body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif; /* 美しいフォント */
  background-color: #f8f9fa; /* 背景色 */
  color: #333; /* 文字色 */
  margin: 0;
  padding: 20px;
}
.center-text {
  text-align: center;
}
h2,
h3 {
  color: #1a237e; /* ヘッダー色 */
  border-bottom: 2px solid #e0e0e0; /* セクションの区切り線 */
  padding-bottom: 5px;
}
p {
  color: #555;
  line-height: 1.6;
}
a {
  color: #1e88e5;
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}
hr {
  border: none;
  border-top: 1px solid #ddd;
  margin: 40px 0;
}
.single-chart {
  background-color: #f0f4f8;
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  margin-bottom: 20px;
}
.container-multi-charts {
  display: flex; /* Flexboxを適用 */
  flex-wrap: wrap;
  gap: 20px;
}
.container-multi-charts > div {
  flex: 1 1 250px;
  background-color: #f0f4f8;
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.loading {
  text-align: center;
  font-size: 18px;
  margin: 20px;
}

.error {
  display: none;
  text-align: center;
  color: red;
  font-size: 18px;
  margin: 20px;
}

.hidden {
  display: none !important;
}