feat: 为TODO列表添加折叠已完成任务功能

- 添加折叠/展开已完成任务的按钮，显示已完成数量
- 实现流畅的折叠展开动画效果（高度、透明度、位移）
- 优化删除和完成任务的动画，增加缩放效果
- 同时支持桌面端和移动端
- 折叠按钮在没有已完成任务时自动隐藏
- 使用 CSS transition 实现平滑的进入退出动画

argontheme.js

@@ -3198,10 +3198,40 @@ $(document).on("click" , "#blog_categories .tag" , function(){
 	// ========== 移动端TODO交互 ==========
 	function updateMobileTodoCount() {
 		var count = $("#mobile-todo-list .mobile-todo-item:not(.todo-completed)").length;
+		var completedCount = $("#mobile-todo-list .mobile-todo-item.todo-completed").length;
 		$("#mobile_todo_count").text(count);
 		// 同步更新桌面端计数
 		$(".todo-count").text(count);
+		
+		// 更新折叠按钮
+		var collapseBtn = $("#mobile-todo-collapse-btn");
+		if (collapseBtn.length) {
+			collapseBtn.find(".mobile-todo-completed-count").text(completedCount);
+			if (completedCount > 0) {
+				collapseBtn.show();
+			} else {
+				collapseBtn.hide();
 			}
+		}
+	}
+	
+	// 移动端折叠/展开已完成任务
+	$(document).on("click", "#mobile-todo-collapse-btn", function(e) {
+		e.stopPropagation();
+		var btn = $(this);
+		var completedItems = $("#mobile-todo-list .mobile-todo-item.todo-completed");
+		var isCollapsed = btn.hasClass("collapsed");
+		
+		if (isCollapsed) {
+			// 展开
+			btn.removeClass("collapsed");
+			completedItems.removeClass("collapsed");
+		} else {
+			// 折叠
+			btn.addClass("collapsed");
+			completedItems.addClass("collapsed");
+		}
+	});
 	
 	// 添加TODO
 	$(document).on("click", "#mobile-todo-add-btn", function() {

sidebar.php

@@ -165,6 +165,15 @@ $author_desc = get_option('argon_sidebar_author_description');
 						<i class="fa fa-check-square-o collapse-icon"></i>
 						<span class="collapse-title"><?php _e('TODO', 'argon'); ?></span>
 						<span class="collapse-badge" id="mobile_todo_count"><?php echo $mobile_uncompleted_count; ?></span>
+						<?php 
+						$mobile_completed_count = count(array_filter($mobile_todos, function($t) { return !empty($t['completed']); }));
+						if ($mobile_completed_count > 0) : 
+						?>
+						<button class="mobile-todo-collapse-btn" id="mobile-todo-collapse-btn" title="<?php _e('折叠/展开已完成', 'argon'); ?>">
+							<i class="fa fa-chevron-down"></i>
+							<span class="mobile-todo-completed-count"><?php echo $mobile_completed_count; ?></span>
+						</button>
+						<?php endif; ?>
 					</div>
 					<i class="fa fa-chevron-down collapse-arrow"></i>
 				</div>
@@ -854,8 +863,15 @@ $author_desc = get_option('argon_sidebar_author_description');
 					<i class="fa fa-list-ul"></i> <?php _e('TODO', 'argon'); ?>
 					<?php 
 					$uncompleted_count = count(array_filter($todos, function($t) { return empty($t['completed']); }));
+					$completed_count = count(array_filter($todos, function($t) { return !empty($t['completed']); }));
 					?>
 					<span class="todo-count" title="<?php echo $is_author ? __('未完成', 'argon') : __('待办事项', 'argon'); ?>"><?php echo $uncompleted_count; ?></span>
+					<?php if ($completed_count > 0) : ?>
+					<button class="todo-collapse-btn" id="todo-collapse-btn" title="<?php _e('折叠/展开已完成', 'argon'); ?>">
+						<i class="fa fa-chevron-down"></i>
+						<span class="todo-completed-count"><?php echo $completed_count; ?></span>
+					</button>
+					<?php endif; ?>
 				</h6>
 				
 				<?php if ($is_author) : ?>
@@ -950,9 +966,26 @@ $author_desc = get_option('argon_sidebar_author_description');
 			
 			function updateCount() {
 				var count = document.querySelectorAll('.todo-item:not(.todo-completed)').length;
+				var completedCount = document.querySelectorAll('.todo-item.todo-completed').length;
 				var countEl = document.querySelector('.todo-count');
 				if (countEl) countEl.textContent = count;
 				
+				// 更新折叠按钮
+				var collapseBtn = document.getElementById('todo-collapse-btn');
+				var completedCountEl = collapseBtn ? collapseBtn.querySelector('.todo-completed-count') : null;
+				if (completedCountEl) {
+					completedCountEl.textContent = completedCount;
+				}
+				
+				// 显示/隐藏折叠按钮
+				if (collapseBtn) {
+					if (completedCount > 0) {
+						collapseBtn.style.display = 'flex';
+					} else {
+						collapseBtn.style.display = 'none';
+					}
+				}
+				
 				var totalCount = document.querySelectorAll('.todo-item').length;
 				var list = document.getElementById('todo-list');
 				if (totalCount > 4) {
@@ -970,6 +1003,30 @@ $author_desc = get_option('argon_sidebar_author_description');
 				}
 			}
 			
