feat: add fade in

packages/base/Resources/Public/JavaScript/fade-in.js

@@ -0,0 +1,40 @@
+(function() {
+  document.addEventListener('DOMContentLoaded', function() {
+    // Elements that should fade in when in view
+    var fadeInElements = document.querySelectorAll('.fade-in-on-scroll');
+
+    // If IntersectionObserver is supported, use it for better performance
+    if ('IntersectionObserver' in window) {
+      var observer = new IntersectionObserver(function(entries, observer) {
+        entries.forEach(function(entry) {
+          if (entry.isIntersecting) {
+            entry.target.classList.add('fade-in-visible');
+            observer.unobserve(entry.target);
+          }
+        });
+      }, { threshold: 0.1 });
+
+      fadeInElements.forEach(function(el) {
+        el.classList.add('fade-in-hidden');
+        observer.observe(el);
+      });
+    } else {
+      // Fallback if IntersectionObserver is not supported
+      fadeInElements.forEach(function(el) {
+        el.classList.add('fade-in-hidden');
+      });
+
+      var checkVisibility = function() {
+        var windowBottom = window.innerHeight + window.scrollY;
+        fadeInElements.forEach(function(el) {
+          if (el.getBoundingClientRect().top + window.scrollY < windowBottom - (el.offsetHeight * 0.1)) {
+            el.classList.add('fade-in-visible');
+          }
+        });
+      };
+
+      window.addEventListener('scroll', checkVisibility);
+      checkVisibility();
+    }
+  });
+})();