feat(v2): style navbar (#1044)

v2/lib/theme/Navbar/index.js

@@ -0,0 +1,37 @@
+import React from 'react';
+import {NavLink} from 'react-router-dom';
+
+import styles from './styles.css';
+
+function Navbar(props) {
+  return (
+    <nav className={styles.navbar}>
+      <div className={styles.navbarInner}>
+        <ul className={styles.navList}>
+          <li className={styles.navListItem}>
+            <NavLink className={styles.navBrand} to="/">
+              <img
+                alt="Docusaurus Logo"
+                className={styles.navLogo}
+                src="/img/docusaurus-logo.svg"
+              />
+              <strong>Docusaurus</strong>
+            </NavLink>
+          </li>
+          {Object.values(props.docsMetadatas).map(metadata => (
+            <li key={metadata.permalink} className={styles.navListItem}>
+              <NavLink
+                activeClassName={styles.navLinkActive}
+                className={styles.navLink}
+                to={metadata.permalink}>
+                {metadata.title}
+              </NavLink>
+            </li>
+          ))}
+        </ul>
+      </div>
+    </nav>
+  );
+}
+
+export default Navbar;