diff --git a/app/main.py b/app/main.py
index 9011a8d..5f25623 100644
--- a/app/main.py
+++ b/app/main.py
@@ -278,9 +278,20 @@ def prometheus_metrics() -> Response:
     return metrics_response()
 
 
+class _NoCacheStatic(StaticFiles):
+    """Dashboard SPA: no-cache header — deploy/değişiklik sonrası tarayıcı ESKİ asset
+    sunmaz (ETag korunur → değişmeyen dosyada 304 hızlı, ama her zaman revalidate).
+    Önceki davranış: ETag var ama Cache-Control yok → tarayıcı heuristik cache'liyor."""
+
+    async def get_response(self, path, scope):
+        resp = await super().get_response(path, scope)
+        resp.headers["Cache-Control"] = "no-cache, must-revalidate"
+        return resp
+
+
 _dashboard_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), "frontend")
 if os.path.isdir(_dashboard_dir):
-    app.mount("/dashboard", StaticFiles(directory=_dashboard_dir, html=True), name="dashboard")
+    app.mount("/dashboard", _NoCacheStatic(directory=_dashboard_dir, html=True), name="dashboard")
 
 # Bitki sağlığı görsel upload'ları (plants.py içinde URL üretiliyor)
 _plant_uploads_dir = os.path.join(os.path.dirname(__file__), "ml", "plant_uploads")
diff --git a/frontend/index.html b/frontend/index.html
index 62d5f3e..a7389bd 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -873,7 +873,7 @@ <h2 id="pageTitle">Dashboard</h2>
                                         <stop offset="100%" stop-color="#f59e0b"/>
                                     </radialGradient>
                                 </defs>
-                                <circle cx="12" cy="12" r="10" fill="url(#sunGrad)"/>
+                                <circle cx="12" cy="12" r="12" fill="url(#sunGrad)"/>
                                 <ellipse cx="9" cy="10" rx="2.5" ry="1.8" fill="#fef9c3" opacity=".6"/>
                             </svg>
                             <svg class="knob-moon" viewBox="0 0 24 24">
@@ -884,7 +884,7 @@ <h2 id="pageTitle">Dashboard</h2>
                                         <stop offset="100%" stop-color="#94a3b8"/>
                                     </radialGradient>
                                 </defs>
-                                <circle cx="12" cy="12" r="10" fill="url(#moonGrad)"/>
+                                <circle cx="12" cy="12" r="12" fill="url(#moonGrad)"/>
                                 <circle cx="14.5" cy="9" r="1.6" fill="#94a3b8" opacity=".55"/>
                                 <circle cx="9" cy="13.5" r="1.2" fill="#94a3b8" opacity=".5"/>
                                 <circle cx="15" cy="15" r="1" fill="#94a3b8" opacity=".5"/>
diff --git a/frontend/src/lib/pages/account.js b/frontend/src/lib/pages/account.js
index 2736a4f..dfc6d22 100644
--- a/frontend/src/lib/pages/account.js
+++ b/frontend/src/lib/pages/account.js
@@ -9,7 +9,7 @@
 import { _fmtDate, _escAttr, showToast } from "../utils.js";
 import { getAuthToken, setAuthToken, clearAuthToken, apiAuth, API_BASE } from "../api.js";
 import { _skeletonBlock, _setBusy } from "../skeleton.js";
-import { setCurrentUser } from "../session.js";
+import { setCurrentUser, getCurrentUser } from "../session.js";
 import { navigate } from "../nav.js";
 import { refreshBell, _hideBell } from "./alerts.js";
 
@@ -317,11 +317,13 @@ export async function loadUsers() {
         .map(r => `<option value="${r}"${r === sel ? ' selected' : ''}>${ROLE_LABELS[r]}</option>`).join('');
     let html = '<table class="detail-table"><caption class="sr-only">Kullanıcı listesi</caption><thead><tr>'
         + '<th>Ad</th><th>E-posta</th><th>Rol</th><th>Çiftlik</th><th>Kayıt</th><th>İşlem</th></tr></thead><tbody>';
+    const me = getCurrentUser();
     for (const u of list) {
+        const isSelf = me && u.id === me.id;
         html += `<tr>
             <td>${_escAttr(u.name)}</td>
             <td>${_escAttr(u.email)}</td>
-            <td><select class="user-role-select" data-action="changeUserRole" data-id="${u.id}">${roleOpts(u.role)}</select></td>
+            <td><select class="user-role-select" data-action="changeUserRole" data-id="${u.id}"${isSelf ? ' disabled title="Kendi rolünü değiştiremezsin — lock-out koruması (başka bir admin değiştirmeli)"' : ''}>${roleOpts(u.role)}</select></td>
             <td>${u.owned_farms_count ?? 0}</td>
             <td>${_fmtDate(u.created_at)}</td>
             <td class="user-actions">
diff --git a/frontend/src/lib/router.js b/frontend/src/lib/router.js
index c08d9eb..e57db90 100644
--- a/frontend/src/lib/router.js
+++ b/frontend/src/lib/router.js
@@ -4,6 +4,8 @@
    Hash-based SPA navigation, sidebar toggle, page title yönetimi.
    ============================================================ */
 
