:root {
  --bg-color: #f4f4f4;
  --text-color: #333;
  --container-bg: #fff;
  --primary-color: #007bff;
  --secondary-color: #28a745;
  --secondary-hover: #218838;
  --shadow-color: rgba(0, 0, 0, 0.1);
  --number-shadow: rgba(0, 123, 255, 0.4);
}

[data-theme='dark'] {
  --bg-color: #1a1a1a;
  --text-color: #f4f4f4;
  --container-bg: #2d2d2d;
  --primary-color: #3793ff;
  --secondary-color: #2fb34b;
  --secondary-hover: #248a3a;
  --shadow-color: rgba(0, 0, 0, 0.5);
  --number-shadow: rgba(0, 123, 255, 0.2);
}

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

.container {
  background-color: var(--container-bg);
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 8px 20px var(--shadow-color);
  text-align: center;
  width: 90%;
  max-width: 500px;
  position: relative;
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
}

#theme-button {
  background: none;
  border: 1px solid var(--text-color);
  color: var(--text-color);
  padding: 5px 10px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.8em;
  box-shadow: none;
  transition: all 0.3s ease;
}

#theme-button:hover {
  background-color: var(--text-color);
  color: var(--container-bg);
}

h1 {
  color: var(--primary-color);
  margin-bottom: 30px;
  font-size: 2.5em;
}

.lotto-numbers {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 15px;
  margin-bottom: 40px;
  min-height: 80px;
}

.number {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  background-color: var(--primary-color);
  color: #fff;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.5em;
  font-weight: bold;
  box-shadow: 0 4px 10px var(--number-shadow);
  transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

.number:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 15px var(--number-shadow);
}

#generate-button {
  background-color: var(--secondary-color);
  color: white;
  padding: 15px 30px;
  font-size: 1.2em;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.3s ease, transform 0.2s ease;
  box-shadow: 0 4px 10px rgba(40, 167, 69, 0.4);
}

#generate-button:hover {
  background-color: var(--secondary-hover);
  transform: translateY(-2px);
}

#generate-button:active {
  transform: translateY(0);
}