/* =========================================
   SIGNAL 共通スタイル
   ========================================= */
:root {
  --bg: repeating-linear-gradient(
    135deg,
    #232323,
    #232323 8px,
    #292929 8px,
    #292929 16px
  );
  --text: #ffffff;
  --muted: #cccccc;
  --link: #90caf9;
  --link-hover: #a3d0ff;
  --card-bg: rgba(255,255,255,0.05);
  --card-border: rgba(255,255,255,0.1);
  --shadow: rgba(0,0,0,0.25);
  --btn-grad-start: #ff7b7b;
  --btn-grad-end: #ffcf6b;
  --btn-text: #222;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', 'Helvetica Neue', Arial, 'ヒラギノ角ゴ', sans-serif;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
}

/* レイアウト */
.center-box {
  min-height: 80vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 4em 1em 0 1em;
}

/* ロゴ */
.logo {
  width: 500px;
  max-width: 90vw;
  margin-bottom: 2.5em;
  filter: drop-shadow(0 2px 12px #111b);
}

/* テキスト */
.description {
  font-size: 1.1em;
  max-width: 900px;
  margin-bottom: 2em;
  color: var(--muted);
  line-height: 1.5;
  white-space: normal;
}

.contact {
  font-size: 1em;
  margin-bottom: 3em;
  color: var(--link);
}

.contact a {
  color: var(--link);
  text-decoration: underline;
}

.contact a:hover,
.contact a:focus-visible {
  color: var(--link-hover);
  outline: none;
}

/* フッター */
footer {
  padding: 1.5em 0 1em 0;
  text-align: center;
  font-size: 0.95em;
  color: #aaa;
}

footer a {
  color: #aaa;
  text-decoration: underline;
  margin: 0 0.6em;
  transition: color 0.2s;
}

footer a:hover,
footer a:focus-visible {
  color: #fff;
  outline: none;
}

/* =========================================
   アプリ一覧ページ用スタイル
   ========================================= */
.app-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2em;
  margin-top: 2em;
  width: 100%;
  max-width: 900px;
}

.app-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 1.5em;
  text-align: center;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  outline: none;
}

.app-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px var(--shadow);
  border-color: rgba(255,255,255,0.2);
}

.app-card:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 0 0 3px rgba(255,255,255,0.25), 0 6px 20px var(--shadow);
  border-color: rgba(255,255,255,0.35);
}

.app-emoji {
  font-size: 2rem;
  margin-bottom: 0.5em;
}

.app-title {
  font-size: 1.2rem;
  font-weight: bold;
  margin-bottom: 0.3em;
}

.app-desc {
  font-size: 0.95rem;
  color: var(--muted);
  line-height: 1.4;
}

/* 「公式サイトを見る」リンクの視認性UP */
.app-link {
  margin-top: 1em;
  font-size: 0.9rem;
  font-weight: bold;
  color: var(--btn-grad-end);
  opacity: 0.95;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.app-card:hover .app-link {
  opacity: 1;
  transform: translateX(2px);
}

/* =========================================
   アプリ一覧ボタン（トップ用）
   ========================================= */
.btn-apps {
  display: inline-block;
  background: linear-gradient(135deg, var(--btn-grad-start), var(--btn-grad-end));
  color: var(--btn-text);
  font-weight: bold;
  text-decoration: none;
  padding: 0.8em 1.8em;
  border-radius: 2em;
  box-shadow: 0 4px 10px rgba(0,0,0,0.3);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  outline: none;
}

.btn-apps:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 18px rgba(0,0,0,0.4);
}

.btn-apps:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 0 0 3px rgba(255,255,255,0.35), 0 6px 18px rgba(0,0,0,0.4);
}

/* =========================================
   レスポンシブ微調整
   ========================================= */
@media (max-width: 480px) {
  .center-box {
    padding-top: 3em;
  }
  .logo {
    width: 78vw;
    margin-bottom: 2em;
  }
  .description {
    font-size: 1rem;
  }
  .app-title {
    font-size: 1.1rem;
  }
  .app-desc {
    font-size: 0.92rem;
  }
}