Update styles and layout for improved responsiveness and consistency:

- **Global fonts**: Adjusted `font-family` fallback to include `serif`.
- **Header improvements**: Refined structure with flexbox, adjusted heights, and fixed responsive issues (e.g., removed hardcoded margins).
- **New Layout styles**: Added scoped `Layout.css` for better layout control and modularity.
- **Links fix**: Corrected casing in `About` and `Contact` links for proper navigation.

styles/components/Layout.css

@@ -0,0 +1,15 @@
+html, body {
+    height: 100%;
+    margin: 0;
+}
+
+body {
+    display: flex;
+    flex-direction: column;
+    min-height: 100vh;
+}
+
+main {
+    flex: 1;
+    padding: 0 1rem;
+}