Add bottom-right corner mode switching with 3s hover timer

src/components/ChessboardRepaintPuzzle.tsx

@@ -96,6 +96,16 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
   const handleSquareClick = (row: number, col: number) => {
     if (isComplete) return;
     
+    // Special case for bottom-right corner
+    if (row === 7 && col === 7) {
+      if (bottomRightMode === 'row') {
+        repaintRow(7);
+      } else {
+        repaintColumn(7);
+      }
+      return;
+    }
+    
     // If clicking on the rightmost column, repaint the entire row
     if (col === 7) {
       repaintRow(row);
@@ -112,11 +122,49 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
     repaint2x2Square(row, col);
   };
 
+  const handleBottomRightHover = () => {
+    // Clear any existing timer
+    if (hoverTimer) {
+      clearTimeout(hoverTimer);
+    }
+    
+    // Set a new timer to switch mode after 3 seconds
+    const timer = setTimeout(() => {
+      setBottomRightMode(prev => prev === 'row' ? 'column' : 'row');
+    }, 3000);
+    
+    setHoverTimer(timer);
+  };
+
+  const handleBottomRightLeave = () => {
+    // Clear the timer when leaving the square
+    if (hoverTimer) {
+      clearTimeout(hoverTimer);
+      setHoverTimer(null);
+    }
+  };
+
   const [hoveredSquare, setHoveredSquare] = useState<{row: number, col: number} | null>(null);
+  const [bottomRightMode, setBottomRightMode] = useState<'row' | 'column'>('row');
+  const [hoverTimer, setHoverTimer] = useState<NodeJS.Timeout | null>(null);
 
   const getAffectedSquares = (row: number, col: number) => {
     const squares: {row: number, col: number}[] = [];
     
+    // Special case for bottom-right corner
+    if (row === 7 && col === 7) {
+      if (bottomRightMode === 'row') {
+        for (let c = 0; c < 8; c++) {
+          squares.push({row: 7, col: c});
+        }
+      } else {
+        for (let r = 0; r < 8; r++) {
+          squares.push({row: r, col: 7});
+        }
+      }
+      return squares;
+    }
+    
     // If clicking on the rightmost column, repaint the entire row
     if (col === 7) {
       for (let c = 0; c < 8; c++) {
@@ -146,6 +194,7 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
     const isBlack = board[row][col];
     const isBottomRow = row === 7;
     const isRightmostCol = col === 7;
+    const isBottomRight = row === 7 && col === 7;
     
     // Check if this square would be affected by hovering over the hovered square
     const isAffected = hoveredSquare && getAffectedSquares(hoveredSquare.row, hoveredSquare.col)
@@ -155,14 +204,26 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
       <div
         key={`${row}-${col}`}
         onClick={() => handleSquareClick(row, col)}
-        onMouseEnter={() => setHoveredSquare({row, col})}
+        onMouseEnter={() => {
-        onMouseLeave={() => setHoveredSquare(null)}
+          setHoveredSquare({row, col});
+          if (isBottomRight) {
+            handleBottomRightHover();
+          }
+        }}
+        onMouseLeave={() => {
+          setHoveredSquare(null);
+          if (isBottomRight) {
+            handleBottomRightLeave();
+          }
+        }}
         className={`
           w-12 h-12 border border-gray-300 flex items-center justify-center cursor-pointer
           transition-all duration-200 hover:scale-105
           ${isBlack ? 'bg-gray-800' : 'bg-gray-100'}
           ${isAffected ? 'border-2 border-red-500' : ''}
+          ${isBottomRight ? 'bg-yellow-50' : ''}
         `}
+        title={isBottomRight ? `Hover for 3s to switch mode (current: ${bottomRightMode})` : undefined}
       />
     );
   };
@@ -237,7 +298,7 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
                 {isComplete ? (
                   "🎉 Congratulations! You achieved exactly one black square!"
                 ) : (
-                  "Click any square to repaint the 2×2 region with that square as top-left. Click rightmost column to repaint entire row, or bottom row to repaint entire column. Hover to preview affected squares!"
+                  "Click any square to repaint the 2×2 region with that square as top-left. Click rightmost column to repaint entire row, or bottom row to repaint entire column. Bottom-right corner switches between row/column mode on 3s hover. Hover to preview affected squares!"
                 )}
               </p>
             </div>
@@ -259,6 +320,10 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
                 <div className="w-5 h-5 border-2 border-red-500"></div>
                 <span>Hover to preview affected squares</span>
               </div>
+              <div className="flex items-center gap-2">
+                <div className="w-5 h-5 bg-yellow-50 border border-gray-300"></div>
+                <span>Bottom-right corner (switchable mode)</span>
+              </div>
             </div>
           </div>
         </CardContent>
@@ -290,6 +355,7 @@ const ChessboardRepaintPuzzle: React.FC<ChessboardRepaintPuzzleProps> = ({ showS
                 <li><strong>Repaint a 2×2 square:</strong> Click any square to flip all four squares in the 2×2 region with that square as the top-left corner.</li>
                 <li><strong>Repaint a row:</strong> Click any square in the rightmost column to flip all squares in that entire row.</li>
                 <li><strong>Repaint a column:</strong> Click any square in the bottom row to flip all squares in that entire column.</li>
+                <li><strong>Bottom-right corner:</strong> Hover for 3 seconds to switch between row and column mode. The corner square is highlighted in light yellow.</li>
                 <li><strong>Preview:</strong> Hover over any square to see which squares will be affected (highlighted with red border).</li>
                 <li><strong>Goal:</strong> Achieve exactly one black square on the entire board.</li>
               </ol>