:root {
  --accent: #0078ff;
  --accent-light: #e7f1ff;
  --bg: #f9fbfd;
  --card-bg: #fff;
  --border: #ddd;
  --text: #333;
  --shadow: 0 3px 8px rgba(0,0,0,0.15);
  --transition: 0.25s ease;
}

/* ===== 全体 ===== */
body {
  margin: 0;
  font-family: "Segoe UI", "Hiragino Sans", "Meiryo", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

/* ===== ヘッダー ===== */
.header {
  position: relative;        /* ホームリンク絶対配置のため */
  text-align: center;        /* タイトル中央 */
  padding: 1rem 2rem;
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}

.header h1 {
  margin: 0;
  font-size: 1.8rem;
}

/* ホームリンク左上固定 */
.header .home-link {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  display: inline-block;
  padding: 6px 14px;
  border-radius: 20px;
  background: var(--card-bg);
  border: 1px solid var(--accent);
  text-decoration: none;
  color: var(--accent);
  font-weight: 500;
  font-size: 0.9rem;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

.header .home-link:hover {
  background: var(--accent);
  color: #fff;
  transform: translateY(-50%) translateY(-2px);
}

/* ===== SP対応 ===== */
@media (max-width: 600px) {
  .header {
    text-align: center;
    padding: 0.5rem 1rem;
  }
  .header .home-link {
    position: static;
    transform: none;
    margin-bottom: 0.5rem;
  }
}

/* ===== タブ ===== */
.tabs {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  background: #fff;
  padding: 1rem;
  border-bottom: 1px solid var(--border);
  box-shadow: 0 1px 6px rgba(0,0,0,0.08);
  position: sticky;
  top: 0;
  z-index: 100;
  overflow-x: auto;
  scrollbar-width: none; /* Firefox */
}

.tabs::-webkit-scrollbar {
  display: none; /* Chrome, Safari */
}

.tab {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: linear-gradient(145deg, #f7faff, #ffffff);
  border: 1px solid var(--border);
  border-radius: 30px;
  padding: 10px 22px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text);
  transition: all 0.25s ease;
  box-shadow: 0 2px 5px rgba(0,0,0,0.08);
  white-space: nowrap;
}

.tab:hover {
  background: linear-gradient(145deg, #eaf3ff, #ffffff);
  color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

.tab.active {
  background: linear-gradient(145deg, var(--accent), #369eff);
  color: #fff;
  font-weight: 600;
  border: 1px solid var(--accent);
  box-shadow: 0 4px 12px rgba(0,120,255,0.3);
  transform: translateY(-2px);
}

.tab.active:hover {
  transform: translateY(-3px);
}

/* ===== モバイルタブ調整 ===== */
@media (max-width: 600px) {
  .tab {
    font-size: 0.95rem;
    padding: 8px 16px;
  }
}

/* ===== メインコンテンツ ===== */
main {
  padding: 1.5rem;
  text-align: center;
}

.intro {
  max-width: 720px;
  margin: 0 auto 1.5rem;
  font-size: 1rem;
  color: #555;
}

/* ===== ギャラリー ===== */
.gallery {
  display: none;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
  justify-items: center;
  align-items: center;
}

.gallery.active {
  display: grid;
}

.gallery img {
  width: 100%;
  max-width: 160px;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border-radius: 12px;
  background: var(--card-bg);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: var(--transition);
}

.gallery img:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 16px rgba(0,0,0,0.25);
}

/* ===== ギャラリー レスポンシブ ===== */
@media (max-width: 1200px) {
  .gallery {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (max-width: 800px) {
  .gallery {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 500px) {
  .gallery {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ===== モーダル ===== */
.modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.85);
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

.modal.show {
  display: flex;
  animation: fadeIn 0.25s ease;
}

.modal img {
  max-width: 90%;
  max-height: 90%;
  border-radius: 10px;
  box-shadow: 0 4px 25px rgba(0,0,0,0.6);
  cursor: zoom-out;
}

.modal-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(0,0,0,0.5);
  border: none;
  color: #fff;
  font-size: 2rem;
  padding: 0.5rem 1rem;
  cursor: pointer;
  border-radius: 5px;
  z-index: 1010;
  transition: background 0.2s;
}

.modal-btn:hover {
  background: rgba(0,0,0,0.8);
}

.modal-btn.left {
  left: 10px;
}

.modal-btn.right {
  right: 10px;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ===== 関連ツールセクション ===== */
.related-tools {
  margin: 3rem auto;
  padding: 1.5rem;
  max-width: 900px;
  background: #fff;
  border-radius: 12px;
  box-shadow: var(--shadow);
  text-align: center;
}

.related-tools h2 {
  font-size: 1.5rem;
  margin-bottom: 0.8rem;
  color: var(--accent);
}

.related-tools p {
  color: #555;
  margin-bottom: 1rem;
}

.tool-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.tool-card {
  display: inline-block;
  padding: 0.8rem 1.2rem;
  background: var(--accent-light);
  border: 1px solid var(--accent);
  border-radius: 10px;
  text-decoration: none;
  color: var(--accent);
  font-weight: 500;
  transition: var(--transition);
}

.tool-card:hover {
  background: var(--accent);
  color: #fff;
  transform: translateY(-2px);
}

.more-tools a {
  color: var(--accent);
  text-decoration: none;
}

.more-tools a:hover {
  text-decoration: underline;
}

/* ===== フッター ===== */
footer {
  text-align: center;
  padding: 20px;
  font-size: 0.9rem;
  color: #777;
  background: #fff;
  margin-top: 2rem;
  border-top: 1px solid var(--border);
}