body {
  background-color: #f4f6f9;
}
.card {
  border: none;
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}
.clock-display {
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: 0.05em;
}
@media (max-width: 576px) {
  .clock-display { font-size: 2.2rem; }
  .btn-punch { width: 100%; padding: 1rem; font-size: 1.1rem; }
}
.table-responsive { border-radius: .5rem; overflow: hidden; }
.navbar-brand { font-weight: 700; }