Improve intersection observers

Author: Tetrakern

css/application.css

@@ -478,7 +478,9 @@ window.addEventListener('scroll.rAF', fcn_throttle(fcn_scrollDirection, 200));
 
 // Main observer
 const /** @const {IntersectionObserver} */ fcn_mainObserver = new IntersectionObserver(
-  ([e]) => fcn_theBody.classList.toggle('is-inside-main', e.intersectionRatio < 1),
+  ([e]) => {
+    fcn_theBody.classList.toggle('is-inside-main', e.intersectionRatio < 1 && e.boundingClientRect.top <= 0);
+  },
   { threshold: [1] }
 );
 

css/complete.css

@@ -1,11 +1,7 @@
 .nav-observer {
+  visibility: hidden;
   position: absolute;
   top: calc(-1px + var(--nav-observer-offset, 0px));
-  left: 0;
-  z-index: -1000;
-  height: 1px;
-  width: 1px;
-  transform: translateZ(0); // Improve performance
 }
 
 @include bp(601px) {