body {
  font-family: "Yu Gothic", sans-serif;
  margin: 0;
  padding: 0;
  background: #fff;
  color: #333;
}

header {
  background: #f8f8f8;
  padding: 15px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 10;
}

.logo {
  font-size: 20px;
  font-weight: bold;
}

/* ▼ PCナビ */
.pc-nav ul {
  list-style: none;
  display: flex;
  gap: 20px;
  margin: 0;
  padding: 0;
}

.pc-nav a {
  text-decoration: none;
  color: #333;
  font-size: 16px;
  transition: 0.3s;
}

.pc-nav a:hover {
  color: #00796b;
  border-bottom: 2px solid #00796b;
}

/* ▼ ハンバーガー */
.menu-toggle {
  width: 30px;
  height: 25px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  height: 3px;
  background: #333;
  border-radius: 2px;
  transition: 0.3s;
}

/* Xアイコン */
.menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}
.menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ▼ スマホメニュー */
#nav-menu {
  position: fixed;
  top: 0;
  right: -100%;
  width: 70%;
  height: 100%;
  background: #fff;
  box-shadow: -2px 0 5px rgba(0, 0, 0, 0.1);
  transition: right 0.3s;
  padding-top: 60px;
  z-index: 9;
}
#nav-menu.active {
  right: 0;
}
#nav-menu ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 20px;
  align-items: center;
}
#nav-menu a {
  text-decoration: none;
  color: #333;
  font-size: 18px;
}

/* ▼ 背景暗く */
#overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: 0.3s;
  z-index: 8;
}
#overlay.active {
  opacity: 1;
  visibility: visible;
}

.hero {
  background: #e0f7fa;
  text-align: center;
  padding: 50px 20px;
}
.hero h1 {
  font-size: 40px;
  margin-bottom: 10px;
}

/* 共通セクション */
.container,
.shop-info,
.access,
.content-categories,
.webgl-section {
  max-width: 1080px;
  margin: 40px auto;
  padding: 0 15px;
}

/* ▼ 分野別カテゴリ */
.content-categories h2 {
  font-size: 24px;
  margin-bottom: 10px;
  color: #00796b;
}
.content-categories p {
  font-size: 16px;
  line-height: 1.6;
  margin-bottom: 30px;
}
.category-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.category-list li {
  background: #f0f0f0;
  border-left: 6px solid #00796b;
  padding: 15px;
  margin-bottom: 20px;
  border-radius: 4px;
  transition: background 0.3s;
}
.category-list li:hover {
  background: #e0f2f1;
}
.category-list h3 {
  margin: 0 0 5px;
  font-size: 18px;
  color: #00796b;
}
.category-list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.4;
}
.category-list a {
  text-decoration: none;
  color: inherit;
  display: block;
}
.category-list a:hover {
  background: #e0f2f1;
}

/* ▼ Unity用セクション */
.unity-demo iframe {
  width: 100%;
  height: 650px;
  border: none;
  border-radius: 8px;
}

/* ▼ ギャラリー系（教材カード） */
.content-gallery {
  display: flex;
  flex-wrap: wrap;
  gap: 30px;
  justify-content: center;
  padding: 40px 15px;
  max-width: 1200px;
  margin: auto;
}
.content-card {
  width: 300px;
  background: #f9f9f9;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s;
}
.content-card:hover {
  transform: translateY(-5px);
}
.content-card img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}
.content-card h3 {
  margin: 16px;
  font-size: 18px;
  color: #00796b;
}
.content-card p {
  margin: 0 16px 16px;
  font-size: 14px;
  color: #555;
}
.content-card a {
  display: block;
  text-decoration: none;
  color: inherit;
}

/* ▼ フッター */
footer {
  background: #333;
  color: #fff;
  text-align: center;
  padding: 10px;
  margin-top: 40px;
}
footer a {
  color: orange;
}
footer a:hover {
  color: #871900;
}

/* ▼ レスポンシブ対応 */
@media (min-width: 768px) {
  .menu-toggle {
    display: none;
  }
  .pc-nav {
    display: block;
  }
  #nav-menu {
    display: none;
  }
  #overlay {
    display: none;
  }
}