Add custom activity support and clear booking data on submission

public/activity.css

@@ -96,6 +96,43 @@
   animation: fadeIn 0.3s ease;
 }
 
+.custom-activity-section {
+  margin-top: 16px;
+  background: var(--color-white);
+  border: 2px solid var(--color-rose);
+  border-radius: var(--radius-md);
+  padding: 16px;
+  box-shadow: var(--shadow-soft);
+  animation: fadeIn 0.3s ease;
+}
+
+.custom-activity-label {
+  display: block;
+  font-family: var(--font-heading);
+  font-weight: 700;
+  font-size: 0.95rem;
+  color: var(--color-rose-dark);
+  margin-bottom: 8px;
+}
+
+.custom-activity-input {
+  width: 100%;
+  padding: 12px 14px;
+  font-family: var(--font-body);
+  font-size: 1rem;
+  color: var(--color-text);
+  background: var(--color-bg);
+  border: 2px solid var(--color-peach);
+  border-radius: var(--radius-md);
+  outline: none;
+  transition: border-color 0.2s ease, box-shadow 0.2s ease;
+}
+
+.custom-activity-input:focus {
+  border-color: var(--color-rose);
+  box-shadow: 0 0 0 3px rgba(224, 87, 126, 0.2);
+}
+
 .hidden {
   display: none !important;
 }