body { margin:0;font-family:Arial;background:#f5f5f5 }
.center { display:flex;justify-content:center;align-items:center;height:100vh }
.card { background:#fff;padding:20px;width:300px }
.layout { display:flex;height:100vh }
.sidebar { width:200px;background:#222;padding:20px }
.sidebar button { width:100%;margin:10px 0;color:#fff;background:#444 }
.content { flex:1;padding:20px;background:#fff }
input,textarea,button{width:100%;margin:6px 0;padding:8px}