IServiceCollection AddJsonApiToolkit(this IServiceCollection services) =>
-            AddJsonApiToolkit(services, _ => { });
+        // Register options
+        services.Configure(configure);
+        // Configure JSON serialization options
+        services.Configure<JsonOptions>(options =>
+        {
+            options.JsonSerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
+            options.JsonSerializerOptions.DefaultIgnoreCondition =
+                JsonIgnoreCondition.WhenWritingNull;
+            options.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;
+        });
 
-        /// <summary>
-        /// Registers JsonApiToolkit services with custom options configuration.
-        /// </summary>
-        /// <param name="services">The service collection.</param>
-        /// <param name="configure">Action to configure JsonApiOptions.</param>
-        public static IServiceCollection AddJsonApiToolkit(
-            this IServiceCollection services,
-            Action<JsonApiOptions> configure
-        )
+        // Configure MVC formatters and filters
+        services.Configure<MvcOptions>(options =>
         {
-            // Register options
-            services.Configure(configure);
-            // Configure JSON serialization options
-            services.Configure<JsonOptions>(options =>
-            {
-                options.JsonSerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
-                options.JsonSerializerOptions.DefaultIgnoreCondition =
-                    JsonIgnoreCondition.WhenWritingNull;
-                options.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;
-            });
+            SystemTextJsonOutputFormatter? jsonOutputFormatter = options
+                .OutputFormatters.OfType<SystemTextJsonOutputFormatter>()
+                .FirstOrDefault();
 
-            // Configure MVC formatters and filters
-            services.Configure<MvcOptions>(options =>
+            if (
+                jsonOutputFormatter?.SupportedMediaTypes.Contains("application/vnd.api+json")
+                == false
+            )
             {
-                SystemTextJsonOutputFormatter? jsonOutputFormatter = options
-                    .OutputFormatters.OfType<SystemTextJsonOutputFormatter>()
-                    .FirstOrDefault();
+                jsonOutputFormatter.SupportedMediaTypes.Add("application/vnd.api+json");
+            }
 
-                if (
-                    jsonOutputFormatter?.SupportedMediaTypes.Contains("application/vnd.api+json")
-                    == false
-                )
-                {
-                    jsonOutputFormatter.SupportedMediaTypes.Add("application/vnd.api+json");
-                }
+            SystemTextJsonInputFormatter? jsonInputFormatter = options
+                .InputFormatters.OfType<SystemTextJsonInputFormatter>()
+                .FirstOrDefault();
 
-                SystemTextJsonInputFormatter? jsonInputFormatter = options
-                    .InputFormatters.OfType<SystemTextJsonInputFormatter>()
-                    .FirstOrDefault();
-
-                if (
-                    jsonInputFormatter?.SupportedMediaTypes.Contains("application/vnd.api+json")
-                    == false
-                )
-                {
-                    jsonInputFormatter.SupportedMediaTypes.Add("application/vnd.api+json");
-                }
+            if (
+                jsonInputFormatter?.SupportedMediaTypes.Contains("application/vnd.api+json")
+                == false
+            )
+            {
+                jsonInputFormatter.SupportedMediaTypes.Add("application/vnd.api+json");
+            }
 
-                options.Filters.AddService<JsonApiContentTypeFilter>();
-            });
+            options.Filters.AddService<JsonApiContentTypeFilter>();
+        });
 
-            // Register filters
-            services.AddScoped<JsonApiExceptionFilter>();
-            services.AddScoped<JsonApiContentTypeFilter>();
+        // Register filters
+        services.AddScoped<JsonApiExceptionFilter>();
+        services.AddScoped<JsonApiContentTypeFilter>();
 
-            // Register query parser service
-            services.AddScoped<IJsonApiQueryParser, JsonApiQueryParserService>();
+        // Register query parser service
+        services.AddScoped<IJsonApiQueryParser, JsonApiQueryParserService>();
 
-            // Register include pattern validator for startup validation
-            services.TryAddEnumerable(
-                ServiceDescriptor.Transient<IApplicationModelProvider, IncludePatternValidator>()
-            );
+        // Register include pattern validator for startup validation
+        services.TryAddEnumerable(
+            ServiceDescriptor.Transient<IApplicationModelProvider, IncludePatternValidator>()
+        );
 
-            return services;
-        }
+        return services;
     }
 }
diff --git a/JsonApiToolkit/Filters/JsonApiContentTypeFilter.cs b/JsonApiToolkit/Filters/JsonApiContentTypeFilter.cs
index 0e7afe2..3866cd5 100644
--- a/JsonApiToolkit/Filters/JsonApiContentTypeFilter.cs
+++ b/JsonApiToolkit/Filters/JsonApiContentTypeFilter.cs
@@ -8,7 +8,7 @@ namespace JsonApiToolkit.Filters;
 /// </summary>
 public class JsonApiContentTypeFilter : IActionFilter
 {
-    private const string s_jsonApiMediaType = "application/vnd.api+json";
+    private const string JsonApiMediaType = "application/vnd.api+json";
 
     /// <summary>
     /// Called before the action executes.
@@ -23,11 +23,11 @@ public void OnActionExecuted(ActionExecutedContext context)
         if (context.Result is ObjectResult objectResult)
         {
             objectResult.ContentTypes.Clear();
-            objectResult.ContentTypes.Add(s_jsonApiMediaType);
+            objectResult.ContentTypes.Add(JsonApiMediaType);
         }
         else if (context.Result is StatusCodeResult)
         {
-            context.HttpContext.Response.ContentType = s_jsonApiMediaType;
+            context.HttpContext.Response.ContentType = JsonApiMediaType;
         }
     }
 }
diff --git a/JsonApiToolkit/Parsing/JsonApiQueryParser.cs b/JsonApiToolkit/Parsing/JsonApiQueryParser.cs
index d169b41..21351ca 100644
--- a/JsonApiToolkit/Parsing/JsonApiQueryParser.cs
+++ b/JsonApiToolkit/Parsing/JsonApiQueryParser.cs
@@ -13,7 +13,7 @@ namespace JsonApiToolkit.Parsing;
 /// </summary>
 public static class JsonApiQueryParser
 {
-    private const int MIN_PAGE_SIZE = 1;
+    private const int MinPageSize = 1;
 
     /// <summary>
     /// Minimum length for a valid filter key: "filter[x]" = 9 characters.
@@ -97,7 +97,7 @@ public static QueryParameters Parse(
                     hasPageNumber && int.TryParse(pageNumber, out int num) ? Math.Max(1, num) : 1, // Default to page 1 if not specified or invalid
                 Size =
                     hasPageSize && int.TryParse(pageSize, out int size)
-                        ? Math.Clamp(size, MIN_PAGE_SIZE, options.MaxPageSize)
+                        ? Math.Clamp(size, MinPageSize, options.MaxPageSize)
                         : options.DefaultPageSize, // Use configured defaults
             };
         }