Add darkened photo hero to shop page

Deliberately using the low-res thumbnail the client dropped in the repo
(180x280px) so the pixelation is visible live — the treatment itself is
the right direction, it just needs a real high-res source photo. No
customers yet, so safe to ship as a visible placeholder rather than a
mockup.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

assets/css/style.css

@@ -128,6 +128,54 @@ main {
   font-size: 0.95rem;
 }
 
+/* Shop hero */
+.shop-hero {
+  position: relative;
+  height: 260px;
+  border-radius: 6px;
+  overflow: hidden;
+  margin: 0.5rem 0 1.5rem;
+}
+
+.shop-hero-img {
+  position: absolute;
+  inset: 0;
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  object-position: center 30%;
+}
+
+.shop-hero-overlay {
+  position: absolute;
+  inset: 0;
+  background:
+    linear-gradient(180deg, rgba(20,32,22,0.35) 0%, rgba(28,42,26,0.55) 55%, var(--paper) 100%),
+    linear-gradient(90deg, rgba(20,32,22,0.45) 0%, rgba(20,32,22,0.05) 45%);
+}
+
+.shop-hero-copy {
+  position: relative;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  padding: 0 1.75rem;
+}
+
+.shop-hero-copy h1 { margin-bottom: 0.3rem; }
+
+.shop-hero-copy p {
+  color: var(--ink-soft);
+  margin: 0;
+  max-width: 34ch;
+  font-size: 0.95rem;
+}
+
+@media (max-width: 620px) {
+  .shop-hero { height: 220px; }
+}
+
 /* Product grid */
 .product-grid {
   display: grid;