+import { getCurrentUser } from "./session.js";
+
 export const pageTitles = {
     dashboard: ['Genel Bakış', 'Tarlanın özeti'],
     fields: ['Tarlalarım', 'Çiftliklerine bağlı tarlalar'],
@@ -20,6 +22,15 @@ export const pageTitles = {
     auth: ['Hesabım', 'Profil ve şifre'],
 };
 
+// Sistem rolleri (developer/overseer/admin) TÜM sistemi görür → çiftçi-odaklı
+// ("kendi tarlan") alt başlıklar yanıltıcı. Bu sayfalarda kapsam-doğru metin:
+const SYSTEM_SUBTITLES = {
+    dashboard: 'Sistem geneli özet',
+    fields: 'Tüm çiftlikler ve tarlalar',
+    sensors: 'Sistemdeki tüm sensörler',
+    irrigation: 'Tüm sulama kayıtları ve önerisi',
+};
+
 /**
  * Sayfa değiştirme fonksiyonu.
  * @param {string} page - Sayfa adı
@@ -45,7 +56,9 @@ export function navigate(page, handlers, startHeroTipRotation) {
         navItem.setAttribute('aria-current', 'page');
     }
     document.getElementById('pageTitle').textContent = pageTitles[page][0];
-    document.getElementById('pageSubtitle').textContent = pageTitles[page][1];
+    const _u = getCurrentUser();
+    const _sysSub = _u && _u.role !== 'farmer' && SYSTEM_SUBTITLES[page];
+    document.getElementById('pageSubtitle').textContent = _sysSub || pageTitles[page][1];
     // Sayfa her zaman TEPEDEN açılsın + a11y odağı (odak kaydırmasın → preventScroll).
     window.scrollTo(0, 0);
     const main = document.getElementById('main-content');
diff --git a/frontend/src/styles/base.css b/frontend/src/styles/base.css
index 485564f..7322b28 100644
--- a/frontend/src/styles/base.css
+++ b/frontend/src/styles/base.css
@@ -11,18 +11,21 @@ input, select { font-family: var(--font); }
 /* Selection highlight */
 ::selection { background: rgba(16,185,129,.28); color: var(--text); }
 
-/* Global scrollbar */
+/* Global scrollbar — SADECE ::-webkit (Chrome/Safari kalıcı özel scrollbar).
+   scrollbar-color KULLANMA: modern Chrome onu görünce ::-webkit'i yok sayıp ince
+   standart (overlay) scrollbar'a geçiyor → scrollbar "kayboluyor".
+   Gece varsayılan = slate; gündüz (yeşil) override → theme-light.css. */
 *::-webkit-scrollbar { width: 10px; height: 10px; }
 *::-webkit-scrollbar-track { background: transparent; }
 *::-webkit-scrollbar-thumb {
-    background: rgba(16,185,129,.28);
+    background: rgba(100,116,139,.55);
     border-radius: 6px;
     border: 2px solid transparent;
     background-clip: padding-box;
     transition: background .2s ease;
 }
 *::-webkit-scrollbar-thumb:hover {
-    background: rgba(16,185,129,.55);
+    background: rgba(148,163,184,.72);
     background-clip: padding-box;
 }
 
diff --git a/frontend/src/styles/theme-light.css b/frontend/src/styles/theme-light.css
index f9bd5a3..43f33f7 100644
--- a/frontend/src/styles/theme-light.css
+++ b/frontend/src/styles/theme-light.css
@@ -132,3 +132,7 @@
 [data-theme="light"] .theme-toggle:hover .toggle-track {
     box-shadow: inset 0 2px 6px rgba(15,23,42,.2), 0 0 0 1px rgba(96,165,250,.4);
 }
+
+/* Light tema scrollbar — ORİJİNAL marka yeşili (açık zeminde mükemmeldi, korundu) */
+[data-theme="light"] *::-webkit-scrollbar-thumb { background: rgba(16,185,129,.28); }
+[data-theme="light"] *::-webkit-scrollbar-thumb:hover { background: rgba(16,185,129,.55); }