:root {
  --bg-color: #f0f2f5;
  --text-color: #1c1e21;
  --card-bg: #ffffff;
  --accent-color: #007bff;
  --button-bg: #f0f0f0;
  --button-hover: #e0e0e0;
  --number-bg: #eee;
  --number-text: #333;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
  --bg-color: #18191a;
  --text-color: #e4e6eb;
  --card-bg: #242526;
  --accent-color: #2d88ff;
  --button-bg: #3a3b3c;
  --button-hover: #4e4f50;
  --number-bg: #3a3b3c;
  --number-text: #e4e6eb;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

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

.theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  padding: 10px;
  cursor: pointer;
  border-radius: 50%;
  border: none;
  background-color: var(--card-bg);
  color: var(--text-color);
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  transition: transform 0.2s;
}

.theme-toggle:hover {
  transform: scale(1.1);
}