fix(single): restore Zibll float dual-column and article chrome

Align single-post layout/visuals with Zibll: fix sidebar-over-content
float geometry (position:unset, 311px token, kill Bootstrap/container
padding and the 280px sidebar override), demote theme-box to spacing-
only, unify breadcrumb/cover/graphic utilities, and split aksrt-single
render helpers under the file-size limit.

assets/css/frontend/single-post/cover.css

@@ -3,14 +3,20 @@
  * The cover stays inside the content column with a fixed aspect ratio box.
  * ============================================================ */
 
-/* ===== Cover (in-column ratio box) ===== */
+/* ===== Cover (in-column ratio box) — Zibll .single-cover ===== */
 .single-cover {
     position: relative;
     overflow: hidden;
-    border-radius: var(--radius-2xl, 16px);
-    box-shadow: var(--shadow-sm);
+    border-radius: var(--main-radius, var(--radius, 8px));
+    box-shadow: 0 0 10px var(--main-shadow, rgba(116, 116, 116, 0.08));
     margin-bottom: 20px;
-    padding-bottom: var(--single-cover-scale, 35%);
+    /* Zibll: padding-bottom: calc(var(--single-cover-scale) + 50px) */
+    padding-bottom: calc(var(--single-cover-scale, 35%) + 50px);
+}
+
+.single-cover-slide {
+    padding-bottom: calc(var(--scale-height, var(--single-cover-scale, 35%)) + 50px);
+    border-radius: var(--main-radius, var(--radius, 8px));
 }
 
 .single-cover > .fit-cover,
@@ -22,6 +28,25 @@
     object-fit: cover;
 }
 
+.single-cover-con {
+    color: #fff;
+    padding: 15px 15px 10px 15px;
+    border-radius: 0 0 var(--main-radius, var(--radius, 8px)) var(--main-radius, var(--radius, 8px));
+    background-image: linear-gradient(0deg, rgba(29, 41, 49, 0.5), rgba(255, 255, 255, 0));
+    padding-top: 2em;
+}
+
+.single-cover-con a {
+    color: #fff;
+}
+
+.single-video .article-title,
+.single-cover-con .article-title {
+    font-size: 18px;
+    font-weight: 700;
+}
+
+/* Legacy overlay helpers (kept for non-zibll markup) */
 .single-cover__overlay {
     position: absolute;
     inset: 0;
@@ -40,7 +65,7 @@
     right: 0;
     padding: 24px;
     color: #fff;
-    border-radius: 0 0 var(--radius-2xl, 16px) var(--radius-2xl, 16px);
+    border-radius: 0 0 var(--main-radius, var(--radius, 8px)) var(--main-radius, var(--radius, 8px));
 }
 
 .single-cover__title,
@@ -155,23 +180,13 @@
     position: relative;
 }
 
-.article-avatar .line-form-line,
-.article-avatar .line-form-line::before {
-    position: absolute;
-    top: 50%;
-    left: calc(52px + 16px);
-    right: 120px;
-    height: 1px;
-    transform: translateY(-50%);
-    background: var(--color-line);
-}
-
-.article-avatar .line-form-line::before {
-    content: "";
-    right: auto;
-    width: 42px;
-    background: var(--color-primary, #f04494);
-    opacity: 0.3;
+/* line-form-line geometry owned by zibll-utilities.css (absolute full-width bottom).
+ * Here only ensure the meta row has height so the rule sits correctly. */
+.article-header .article-avatar .relative {
+    margin-top: 20px;
+    position: relative;
+    min-height: 1px;
+    padding-bottom: 1px;
 }
 
 /* ===== Article Card ===== */
@@ -253,11 +268,11 @@
 .single-cover-slide-wrap {
   position: relative;
   overflow: hidden;
-  border-radius: var(--radius-2xl, 16px);
+  border-radius: var(--main-radius, var(--radius, 8px));
 }
 .single-cover-slide-wrap .abs-center.left-bottom {
   z-index: 2;
-  padding: 18px 20px;
+  padding: 15px 15px 10px 15px;
   color: #fff;
 }
 .article-avatar name.flex {
@@ -277,11 +292,23 @@
 
 /* Slide cover overlay (injected by aksrt_render_slider overlay_html) */
 .aksrt-slider-wrapper--has-overlay,
-.aksrt-slider-wrapper--scale { position: relative; overflow: hidden; border-radius: var(--radius-2xl, 16px); }
+.aksrt-slider-wrapper--scale {
+  position: relative;
+  overflow: hidden;
+  border-radius: var(--main-radius, var(--radius, 8px));
+}
 .aksrt-slider-wrapper--scale .new-swiper { position: absolute; inset: 0; width: 100%; height: 100%; }
 .aksrt-slider-wrapper--scale .swiper-slide img.fit-cover { width: 100%; height: 100%; object-fit: cover; }
 .aksrt-slider-overlay { position: absolute; inset: 0; z-index: 3; pointer-events: none; }
-.aksrt-slider-overlay .abs-center.left-bottom { pointer-events: none; padding: 18px 20px; color: #fff; }
+.aksrt-slider-overlay .abs-center.left-bottom {
+  pointer-events: none;
+  padding: 15px 15px 10px 15px;
+  color: #fff;
+  background-image: linear-gradient(0deg, rgba(29, 41, 49, 0.5), rgba(255, 255, 255, 0));
+  padding-top: 2em;
+  width: 100%;
+  box-sizing: border-box;
+}
 .aksrt-slider-overlay .article-title,
 .aksrt-slider-overlay .article-title.title-h-left { color: #fff; text-shadow: 0 1px 4px rgba(0,0,0,.45); }
 .aksrt-slider-overlay .breadcrumb a,