diff --git a/orangepi-server/static/app.js b/orangepi-server/static/app.js
index fd15361..10036fa 100644
--- a/orangepi-server/static/app.js
+++ b/orangepi-server/static/app.js
@@ -151,21 +151,21 @@ const MAP = {
 const $ = (sel) => document.querySelector(sel);
 const $$ = (sel) => document.querySelectorAll(sel);
 
-function t(key) {
+function i18n(key) {
     return I18N[State.lang][key] || I18N.en[key] || key;
 }
 
 function applyI18n() {
     document.documentElement.lang = State.lang;
     document.body.dataset.lang = State.lang;
-    document.title = t("page_title");
+    document.title = i18n("page_title");
     $$("[data-i18n]").forEach(el => {
         const k = el.getAttribute("data-i18n");
-        el.textContent = t(k);
+        el.textContent = i18n(k);
     });
     $$("[data-i18n-title]").forEach(el => {
         const k = el.getAttribute("data-i18n-title");
-        el.title = t(k);
+        el.title = i18n(k);
     });
 }
 
@@ -384,7 +384,7 @@ function drawZones(zones) {
             ctx.save();
             ctx.font = "bold 11px 'Inter', system-ui, sans-serif";
             ctx.textAlign = "center";
-            const occText = z.occupied ? t("occupied") : t("empty");
+            const occText = z.occupied ? i18n("occupied") : i18n("empty");
             ctx.fillStyle = z.occupied ? "#ffffff" : hexToRgba("#000000", 0.55);
             const label = `Z${z.id} · ${occText}`;
             const metrics = ctx.measureText(label);
@@ -591,13 +591,13 @@ function refreshPanels() {
         row.innerHTML = `
             <div class="target-slot s${idx+1}">T${t.slot}</div>
             <div class="target-detail">
-                <span class="status ${statusKey}">${t(statusKey)}</span>
+                <span class="status ${statusKey}">${i18n(statusKey)}</span>
                 <div class="target-metrics">
-                    <div>${t("x_coord")}: <b>${t.x_mm} mm</b></div>
-                    <div>${t("y_coord")}: <b>${t.y_mm} mm</b></div>
-                    <div>${t("speed")}: <b>${speedTxt} cm/s</b></div>
-                    <div>${t("distance")}: <b>${distanceKm} m</b></div>
-                    <div style="grid-column: span 2;">${t("angle")}: <b>${angleTxt}</b></div>
+                    <div>${i18n("x_coord")}: <b>${t.x_mm} mm</b></div>
+                    <div>${i18n("y_coord")}: <b>${t.y_mm} mm</b></div>
+                    <div>${i18n("speed")}: <b>${speedTxt} cm/s</b></div>
+                    <div>${i18n("distance")}: <b>${distanceKm} m</b></div>
+                    <div style="grid-column: span 2;">${i18n("angle")}: <b>${angleTxt}</b></div>
                 </div>
             </div>`;
         tl.appendChild(row);
@@ -612,10 +612,10 @@ function refreshPanels() {
         row.innerHTML = `
             <div class="zone-swatch z${idx+1}"></div>
             <div class="zone-info">
-                <div class="zone-name">${t("zone_"+(idx+1))} · Z${z.id}</div>
+                <div class="zone-name">${i18n("zone_"+(idx+1))} · Z${z.id}</div>
                 <div class="zone-coord">[${z.x1}, ${z.y1}] → [${z.x2}, ${z.y2}]</div>
             </div>
-            <div class="zone-badge ${z.occupied ? "occupied" : "empty"}">${z.occupied ? t("occupied") : t("empty")}</div>
+            <div class="zone-badge ${z.occupied ? "occupied" : "empty"}">${z.occupied ? i18n("occupied") : i18n("empty")}</div>
         `;
         zl.appendChild(row);
     });
@@ -629,22 +629,22 @@ function buildEditorInputs() {
         const block = document.createElement("div");
         block.className = "zone-editor-block";
         block.innerHTML = `
-            <label>${t("zone_"+(idx+1))} — Z${z.id}</label>
+            <label>${i18n("zone_"+(idx+1))} — Z${z.id}</label>
             <div class="coord-grid">
                 <div class="coord-field">
-                    <label>${t("edit_zone_x1")}</label>
+                    <label>${i18n("edit_zone_x1")}</label>
                     <input type="number" data-zone="${idx}" data-field="x1" value="${z.x1}">
                 </div>
                 <div class="coord-field">
-                    <label>${t("edit_zone_y1")}</label>
+                    <label>${i18n("edit_zone_y1")}</label>
                     <input type="number" data-zone="${idx}" data-field="y1" value="${z.y1}">
                 </div>
                 <div class="coord-field">
-                    <label>${t("edit_zone_x2")}</label>
+                    <label>${i18n("edit_zone_x2")}</label>
                     <input type="number" data-zone="${idx}" data-field="x2" value="${z.x2}">
                 </div>
                 <div class="coord-field">
-                    <label>${t("edit_zone_y2")}</label>
+                    <label>${i18n("edit_zone_y2")}</label>
                     <input type="number" data-zone="${idx}" data-field="y2" value="${z.y2}">
                 </div>
             </div>`;
@@ -719,7 +719,7 @@ function connectWS() {
         console.warn("[Radar] WebSocket closed (code=" + ev.code + " reason=" + ev.reason + ")");
         State.browserWsConnected = false;
         updateWsStatus("err");
-        if (wsReconnectTimer == null) toast(t("ws_reconnecting"), "warning");
+        if (wsReconnectTimer == null) toast(i18n("ws_reconnecting"), "warning");
         scheduleReconnect();
     };
     _activeWs.onerror = (ev) => {
@@ -741,14 +741,14 @@ function updateWsStatus(kind) {
     const dot = chip.querySelector(".status-dot");
     const txt = chip.querySelector("span:last-child");
     dot.className = "status-dot " + (kind === "ok" ? "status-ok" : kind === "err" ? "status-err" : "status-warn");
-    txt.textContent = kind === "ok" ? t("ws_connected") : kind === "err" ? t("ws_disconnected") : t("ws_connecting");
+    txt.textContent = kind === "ok" ? i18n("ws_connected") : kind === "err" ? i18n("ws_disconnected") : i18n("ws_connecting");
 }
 function updateEsp32Status(connected) {
     const chip = $("#statusEsp32");
     const dot = chip.querySelector(".status-dot");
     const txt = chip.querySelector("span:last-child");
     dot.className = "status-dot " + (connected ? "status-ok" : "status-err");
-    txt.textContent = connected ? t("esp32_connected") : t("esp32_disconnected");
+    txt.textContent = connected ? i18n("esp32_connected") : i18n("esp32_disconnected");
 }
 
 /* Called on every broadcast frame from backend */
@@ -851,11 +851,11 @@ function initUI() {
                 body: JSON.stringify(payload),
             });
             if (!res.ok) throw new Error("HTTP " + res.status);
-            toast(t("zone_saved"), "success");
+            toast(i18n("zone_saved"), "success");
             $("#zoneEditor").hidden = true;
         } catch (err) {
             console.error(err);
-            toast(t("zone_save_error") + ": " + err.message, "error");
+            toast(i18n("zone_save_error") + ": " + err.message, "error");
         }
     });