style: drop icon slop, swap primary to caramel, kill particles

- Remove 8 duplicated generic SVG icons from tech cards
- Switch --color-primary from teal (#1D7874) to gold (#D4A574)
- Remove particle canvas system (~70 lines JS, canvas element, CSS)
- Grain texture + steam now carry atmosphere alone

styles.css

@@ -17,7 +17,7 @@
     --text-body: var(--color-coffee-dark);
     --bg-surface-rgb: 255, 255, 255;
     --bg-surface: rgba(var(--bg-surface-rgb), 0.7);
-    --color-primary: var(--color-teal);
+    --color-primary: var(--color-gold);
     --color-secondary: var(--color-gold);
     
     --border-subtle: rgba(111, 78, 55, 0.15);
@@ -934,17 +934,7 @@ footer a:hover {
     transition: none;
 }
 
-/* ===== PARTICLE CANVAS ===== */
-#particles {
-    position: fixed;
-    top: 0;
-    left: 0;
-    width: 100%;
-    height: 100%;
-    pointer-events: none;
-    z-index: -1;
-    opacity: 0.6;
-}
+/* ===== PARTICLE CANVAS (removed) ===== */
 
 /* ===== TYPEWRITER EFFECT ===== */
 .typewriter {