fix(spa): complete checkout flow, UI standardization, and tailwind v4 styling fixes

apps/spa/tailwind.config.js

@@ -18,6 +18,19 @@ export default {
           bg: "#FFF0F5",
           black: "#333333",
         },
+        night: {
+          900: "#111827",
+        },
+        cyan: {
+          glow: "#06b6d4",
+        },
+        spa: {
+          light: "#FDFDF9",   // Off-white/Cream
+          sage: "#EAEFEA",    // Soft Sage Green
+          stone: "#4B4B46",   // Dark Stone Gray
+          forest: "#1F3D2D",  // Deep Forest Green
+          gold: "#D4AF37",    // Elegant Gold
+        }
       },
       boxShadow: {
         'brutal': '0 10px 25px rgba(0,0,0,0.05)',