Refactor project data structure, add internationalization support, and enhance UI components

- Updated project data files to improve formatting and consistency.
- Introduced language support with English and Dutch translations.
- Implemented language switcher and dark mode toggle in the header and footer.
- Enhanced navigation components to utilize internationalized strings.
- Refactored layout components to use Grid2 for better responsiveness.
- Improved accessibility and usability across various components.

src/components/blog-accordion/BlogAccordion.jsx

@@ -1,37 +1,48 @@
 import React from "react";
 import {
-  Accordion,
-  AccordionSummary,
-  AccordionDetails,
-  Typography,
+	Accordion,
+	AccordionSummary,
+	AccordionDetails,
+	Typography,
 } from "@mui/material";
 
 import ExpandMoreIcon from "@mui/icons-material/ExpandMore";
 
 const BlogAccordion = ({ blogContent }) => {
-  return blogContent.map(({ title, description }) => (
-    <Accordion
-      // defaultExpanded
-      // slotProps={{ unmountOnExit: true }}
-      key={title}
-      sx={{ background: "transparent" }}
-    >
-      <AccordionSummary
-        expandIcon={<ExpandMoreIcon />}
-        aria-controls="panel1a-content"
-        id="panel1a-header"
-      >
-        <Typography variant="h5">{title}</Typography>
-      </AccordionSummary>
-      <AccordionDetails>
-        {description.map((lineContent, idx) => (
-          <Typography key={idx} paragraph>
-            {lineContent}
-          </Typography>
-        ))}
-      </AccordionDetails>
-    </Accordion>
-  ));
+	// normalize blogContent to an array to avoid `map` errors
+	const items = Array.isArray(blogContent)
+		? blogContent
+		: blogContent
+		? [blogContent]
+		: [];
+
+	if (items.length === 0) return null;
+
+	return items.map(({ title, description }, itemIdx) => {
+		const lines = Array.isArray(description)
+			? description
+			: description
+			? [description]
+			: [];
+
+		return (
+			<Accordion key={title ?? itemIdx}>
+				<AccordionSummary
+					expandIcon={<ExpandMoreIcon />}
+					aria-controls={`panel-${itemIdx}-content`}
+					id={`panel-${itemIdx}-header`}>
+					<Typography variant="h5">{title}</Typography>
+				</AccordionSummary>
+				<AccordionDetails>
+					{lines.map((lineContent, idx) => (
+						<Typography key={`${itemIdx}-${idx}`} paragraph>
+							{lineContent}
+						</Typography>
+					))}
+				</AccordionDetails>
+			</Accordion>
+		);
+	});
 };
 
 export default BlogAccordion;