Fix multi-comments & Gemini style

source/css/_mixins.styl

@@ -249,3 +249,23 @@ button($color) {
     color: white;
   }
 }
+
+gemini-block() {
+  background: var(--content-bg-color);
+  border-radius: $border-radius-inner;
+  box-shadow: $box-shadow-inner;
+}
+
+gemini-block-not-first() {
+  border-radius: $border-radius;
+  box-shadow: $box-shadow;
+  margin-top: $sidebar-offset;
+
+  +tablet() {
+    margin-top: $content-tablet-padding;
+  }
+
+  +mobile() {
+    margin-top: $content-mobile-padding;
+  }
+}

source/css/_schemes/Gemini/index.styl

@@ -24,26 +24,20 @@
 // Desktop layout styles.
 // ==================================================
 // Post blocks.
-.main-inner > {
+.main-inner {
   .sub-menu, .post-block, .tabs-comment, .comments, .pagination {
-    background: var(--content-bg-color);
-    border-radius: $border-radius-inner;
-    box-shadow: $box-shadow-inner;
+    gemini-block();
+  }
 
-    &:not(:first-child):not(.sub-menu) {
-      border-radius: $border-radius;
-      box-shadow: $box-shadow;
-      margin-top: $sidebar-offset;
-
-      +tablet() {
-        margin-top: $content-tablet-padding;
-      }
-
-      +mobile() {
-        margin-top: $content-mobile-padding;
-      }
+  .post-block:not(:first-child) {
+    &:not(:first-child) {
+      gemini-block-not-first();
     }
   }
+
+  .tabs-comment, .comments, .pagination {
+    gemini-block-not-first();
+  }
 }
 
 // Post & Comments blocks.

source/js/utils.js

@@ -175,9 +175,12 @@ NexT.utils = {
         const tabContent = nav.nextElementSibling;
         tabContent.style.overflow = 'hidden';
         tabContent.style.transition = 'height 1s';
-        const prevHeight = parseInt(window.getComputedStyle(tabContent.querySelector('.active')).height.replace('px', ''), 10);
-        const paddingTop = parseInt(window.getComputedStyle(tabContent.querySelector('.active')).paddingTop.replace('px', ''), 10);
-        const marginBottom = parseInt(window.getComputedStyle(tabContent.querySelector('.active').firstChild).marginBottom.replace('px', ''), 10);
+        // Comment system selection tab does not contain .active class.
+        const activeTab = tabContent.querySelector('.active') || tabContent.firstChild;
+        // Hight might be `auto`.
+        const prevHeight = parseInt(window.getComputedStyle(activeTab).height.replace('px', ''), 10) || 0;
+        const paddingTop = parseInt(window.getComputedStyle(activeTab).paddingTop.replace('px', ''), 10);
+        const marginBottom = parseInt(window.getComputedStyle(activeTab.firstChild).marginBottom.replace('px', ''), 10);
         tabContent.style.height = prevHeight + paddingTop + marginBottom + 'px';
         // Add & Remove active class on `nav-tabs` & `tab-content`.
         [...nav.children].forEach(target => {