diff --git a/server.js b/server.js
index f6b140c..fa4f451 100644
--- a/server.js
+++ b/server.js
@@ -179,6 +179,30 @@ function layout(title, body, { authenticated = false, activePath = "/", subtitle
         </div>
       ` : body}
     </div>
+    <div id="modal-root"></div>
+    <script>
+      (function () {
+        function closeModal() {
+          var modalRoot = document.getElementById('modal-root');
+          if (modalRoot) modalRoot.innerHTML = '';
+        }
+        document.addEventListener('click', function (event) {
+          var close = event.target.closest && event.target.closest('[data-modal-close]');
+          if (!close) return;
+          event.preventDefault();
+          closeModal();
+        });
+        document.addEventListener('keydown', function (event) {
+          if (event.key === 'Escape') closeModal();
+        });
+        document.addEventListener('htmx:afterSwap', function (event) {
+          if (event.detail && event.detail.target && event.detail.target.id === 'modal-root') {
+            var root = document.getElementById('modal-root');
+            if (root) root.scrollTop = 0;
+          }
+        });
+      })();
+    </script>
   </body>
 </html>`;
 }
@@ -503,7 +527,11 @@ function renderOrderDetail(order) {
   return `
     <div class="stack">
       <section class="panel">
-        ${panelHeader(`${order.patient} · ${order.id}`, "Order detail with the same structure as the proposed master-detail workflow.", `<a class="btn btn-secondary" href="/orders/${order.id}/pesan-khusus">Pesan khusus</a>`)}
+        ${panelHeader(
+          `${order.patient} · ${order.id}`,
+          "Order detail with the same structure as the proposed master-detail workflow.",
+          `<button class="btn btn-secondary" type="button" hx-get="/fragments/modals/pesan-khusus?order_id=${escapeHtml(order.id)}" hx-target="#modal-root" hx-swap="innerHTML">Pesan khusus</button>`,
+        )}
         <div class="grid grid-3">
           <div class="card"><span class="muted">Status</span><div style="margin-top:8px">${statusBadge(order.status)}</div></div>
           <div class="card"><span class="muted">Patient</span><strong style="display:block; margin-top:8px">${escapeHtml(order.patient)}</strong><span class="muted">${escapeHtml(order.mode)} · ${escapeHtml(order.age)} years</span></div>
@@ -613,7 +641,7 @@ function renderOrderForm(step, stepKey = "demografi") {
         ${steps
           .map(
             (item, index) => `
-              <a class="step ${index === activeIndex ? "active" : ""}" href="/orders/new/${item[0]}">
+              <a class="step ${index === activeIndex ? "active" : ""}" href="/orders/new/${item[0]}" hx-get="/fragments/forms/order-step/${item[0]}" hx-target="#order-step-fragment" hx-push-url="true">
                 <strong>${escapeHtml(item[1])}</strong>
                 <span>${escapeHtml(item[2])}</span>
               </a>
@@ -973,7 +1001,7 @@ function problemLoginPage() {
 
 function orderNewPage(path) {
   const step = path.split("/").filter(Boolean)[2] || "demografi";
-  return layout("Create Order", renderOrderForm({}, step), {
+  return layout("Create Order", `<div id="order-step-fragment">${renderOrderForm({}, step)}</div>`, {
     authenticated: true,
     activePath: "/orders",
     subtitle: "The new project collapses the old step-heavy flow into a cleaner shell while keeping the same workflow.",
@@ -1557,27 +1585,30 @@ function fragmentOrderStep(step) {
 function fragmentPesanKhusus(orderId) {
   const order = mockOrders.find((item) => item.id === orderId) || mockOrders[0];
   return `
-    <section class="panel">
-      ${panelHeader("Pesan khusus", "Desktop can treat this as a modal-style panel; mobile reads it as a dedicated page.", `<a class="btn btn-secondary" href="/orders/${order.id}">Back</a>`)}
-      <div class="detail-grid">
-        <div class="card">
-          <strong>${escapeHtml(order.patient)}</strong>
-          <p class="muted">${escapeHtml(order.id)}</p>
-          <div style="margin-top:12px">${statusBadge(order.status)}</div>
-          <p style="margin-top:14px" class="muted">${escapeHtml(order.message)}</p>
-        </div>
-        <form class="form card" action="/orders/${order.id}/pesan-khusus" method="post">
-          <label class="field">
-            <span>Special message</span>
-            <textarea name="pesan_khusus" placeholder="Type a special note for this order..." required>${escapeHtml(order.message)}</textarea>
-          </label>
-          <div class="topbar-actions" style="justify-content:flex-start">
-            <button class="btn btn-primary" type="submit">Save message</button>
-            <a class="btn btn-secondary" href="/orders/${order.id}">Cancel</a>
+    <div class="modal-shell" role="dialog" aria-modal="true" aria-labelledby="pesan-khusus-title">
+      <div class="modal-backdrop" data-modal-close></div>
+      <section class="modal-card panel">
+        ${panelHeader("Pesan khusus", "Desktop opens this as a modal, mobile can still use it as a full sheet.", `<button class="btn btn-secondary" type="button" data-modal-close>Close</button>`)}
+        <div class="detail-grid">
+          <div class="card">
+            <strong>${escapeHtml(order.patient)}</strong>
+            <p class="muted">${escapeHtml(order.id)}</p>
+            <div style="margin-top:12px">${statusBadge(order.status)}</div>
+            <p style="margin-top:14px" class="muted">${escapeHtml(order.message)}</p>
           </div>
-        </form>
-      </div>
-    </section>
+          <form class="form card" action="/orders/${order.id}/pesan-khusus" method="post">
+            <label class="field">
+              <span>Special message</span>
+              <textarea name="pesan_khusus" placeholder="Type a special note for this order..." required>${escapeHtml(order.message)}</textarea>
+            </label>
+            <div class="topbar-actions" style="justify-content:flex-start">
+              <button class="btn btn-primary" type="submit">Save message</button>
+              <button class="btn btn-secondary" type="button" data-modal-close>Cancel</button>
+            </div>
+          </form>
+        </div>
+      </section>
+    </div>
   `;
 }
 
diff --git a/styles.css b/styles.css
index 67031c1..b4caa0f 100644
--- a/styles.css
+++ b/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) {