Implement 10 UI/UX improvements and bug fixes

- Fix outdated Todoist task URL format (showTask -> app/task)
- Fix quick-add date defaulting to tomorrow in evening (client-side JS)
- Add tap-to-expand for task descriptions with checkbox completion
- Add visual differentiation: overdue (red), future (gray), today (normal)
- Sort tasks by urgency: overdue > today-timed > today-allday > future
- Keep completed tasks visible with strikethrough until refresh
- Add random Unsplash landscape background with content overlay
- Hide future tasks behind collapsible fold with count badge
- Unified modal menu for Quick Add + Bug Report (Ctrl+K shortcut)
- Click task title to edit description in modal

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

3 files changed, 203 insertions, 38 deletions

diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
index e4d6457..73a05f0 100644
--- a/internal/handlers/handlers.go
+++ b/internal/handlers/handlers.go
@@ -78,15 +78,21 @@ func (h *Handler) HandleDashboard(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Generate random background URL (Unsplash Source API)
+	// Add timestamp to prevent caching
+	backgroundURL := fmt.Sprintf("https://source.unsplash.com/1920x1080/?landscape,nature&t=%d", time.Now().UnixNano())
+
 	// Wrap dashboard data with active tab for template
 	data := struct {
 		*models.DashboardData
-		ActiveTab string
-		CSRFToken string
+		ActiveTab     string
+		CSRFToken     string
+		BackgroundURL string
 	}{
 		DashboardData: dashboardData,
 		ActiveTab:     tab,
 		CSRFToken:     auth.GetCSRFTokenFromContext(ctx),
+		BackgroundURL: backgroundURL,
 	}
 
 	if err := h.templates.ExecuteTemplate(w, "index.html", data); err != nil {
@@ -411,7 +417,7 @@ func (h *Handler) convertSyncItemToTask(item api.SyncItemResponse, projectMap ma
 		Priority:    item.Priority,
 		Completed:   false,
 		Labels:      item.Labels,
-		URL:         fmt.Sprintf("https://todoist.com/showTask?id=%s", item.ID),
+		URL:         fmt.Sprintf("https://todoist.com/app/task/%s", item.ID),
 	}
 
 	if item.AddedAt != "" {
@@ -728,6 +734,34 @@ func (h *Handler) HandleCompleteAtom(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Get task title before removing from cache
+	var title string
+	switch source {
+	case "todoist":
+		if tasks, err := h.store.GetTasks(); err == nil {
+			for _, t := range tasks {
+				if t.ID == id {
+					title = t.Content
+					break
+				}
+			}
+		}
+	case "trello":
+		if boards, err := h.store.GetBoards(); err == nil {
+			for _, b := range boards {
+				for _, c := range b.Cards {
+					if c.ID == id {
+						title = c.Name
+						break
+					}
+				}
+			}
+		}
+	}
+	if title == "" {
+		title = "Task"
+	}
+
 	// Remove from local cache
 	switch source {
 	case "todoist":
@@ -740,8 +774,19 @@ func (h *Handler) HandleCompleteAtom(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// Return 200 OK with empty body to remove the element from DOM
-	w.WriteHeader(http.StatusOK)
+	// Return completed task HTML (stays visible with strikethrough until refresh)
+	w.Header().Set("Content-Type", "text/html")
+	completedHTML := fmt.Sprintf(`<div class="task-item bg-gray-100 rounded-lg shadow-sm border-l-4 border-gray-300 opacity-60">
+		<div class="flex items-start gap-2 sm:gap-3 p-3 sm:p-4">
+			<input type="checkbox" checked disabled class="mt-1 h-5 w-5 rounded border-gray-300 text-green-600 cursor-not-allowed flex-shrink-0">
+			<span class="text-lg flex-shrink-0">✓</span>
+			<div class="flex-1 min-w-0">
+				<h3 class="text-sm font-medium text-gray-400 line-through break-words">%s</h3>
+				<div class="text-xs text-green-600 mt-1">Completed</div>
+			</div>
+		</div>
+	</div>`, template.HTMLEscapeString(title))
+	w.Write([]byte(completedHTML))
 }
 
