:root {
  --primary-color: #2c3e50;
  --secondary-color: #e74c3c;
  --background-light: #fdfdfd;
  --text-dark: #333333;
  --border-color: #bdc3c7;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Geneva, sans-serif;
  color: var(--text-dark);
  background-color: var(--background-light);
  line-height: 1.6;
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: 100vh;
}

/* Header and Navigation */
header {
  background-color: var(--primary-color);
  color: white;
  padding: 1.5rem;
  text-align: center;
}

nav ul {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  list-style: none;
  margin-top: 1rem;
}

nav ul li {
  margin: 0 1rem;
}

nav ul li a {
  color: white;
  text-decoration: none;
  font-weight: bold;
  padding: 0.5rem;
  border-radius: 4px;
  transition: background-color 0.3s;
}

nav ul li a:hover, nav ul li a:focus {
  background-color: var(--secondary-color);
  outline: 2px solid white;
}

/* Main Content */
main {
  padding: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

/* Images and Figures */
figure {
  margin: 1.5rem 0;
  text-align: center;
}

img {
  max-width: 100%;
  height: auto;
  border: 2px solid var(--border-color);
  border-radius: 8px;
}

figcaption {
  font-size: 0.9rem;
  color: #555;
  margin-top: 0.5rem;
  font-style: italic;
}

/* Lists Styling */
.simple-list {
  list-style-type: square;
  margin-left: 2rem;
  margin-bottom: 1.5rem;
}

.complex-list {
  margin-left: 1.5rem;
}

.complex-list > li {
  font-weight: bold;
  margin-top: 1rem;
  color: var(--primary-color);
}

.complex-list .nested-list {
  list-style-type: circle;
  font-weight: normal;
  margin-left: 2rem;
  color: var(--text-dark);
}

/* Table Styling */
.table-container {
  overflow-x: auto;
}

.complex-table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background-color: white;
}

.complex-table th, .complex-table td {
  border: 1px solid var(--border-color);
  padding: 12px;
  text-align: left;
}

.complex-table th {
  background-color: var(--primary-color);
  color: white;
}

.complex-table tbody tr:nth-child(even) {
  background-color: #f2f2f2;
}

.contact-form {
  display: flex;
  flex-direction: column;
  max-width: 500px;
  gap: 1rem;
}

.contact-form label {
  font-weight: bold;
}

.contact-form input, .contact-form select, .contact-form textarea {
  padding: 0.8rem;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  font-family: inherit;
}

.contact-form button {
  background-color: var(--secondary-color);
  color: white;
  padding: 1rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: bold;
}

.contact-form button:hover {
  background-color: #c0392b;
}

/* Footer */
footer {
  background-color: var(--primary-color);
  color: white;
  text-align: center;
  padding: 1rem;
  margin-top: 2rem;
}