html {
  box-sizing: border-box;
  font-family: sans-serif;
  color: #333;
}
*, *:before, *:after {
  box-sizing: inherit;
}

body {
  margin: 0;
  line-height: 1.6;
  background: #f9f9f9;
}

/* ヘッダー・ナビゲーション */
header {
  background: #ffffff;
  border-bottom: 1px solid #ccc;
  padding: 0.5em 1em;
  display: flex;
  align-items: center;
  justify-content: space-between;
  /* 追加 */
  position: relative;
  z-index: 999;
}

header .site-title {
  font-size: 1.5em;
  font-weight: bold;
  color: #006699;
  text-decoration: none;
}

nav {
  display: flex;
  gap: 1em;
}

nav a {
  text-decoration: none;
  color: #333;
  font-weight: bold;
}

nav a:hover {
  color: #006699;
}

/* モバイル用トグルボタン */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5em;
  cursor: pointer;
}

/* メインビジュアル */
.hero {
  position: relative;
  color: white;
  text-align: center;
  background: url("images/main-visual.jpg") no-repeat center center/cover;
  min-height: 50vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 2em;
  /* z-indexは付与しない、または低い値を指定 */
  z-index: 1;
}

.hero h1 {
  font-size: 2em;
  max-width: 600px;
  margin: 0 auto;
  text-shadow: 0 2px 5px rgba(0,0,0,0.7);
}

.main-content {
  padding: 2em 1em;
  max-width: 1000px;
  margin: 0 auto;
  background: #fff;
  margin-top: -2em;
  position: relative;
  z-index: 10; /* ここを必要に応じて調整：ヘッダーが999なのでmainより後ろにならない */
}

section {
  margin-bottom: 2em;
}

h2 {
  border-left: 5px solid #006699;
  padding-left: 0.5em;
  font-size: 1.5em;
  margin-bottom: 0.5em;
}

.intro-text, .content-text {
  margin-bottom: 1em;
}

.banner-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1em;
  margin-bottom: 2em;
}

.banner-links a {
  flex: 1;
  min-width: 250px;
  text-align: center;
  background: #e6f2f7;
  padding: 1em;
  border-radius: 5px;
  text-decoration: none;
  color: #333;
  font-weight: bold;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.banner-links a img {
  display: block;
  max-width: 80px;
  margin: 0 auto 0.5em;
}

.banner-links a:hover {
  background: #d9edf3;
}

footer {
  background: #222;
  color: #fff;
  padding: 1em;
  font-size: 0.9em;
}

footer a {
  color: #fff;
  text-decoration: underline;
}

footer .credits {
  margin-top: 0.5em;
  font-size: 0.8em;
}

/* レイアウト共通 */
.content-section {
  display: flex;
  gap: 2em;
  flex-wrap: wrap;
}

.content-section img {
  max-width: 100%;
  height: auto;
}

/* サイドバー（必要な場合） */
.sidebar {
  flex: 1 1 200px;
  min-width: 200px;
  max-width: 300px;
}
.main-column {
  flex: 3 1 600px;
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
  nav {
    display: none;
    flex-direction: column;
    background: #fff;
    position: absolute;
    top: 60px;
    right: 1em;
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
    padding: 1em;
  }
  
  nav.show {
    display: flex;
  }
  
  .menu-toggle {
    display: block;
  }
  
  .hero h1 {
    font-size: 1.5em;
  }

  .banner-links {
    flex-direction: column;
  }
}

/* その他ページ固有のスタイル例 */
.status-page img.comparison {
  display: block;
  margin: 1em auto;
  max-width: 400px;
}

.action-page .action-list {
  display: flex;
  flex-wrap: wrap;
  gap: 1em;
}

.action-page .action-item {
  flex: 1 1 250px;
  background: #eef8fa;
  padding: 1em;
  border-radius: 5px;
}

.action-page .action-item img {
  max-width: 150px;
  display: block;
  margin-bottom: 0.5em;
}

.our-efforts-page .gallery {
  display: flex;
  flex-wrap: wrap;
  gap: 1em;
}
.our-efforts-page .gallery img {
  width: 250px;
  border: 1px solid #ccc;
  border-radius: 5px;
}