 // HandleUnifiedAdd creates a task in Todoist or a card in Trello from the Quick Add form
@@ -875,3 +920,98 @@ func (h *Handler) HandleReportBug(w http.ResponseWriter, r *http.Request) {
 	// Return updated bug list
 	h.HandleGetBugs(w, r)
 }
+
+// HandleGetTaskDetail returns task details as HTML for modal
+func (h *Handler) HandleGetTaskDetail(w http.ResponseWriter, r *http.Request) {
+	id := r.URL.Query().Get("id")
+	source := r.URL.Query().Get("source")
+
+	if id == "" || source == "" {
+		http.Error(w, "Missing id or source", http.StatusBadRequest)
+		return
+	}
+
+	var title, description string
+	switch source {
+	case "todoist":
+		tasks, err := h.store.GetTasks()
+		if err == nil {
+			for _, t := range tasks {
+				if t.ID == id {
+					title = t.Content
+					description = t.Description
+					break
+				}
+			}
+		}
+	case "trello":
+		boards, err := h.store.GetBoards()
+		if err == nil {
+			for _, b := range boards {
+				for _, c := range b.Cards {
+					if c.ID == id {
+						title = c.Name
+						// Card model doesn't store description, leave empty
+						description = ""
+						break
+					}
+				}
+			}
+		}
+	}
+
+	w.Header().Set("Content-Type", "text/html")
+	html := fmt.Sprintf(`
+		<div class="p-4">
+			<h3 class="font-semibold text-gray-900 mb-3">%s</h3>
+			<form hx-post="/tasks/update" hx-swap="none" hx-on::after-request="if(event.detail.successful) { closeTaskModal(); htmx.trigger(document.body, 'refresh-tasks'); }">
+				<input type="hidden" name="id" value="%s">
+				<input type="hidden" name="source" value="%s">
+				<label class="block text-sm font-medium text-gray-700 mb-1">Description</label>
+				<textarea name="description" class="w-full border border-gray-300 rounded-lg px-3 py-2 text-sm mb-3 h-32">%s</textarea>
+				<button type="submit" class="w-full bg-primary-600 hover:bg-primary-700 text-white px-4 py-2 rounded-lg text-sm font-medium">Save</button>
+			</form>
+		</div>
+	`, template.HTMLEscapeString(title), template.HTMLEscapeString(id), template.HTMLEscapeString(source), template.HTMLEscapeString(description))
+	w.Write([]byte(html))
+}
+
+// HandleUpdateTask updates a task description
+func (h *Handler) HandleUpdateTask(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "Failed to parse form", http.StatusBadRequest)
+		return
+	}
+
+	id := r.FormValue("id")
+	source := r.FormValue("source")
+	description := r.FormValue("description")
+
+	if id == "" || source == "" {
+		http.Error(w, "Missing id or source", http.StatusBadRequest)
+		return
+	}
+
+	var err error
+	switch source {
+	case "todoist":
+		updates := map[string]interface{}{"description": description}
+		err = h.todoistClient.UpdateTask(ctx, id, updates)
+	case "trello":
+		updates := map[string]interface{}{"desc": description}
+		err = h.trelloClient.UpdateCard(ctx, id, updates)
+	default:
+		http.Error(w, "Unknown source", http.StatusBadRequest)
+		return
+	}
+
+	if err != nil {
+		http.Error(w, "Failed to update task", http.StatusInternalServerError)
+		log.Printf("Error updating task: %v", err)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}
diff --git a/internal/handlers/handlers_test.go b/internal/handlers/handlers_test.go
index 6e9346a..e4a9f05 100644
--- a/internal/handlers/handlers_test.go
+++ b/internal/handlers/handlers_test.go
@@ -79,6 +79,10 @@ func (m *mockTodoistClient) CreateTask(ctx context.Context, content, projectID s
 	return nil, nil
 }
 
+func (m *mockTodoistClient) UpdateTask(ctx context.Context, taskID string, updates map[string]interface{}) error {
+	return m.err
+}
+
 func (m *mockTodoistClient) CompleteTask(ctx context.Context, taskID string) error {
 	return nil
 }
diff --git a/internal/handlers/tabs.go b/internal/handlers/tabs.go
index bd15710..2f22c44 100644
--- a/internal/handlers/tabs.go
+++ b/internal/handlers/tabs.go
@@ -25,6 +25,25 @@ func isActionableList(name string) bool {
 		strings.Contains(lower, "today")
 }
 
