style: adjust pinboard positioning and radius

public/assets/pinboard.css

@@ -8,6 +8,9 @@
 
 .pinboard {
   --pin-gap: 1.25rem;
+  margin-top: -80px;
+  position: relative;
+  z-index: 1;
 }
 
 .pinboard__surface {
@@ -15,7 +18,7 @@
   min-height: 42rem;
   padding: 1.2rem;
   border: 30px solid #cba888;
-  border-radius: 1.2rem;
+  border-radius: 0.7rem;
   overflow: hidden;
   background:
     radial-gradient(circle at 20% 10%, rgba(255, 255, 255, 0.18), transparent 42%),