diff --git a/time_tracker.py b/time_tracker.py
index 7ff0afb..bd82aee 100644
--- a/time_tracker.py
+++ b/time_tracker.py
@@ -1,10 +1,6 @@
 #!/usr/bin/env python3
 
-#TODO:
-# - alternating colors for each hour
-# - more compact user interface
-# - button to open the archive csv in text editor (vim)
-# - make sure it runs on windows
+
 
 import tkinter as tk
 from tkinter import ttk, messagebox, filedialog
@@ -24,14 +20,26 @@ drag_info = {
 }
 
 class ClickableCell(tk.Frame):
-    def __init__(self, parent, row_col_key, callback, width=5, height=2):
+    def __init__(self, parent, row_col_key, callback, width=5, height=2, start_hour=9):
         super().__init__(parent, relief="solid", borderwidth=1, width=width, height=height)
         self.row_col_key = row_col_key
         self.callback = callback
         self.checked = False
-
-        # Create label
-        self.label = tk.Label(self, text=" ", bg="white", width=width, height=height)
+        self.start_hour = start_hour
+        
+        # Calculate which hour this cell represents based on column index
+        col_idx = row_col_key[1]
+        hour_offset = col_idx // 4  # 4 cells per hour (15-minute intervals)
+        current_hour = start_hour + hour_offset
+        
+        # Determine background color based on hour (alternating pattern)
+        if current_hour % 2 == 0:
+            self.default_bg = "#e8e8e8"  # Medium gray for even hours
+        else:
+            self.default_bg = "#f5f5f5"   # Light gray for odd hours
+        
+        # Create label with hour-based background
+        self.label = tk.Label(self, text=" ", bg=self.default_bg, width=width, height=height)
         self.label.pack(fill="both", expand=True)
 
         # Bind only click events for now
@@ -51,7 +59,7 @@ class ClickableCell(tk.Frame):
         if self.checked:
             self.label.config(bg="lightblue", text="✓")
         else:
-            self.label.config(bg="white", text=" ")
+            self.label.config(bg=self.default_bg, text=" ")
         self.callback(self.row_col_key, self.checked)
         drag_info['last_cell'] = self.row_col_key
 
@@ -68,7 +76,7 @@ class ClickableCell(tk.Frame):
             return True
         elif mode == 'erase' and self.checked:
             self.checked = False
-            self.label.config(bg="white", text=" ")
+            self.label.config(bg=self.default_bg, text=" ")
             self.callback(self.row_col_key, False)
             return True
         return False
@@ -78,7 +86,7 @@ class ClickableCell(tk.Frame):
         if checked:
             self.label.config(bg="lightblue", text="✓")
         else:
-            self.label.config(bg="white", text=" ")
+            self.label.config(bg=self.default_bg, text=" ")
 
 class TimeTracker:
     def __init__(self, root):
@@ -388,7 +396,7 @@ class TimeTracker:
         self.time_cells[row_num] = {}
         time_slots = self.work_hours * 4  # Calculate based on current settings
         for i in range(time_slots):
-            cell = ClickableCell(self.scrollable_frame, (row_num, i), self.on_time_cell_clicked, width=5, height=1)
+            cell = ClickableCell(self.scrollable_frame, (row_num, i), self.on_time_cell_clicked, width=5, height=1, start_hour=self.start_hour)
             cell.grid(row=row_num, column=4 + i, sticky="nsew", padx=1, pady=1)
             self.time_cells[row_num][i] = cell
 
@@ -469,7 +477,7 @@ class TimeTracker:
                         if cell.checked:
                             cell.label.config(bg="lightblue", text="✓")
                         else:
-                            cell.label.config(bg="white", text=" ")
+                            cell.label.config(bg=cell.default_bg, text=" ")
 
         self.update_total_hours(row_num)
         self.update_day_total()