Header to it's own component.

src/App.css

@@ -1,14 +1,3 @@
 .App {
   text-align: center;
 }
-
-.App-header {
-  background-color: #282c34;
-  min-height: 100vh;
-  display: flex;
-  flex-direction: column;
-  align-items: center;
-  justify-content: center;
-  font-size: calc(10px + 2vmin);
-  color: white;
-}

src/App.tsx

@@ -1,12 +1,10 @@
 import './App.css';
+import { Header } from "./components/header"
 
 function App() {
   return (
     <div className="App">
-      <header className="App-header">
+      <Header />
-        <h1>Lintu ja Maslo</h1>
-        <p><i>Elokuussa 2022</i></p>
-      </header>
     </div>
   );
 }

src/components/header.tsx

@@ -0,0 +1,10 @@
+import "./../styles/header.css"
+
+export const Header = () => {
+    return (
+        <header className="App-header">
+            <h1>Lintu ja Maslo</h1>
+            <p><i>Elokuussa 2022</i></p>
+        </header>
+    )
+}

src/styles/header.css

@@ -0,0 +1,10 @@
+.App-header {
+  background-color: #282c34;
+  min-height: 100vh;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(10px + 2vmin);
+  color: white;
+}