body {
  font-family: Arial, sans-serif;
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
  background-color: #f4f4f4;
  transition: background-color 0.3s, color 0.3s;
}

body.dark-theme {
  background-color: #1a1a1a;
  color: #e0e0e0;
}

#question-container {
  background-color: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

body.dark-theme #question-container {
  background-color: #2d2d2d;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.math-equation {
  margin-bottom: 20px;
  font-size: 1.2em;
}

.option {
  margin: 10px 0;
}

button {
  padding: 10px 20px;
  background-color: #4CAF50;
  color: black;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

button:hover {
  background-color: #45a049;
}

body.dark-theme button {
  background-color: #45a049;
  color:white;
}

body.dark-theme button:hover {
  background-color: #4CAF50;
}

button:disabled {
  background-color: #cccccc;
  cursor: not-allowed;
}

body.dark-theme button:disabled {
  background-color: #555555;
}

#result {
  margin-top: 10px;
  font-weight: bold;
}

#values-display {
  margin-top: 10px;
  font-style: italic;
  color: #555;
}

body.dark-theme #values-display {
  color: #bbb;
}

.theme-switch {
  position: fixed;
  top: 10px;
  right: 10px;
  padding: 10px;
  background-color: #fff;
  border: 1px solid #ccc;
  border-radius: 4px;
  cursor: pointer;
}

body.dark-theme .theme-switch {
  background-color: #2d2d2d;
  border-color: #444;
}