Added new kb article for customizing the Menu styles (#2252)

* docs(Menu): add kb for menu with custom styles

* docs(Menu): apply suggestion

* kb(menu): improve article and remove some typos

---------

Co-authored-by: Tsvetomir Hristov <106250052+Tsvetomir-Hr@users.noreply.github.com>
Co-authored-by: Hristian Stefanov <Hristian.Stefanov@progress.com>

Author: 3 people

knowledge-base/menu-custom-styling.md

@@ -0,0 +1,119 @@
+---
+title: How to Customize the Default Menu Styles - Fonts and Background Colors
+description: Learn how to change the font color, weight, and background colors of the Menu component in a Telerik Blazor application to improve UI contrast.
+type: how-to
+page_title: How to Customize the Default Menu Styles - Fonts and Background Colors
+slug: menu-kb-custom-styling
+tags: menu, styling
+res_type: kb
+ticketid: 1657882, 1543208
+---
+
+## Environment
+
+<table>
+    <tbody>
+        <tr>
+            <td>Product</td>
+            <td>Menu for Blazor</td>
+        </tr>
+    </tbody>
+</table>
+
+## Description
+
+This KB article answers the following questions:
+- How do I change the font color and weight of the top-level menu items in a Blazor application?
+- How can I customize the background color of dropdown menus in a Blazor application?
+- What CSS selectors are needed to style the Telerik Menu in Blazor?
+
+## Solution
+
+To customize the appearance of the Menu items: 
+
+1. Override the default theme styles. 
+2. Use a custom CSS to change the font color and weight of the root menu items. 
+3. Customize the background and font colors of the child menu items.
+
+>caption Menu component with custom CSS styles
+
+````CSHTML
+<style>
+    /* root menu item default state */
+    .custom-menu-styles.k-menu > .k-item {
+        color: #fff;
+        font-weight: bold;
+    }
+
+        /* root menu item hover state */
+        .custom-menu-styles.k-menu > .k-item:hover {
+            background: #fff;
+            color: #000;
+        }
+
+    /* child menu item default state */
+    .k-menu-group .k-item {
+        background: #ff9;
+    }
+
+        /* child menu item hover state */
+        .k-menu-group .k-item:hover {
+            background: #ff3;
+        }
+</style>
+
+<div style="background: orange; padding:1em; width: 60%">
+    <TelerikMenu Data="@Data" Class="custom-menu-styles"></TelerikMenu>
+</div>
+
+@code {
+    public List<Product> Data { get; set; }
+
+    protected override void OnInitialized()
+    {
+        Data = new List<Product>();
+
+        string[] mainMenuItems = { "Home", "About Us", "Services" };
+        string[][] subMenuItems = {
+        new string[] { "Overview", "News", "Updates" },
+        new string[] { "Company", "Team", "Careers" },
+        new string[] { "Consulting", "Support", "Development" }
+    };
+
+        int idCounter = 1;
+
+        for (int i = 0; i < mainMenuItems.Length; i++)
+        {
+            var mainProduct = new Product
+                {
+                    ID = idCounter++,
+                    Text = mainMenuItems[i],
+                    Items = new List<Product>()
+                };
+
+            foreach (var subItem in subMenuItems[i])
+            {
+                mainProduct.Items.Add(new Product
+                    {
+                        ID = idCounter++,
+                        Text = subItem
+                    });
+            }
+
+            Data.Add(mainProduct);
+        }
+    }
+
+    public class Product
+    {
+        public int ID { get; set; }
+        public string Text { get; set; }
+        public List<Product> Items { get; set; }
+    }
+}
+````
+
+## See Also
+
+- [Telerik Blazor Menu - Overview]({%slug components/menu/overview%})
+- [Telerik Blazor Styling and Themes - Override Theme Styles]({%slug themes-override%})