/* ページ全体 */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  flex-direction: column;
  font-family: 'Segoe UI', sans-serif;
  color: #333;
  background: linear-gradient(135deg, #e0f7fa 0%, #ffffff 100%);
}

/* ヘッダー */
header {
  text-align: center;
  padding: 1.5rem;
  color: #fff;
  background: linear-gradient(to right, #6ec1e4, #3fa3d1);
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.date {
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
  opacity: 0.9;
}

.main-title {
  margin: 0.2rem 0;
  font-size: 2rem;
}

.sub-title {
  margin: 0;
  font-size: 1.2rem;
  font-weight: 300;
  opacity: 0.9;
}

/* カードのレイアウト */
main {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 2rem;
  padding: 2rem;
  max-width: 100%;
  margin: 0 auto;
}

/* カード */
.link-card {
  text-decoration: none;
  color: inherit;
}

.card-content {
  background: white;
  border-radius: 16px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.1);
  padding: 1.5rem;
  text-align: center;
  transition: transform 0.3s, box-shadow 0.3s;
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
  min-height: 200px;
}

.card-content:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 0 12px 24px rgba(0,0,0,0.15);
}

/* アイコン */
.card-content img {
  width: auto;       /* 幅は自動 */
  max-width: 100px;  /* 最大幅（大画面用） */
  height: auto;
  object-fit: contain;
  margin-bottom: 1rem;
}

/* タイトルをカード下部中央に固定 */
.card-title {
  position: absolute;
  bottom: 1rem;
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
  font-size: 1.2rem;
  font-weight: bold;
  color: #3fa3d1;
  width: 90%;
}

/* フッター */
footer {
  text-align: center;
  padding: 1rem;
  font-size: 0.8rem;
  color: #555;
  background-color: rgba(255, 255, 255, 0.8);
}

/* 大きい画面でもっと大きく */
@media (min-width: 1200px) {
  .card-content img {
    max-width: 100px;
  }
}

/* 中くらいの画面サイズ */
@media (max-width: 900px) {
  .card-content img {
    max-width: 100px;
  }
}

/* 小さい画面（スマホ）では小さく */
@media (max-width: 600px) {
  .card-content img {
    max-width: 100px;
  }
}

.copy-button-container {
  text-align: center;
  margin-top: 2rem;
}

.copy-btn {
  background: linear-gradient(135deg, #4a90e2, #357ABD);
  border: none;
  border-radius: 30px;
  color: white;
  font-size: 1.3rem;
  padding: 0.8rem 2.5rem;
  cursor: pointer;
  box-shadow: 0 6px 12px rgba(53, 122, 189, 0.6);
  transition: background 0.3s ease, box-shadow 0.3s ease;
  user-select: none;
}

.copy-btn:hover {
  background: linear-gradient(135deg, #357ABD, #285EAA);
  box-shadow: 0 8px 20px rgba(40, 94, 170, 0.8);
}

.copy-btn:active {
  transform: scale(0.97);
  box-shadow: 0 4px 10px rgba(40, 94, 170, 0.9);
}