body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Fira Sans,Droid Sans,Helvetica Neue,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;background-color:#f9f9f9}code{font-family:source-code-pro,Menlo,Monaco,Consolas,Courier New,monospace;background-color:#e0e0e0;padding:2px 5px;border-radius:3px}button{padding:10px 20px;font-size:16px;border:none;border-radius:5px;background-color:#007bff;color:#fff;cursor:pointer;transition:background-color .3s}button:hover{background-color:#0056b3}h1,h2,h3,h4{color:#333}ul{line-height:1.8}