优化加载卡顿问题，最稳定版本

themes/Ying/layouts/_default/single.html

@@ -28,10 +28,11 @@
         function initPostScrollspy() {
             var content = document.getElementById('post-writing');
             if (!content) return;
-            content.querySelectorAll('h2, h3, h4, p, ul, ol, blockquote, table').forEach(function(el) {
+            // 只给关键元素加动画，减少 observer 数量
+            content.querySelectorAll('h2, h3, blockquote, table, figure').forEach(function(el) {
                 if (!el.hasAttribute('uk-scrollspy')) el.setAttribute('uk-scrollspy', 'cls: uk-animation-fade; delay: 60');
             });
-            content.querySelectorAll('figure, img, .post-video, .link-card').forEach(function(el) {
+            content.querySelectorAll('.post-video, .link-card').forEach(function(el) {
                 if (!el.hasAttribute('uk-scrollspy')) el.setAttribute('uk-scrollspy', 'cls: uk-animation-slide-bottom-small; delay: 100');
             });
         }