Fix mobile form overflow on saatavuus section

- Add width: 100% to availability check inputs
- Reduce form padding on mobile (32px → 20px, 24px → 16px)
- Add overflow-x: hidden to body

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

style.css

@@ -24,6 +24,7 @@ body {
     color: var(--text);
     line-height: 1.7;
     -webkit-font-smoothing: antialiased;
+    overflow-x: hidden;
 }
 
 .container {
@@ -602,6 +603,7 @@ img {
 }
 
 .availability-check-fields input {
+    width: 100%;
     padding: 11px 14px;
     border: 1.5px solid var(--border);
     border-radius: 8px;
@@ -785,6 +787,14 @@ img {
         gap: 32px;
     }
 
+    .form {
+        padding: 20px;
+    }
+
+    .availability-check {
+        padding: 16px;
+    }
+
     .form-row {
         grid-template-columns: 1fr;
     }