/* ケース */
#case {
  font-family: "Noto Sans JP", sans-serif;
  margin: 0;
  padding: 0;
  color: #333;
}

#case h3 {
  text-align: center;
}

#case header {
  background: #2a4d69;
  color: white;
  padding: 20px;
  text-align: center;
  font-size: 1.8em;
}

#case nav {
  background: #4b86b4;
}

#case nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
}

#case nav li {
  margin: 0 15px;
}

#case nav a {
  color: white;
  text-decoration: none;
  font-weight: bold;
}

#case .sub-header {
  text-align: center;
  background: #adcbe3;
  padding: 10px;
  margin-bottom: 20px;
}

#case main {
  width: 90%;
  max-width: 1000px;
  margin: 0 auto;
}

#case .content-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

#case .graph-block,
#case .explanation-block {
  background: white;
  border: 2px solid #ccc;
  border-radius: 20px;
  padding: 20px;
  width: 47%;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}

#case img {
  object-fit: cover;
}

#case .graph-box {
  height: 250px;
  background: #eef2f3;
  border-radius: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #888;
  position: relative;
}

#case footer {
  text-align: center;
  background: #2a4d69;
  color: white;
  padding: 15px;
  margin-top: 40px;
  font-size: 0.9em;
}