优化Presentation组件，支持添加背景

components/presentation/Presentation.css

@@ -28,6 +28,25 @@
   color: white !important;
 }
 
+/* 带背景的幻灯片文字颜色 */
+.reveal-container .reveal .slides section[data-background] {
+  color: white !important;
+}
+
+.reveal-container .reveal .slides section[data-background] h1,
+.reveal-container .reveal .slides section[data-background] h2,
+.reveal-container .reveal .slides section[data-background] h3,
+.reveal-container .reveal .slides section[data-background] h4,
+.reveal-container .reveal .slides section[data-background] h5,
+.reveal-container .reveal .slides section[data-background] h6 {
+  color: white !important;
+}
+
+.reveal-container .reveal .slides section[data-background] p,
+.reveal-container .reveal .slides section[data-background] li {
+  color: rgba(255, 255, 255, 0.9) !important;
+}
+
 .reveal-container .reveal .slides section h1,
 .reveal-container .reveal .slides section h2,
 .reveal-container .reveal .slides section h3,

components/presentation/Presentation.jsx

@@ -25,7 +25,7 @@ const REVEAL_CONFIG = {
   fragmentInURL: false,
   embedded: false,
   help: true,
-  showNotes: false,
+  showNotes: true,
   autoPlayMedia: null,
   preloadIframes: null,
   autoSlide: 0,
@@ -99,14 +99,24 @@ export default function Presentation({ data }) {
       const trimmedSection = section.trim();
       if (!trimmedSection) return '';
       
-      const htmlContent = marked(trimmedSection);
+      // 检查是否有背景设置
+      const backgroundMatch = trimmedSection.match(/<!-- \.slide: data-background="([^"]+)"[^>]* -->/);
+      let backgroundAttr = '';
+      let contentWithoutBackground = trimmedSection;
+      
+      if (backgroundMatch) {
+        backgroundAttr = ` data-background="${backgroundMatch[1]}"`;
+        contentWithoutBackground = trimmedSection.replace(/<!-- \.slide: data-background="[^"]+"[^>]* -->/g, '');
+      }
+      
+      const htmlContent = marked(contentWithoutBackground);
       
       // 如果是第一个幻灯片且没有标题，添加标题
       if (index === 0 && !htmlContent.includes('<h1>') && data.title) {
-        return `<section><h1>${data.title}</h1>${htmlContent}</section>`;
+        return `<section${backgroundAttr}><h1>${data.title}</h1>${htmlContent}</section>`;
       }
       
-      return `<section>${htmlContent}</section>`;
+      return `<section${backgroundAttr}>${htmlContent}</section>`;
     }).join('');
   };