html {
  font-size: 14px;
  position: relative;
  min-height: 100%;
}

@media (min-width: 768px) {
  html {
    font-size: 16px;
  }
}

body {
  margin-bottom: 60px;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f8f9fa;
  color: #212529;
}

.btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
  box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem #258cfb;
}

.form-floating > .form-control-plaintext::placeholder, .form-floating > .form-control::placeholder {
  color: var(--bs-secondary-color);
  text-align: end;
}

.form-floating > .form-control-plaintext:focus::placeholder, .form-floating > .form-control:focus::placeholder {
  text-align: start;
}

.payment-container {
  max-width: 500px;
  margin: 40px auto;
  padding: 30px;
  background-color: #fff;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.payment-title {
  text-align: center;
  margin-bottom: 30px;
  color: #333;
  font-weight: 600;
}

.card-container {
  perspective: 1000px;
  margin-bottom: 30px;
}

.credit-card {
  width: 100%;
  height: 200px;
  border-radius: 16px;
  background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
  padding: 20px;
  color: white;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.credit-card.flipped {
  transform: rotateY(180deg);
}

.credit-card-front, .credit-card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.credit-card-back {
  transform: rotateY(180deg);
}

.card-number {
  font-size: 1.4rem;
  letter-spacing: 2px;
  text-align: center;
  margin: 20px 0;
}

.card-holder, .card-expiry {
  font-size: 0.9rem;
  text-transform: uppercase;
}

.card-expiry {
  text-align: right;
}

.card-brand {
  position: absolute;
  top: 20px;
  right: 20px;
  height: 40px;
  width: 60px;
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
}

.card-brand.visa {
  background-image: url('data:image/svg+xml;base64,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');
}

.card-brand.mastercard {
  background-image: url('data:image/svg+xml;base64,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');
}

.card-brand.troy {
  background-image: url('data:image/svg+xml;base64,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');
}

.card-cvv {
  position: absolute;
  top: 50%;
  right: 20px;
  transform: translateY(-50%);
  background-color: #fff;
  color: #000;
  padding: 5px 10px;
  border-radius: 4px;
  font-size: 1rem;
}

.magnetic-strip {
  position: absolute;
  top: 30px;
  width: 100%;
  height: 40px;
  background-color: #444;
  left: 0;
}

.payment-form .form-group {
  margin-bottom: 20px;
}

.payment-form label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  color: #495057;
}

.payment-form input, .payment-form select {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid #ced4da;
  border-radius: 8px;
  font-size: 1rem;
  transition: border-color 0.3s, box-shadow 0.3s;
}

.payment-form input:focus, .payment-form select:focus {
  border-color: #80bdff;
  outline: 0;
  box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

.form-row {
  display: flex;
  gap: 15px;
}

.form-row .form-group {
  flex: 1;
}

.submit-button {
  width: 100%;
  padding: 14px;
  background-color: #0056b3;
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.3s;
  margin-top: 10px;
}

.submit-button:hover {
  background-color: #004494;
}

.submit-button:active {
  transform: translateY(1px);
}

.error-message {
  background-color: #f8d7da;
  color: #721c24;
  padding: 12px 15px;
  border-radius: 8px;
  margin-top: 20px;
  border-left: 4px solid #f5c6cb;
}

.card-flip-button {
  position: absolute;
  top: 10px;
  left: 10px;
  background: rgba(255, 255, 255, 0.2);
  border: none;
  color: white;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  z-index: 10;
}

.card-flip-button:hover {
  background: rgba(255, 255, 255, 0.3);
}

@media (max-width: 576px) {
  .payment-container {
    padding: 20px;
    margin: 20px auto;
  }
  
  .form-row {
    flex-direction: column;
    gap: 10px;
  }
  
  .credit-card {
    height: 180px;
  }
  
  .card-number {
    font-size: 1.2rem;
  }
}