style: 优化文章内容中各级标题的视觉样式

src/app.css

@@ -494,18 +494,50 @@ body.single-col .post-list {
 }
 
 .article-content h2 {
-	font-size: 1.5em;
+	font-size: 1.6em;
-	margin: 1.005em 0 0.375em;
+	margin: 1.5em 0 0.8em;
-	border-bottom: none;
+	padding-left: 14px;
-	padding-bottom: 0;
+	border-left: 5px solid var(--accent-color);
+	line-height: 1.4;
+	background: linear-gradient(to right, rgba(65, 155, 56, 0.08) 0%, transparent 100%);
+	padding-top: 4px;
+	padding-bottom: 4px;
 }
 
 .article-content h3 {
-	font-size: 1.17em;
+	font-size: 1.3em;
-	margin: 1em 0 0.2925em;
+	margin: 1.2em 0 0.6em;
+	display: flex;
+	align-items: center;
+}
+
+.article-content h3::before {
+	content: '#';
+	color: var(--accent-color);
+	margin-right: 8px;
+	font-weight: bold;
+	font-size: 1.1em;
+}
+
+.article-content h4 {
+	font-size: 1.1em;
+	margin: 1em 0 0.5em;
+	position: relative;
+	padding-left: 12px;
+}
+
+.article-content h4::before {
+	content: '';
+	position: absolute;
+	left: 0;
+	top: 50%;
+	transform: translateY(-50%);
+	width: 4px;
+	height: 4px;
+	border-radius: 50%;
+	background-color: var(--accent-color);
 }
 
-.article-content h4,
 .article-content h5,
 .article-content h6 {
 	font-size: 1em;