:root {
  --bg: #e0fcff;
  --text: #333;
  --accent: #4caf50;
  --secondary: #ffffff; /* White background for quiz cards */
}

body.dark-mode {
  --bg: #121212;
  --text: #f0f0f0;
  --accent: #90ee90;
  --secondary: #2a2a2a;
}

body {
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', sans-serif;
  background-color: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
}

.container {
  width: 90%;
  max-width: 650px;
  background: var(--secondary);
  padding: 2rem;
  border-radius: 16px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2);
  transition: background 0.3s;
}

h1, h2 {
  text-align: center;
  margin-bottom: 1.5rem;
  color: var(--text);
}

input, button {
  width: 100%;
  padding: 12px;
  font-size: 16px;
  margin-top: 10px;
  border-radius: 8px;
  border: none;
  outline: none;
  box-sizing: border-box;
}

button {
  background-color: var(--accent);
  color: white;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background-color: #388e3c;
}

ul#options {
  list-style: none;
  padding: 0;
}

ul#options li {
  background: var(--bg);
  margin: 10px 0;
  padding: 12px;
  border: 2px solid var(--accent);
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.3s, color 0.3s;
}

ul#options li:hover,
ul#options li.selected {
  background-color: var(--accent);
  color: white;
}

.navigation {
  display: flex;
  justify-content: space-between;
  margin-top: 1.5rem;
  gap: 1rem;
}

#progress-bar {
  height: 8px;
  background: var(--accent);
  border-radius: 4px;
  margin-bottom: 16px;
  transition: width 0.3s;
}

#darkModeToggle {
  font-size: 18px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text);
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  font-size: 18px;
  font-weight: 500;
  color: var(--text);
}

.left-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 1rem;
  margin-bottom: 1rem;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: bold;
  font-size: 1rem;
}

/* Responsive Design */
@media (max-width: 480px) {
  .container {
    padding: 1.2rem;
  }

  h1, h2 {
    font-size: 1.5rem;
  }

  button {
    font-size: 15px;
  }

  .navigation {
    flex-direction: column;
    gap: 10px;
  }

  .top-bar {
    flex-direction: column;
    gap: 8px;
  }
}