html,
body {
  height: 100%; /* Ensure the body takes the full height */
  margin: 0;
}

body {
  font-family: Arial, sans-serif;
  color: #333;
  background-color: #f4f4f4;
  display: flex;
  flex-direction: column; /* Aligns the body content in a column layout */
}

.header {
  background-color: #000;
  color: white;
  padding: 20px 0;
  text-align: center;
}

.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.header h1 {
  margin: 0;
}

nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  text-align: left;
  display: flex;
  justify-content: flex-start;
  flex-wrap: wrap;
  margin-left: auto;
  margin-right: auto;
}

nav ul li {
  display: inline-block;
  margin: 0 15px;
}

nav ul li a {
  color: white;
  text-decoration: none;
  font-weight: bold;
}

nav ul li a:hover {
  text-decoration: underline;
}

.main {
  flex: 1; /* Takes up remaining space */
  padding: 20px;
  text-align: center;
  max-width: 1200px;
  margin: 0 auto;
}

.intro,
.concept,
.graph {
  margin-bottom: 40px;
  padding: 0 20px;
}

.intro h2,
.concept h3,
.graph h3 {
  color: #000;
  font-weight: bold;
}

.intro p,
.concept p,
.graph p {
  text-align: justify;
  margin: 0 auto;
  max-width: 800px;
  margin-bottom: 20px;
}

.learn-more {
  display: inline-block;
  padding: 10px 20px;
  margin-top: 20px;
  background-color: #333;
  color: white;
  text-decoration: none;
  border-radius: 5px;
  font-weight: bold;
}

.learn-more:hover {
  background-color: #222;
}

.footer {
  background-color: #000;
  color: white;
  padding: 10px 0;
  text-align: center;
}

.container {
  text-align: center;
}

.button {
  display: inline-block;
  padding: 15px 30px;
  font-size: 1.5rem;
  color: #ffffff;
  background-color: #000000; /* Black button */
  border: 2px solid #ffffff;
  border-radius: 5px;
  text-decoration: none;
  text-align: center;
  transition: all 0.3s ease;
  cursor: pointer;
}

.button:hover {
  background-color: #ffffff;
  color: #000000;
  border-color: #000000;
}