diff --git a/index.html b/index.html
index 6788313..7d80b08 100644
--- a/index.html
+++ b/index.html
@@ -597,12 +597,13 @@
                 // Custom input for horizontal definition
                 const customH = document.createElement('div');
                 customH.style.display = 'flex';
+                customH.style.flexDirection = 'column';
                 customH.style.gap = '8px';
                 customH.style.marginTop = '8px';
                 const inputH = document.createElement('input');
                 inputH.type = 'text';
                 inputH.value = grid[row][col].definitionH || '';
-                inputH.style.flex = '1';
+                inputH.style.width = '100%';
                 const saveH = document.createElement('button');
                 saveH.className = 'btn-primary';
                 saveH.textContent = 'Enregistrer (H)';
@@ -655,12 +656,13 @@
                 // Custom input for vertical definition
                 const customV = document.createElement('div');
                 customV.style.display = 'flex';
+                customV.style.flexDirection = 'column';
                 customV.style.gap = '8px';
                 customV.style.marginTop = '8px';
                 const inputV = document.createElement('input');
                 inputV.type = 'text';
                 inputV.value = grid[row][col].definitionV || '';
-                inputV.style.flex = '1';
+                inputV.style.width = '100%';
                 const saveV = document.createElement('button');
                 saveV.className = 'btn-primary';
                 saveV.textContent = 'Enregistrer (V)';
@@ -1066,6 +1068,14 @@
             if (e.ctrlKey || e.altKey || e.metaKey) return;
             if (document.getElementById('gridScreen').style.display === 'none') return;
 
+            // If modal is open, do not interact with grid via keyboard
+            const modal = document.getElementById('definitionModal');
+            if (modal.classList.contains('show')) return;
+
+            // don't intercept when focus is inside an input/textarea/contentEditable
+            const ae = document.activeElement;
+            if (ae && (ae.tagName === 'INPUT' || ae.tagName === 'TEXTAREA' || ae.isContentEditable)) return;
+
             // Toggle orientation with Tab when an active cell exists
             if (e.key === 'Tab') {
                 if (!activeCell) return;
@@ -1078,6 +1088,17 @@
             if (!activeCell) return;
             const { row, col } = activeCell;
 
+            // Delete key: transform active cell into empty letter
+            if (e.key === 'Delete') {
+                e.preventDefault();
+                grid[row][col].type = 'letter';
+                grid[row][col].letter = '';
+                grid[row][col].definitionH = '';
+                grid[row][col].definitionV = '';
+                renderGrid();
+                return;
+            }
+
             // Enter: transform empty letter into definition (or open modal if definition exists)
             if (e.key === 'Enter') {
                 e.preventDefault();