+// atomUrgencyTier returns the urgency tier for sorting:
+// 0: Overdue, 1: Today with time, 2: Today all-day, 3: Future, 4: No due date
+func atomUrgencyTier(a models.Atom) int {
+	if a.DueDate == nil {
+		return 4 // No due date
+	}
+	if a.IsOverdue {
+		return 0 // Overdue
+	}
+	if a.IsFuture {
+		return 3 // Future
+	}
+	// Due today
+	if a.HasSetTime {
+		return 1 // Today with specific time
+	}
+	return 2 // Today all-day
+}
+
 // TabsHandler handles tab-specific rendering with Atom model
 type TabsHandler struct {
 	store     *store.Store
@@ -88,41 +107,31 @@ func (h *TabsHandler) HandleTasks(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// Compute UI fields (IsOverdue, HasSetTime)
+	// Compute UI fields (IsOverdue, IsFuture, HasSetTime)
 	for i := range atoms {
 		atoms[i].ComputeUIFields()
 	}
 
-	// Sort atoms: by DueDate (earliest first), then by HasSetTime, then by Priority
+	// Sort atoms by urgency tiers:
+	// 1. Overdue (before today)
+	// 2. Today with specific time
+	// 3. Today all-day (midnight)
+	// 4. Future
+	// 5. No due date
+	// Within each tier: sort by due date/time, then by priority
 	sort.SliceStable(atoms, func(i, j int) bool {
-		// Handle nil due dates (push to end)
-		if atoms[i].DueDate == nil && atoms[j].DueDate != nil {
-			return false
-		}
-		if atoms[i].DueDate != nil && atoms[j].DueDate == nil {
-			return true
+		// Compute urgency tier (lower = more urgent)
+		tierI := atomUrgencyTier(atoms[i])
+		tierJ := atomUrgencyTier(atoms[j])
+
+		if tierI != tierJ {
+			return tierI < tierJ
 		}
 
-		// Both have due dates
+		// Same tier: sort by due date/time if both have dates
 		if atoms[i].DueDate != nil && atoms[j].DueDate != nil {
-			// Compare by date only (ignore time)
-			dateI := atoms[i].DueDate.Truncate(24 * time.Hour)
-			dateJ := atoms[j].DueDate.Truncate(24 * time.Hour)
-
-			if !dateI.Equal(dateJ) {
-				return dateI.Before(dateJ)
-			}
-
-			// Same day: tasks with set times come before midnight tasks
-			if atoms[i].HasSetTime != atoms[j].HasSetTime {
-				return atoms[i].HasSetTime
-			}
-
-			// Both have set times or both are midnight, sort by actual time
-			if atoms[i].HasSetTime && atoms[j].HasSetTime {
-				if !atoms[i].DueDate.Equal(*atoms[j].DueDate) {
-					return atoms[i].DueDate.Before(*atoms[j].DueDate)
-				}
+			if !atoms[i].DueDate.Equal(*atoms[j].DueDate) {
+				return atoms[i].DueDate.Before(*atoms[j].DueDate)
 			}
 		}
 
@@ -130,15 +139,27 @@ func (h *TabsHandler) HandleTasks(w http.ResponseWriter, r *http.Request) {
 		return atoms[i].Priority > atoms[j].Priority
 	})
 
+	// Partition atoms into current (overdue + today) and future
+	var currentAtoms, futureAtoms []models.Atom
+	for _, a := range atoms {
+		if a.IsFuture {
+			futureAtoms = append(futureAtoms, a)
+		} else {
+			currentAtoms = append(currentAtoms, a)
+		}
+	}
+
 	// Render template
 	data := struct {
-		Atoms  []models.Atom
-		Boards []models.Board
-		Today  string
+		Atoms       []models.Atom // Current tasks (overdue + today)
+		FutureAtoms []models.Atom // Future tasks (hidden by default)
+		Boards      []models.Board
+		Today       string
 	}{
-		Atoms:  atoms,
-		Boards: boards,
-		Today:  time.Now().Format("2006-01-02"),
+		Atoms:       currentAtoms,
+		FutureAtoms: futureAtoms,
+		Boards:      boards,
+		Today:       time.Now().Format("2006-01-02"),
 	}
 
 	if err := h.templates.ExecuteTemplate(w, "tasks-tab", data); err != nil {