Polish order modal and stepper UI

styles.css

@@ -798,6 +798,31 @@ tr:last-child td {
   display: none !important;
 }
 
+.modal-shell {
+  position: fixed;
+  inset: 0;
+  z-index: 40;
+  display: grid;
+  place-items: center;
+  padding: 22px;
+}
+
+.modal-backdrop {
+  position: absolute;
+  inset: 0;
+  background: rgba(15, 23, 42, 0.5);
+  backdrop-filter: blur(10px);
+}
+
+.modal-card {
+  position: relative;
+  z-index: 1;
+  width: min(980px, 100%);
+  max-height: calc(100vh - 44px);
+  overflow: auto;
+  box-shadow: var(--shadow-lg);
+}
+
 .desktop-only {
   display: block;
 }
@@ -872,6 +897,17 @@ tr:last-child td {
   .auth-screen {
     padding: 12px;
   }
+
+  .modal-shell {
+    padding: 0;
+    place-items: stretch;
+  }
+
+  .modal-card {
+    width: 100%;
+    max-height: 100vh;
+    border-radius: 0;
+  }
 }
 
 @media (max-width: 620px) {