body {
  font-family: Arial, Helvetica, sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f5f5;
  color: #333;
}
.container {
  max-width: 960px;
  margin: 20px auto;
  padding: 20px;
  background: #fff;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
h1 {
  text-align: center;
  margin-bottom: 20px;
}
.editor textarea {
  width: 100%;
  height: 300px;
  box-sizing: border-box;
  resize: vertical;
  padding: 10px;
  font-family: monospace;
  font-size: 14px;
  border: 1px solid #ccc;
}
.preview {
  margin-top: 20px;
  padding: 15px;
  border: 1px solid #ddd;
  min-height: 200px;
  background: #fafafa;
}