:root {
      --bg: #f7f7fb;
      --card: #ffffff;
      --accent: #2563eb;
      --muted: #6b7280;
      --radius: 12px;
      --max-width: 1100px;
      --font-sans: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
    }

    body {
      font-family: 'Shippori Mincho', serif;
      font-weight: 700;
      margin: 0;
      padding: 0;
      background: #eef3ff;
      color: #222;
      line-height: 1.8;
    }

    .shippori-mincho-regular {
      font-family: 'Shippori Mincho', serif;
      font-weight: 700;
    }

    .lead {
      background: linear-gradient(90deg, rgba(37, 99, 235, 0.08), rgba(99, 102, 241, 0.05));
      padding: 20px 24px;
      border-radius: 12px;
      border-left: 4px solid var(--accent);
      font-size: 1.1rem;
      line-height: 1.8;
      margin-bottom: 24px;
    }

    /* ヘッダー */
    header.site-header {
      background: linear-gradient(90deg, var(--card), #f3f4f6);
      padding: 18px 20px;
      border-radius: 18px;
      margin: 20px auto 0;
      max-width: var(--max-width);
      display: flex;
      align-items: center;
      justify-content: space-between;
      box-shadow: 0 6px 18px rgba(15, 23, 42, 0.06);
      flex-wrap: nowrap;
    }

    .brand {
      display: flex;
      align-items: center;
      gap: 12px;
      flex: 1;
      min-width: 0;
    }

    .brand .logo {
      width: 48px;
      height: 48px;
      border-radius: 10px;
      background: linear-gradient(135deg, var(--accent), #7c3aed);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 700;
      font-size: 18px;
    }

    nav.main-nav {
      display: flex;
      gap: 10px;
      white-space: nowrap;
    }

    nav.main-nav a {
      margin-left: 16px;
      text-decoration: none;
      color: var(--muted);
      font-weight: 600;
    }

    nav.main-nav a:hover {
      color: var(--accent);
    }



.post-container {
    background-color: #ffffff;
  max-width: 600px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

    /* 戻るボタン */
    .back {
      display: inline-block;
      margin-top: 2.5rem;
      padding: 0.5rem 1.2rem;
      border: 1px solid #444;
      border-radius: 4px;
      text-decoration: none;
      color: #222;
      font-size: 0.9rem;
    }

    .back:hover {
      background: #eee;
    }


    
.site-footer {
  position: relative;
  text-align: center;
  padding: 1.5rem 1rem;
  background: #0a0a2a;
  color: #fff;
  font-size: 0.9rem;
  overflow: hidden;

}

/* 星の共通スタイル */
.star-field span {
  position: absolute;
  border-radius: 50%;
  background: white;
  opacity: 0.8;
  animation: moveStars linear infinite;
}

/* 星のサイズ・高さ・速度を個別設定 */
.star-field span:nth-child(1) {
  width: 1px;
  height: 1px;
  top: 10%;
  left: -5%;
  animation-duration: 6s;
  animation-delay: 0s;
}

.star-field span:nth-child(2) {
  width: 2px;
  height: 2px;
  top: 30%;
  left: -5%;
  animation-duration: 8s;
  animation-delay: 1s;
}

.star-field span:nth-child(3) {
  width: 1.5px;
  height: 1.5px;
  top: 50%;
  left: -5%;
  animation-duration: 7s;
  animation-delay: 2s;
}

.star-field span:nth-child(4) {
  width: 3px;
  height: 3px;
  top: 70%;
  left: -5%;
  animation-duration: 9s;
  animation-delay: 3s;
}

.star-field span:nth-child(5) {
  width: 2px;
  height: 2px;
  top: 90%;
  left: -5%;
  animation-duration: 10s;
  animation-delay: 4s;
}

.star-field span:nth-child(6) {
  width: 1px;
  height: 1px;
  top: 20%;
  left: -5%;
  animation-duration: 7s;
  animation-delay: 5s;
}

.star-field span:nth-child(7) {
  width: 2.5px;
  height: 2.5px;
  top: 40%;
  left: -5%;
  animation-duration: 8s;
  animation-delay: 1.5s;
}

.star-field span:nth-child(8) {
  width: 1.5px;
  height: 1.5px;
  top: 60%;
  left: -5%;
  animation-duration: 9s;
  animation-delay: 2.5s;
}

.star-field span:nth-child(9) {
  width: 1px;
  height: 1px;
  top: 80%;
  left: -5%;
  animation-duration: 6s;
  animation-delay: 0.5s;
}

.star-field span:nth-child(10) {
  width: 3px;
  height: 3px;
  top: 95%;
  left: -5%;
  animation-duration: 10s;
  animation-delay: 3.5s;
}

@keyframes moveStars {
  0% {
    transform: translateX(0);
    opacity: 0.8;
  }

  50% {
    opacity: 1;
  }

  100% {
    transform: translateX(110vw);
    opacity: 0;
  }
}

/* 投稿一覧コンテナ */
.post-list {
  max-width: 900px;
  margin: 30px auto;
  padding: 1rem 1.2rem;
  background: #ffffff;
  border-radius: 16px;
  box-shadow: 0 6px 18px rgba(0,0,0,0.05);
}

/* タイトル */
.post-list h1 {
  margin-bottom: 1.2rem;
  font-size: 1.6rem;
  border-left: 5px solid var(--accent);
  padding-left: 12px;
}

/* 一覧リスト */
.archive-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.archive-list li {
  padding: 14px 8px;
  border-bottom: 1px solid #e5e7eb;
}

.archive-list li:last-child {
  border-bottom: none;
}

.archive-list a {
  text-decoration: none;
  color: #222;
  font-size: 1.05rem;
  display: block;
  transition: 0.2s;
}

.archive-list a:hover {
  color: var(--accent);
  transform: translateX(4px);
}