body {
  margin: 0;
  font-family: 'Poppins', sans-serif;
  background-color: #f9f9fc;
  color: #222;
  line-height: 1.6;
}

header {
  text-align: center;
  padding: 2rem 1rem 1rem;
  background-color: #f5f7fa;
  border-bottom: 2px solid #e0e0e0;
}

header img {
  width: 120px;
  margin-bottom: 1rem;
}

.intro-text {
  max-width: 800px;
  margin: 0 auto;
  font-size: 1rem;
  color: #555;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

.hidden {
  display: none;
}

h2 {
  font-size: 1.6rem;
  margin-bottom: 1.2rem;
  color: #111;
}

label {
  display: block;
  margin-bottom: 1.2rem;
}

input[type="number"] {
  width: 100%;
  padding: 0.6rem;
  font-size: 1rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  box-sizing: border-box;
}

button {
  background-color: #00bcd4;
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  border-radius: 6px;
  cursor: pointer;
  margin-top: 1rem;
}

button:hover {
  background-color: #0097a7;
}

.tooltip-icon {
  display: inline-block;
  background-color: #00bcd4;
  color: white;
  font-size: 0.8rem;
  width: 18px;
  height: 18px;
  text-align: center;
  line-height: 18px;
  border-radius: 50%;
  margin-left: 5px;
  cursor: pointer;
  position: relative;
}

.tooltip-icon:hover::after {
  content: attr(data-tooltip);
  position: absolute;
  top: 120%;
  left: 50%;
  transform: translateX(-50%);
  background: #333;
  color: white;
  padding: 0.5rem;
  font-size: 0.85rem;
  border-radius: 4px;
  white-space: nowrap;
  z-index: 10;
}

#chart-container {
  max-width: 600px;
  margin: 2rem auto;
}

footer {
  background-color: #f1f1f1;
  padding: 2rem;
  text-align: center;
  font-size: 0.9rem;
  color: #555;
  border-top: 2px solid #e0e0e0;
}

.footer-links {
  margin-bottom: 1rem;
}

.footer-links a {
  color: #555;
  margin: 0 10px;
  text-decoration: none;
}