refactor: 改进 Markdown 编辑器高度与布局样式

src/lib/components/admin/MarkdownEditor.svelte

@@ -91,18 +91,15 @@
 			boxShadow: '0 0 0 3px rgba(65, 155, 56, 0.08)'
 		},
 		'.cm-content': {
-			minHeight: '400px',
 			padding: '12px 14px',
 			lineHeight: '1.8'
 		},
 		'.cm-scroller': {
-			overflow: 'auto',
-			minHeight: '400px'
+			overflow: 'auto'
 		},
 		'.cm-gutters': {
 			backgroundColor: 'rgba(0, 0, 0, 0.03)',
 			color: 'rgba(0, 0, 0, 0.4)',
-			minHeight: '400px',
 			borderRight: '1px solid rgba(0, 0, 0, 0.12)',
 			borderTopLeftRadius: '0',
 			borderBottomLeftRadius: '0'
@@ -377,6 +374,14 @@
 
 	.editor-container {
 		width: 100%;
+		min-height: 400px;
+		display: flex;
+		flex-direction: column;
+	}
+
+	.editor-container :global(.cm-editor) {
+		flex: 1;
+		height: 100%;
 	}
 
 	.md-toolbar {