body {
  font-family: 'Arial', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: #333;
}

.container {
  background: #fff;
  padding: 40px 30px;
  border-radius: 15px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  max-width: 400px;
  width: 90%;
  text-align: center;
}

.logo {
  width: 120px;
  margin-bottom: 20px;
}

h1 {
  margin-bottom: 25px;
  font-size: 24px;
  color: #333;
}

.payment-form .form-group {
  display: flex;
  flex-direction: column;
  gap: 15px;
  margin-bottom: 20px;
}

.input-icon {
  position: relative;
}

.input-icon span {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
}

.input-icon input {
  padding: 12px 15px 12px 35px;
  border: 1px solid #ccc;
  border-radius: 8px;
  font-size: 16px;
  width: 100%;
  transition: 0.3s;
}

.input-icon input:focus {
  border-color: #667eea;
  box-shadow: 0 0 5px rgba(102,126,234,0.5);
  outline: none;
}

#display-amount {
  margin-bottom: 20px;
  font-weight: bold;
  color: #555;
}

#checkout-button {
  width: 100%;
  padding: 15px;
  background: #667eea;
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 18px;
  cursor: pointer;
  transition: 0.3s;
}

#checkout-button:hover {
  background: #5469d4;
}

.stripe-info {
  margin-top: 20px;
  font-size: 14px;
  color: #666;
}

@media (min-width: 500px) {
  .payment-form .form-group {
    flex-direction: row;
  }
  .payment-form .form-group .input-icon {
    flex: 1;
  }
}