body {
  background: #f6f8fa;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial;
}
.markdown-body {
  box-sizing: border-box;
  min-width: 200px;
  max-width: 900px;
  margin: 40px auto;
  padding: 30px;
  background: #fff;
  border-radius: 6px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
}