:root { color-scheme: light dark; --paper: #f4ede7; --surface: #fffcfa; --ink: #271a2f; --muted: #655569; --plum: #7d4663; --line: #d8c9cf; --selected: #f4e7ee; --button: #e5d9e0; }
* { box-sizing: border-box; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 15px/1.75 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif; }
a { color: var(--plum); text-underline-offset: 4px; }
.topbar, main, footer { width: min(1120px, calc(100% - 64px)); margin-inline: auto; }
.topbar { height: 80px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); }
.brand { display: flex; gap: 10px; align-items: center; color: var(--ink); text-decoration: none; font: 26px "STKaiti", "KaiTi", serif; }
.brand img { object-fit: contain; }
.back-link { font-size: 14px; }
.intro { padding: 42px 0 28px; }
.preview-label { font-size: 13px; color: var(--plum); margin: 0 0 8px; }
h1 { font: 38px/1.35 "STKaiti", "KaiTi", serif; margin: 0 0 10px; }
p { margin: 0; color: var(--muted); }
h2 { font-size: 19px; margin: 0 0 10px; font-weight: 600; }
h3 { font-size: 14px; margin: 0 0 6px; font-weight: 600; }
.checkout-layout { display: grid; grid-template-columns: minmax(0, 1.45fr) minmax(320px, 1fr); gap: 44px; align-items: start; }
fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
legend { font-size: 19px; font-weight: 600; margin-bottom: 16px; padding: 0; }
.plan { display: flex; align-items: start; gap: 14px; background: var(--surface); border: 1px solid var(--line); padding: 21px 24px; margin-bottom: 14px; cursor: pointer; }
.plan:has(input:checked) { background: var(--selected); border-color: var(--plum); box-shadow: inset 3px 0 var(--plum); }
input { accent-color: var(--plum); width: 18px; height: 18px; margin: 7px 0 0; flex-shrink: 0; }
.plan-body { flex: 1; min-width: 0; }
.plan-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; }
.plan-heading strong { font-size: 20px; font-weight: 600; }
.price { font-size: 28px; font-variant-numeric: tabular-nums; color: var(--plum); white-space: nowrap; }
.price small { font-size: 13px; color: var(--muted); }
.plan-description { display: block; margin: 2px 0 12px; color: var(--muted); font-size: 13px; }
.features { font-size: 14px; display: block; }
.compatibility { font-size: 12px; line-height: 1.8; }
.delivery { margin: 24px 0 0; }
.delivery h2 { font-size: 15px; }
.delivery p { font-size: 13px; }
.summary { background: var(--surface); border-top: 3px solid var(--plum); padding: 25px 28px; }
.summary-caption { font-size: 13px; }
dl { margin: 22px 0; }
dl > div { display: flex; justify-content: space-between; gap: 20px; margin: 12px 0; }
dt { color: var(--muted); } dd { margin: 0; text-align: right; }
.total { border-top: 1px solid var(--line); padding: 22px 0; display: flex; align-items: baseline; justify-content: space-between; gap: 16px; }
.total strong { color: var(--plum); font-size: 35px; font-weight: 600; font-variant-numeric: tabular-nums; }
button { width: 100%; padding: 15px 10px; font: inherit; font-weight: 600; border: 1px solid var(--line); background: var(--button); color: var(--muted); cursor: not-allowed; }
.payment-note { font-size: 12px; margin-top: 12px; }
.service-info { margin: 35px 0; padding-top: 24px; border-top: 1px solid var(--line); }
.info-grid { display: grid; grid-template-columns: 1fr 1.15fr 1.5fr; gap: 28px; }
.info-grid p { font-size: 12px; }
footer { padding: 20px 0 28px; border-top: 1px solid var(--line); display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; font-size: 12px; color: var(--muted); }
:focus-visible { outline: 2px solid var(--plum); outline-offset: 5px; }
@media (max-width: 767px) {
  .topbar, main, footer { width: calc(100% - 36px); }
  .topbar { height: 68px; }
  .intro { padding-top: 28px; }
  h1 { font-size: 30px; }
  .checkout-layout, .info-grid { grid-template-columns: 1fr; gap: 24px; }
  .plan { padding: 18px 16px; }
  .plan-heading strong { font-size: 18px; }
  .price { font-size: 26px; }
  .summary { padding: 22px; }
}
@media (prefers-color-scheme: dark) {
  :root { --paper: #201c22; --surface: #2c252e; --ink: #f6edf2; --muted: #d0bfce; --plum: #e1a8c7; --line: #655362; --selected: #3d2c3a; --button: #493b46; }
}