:root {
  --background: #f8f9fa;
  --foreground: #1f2937;
  --card: #ffffff;
  --primary: #0d6efd;
  --primary-foreground: #f8fafc;
  --success: #198754;
  --border: #dee2e6;
  --muted: #6c757d;
  --shadow-soft: 0 2px 15px rgba(0, 0, 0, 0.08);
  --shadow-medium: 0 4px 25px rgba(0, 0, 0, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Geist", "Inter", system-ui, -apple-system, sans-serif;
  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
  color: var(--foreground);
  min-height: 100vh;
}

.card {
  transition: box-shadow 0.3s ease;
}

.card:hover {
  box-shadow: var(--shadow-medium);
}

.code-input {
  border: 2px solid var(--border) !important;
  border-radius: 0.5rem !important;
  width: 52px;
  height: 60px;
  padding: 0.55rem 0.55rem;
  font-size: 1.4rem;
  line-height: 1.35;
  transition: all 0.2s ease;
}

.code-input:focus {
  border-color: var(--primary) !important;
  box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.15) !important;
  transform: translateY(-2px);
}

.code-input::placeholder {
  color: #ced4da;
}

.btn-primary {
  background: linear-gradient(135deg, #0d6efd 0%, #0056d2 100%);
  border: none;
  transition: all 0.3s ease;
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(13, 110, 253, 0.4);
}

.btn-primary:active {
  transform: translateY(0);
}

.animate-fade-in {
  animation: fadeInUp 0.5s ease forwards;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.letter-spacing-2 {
  letter-spacing: 2px;
}

.bg-success.bg-gradient {
  background: linear-gradient(135deg, #198754 0%, #157347 100%) !important;
}

@media (max-width: 575.98px) {
  .card-header {
    padding: 1.5rem 1rem !important;
  }

  .card-body {
    padding: 1rem !important;
  }

  .code-input {
    width: 50px;
    height: 56px;
    padding: 0.55rem 0.5rem;
    font-size: 1.3rem;
  }
}