+			// 折叠/展开已完成任务
+			var collapseBtn = document.getElementById('todo-collapse-btn');
+			if (collapseBtn) {
+				collapseBtn.addEventListener('click', function(e) {
+					e.stopPropagation();
+					var completedItems = document.querySelectorAll('.todo-item.todo-completed');
+					var isCollapsed = collapseBtn.classList.contains('collapsed');
+					
+					if (isCollapsed) {
+						// 展开
+						collapseBtn.classList.remove('collapsed');
+						completedItems.forEach(function(item) {
+							item.classList.remove('collapsed');
+						});
+					} else {
+						// 折叠
+						collapseBtn.classList.add('collapsed');
+						completedItems.forEach(function(item) {
+							item.classList.add('collapsed');
+						});
+					}
+				});
+			}
+			
 			// 添加 TODO
 			if (isAuthor) {
 				var input = document.getElementById('todo-input');

style.css

@@ -10973,11 +10973,31 @@ html.darkmode.amoled-dark #content:after {
 		opacity: 0.6;
 		order: 1;
 		transform: scale(0.98);
+		max-height: 500px;
+		overflow: hidden;
+		transition: all var(--animation-normal) var(--ease-emphasized),
+					max-height var(--animation-normal) var(--ease-emphasized),
+					margin var(--animation-normal) var(--ease-emphasized),
+					padding var(--animation-normal) var(--ease-emphasized),
+					opacity var(--animation-normal) var(--ease-emphasized);
+	}
+	
+	.mobile-todo-item.todo-completed.collapsed {
+		max-height: 0;
+		margin-bottom: 0;
+		padding-top: 0;
+		padding-bottom: 0;
+		opacity: 0;
+		transform: translateY(-10px) scale(0.9);
 	}
 	
 	.mobile-todo-item.todo-completing {
 		opacity: 0;
 		transform: translateX(40px) scale(0.85);
+		max-height: 0;
+		margin-bottom: 0;
+		padding-top: 0;
+		padding-bottom: 0;
 		transition: all 0.4s var(--ease-emphasized-accelerate);
 	}
 	
@@ -10997,6 +11017,43 @@ html.darkmode.amoled-dark #content:after {
 		opacity: 0.35;
 	}
 	
+	/* 移动端折叠已完成按钮 */
+	.mobile-todo-collapse-btn {
+		display: flex;
+		align-items: center;
+		gap: 3px;
+		background: rgba(var(--themecolor-rgbstr), 0.12);
+		color: var(--themecolor);
+		border: none;
+		border-radius: 8px;
+		padding: 2px 6px;
+		font-size: 10px;
+		font-weight: 600;
+		cursor: pointer;
+		transition: all var(--animation-fast) var(--ease-standard);
+		margin-left: 6px;
+		flex-shrink: 0;
+	}
+	
+	.mobile-todo-collapse-btn:active {
+		background: rgba(var(--themecolor-rgbstr), 0.25);
+		transform: scale(0.92);
+	}
+	
+	.mobile-todo-collapse-btn i {
+		font-size: 8px;
+		transition: transform var(--animation-fast) var(--ease-standard);
+	}
+	
+	.mobile-todo-collapse-btn.collapsed i {
+		transform: rotate(-90deg);
+	}
+	
+	.mobile-todo-completed-count {
+		min-width: 10px;
+		text-align: center;
+	}
+
 	#navbar_global {
 		background: var(--color-foreground);
 	}
@@ -12559,6 +12616,42 @@ html.navbar-absolute #leftbar_part3.sticky {
 	margin-left: auto;
 }
 
+/* 折叠已完成按钮 */
+.todo-collapse-btn {
+	display: flex;
+	align-items: center;
+	gap: 4px;
+	background: rgba(var(--themecolor-rgbstr), 0.1);
+	color: var(--themecolor);
+	border: none;
+	border-radius: 8px;
+	padding: 2px 7px;
+	font-size: 10px;
+	font-weight: 600;
+	cursor: pointer;
+	transition: all var(--animation-fast) var(--ease-standard);
+	margin-left: 6px;
+}
+
+.todo-collapse-btn:hover {
+	background: rgba(var(--themecolor-rgbstr), 0.2);
+	transform: scale(1.05);
+}
+
+.todo-collapse-btn i {
+	font-size: 9px;
+	transition: transform var(--animation-fast) var(--ease-standard);
+}
+
+.todo-collapse-btn.collapsed i {
+	transform: rotate(-90deg);
+}
+
+.todo-completed-count {
+	min-width: 12px;
+	text-align: center;
+}
+
 /* 站长端：显示未完成数<E68890>?*/
 .todo-count::before {
 	content: '';
@@ -12734,7 +12827,11 @@ html.navbar-absolute #leftbar_part3.sticky {
 
 .todo-item.todo-completing {
 	opacity: 0;
-	transform: translateX(30px);
+	transform: translateX(30px) scale(0.9);
+	max-height: 0;
+	margin-bottom: 0;
+	padding-top: 0;
+	padding-bottom: 0;
 	transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
 }
 
@@ -12746,6 +12843,22 @@ html.navbar-absolute #leftbar_part3.sticky {
 .todo-item.todo-completed {
 	opacity: 0.7;
 	order: 1;
+	max-height: 500px;
+	overflow: hidden;
+	transition: all var(--animation-normal) var(--ease-emphasized),
+				max-height var(--animation-normal) var(--ease-emphasized),
+				margin var(--animation-normal) var(--ease-emphasized),
+				padding var(--animation-normal) var(--ease-emphasized),
+				opacity var(--animation-normal) var(--ease-emphasized);
+}
+
+.todo-item.todo-completed.collapsed {
+	max-height: 0;
+	margin-bottom: 0;
+	padding-top: 0;
+	padding-bottom: 0;
+	opacity: 0;
+	transform: translateY(-10px);
 }
 
 .todo-item.todo-completed:hover {