fix

components/HabitHeatmap.tsx

@@ -2,6 +2,8 @@
 
 import HeatMap from '@uiw/react-heat-map'
 import { Habit } from '@/lib/types'
+import { getDateInTimezone } from '@/lib/utils'
+import { useSettings } from '@/hooks/useSettings'
 
 interface HabitHeatmapProps {
   habits: Habit[]
@@ -24,9 +26,12 @@ export default function HabitHeatmap({ habits }: HabitHeatmapProps) {
     count
   }))
 
+  const { settings } = useSettings()
+
   // Get start date (30 days ago)
-  const startDate = new Date()
-  startDate.setDate(startDate.getDate() - 30)
+  const now = getDateInTimezone(new Date(), settings.system.timezone)
+  const startDate = now
+  startDate.setDate(now.getDate() - 30)
 
   return (
     <div className="p-4 bg-white rounded-lg shadow">

hooks/useHabits.tsx

@@ -5,7 +5,7 @@ import { toast } from '@/hooks/use-toast'
 import { ToastAction } from '@/components/ui/toast'
 import { Undo2 } from 'lucide-react'
 import { Habit } from '@/lib/types'
-import { getTodayInTimezone } from '@/lib/utils'
+import { getDateInTimezone, getTodayInTimezone } from '@/lib/utils'
 
 export function useHabits() {
   const [habits, setHabits] = useState<Habit[]>([])
@@ -21,7 +21,7 @@ export function useHabits() {
   }
 
   const addHabit = async (habit: Omit<Habit, 'id'>) => {
-    const newHabit = { ...habit, id: Date.now().toString() }
+    const newHabit = { ...habit, id: getDateInTimezone(new Date(), settings.system.timezone).getTime().toString() }
     const newHabits = [...habits, newHabit]
     setHabits(newHabits)
     await saveHabitsData({ habits: newHabits })
@@ -74,7 +74,7 @@ export function useHabits() {
   }
 
   const undoComplete = async (habit: Habit) => {
-    const today = new Date().toISOString().split('T')[0]
+    const today = getTodayInTimezone(settings.system.timezone)
     const updatedHabit = {
       ...habit,
       completions: habit.completions.filter(date => date !== today)