udpate for coming soon

components/SiteHeader.tsx

@@ -1,7 +1,9 @@
 import Link from "next/link";
+import LanguageSwitcher from "@/components/LanguageSwitcher";
 import ThemeToggle from "@/components/ThemeToggle";
 import type { Locale } from "@/lib/i18n";
 import type { CommonContent } from "@/content/types";
+import { isComingSoonMode } from "@/lib/site";
 
 type SiteHeaderProps = {
   locale: Locale;
@@ -9,13 +11,34 @@ type SiteHeaderProps = {
 };
 
 export default function SiteHeader({ locale, common }: SiteHeaderProps) {
+  const isComingSoon = isComingSoonMode();
+
   return (
     <header className="site-header">
       <div className="container bar">
-        <Link href={`/${locale}`} className="brand">
-          {common.siteTitle}
-        </Link>
-        <ThemeToggle />
+        <div className="brand-block">
+          <Link href={`/${locale}`} className="brand">
+            {common.siteTitle}
+          </Link>
+          <span className="brand-tagline">{common.siteTagline}</span>
+        </div>
+
+        {!isComingSoon ? (
+          <nav className="header-nav" aria-label={common.navLabel}>
+            <Link href={`/${locale}`}>{common.nav.home}</Link>
+            <Link href={`/${locale}/about`}>{common.nav.about}</Link>
+            <Link href={`/${locale}/contact`}>{common.nav.contact}</Link>
+          </nav>
+        ) : null}
+
+        <div className="header-actions">
+          <LanguageSwitcher locale={locale} label={common.languageSwitcherLabel} />
+          <ThemeToggle
+            label={common.themeToggleLabel}
+            lightLabel={common.themeLight}
+            darkLabel={common.themeDark}
+          />
+        </div>
       </div>
     </header>
   );