/* ========================================
  ステップ1: 全体フォントと余白の最適化
======================================== */
:root {
  --font-main: 'Noto Sans JP', sans-serif;
  --color-main: #f9f9f9;
  --color-text: #333;
  --color-muted: #777;
  --color-accent: #00796b;
  --color-bg-card: #fff;
  --color-shadow: rgba(0,0,0,0.1);
  --radius-base: 12px;
  --transition-base: all 0.3s ease;
}

body {
  font-family: var(--font-main);
  font-size: 16px;
  color: var(--color-text);
  background-color: var(--color-main);
  line-height: 1.8;
  margin: 0;
  padding: 0;
}

h1, h2, h3 {
  font-weight: 600;
  margin-bottom: 0.5em;
}
p {
  margin-bottom: 1.2em;
  color: var(--color-text);
}

/* ========================================
  ステップ2: スマホ向けレスポンシブ最適化
======================================== */
@media (max-width: 768px) {
  body {
    font-size: 15px;
    padding: 1rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  .header-nav-list {
    flex-direction: column;
  }

  table {
    font-size: 0.95rem;
    word-break: break-word;
  }

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

/* ========================================
  ステップ3: UIアニメーションの追加
======================================== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  animation: fadeUp 0.6s ease forwards;
}
@keyframes fadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.card {
  background-color: var(--color-bg-card);
  border-radius: var(--radius-base);
  box-shadow: 0 6px 16px var(--color-shadow);
  padding: 2rem;
  margin-bottom: 2rem;
  transition: var(--transition-base);
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.12);
}

a {
  color: var(--color-accent);
  transition: var(--transition-base);
}
a:hover {
  color: #004d40;
  text-decoration: underline;
}

button, .btn {
  background-color: var(--color-accent);
  color: white;
  border: none;
  padding: 0.6em 1.4em;
  font-size: 1em;
  border-radius: var(--radius-base);
  transition: var(--transition-base);
}
button:hover, .btn:hover {
  background-color: #004d40;
}
#contents {
  max-width: 960px;
  width: 100%;
  margin: 0 auto;
  padding: 0 1rem;
  box-sizing: border-box;
}