:root {
  --bg-color: #f4f4f9;
  --container-bg: #ffffff;
  --text-color: #333333;
  --btn-bg: #6200ea;
  --btn-hover: #7f39fb;
  --lotto-num-bg: #e0e0e0;
  --shadow-color: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
  --bg-color: #1a1a1a;
  --container-bg: #2c2c2c;
  --text-color: #ffffff;
  --btn-bg: #6200ea;
  --btn-hover: #7f39fb;
  --lotto-num-bg: #444444;
  --shadow-color: rgba(0, 0, 0, 0.5);
}

body {
  font-family: sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  transition: background-color 0.3s, color 0.3s;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='40' height='40' viewBox='0 0 40 40'%3E%3Cg fill-rule='evenodd'%3E%3Cg fill='%239C92AC' fill-opacity='0.1'%3E%3Cpath d='M0 38.59l2.83-2.83 1.41 1.41L1.41 40H0v-1.41zM0 1.4l2.83 2.83 1.41-1.41L1.41 0H0v1.41zM38.59 40l-2.83-2.83 1.41-1.41L40 38.59V40h-1.41zM40 1.4l-2.83 2.83-1.41-1.41L38.59 0H40v1.41z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.container {
  text-align: center;
  background-color: var(--container-bg);
  padding: 40px;
  border-radius: 15px;
  box-shadow: 0 10px 20px var(--shadow-color), 0 6px 6px var(--shadow-color);
  transition: background-color 0.3s, box-shadow 0.3s;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 30px;
}

#generate-btn {
  background-color: var(--btn-bg);
  color: #fff;
  border: none;
  padding: 15px 30px;
  font-size: 1.2rem;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 0 10px var(--btn-bg);
}

#generate-btn:hover {
  background-color: var(--btn-hover);
  box-shadow: 0 0 15px var(--btn-hover);
}

#theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  padding: 10px 20px;
  border-radius: 20px;
  border: none;
  background-color: var(--btn-bg);
  color: #fff;
  cursor: pointer;
  font-weight: bold;
  transition: background-color 0.3s;
}

lotto-display {
  display: block;
  margin-bottom: 30px;
}

/* Note: The lotto-number styles are inside the Shadow DOM of lotto-display.
   We should pass the theme colors to it or use CSS variables that can pierce the Shadow DOM.
*/