refactor: remove forum and topic feature chains

assets/css/frontend/pages/base-3.css

@@ -122,72 +122,3 @@
   color: var(--color-ink-3);
 }
 
-/* ============================================================
- * Forum Page
- * ============================================================ */
-
-.aksrt-forum-header {
-  padding: clamp(32px, 5vw, 64px) 0 clamp(16px, 3vw, 32px);
-  background: linear-gradient(135deg, var(--color-primary-soft, #e6f4ff) 0%, var(--surface-2, #f5f7fa) 100%);
-  margin-bottom: 32px;
-  text-align: center;
-}
-
-.aksrt-forum-header__title {
-  font: 700 clamp(28px, 4vw, 40px)/1.15 var(--font-display, inherit);
-  margin: 0 0 8px;
-  color: var(--color-ink);
-}
-
-.aksrt-forum-header__desc {
-  margin: 0 0 24px;
-  color: var(--color-ink-2, #666);
-  font-size: 15px;
-}
-
-.aksrt-forum-header__stats {
-  display: flex;
-  justify-content: center;
-  gap: 32px;
-}
-
-.aksrt-forum-header__stat-num {
-  display: block;
-  font-size: 28px;
-  font-weight: 700;
-  color: var(--color-primary);
-}
-
-.aksrt-forum-header__stat-label {
-  font-size: 13px;
-  color: var(--color-ink-3, #999);
-}
-
-.aksrt-forum__layout {
-  display: grid;
-  grid-template-columns: 1fr 280px;
-  gap: 24px;
-}
-
-@media (max-width: 1023px) {
-  .aksrt-forum__layout {
-    grid-template-columns: 1fr;
-  }
-}
-
-.aksrt-forum-section__title {
-  display: flex;
-  align-items: center;
-  gap: 8px;
-  font-size: 16px;
-  font-weight: 600;
-  color: var(--color-ink);
-  margin: 0 0 16px;
-  padding-bottom: 8px;
-  border-bottom: 1px solid var(--color-line, #e8e8e8);
-}
-
-.aksrt-forum-section__title i {
-  color: var(--color-primary);
-}
-