:root {
  --bg: #f3f6fb;
  --card: #ffffff;
  --text: #1a2233;
  --text-secondary: #5c6b82;
  --text-tertiary: #8b97a8;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-soft: #eff6ff;
  --ali: #1677ff;
  --ali-soft: #e8f3ff;
  --wx: #07c160;
  --wx-soft: #e8faf0;
  --success: #059669;
  --success-soft: #ecfdf5;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --border: #e8edf4;
  --shadow-sm: 0 4px 16px rgba(26, 34, 51, 0.06);
  --shadow-md: 0 12px 40px rgba(26, 34, 51, 0.1);
  --shadow-lg: 0 24px 64px rgba(26, 34, 51, 0.14);
  --radius: 16px;
  --radius-lg: 24px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.page-bg {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 70% 50% at 50% -20%, rgba(37, 99, 235, 0.12), transparent 55%),
    radial-gradient(ellipse 40% 30% at 100% 50%, rgba(7, 193, 96, 0.06), transparent 50%),
    linear-gradient(180deg, #f8fafc 0%, var(--bg) 100%);
}

/* Top bar */
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.topbar-inner {
  max-width: 480px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: inherit;
}

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 16px;
  font-weight: 800;
  color: #fff;
  background: linear-gradient(135deg, #3b82f6, #1d4ed8);
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.35);
}

.brand-name {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.secure-tag {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  font-weight: 600;
  color: var(--success);
  padding: 6px 10px;
  border-radius: 999px;
  background: var(--success-soft);
}

/* Main */
.main {
  position: relative;
  max-width: 480px;
  margin: 0 auto;
  padding: 24px 16px 100px;
}

.checkout {
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid rgba(255, 255, 255, 0.8);
  overflow: hidden;
}

.checkout-intro {
  padding: 28px 24px 8px;
}

.checkout-intro h1 {
  margin: 0 0 8px;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.checkout-intro p {
  margin: 0;
  font-size: 14px;
  color: var(--text-secondary);
}

.order-preview {
  margin: 16px 20px 0;
  padding: 16px;
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: var(--primary-soft);
  border-radius: var(--radius);
  border: 1px solid #dbeafe;
}

.preview-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-size: 15px;
  font-weight: 700;
  color: var(--primary);
  background: #fff;
  box-shadow: var(--shadow-sm);
}

.preview-body { flex: 1; min-width: 0; }

.field-inline { display: block; }

.field-label {
  display: block;
  font-size: 12px;
  color: var(--text-tertiary);
  margin-bottom: 6px;
  font-weight: 500;
}

.field-inline input {
  width: 100%;
  border: none;
  background: transparent;
  padding: 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  outline: none;
  font-family: inherit;
}

.field-inline input::placeholder {
  color: var(--text-tertiary);
  font-weight: 400;
}

.pay-form { padding: 8px 0 0; }

.section {
  padding: 20px 24px;
  border-top: 1px solid var(--border);
}

.section-title {
  margin: 0 0 14px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
}

.amount-display {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 14px;
}

.currency {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-tertiary);
}

.amount-display input {
  width: 100%;
  max-width: 200px;
  border: none;
  background: transparent;
  font-size: 40px;
  font-weight: 800;
  color: var(--text);
  outline: none;
  font-family: inherit;
  letter-spacing: -0.03em;
  -moz-appearance: textfield;
}

.amount-display input::-webkit-outer-spin-button,
.amount-display input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.quick-amounts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.amount-chip {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  background: #fff;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.amount-chip:hover {
  border-color: #93c5fd;
  color: var(--primary);
}

.amount-chip.active {
  border-color: var(--primary);
  background: var(--primary-soft);
  color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.field-tip {
  margin: 10px 0 0;
  font-size: 12px;
  color: var(--text-tertiary);
}

.pay-methods {
  display: grid;
  gap: 10px;
}

.method {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border-radius: var(--radius);
  border: 2px solid var(--border);
  background: #fff;
  cursor: pointer;
  transition: all 0.2s;
}

.method:hover {
  border-color: #cbd5e1;
}

.method.active {
  border-color: var(--primary);
  background: var(--primary-soft);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.08);
}

.method input { display: none; }

.method-radio {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid #cbd5e1;
  flex-shrink: 0;
  position: relative;
  transition: 0.2s;
}

.method.active .method-radio {
  border-color: var(--primary);
  background: var(--primary);
}

.method.active .method-radio::after {
  content: "";
  position: absolute;
  inset: 5px;
  background: #fff;
  border-radius: 50%;
}

.method-logo {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-size: 18px;
  font-weight: 800;
  flex-shrink: 0;
}

.method-logo.ali {
  background: var(--ali-soft);
  color: var(--ali);
}

.method-logo.wx {
  background: var(--wx-soft);
  color: var(--wx);
}

.method-info strong {
  display: block;
  font-size: 15px;
  font-weight: 600;
}

.method-info small {
  display: block;
  font-size: 12px;
  color: var(--text-tertiary);
  margin-top: 2px;
}

