* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
  transition: all 0.3s ease;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  width: 90%;
  max-width: 600px;
  text-align: center;
}

h1 {
  margin-bottom: 30px;
}

.theme-box {
  display: flex;
  gap: 15px;
  justify-content: center;
  margin-bottom: 30px;
}

.theme-btn {
  padding: 12px 20px;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  font-weight: bold;
}

.preview {
  padding: 30px;
  border-radius: 20px;
}

body.light {
  background: #f1f5f9;
  color: #111827;
}

body.light .preview {
  background: white;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

body.dark {
  background: #111827;
  color: #f9fafb;
}

body.dark .preview {
  background: #1f2933;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}

body.neon {
  background: radial-gradient(circle at top, #0f172a, #020617);
  color: #22c55e;
}

body.neon .preview {
  background: rgba(0, 0, 0, 0.6);
  border: 1px solid #22c55e;
  box-shadow: 0 0 25px #22c55e;
}

.light {
  background: #e5e7eb;
}
.dark {
  background: #374151;
  color: white;
}
.neon {
  background: #22c55e;
  color: black;
}