* {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
     font-family: "Inter", sans-serif;
 }

 body {
     background: #fafafa;
     padding: 0;
 }

 .container {
     max-width: 1100px;
     margin: auto;
     padding: 30px;
 }

 #header-placeholder,
 #footer-placeholder {
     width: 100%;
     box-sizing: border-box;
 }

 .page-title {
     font-size: 24px;
     font-weight: 600;
     margin-bottom: 25px;
 }

 .checkout-grid {
     display: grid;
     grid-template-columns: 2fr 1fr;
     gap: 30px;
 }

 .checkout-left {
     background: white;
     padding: 25px;
     border-radius: 10px;
     border: 1px solid #eaeaea;
 }

 .checkout-right {
     background: white;
     padding: 25px;
     border-radius: 10px;
     border: 1px solid #eaeaea;
     height: fit-content;
 }

 .form-row {
     display: flex;
     gap: 20px;
     margin-bottom: 20px;
 }

 .form-group {
     flex: 1;
     display: flex;
     flex-direction: column;
     margin-bottom: 15px;
 }

 label {
     font-size: 13px;
     margin-bottom: 5px;
     color: #333;
 }

 input[type="text"],
 input[type="number"],
 input[type="email"] {
     padding: 10px;
     border-radius: 6px;
     border: 1px solid #ddd;
     font-size: 14px;
 }

 .payment-title {
     font-size: 16px;
     font-weight: 600;
     margin: 20px 0 10px;
 }

 .payment-box {
     border: 1px solid #e1e1e1;
     padding: 20px;
     border-radius: 10px;
 }

 .payment-header {
     display: flex;
     justify-content: space-between;
     margin-bottom: 15px;
 }

 .payment-header input {
     margin-right: 8px;
 }

 .cards {
     font-size: 12px;
     opacity: 0.6;
 }

 .paypal-option {
     margin-top: 20px;
 }

 .order-card {
     border: 1px solid #eee;
     padding: 15px;
     border-radius: 10px;
     margin-bottom: 15px;
 }

 .order-info {
     display: flex;
     gap: 15px;
 }

 .order-img {
     width: 80px;
     height: 80px;
     border-radius: 8px;
     object-fit: cover;
     display: block;
     flex: 0 0 80px;
 }

 .order-text .course-category {
     color: dodgerblue;
     font-size: 12px;
     margin-bottom: 3px;
 }

 .course-title {
     font-weight: 600;
     line-height: 1.3;
 }

 .course-meta {
     font-size: 12px;
     margin: 4px 0;
     opacity: 0.6;
 }

 .course-price {
     font-weight: 600;
     margin-top: 5px;
 }

 .coupon-btn {
     width: 100%;
     border: 1px dashed #bbb;
     background: none;
     padding: 10px;
     margin: 10px 0 20px;
     border-radius: 8px;
     cursor: pointer;
 }

 .pricing-box {
     border: 1px solid #eee;
     padding: 15px;
     border-radius: 10px;
     margin-bottom: 20px;
 }

 .price-row,
 .price-total {
     display: flex;
     justify-content: space-between;
     margin-bottom: 8px;
     font-size: 14px;
 }

 .price-total {
     font-weight: 600;
     font-size: 16px;
     margin-top: 10px;
 }

 .form-message {
     margin-top: 10px;
     color: #d63333;
     min-height: 20px;
     font-size: 14px;
     margin-bottom: 8px;
 }

 .checkout-btn {
     width: 100%;
     padding: 12px;
     background: linear-gradient(90deg, #0c0f3d, #1b1f56);
     color: white;
     border-radius: 8px;
     border: none;
     font-weight: 600;
     cursor: pointer;
     display: inline-block;
     text-align: center;
     transition: transform 0.15s ease, box-shadow 0.15s ease, opacity 0.15s ease;
     box-shadow: 0 2px 10px rgba(12, 15, 61, 0.12);
 }

 .checkout-btn:hover {
     transform: translateY(-3px);
     box-shadow: 0 8px 24px rgba(12, 15, 61, 0.16);
 }

 .checkout-btn:focus-visible {
     outline: 3px solid rgba(37, 99, 235, 0.12);
     outline-offset: 3px;
     border-radius: 8px;
 }

 .checkout-btn[disabled] {
     opacity: 0.6;
     cursor: not-allowed;
     transform: none;
     box-shadow: none;
 }

 .checkout-btn .spinner {
     display: inline-block;
     margin-right: 8px;
     width: 14px;
     height: 14px;
     border: 2px solid rgba(255, 255, 255, 0.4);
     border-top-color: #fff;
     border-radius: 50%;
     animation: spin 1s linear infinite;
     vertical-align: middle;
 }

 @keyframes spin {
     to {
         transform: rotate(360deg);
     }
 }