:root {
  --background-color: #ffffff;
  --text-color: #333333;
  --button-bg: #f0f0f0;
  --button-text: #333333;
  --border-color: #dddddd;
  --header-bg: #f8f9fa;
}

[data-theme="dark"] {
  --background-color: #222222;
  --text-color: #eeeeee;
  --button-bg: #444444;
  --button-text: #eeeeee;
  --border-color: #444444;
  --header-bg: #333333;
}

body {
  background-color: var(--background-color);
  color: var(--text-color);
  font-family: sans-serif;
  transition: background-color 0.3s, color 0.3s;
  margin: 0;
  padding: 0;
}

header {
  background-color: var(--header-bg);
  padding: 1rem;
  display: flex;
  justify-content: flex-end;
  border-bottom: 1px solid var(--border-color);
}

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

#theme-toggle {
  background-color: var(--button-bg);
  color: var(--button-text);
  border: 1px solid var(--border-color);
  border-radius: 5px;
  padding: 0.5rem 1rem;
  cursor: pointer;
}

ul {
  padding-left: 20px;
}

li {
  margin-bottom: 0.5rem;
}

.curriculum-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 2rem;
}

.curriculum-table th,
.curriculum-table td {
  border: 1px solid var(--border-color);
  padding: 0.75rem;
  text-align: left;
  vertical-align: top;
}

.curriculum-table thead th {
  background-color: var(--header-bg);
  font-weight: bold;
}