fix: add favicon and repair tagline markup

Author: akira

favicon.ico

@@ -5,6 +5,7 @@
   <meta http-equiv="Content-Security-Policy" content="default-src 'self'; base-uri 'none'; object-src 'none'; frame-ancestors 'none'; form-action 'self'; script-src 'self' https://cdn.jsdelivr.net; script-src-attr 'none'; style-src 'self' https://fonts.googleapis.com; font-src https://fonts.gstatic.com; img-src 'self' https: data:; connect-src 'self' https:;">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>Toppy DNS / Email Auth Quick Check</title>
+  <link rel="icon" href="favicon.ico">
   <link rel="preconnect" href="https://fonts.googleapis.com">
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
   <link href="https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600&family=IBM+Plex+Mono:wght@400;500&display=swap" rel="stylesheet">
@@ -69,7 +70,7 @@
       <div class="flex flex-center-wrap">
         <h1 data-i18n="hero.title">業務用メールのなりすまし対策を安全に実施</h1>
       </div>
-      <p class="tagline" data-i18n="hero.tagline">ドメイン名を入力 → SPF / DKIM / DMARC を一括診断.修正案はコピペ1回・元に戻す手順つきで,安全に実施できる</p>
+      <p class="tagline" data-i18n="hero.tagline">公開DNSに設定されたSPF,DKIM, DMARC 情報をもとに,なりすまし対策の有無を推定評価します</p>
       <p class="tiny muted mt-10" data-i18n="hero.free">完全無料（登録不要）</p>
       <p class="tiny muted mt-4">PRs for typos are welcome on <a href="https://github.com/thinksyncs/toppy-dns-quickcheck" target="_blank" rel="noopener">GitHub</a>.</p>
       <div class="flex mt-18 z-1">

index.html

@@ -20,6 +20,7 @@
   <meta http-equiv="Content-Security-Policy" content="default-src 'self'; base-uri 'none'; object-src 'none'; frame-ancestors 'none'; form-action 'self'; script-src 'self' https://cdn.jsdelivr.net; script-src-attr 'none'; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src https://fonts.gstatic.com; img-src 'self' https: data:; connect-src 'self' https:;">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>Toppy DNS / RUA サービス仕様</title>
+  <link rel="icon" href="favicon.ico">
   <link rel="preconnect" href="https://fonts.googleapis.com">
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
   <link href="https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600&family=IBM+Plex+Mono:wght@400;500&display=swap" rel="stylesheet">