.site-header { position: sticky; transform: none !important; }
.checkout-page { padding: 2rem 0 5rem; min-height: 80vh; }
.checkout-title { font-family: var(--font-head); font-size: 2rem; font-weight: 500; margin-bottom: 2.5rem; }
.checkout-layout { display: grid; grid-template-columns: 1fr 400px; gap: 3rem; align-items: start; }
.form-section { background: var(--bg-2); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.75rem; margin-bottom: 1.25rem; }
.form-section-title { font-family: var(--font-head); font-size: 1.2rem; font-weight: 500; margin-bottom: 1.25rem; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-group { display: flex; flex-direction: column; gap: .4rem; }
.form-group.form-group-sm { max-width: 120px; }
.form-group label { font-size: .82rem; font-weight: 600; color: var(--text-muted); letter-spacing: .04em; text-transform: uppercase; }
.form-group .req { color: var(--accent); }
.form-group input, .form-group select, .form-group textarea {
  background: var(--bg-card); border: 1.5px solid var(--border);
  border-radius: var(--radius-sm); color: var(--text);
  padding: .7rem .9rem; font-family: var(--font-body); font-size: .9rem;
  transition: border-color .2s;
  width: 100%;
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  outline: none; border-color: var(--accent);
}
.form-group input.error, .form-group select.error { border-color: #e05a2b; }
.form-group textarea { resize: vertical; min-height: 60px; }
select option { background: var(--bg-card); }

.checkbox-label { display: flex; align-items: center; gap: .75rem; cursor: pointer; }
.checkbox-label input[type="checkbox"] { width: 18px; height: 18px; accent-color: var(--accent); cursor: pointer; }
.checkbox-label span { font-size: .9rem; }

.billing-section { animation: fadeIn .3s ease; }
@keyframes fadeIn { from{opacity:0;transform:translateY(-8px)} to{opacity:1;transform:none} }

.shipping-options { display: flex; flex-direction: column; gap: .75rem; }
.shipping-loading { color: var(--text-muted); font-size: .88rem; }
.shipping-option {
  display: flex; align-items: center; gap: 1rem;
  background: var(--bg-card); border: 2px solid var(--border); border-radius: var(--radius-sm);
  padding: 1rem; cursor: pointer; transition: border-color .2s;
}
.shipping-option:hover { border-color: var(--border-2); }
.shipping-option.selected { border-color: var(--accent); }
.shipping-option input[type="radio"] { accent-color: var(--accent); width: 18px; height: 18px; }
.shipping-option-info { flex: 1; }
.shipping-option-name { font-weight: 600; font-size: .9rem; }
.shipping-option-zone { font-size: .78rem; color: var(--text-muted); }
.shipping-option-price { font-weight: 700; color: var(--accent); }
.shipping-option-free { color: #2e8b5a; font-weight: 700; }
.no-shipping-msg { color: var(--text-muted); font-size: .85rem; padding: .5rem 0; }

.order-summary {
  background: var(--bg-2); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.75rem; position: sticky; top: 6rem;
}
.order-summary-title { font-family: var(--font-head); font-size: 1.2rem; font-weight: 500; margin-bottom: 1.25rem; }
.order-items { display: flex; flex-direction: column; gap: .85rem; margin-bottom: 1.5rem; border-bottom: 1px solid var(--border); padding-bottom: 1.25rem; }
.order-item { display: flex; gap: 1rem; align-items: center; }
.order-item-img { width: 60px; height: 60px; border-radius: var(--radius-sm); overflow: hidden; flex-shrink: 0; background: var(--bg-card); }
.order-item-img img { width:100%;height:100%;object-fit:cover; }
.order-item-body { flex: 1; min-width: 0; }
.order-item-name { font-size: .88rem; font-weight: 600; }
.order-item-qty  { font-size: .78rem; color: var(--text-muted); }
.order-item-price { font-weight: 700; font-size: .9rem; white-space: nowrap; }
.order-summary-line { display: flex; justify-content: space-between; font-size: .9rem; margin-bottom: .65rem; }
.order-total { font-size: 1.1rem; font-weight: 700; padding-top: .65rem; border-top: 1px solid var(--border); margin-top: .4rem; }
.free-shipping-info { background: rgba(46,139,90,.07); border: 1px solid rgba(46,139,90,.2); border-radius: var(--radius-sm); padding: .65rem 1rem; font-size: .82rem; color: #2e8b5a; margin-bottom: 1rem; text-align: center; }
.course-notice { background: rgba(132,160,198,.1); border: 1px solid var(--border-2); border-radius: var(--radius-sm); padding: .75rem 1rem; font-size: .82rem; color: var(--text-mid); margin-bottom: 1rem; text-align: center; line-height: 1.5; }

.checkout-submit { margin-top: 1.5rem; gap: .6rem; font-size: 1rem; padding: 1.05rem; }
.checkout-secure { text-align: center; font-size: .78rem; color: var(--text-muted); margin-top: .65rem; }
.checkout-error { background: rgba(224,90,43,.08); border: 1px solid rgba(224,90,43,.25); border-radius: var(--radius-sm); padding: .75rem 1rem; font-size: .85rem; color: #e05a2b; margin-top: .75rem; text-align: center; }

.checkout-submit.loading { opacity: .65; cursor: wait; pointer-events: none; }

@media (max-width: 1024px) {
  .checkout-layout { grid-template-columns: 1fr; }
  .order-summary { position: static; }
}
@media (max-width: 768px) {
  .form-row { grid-template-columns: 1fr; }
  .form-group.form-group-sm { max-width: 100%; }
}