body {
  margin:0;
  font-family:Arial;
  background:#0f172a;
  color:white;
}
.container { padding:2rem; }

.site-header {
  position:sticky;
  top:0;
  background:#1e293b;
  padding:1rem;
}
.site-header .container {
  display:flex;
  justify-content:space-between;
}
.site-header a { color:#38bdf8; margin-left:10px; }

.site-footer {
  background:#1e293b;
  text-align:center;
  padding:1rem;
  margin-top:2rem;
}

input, button {
  display:block;
  margin:10px 0;
  padding:10px;
}