body{font-family:Arial;background:#f4f6f8;display:flex;flex-direction:column;align-items:center}
.container{background:#fff;padding:20px;width:90%;max-width:900px;border-radius:10px;box-shadow:0 4px 12px rgba(0,0,0,.1);margin:20px}
.nav{display:flex;gap:10px;margin:20px}
.nav a{text-decoration:none;padding:6px 12px;background:#e9ecef;border-radius:5px;color:#000}
.nav a:hover{background:#0d6efd;color:#fff}
input,button{width:100%;margin:10px 0}
button{background:#0d6efd;color:#fff;border:none;padding:10px;border-radius:5px}
canvas{max-width:100%;border:1px dashed #ccc;margin:10px 0}
.row{display:flex;gap:10px}