/* 基本設定 */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
  line-height: 1.8;
  color: #333333;
  background-color: #f9f9f9;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}

.text-center {
  text-align: center;
}

/* ヘッダー */
.site-header {
  background-color: #ffffff;
  border-bottom: 1px solid #e5e7eb;
  padding: 12px 0;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-logo-group {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  min-width: 0;
}

.site-logo {
  height: 32px;
  width: auto;
  display: block;
  flex-shrink: 0;
}

.site-title-text {
  font-size: 1rem;
  font-weight: 700;
  color: #1e293b;
  line-height: 1.2;
}

.header-btn {
  background-color: #2563eb;
  color: #ffffff;
  padding: 8px 12px;
  text-decoration: none;
  border-radius: 6px;
  font-weight: 600;
  font-size: 0.8rem;
  white-space: nowrap;
  flex-shrink: 0;
  margin-left: 8px;
  transition: background-color 0.2s ease;
}

.header-btn:hover {
  background-color: #1d4ed8;
}

/* トピックス一覧（トップページ） */
.topics-section {
  padding: 30px 0;
}

.section-title {
  font-size: 1.5rem;
  color: #2d6a4f;
  margin-bottom: 20px;
  border-bottom: 2px solid #2d6a4f;
  padding-bottom: 5px;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.article-card a {
  text-decoration: none;
  color: #333333;
  display: block;
}

.card-image {
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border-radius: 8px;
  margin-bottom: 10px;
  background-color: #eeeeee;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.card-title {
  font-size: 0.95rem;
  line-height: 1.4;
  font-weight: bold;
}

/* 記事コンテンツ */
.news-article {
  background-color: #ffffff;
  margin: 30px 0;
  padding: 40px;
  border-radius: 4px;
  border: 1px solid #e0e0e0;
}

.article-title {
  font-size: 2rem;
  line-height: 1.3;
  margin-bottom: 15px;
  color: #111111;
}

.article-meta {
  font-size: 0.9rem;
  color: #666666;
  margin-bottom: 25px;
  padding-bottom: 15px;
  border-bottom: 1px solid #eeeeee;
}

.article-meta span, 
.article-meta time {
  margin-right: 15px;
}

.article-image {
  margin-bottom: 30px;
}

.article-image img {
  width: 100%;
  height: auto;
  display: block;
}

.article-body p {
  margin-bottom: 1.5em;
  font-size: 1.05rem;
}

.article-body h2 {
  font-size: 1.5rem;
  margin: 2em 0 1em 0;
  padding-bottom: 5px;
  border-bottom: 2px solid #333333;
}

.article-body ul {
  margin-bottom: 1.5em;
  padding-left: 20px;
}

.article-body li {
  margin-bottom: 0.5em;
  font-size: 1.05rem;
}

.article-body a {
  color: #2563eb;
  text-decoration: underline;
}

/* 前の記事 / 次の記事 ナビゲーション */
.article-nav {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid #eeeeee;
}

.nav-card {
  display: flex;
  flex-direction: column;
  width: 48%;
  text-decoration: none;
  color: #333333;
}

.nav-next {
  text-align: right;
  align-items: flex-end;
}

.nav-prev {
  text-align: left;
  align-items: flex-start;
}

.nav-label {
  font-size: 0.85rem;
  color: #2563eb;
  font-weight: bold;
  margin-bottom: 8px;
}

.nav-content {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-next .nav-content {
  flex-direction: row-reverse;
}

.nav-thumb {
  width: 80px;
  height: 50px;
  object-fit: cover;
  border-radius: 4px;
  flex-shrink: 0;
  background-color: #eeeeee;
}

.nav-title {
  font-size: 0.9rem;
  font-weight: bold;
  line-height: 1.4;
  display: -webkit-box;
  line-clamp: 2;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.nav-card:hover .nav-title {
  color: #2563eb;
}

/* 補足注記 */
.disclaimer {
  max-width: 800px;
  margin: 0 auto 30px auto;
  padding: 0 20px;
}

.disclaimer p {
  font-size: 0.85rem;
  color: #666666;
  line-height: 1.6;
}

/* フッター */
.site-footer {
  text-align: center;
  padding: 30px 0;
  font-size: 0.85rem;
  color: #777777;
}

/* レスポンシブ設定 */
@media (max-width: 1080px) {
  .container,
  .disclaimer {
    max-width: 100%;
  }

  .article-nav {
    margin-top: 35px;
  }
}

@media (max-width: 768px) {
  .container,
  .disclaimer {
    max-width: 720px;
  }

  .article-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
  }

  .news-article {
    padding: 30px 20px;
  }

  .article-title {
    font-size: 1.6rem;
  }

  .article-nav {
    margin-top: 30px;
    padding-top: 15px;
    gap: 15px;
  }

  .nav-thumb {
    width: 64px;
    height: 40px;
  }

  .nav-title {
    font-size: 0.85rem;
  }

  .disclaimer p {
    font-size: 0.8rem;
  }
}

@media (max-width: 450px) {
  .container,
  .disclaimer {
    padding: 0 12px;
  }

  .site-title-text {
    font-size: 0.85rem;
  }

  .site-logo {
    height: 28px;
  }

  .header-btn {
    padding: 6px 10px;
    font-size: 0.75rem;
  }

  .news-article {
    padding: 20px 15px;
    margin: 15px 0;
  }

  .article-title {
    font-size: 1.35rem;
  }

  .article-body p,
  .article-body li {
    font-size: 0.95rem;
  }

  .article-nav {
    flex-direction: column;
    gap: 20px;
    margin-top: 25px;
    padding-top: 15px;
  }

  .nav-card {
    width: 100%;
  }

  .nav-next {
    text-align: left;
    align-items: flex-start;
  }

  .nav-next .nav-content {
    flex-direction: row;
  }

  .nav-next .nav-label {
    width: 100%;
    text-align: right;
  }

  .disclaimer p {
    font-size: 0.75rem;
  }
}