diff --git a/frontend/src/pages/CausalLab.tsx b/frontend/src/pages/CausalLab.tsx
index ef99c93..1939176 100644
--- a/frontend/src/pages/CausalLab.tsx
+++ b/frontend/src/pages/CausalLab.tsx
@@ -386,6 +386,7 @@ function TabLibrary({ initialTemplateId }: { initialTemplateId?: number | null }
   const [genTheory, setGenTheory]   = useState(false)
   const [editCoefs, setEditCoefs]   = useState<Record<string, number>>({})
   const [editEdgesLag, setEdgesLag] = useState<CausalEdge[]>([])
+  const [lagDirty, setLagDirty]   = useState(false)
   const [loading, setLoading]     = useState(true)
   const [apiError, setApiError]   = useState<string | null>(null)
   const [debugInfo, setDebugInfo] = useState<Record<string, unknown> | null>(null)
@@ -414,6 +415,7 @@ function TabLibrary({ initialTemplateId }: { initialTemplateId?: number | null }
       Object.entries(t.graph_json?.coefficients || {}).map(([k, v]) => [k, v.value])
     ))
     setEdgesLag(JSON.parse(JSON.stringify(t.graph_json?.edges || [])))
+    setLagDirty(false)
   }
 
   async function saveCoefs() {
@@ -441,6 +443,7 @@ function TabLibrary({ initialTemplateId }: { initialTemplateId?: number | null }
       const fresh = await api(`/api/causal-lab/template/${selected.id}`)
       setSelected(fresh)
       setEdgesLag(JSON.parse(JSON.stringify(fresh.graph_json?.edges || [])))
+      setLagDirty(false)
     } finally { setSavingLag(false) }
   }
 
@@ -474,6 +477,7 @@ function TabLibrary({ initialTemplateId }: { initialTemplateId?: number | null }
       [field]: val === '' ? (field === 'decay_days' ? null : undefined)
                           : (field === 'decay_days' ? parseFloat(val) : parseInt(val)),
     }))
+    setLagDirty(true)
   }
 
   async function deleteTemplate() {
@@ -642,8 +646,12 @@ function TabLibrary({ initialTemplateId }: { initialTemplateId?: number | null }
                 ))}
               </div>
               <button onClick={saveTemporalParams} disabled={savingLag}
-                className="mt-4 px-4 py-2 bg-yellow-700 hover:bg-yellow-600 disabled:opacity-50 rounded text-xs font-medium text-white">
-                {savingLag ? 'Sauvegarde…' : 'Sauvegarder les paramètres temporels'}
+                className={clsx(
+                  'mt-4 px-4 py-2 rounded text-xs font-medium text-white disabled:opacity-50 transition-all',
+                  lagDirty ? 'bg-amber-600 hover:bg-amber-500 ring-2 ring-amber-400/50 animate-pulse'
+                           : 'bg-slate-700 hover:bg-slate-600'
+                )}>
+                {savingLag ? 'Sauvegarde…' : lagDirty ? '⚠ Sauvegarder les paramètres temporels' : 'Paramètres temporels sauvegardés'}
               </button>
             </div>
           )}