feat(standard-styling) Enhance search and styling

Improves search bar with SVG icon support for better visual consistency.

Adds utility SCSS file for managing global styles like heading selectors.

Introduces a checkmark SVG asset and reorganizes custom SCSS files following the 7-in-1 structure for better maintainability.

Comments out optional USP bar code in header.tpl to allow easy activation.

falcon/_dev/css/theme/custom/_custom.scss

@@ -1,11 +1,18 @@
-// NOTE: All bootstrap overrides have been configured under themes/falcon/_dev/css/abstracts/variables/bootstrap
+/* 
+This is the main custom SCSS file for the Falcon theme. 
+
+I am loosely following the 7 in 1 structure for better organization of the styles. Learn more here:
+https://medium.com/@diyorbekjuraev77/be-a-master-at-creating-the-7-1-sass-pattern-776fdfb5a3b1
+
+⚠️NOTE: All bootstrap overrides have been configured under themes/falcon/_dev/css/abstracts/variables/bootstrap
+*/
 
 //Abstracts: Things used throughout the site such as utility classes and generic overrides.
+@import "abstracts/utilities";
 //@import "abstracts/base";
 //@import "abstracts/utilities";
 
 // Components: parts of the theme itself that are not associated with a module.
-//@import "components/";
 @import "components/forms";
 
 // Modules: Styling for specific modules.

falcon/_dev/css/theme/custom/abstracts/_utilities.scss

@@ -0,0 +1,3 @@
+// Header selector for interpolation
+// Example usage: #{$headings} { ... }
+$headings: "h1, h2, h3, h4, h5, h6, .h1, .h2, .h3, .h4, .h5, .h6";

falcon/_dev/img/checkmark.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-check2" viewBox="0 0 16 16">
+  <path d="M13.854 3.646a.5.5 0 0 1 0 .708l-7 7a.5.5 0 0 1-.708 0l-3.5-3.5a.5.5 0 1 1 .708-.708L6.5 10.293l6.646-6.647a.5.5 0 0 1 .708 0"/>
+</svg>

falcon/modules/is_searchbar/views/templates/hook/is_searchbar.tpl

@@ -9,7 +9,12 @@
 					   name="s"
 					   value="{$search_string}">
 				<button type="submit" class="search-form__btn btn">
-					<span class="material-icons">search</span>
+                    {capture name="svg_output"}{svg_icon file='search.svg'}{/capture}
+                    {if $smarty.capture.svg_output}
+                        {$smarty.capture.svg_output nofilter}
+                    {else}
+                        <span class="header-top__icon material-icons">search</span>
+                    {/if}
 				</button>
 			</div>
 		</form>

falcon/templates/_partials/header.tpl

@@ -37,7 +37,6 @@
         <div class="header-top js-header-top">
             <div class="header-top__content pb-md-0 py-2">
                 <div class="container">
-
                     <div class="row header-top__row">
 
                         <div class="col flex-grow-0 header-top__block header-top__block--menu-toggle d-block d-md-none">