✨ feat: add date visibility options to post list (#330)

Co-authored-by: welpo <welpo@users.noreply.github.com>

sass/main.scss

@@ -276,6 +276,10 @@ video {
     margin-bottom: 2rem;
 }
 
+.mobile-only {
+    display: none;
+}
+
 @media only screen and (max-width: 1000px) {
     .content {
         max-width: var(--normal-layout-width);
@@ -292,6 +296,10 @@ video {
         max-width: none;
         overflow-x: auto;
     }
+
+    .mobile-only {
+        display: block;
+    }
 }
 
 @media only screen and (max-width: 600px) {