style: 优化卡片链接布局并调整封面图片显示样式

src/app.css

@@ -318,6 +318,8 @@ body.single-col .post-list {
 
 .card-link {
 	display: block;
+	max-width: 640px;
+	margin: 0 auto;
 }
 
 .card {
@@ -1388,21 +1390,17 @@ footer section p:first-child {
 	margin-right: 2px;
 }
 
-/* Featured Image Styles */
 .post-cover {
 	width: 100%;
 	height: auto;
 	overflow: hidden;
 	border-bottom: none;
-	text-align: center;
 }
 
 .post-cover img {
-	max-width: 100%;
+	width: 100%;
 	height: auto;
-	max-height: 260px;
 	display: block;
-	margin: 0 auto;
 	border-radius: 0;
 }