body{font-family:Arial,sans-serif;margin:0}.app{display:flex;flex-direction:column;min-height:100vh}.main-container{display:flex;flex:1 1}.content{flex:70% 1;padding:1rem}.sidebar{background-color:#f4f4f4;flex:30% 1;padding:1rem}footer{background-color:#333;color:#fff;padding:1rem;text-align:center}