:root {
  --main-blue: #2b3a67;
  --accent-blue: #4a79b7;
  --light-bg: #f3f5f8;
  --text-color: #222;
}

body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
  color: var(--text-color);
  background: linear-gradient(#eef1f4, #f7f9fb);
  line-height: 1.8;
}

/* ==== ヘッダー ==== */
header.header {
  background: url("../img/heading/lungfish_hero.jpg") center/cover no-repeat;
  height: 260px;
  color: white;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  align-items: flex-start;
  padding: 2rem 3rem;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.8);
  box-shadow: inset 0 -100px 80px rgba(0, 0, 0, 0.5);
}

header.header h1 {
  font-size: 2rem;
  margin: 0;
  letter-spacing: 0.05em;
}

header.header .subtitle {
  font-size: 1rem;
  opacity: 0.85;
}

/* ==== 本文エリア ==== */
main {
  background-color: #fff;
  max-width: 900px;
  margin: 20px auto;
  padding: 2.5rem 2rem;
  box-shadow: 0 3px 8px rgba(0, 0, 0, 0.1);
  border-radius: 6px;
  position: relative;
  z-index: 2;
}

h2 {
  color: var(--main-blue);
  border-bottom: 2px solid var(--main-blue);
  margin: 2rem 0 1rem;
  padding-bottom: 0.3rem;
  font-size: 1.3rem;
}

p {
  margin: 1rem 0;
}

ul {
  padding-left: 1.5rem;
  margin-top: 0.5rem;
}

.signature {
  text-align: right;
  margin-top: 1.5rem;
  font-weight: bold;
}

/* ==== ギャラリー ==== */
.gallery-grid {
  display: flex;
  justify-content: center;
  margin-top: 2rem;
}
.gallery-grid img {
  max-width: 600px;
  width: 90%;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}

/* ==== 活動セクション ==== */
.activities a {
  display: inline-block;
  margin: 0.3rem 0;
  padding: 0.5rem 1rem;
  background: var(--accent-blue);
  color: #fff;
  border-radius: 4px;
  text-decoration: none;
  transition: background 0.3s;
}
.activities a:hover {
  background: #2b3a67;
}

/* ==== 事務局 ==== */
address {
  font-style: normal;
  line-height: 1.6;
  margin-top: 1rem;
  background-color: var(--light-bg);
  padding: 1rem;
  border-left: 4px solid var(--main-blue);
}

/* ==== フッター ==== */
footer.footer {
  background: #1f2a4a;
  color: #eaeaea;
  text-align: center;
  padding: 1rem;
  font-size: 0.9rem;
  margin-top: 3rem;
}

/* ==== スマートフォン対応 ==== */
@media (max-width: 700px) {
  header.header {
    height: 180px;
    padding: 1rem 1.5rem;
  }
  main {
    padding: 1.5rem;
    margin-top: -40px;
  }
  h2 {
    font-size: 1.1rem;
  }
  .gallery-grid img {
    max-width: 100%;
    width: 100%;
  }
}