.summary-bar {
  padding: 20px 24px 24px;
  background: linear-gradient(180deg, #f8fafc, #fff);
  border-top: 1px solid var(--border);
}

.summary-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  font-size: 14px;
  color: var(--text-secondary);
}

.summary-row strong {
  font-size: 24px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
}

.submit-btn {
  width: 100%;
  border: none;
  border-radius: 14px;
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: inherit;
  font-size: 17px;
  font-weight: 700;
  color: #fff;
  cursor: pointer;
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  box-shadow: 0 10px 28px rgba(37, 99, 235, 0.35);
  transition: transform 0.15s, box-shadow 0.2s, opacity 0.2s;
}

.submit-btn:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 14px 36px rgba(37, 99, 235, 0.4);
}

.submit-btn:disabled {
  opacity: 0.7;
  cursor: wait;
}

.submit-amount {
  font-size: 18px;
  font-weight: 800;
}

.agree-text {
  margin: 12px 0 0;
  text-align: center;
  font-size: 11px;
  color: var(--text-tertiary);
}

/* Bottom sheet */
.sheet-mask {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  z-index: 40;
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}

.sheet-mask.visible {
  opacity: 1;
  pointer-events: auto;
}

.pay-sheet {
  position: fixed;
  left: 50%;
  bottom: 0;
  transform: translate(-50%, 100%);
  width: min(480px, 100%);
  z-index: 50;
  background: var(--card);
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  box-shadow: var(--shadow-lg);
  transition: transform 0.35s cubic-bezier(0.32, 0.72, 0, 1);
}

.pay-sheet.visible {
  transform: translate(-50%, 0);
}

.pay-sheet.hidden {
  visibility: hidden;
}

.pay-sheet.visible.hidden {
  visibility: visible;
}

.sheet-handle {
  width: 40px;
  height: 4px;
  margin: 12px auto 0;
  border-radius: 999px;
  background: #e2e8f0;
}

.sheet-body {
  padding: 24px 24px 32px;
  text-align: center;
}

.sheet-status { margin-bottom: 16px; }

.status-ring {
  width: 72px;
  height: 72px;
  margin: 0 auto;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 32px;
  font-weight: 700;
}

.status-ring.ok {
  background: var(--success-soft);
  color: var(--success);
}

.status-ring.err {
  background: var(--danger-soft);
  color: var(--danger);
}

.status-ring.wait {
  background: var(--primary-soft);
  color: var(--primary);
  animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.04); }
}

.sheet-body h2 {
  margin: 0 0 8px;
  font-size: 20px;
  font-weight: 700;
}

.sheet-body > p {
  margin: 0 0 20px;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.order-info {
  margin: 0 0 20px;
  padding: 16px;
  border-radius: var(--radius);
  background: #f8fafc;
  border: 1px solid var(--border);
  text-align: left;
}

.order-info:empty { display: none; }

.order-info .row {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  font-size: 13px;
  padding: 6px 0;
}

.order-info .row:not(:last-child) {
  border-bottom: 1px dashed var(--border);
}

.order-info dt {
  color: var(--text-tertiary);
  font-weight: 500;
}

.order-info dd {
  margin: 0;
  font-weight: 600;
  text-align: right;
  word-break: break-all;
  max-width: 60%;
}

.sheet-actions {
  display: grid;
  gap: 10px;
  margin-bottom: 12px;
}

.btn-primary,
.btn-secondary {
  display: block;
  width: 100%;
  padding: 14px;
  border-radius: 12px;
  font-size: 15px;
  font-weight: 600;
  font-family: inherit;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: 0.2s;
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
  color: var(--text);
  background: #fff;
  border: 1px solid var(--border);
}

.btn-secondary:hover { background: #f8fafc; }

.btn-text {
  border: none;
  background: none;
  color: var(--text-tertiary);
  font-size: 14px;
  cursor: pointer;
  padding: 8px;
  font-family: inherit;
}

.btn-text:hover { color: var(--primary); }

.site-footer {
  text-align: center;
  padding: 24px 16px;
  font-size: 12px;
  color: var(--text-tertiary);
}

.site-footer p { margin: 0; }

/* Pay result page */
.result-page {
  max-width: 420px;
  margin: 48px auto;
  padding: 40px 28px;
  text-align: center;
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.result-page .status-ring { margin-bottom: 20px; }

.result-page h1 {
  margin: 0 0 10px;
  font-size: 22px;
}

.result-page .desc {
  color: var(--text-secondary);
  font-size: 14px;
  margin: 0 0 24px;
}

.result-card {
  padding: 16px;
  border-radius: var(--radius);
  background: #f8fafc;
  border: 1px solid var(--border);
  text-align: left;
  margin-bottom: 24px;
}

.result-card .row {
  display: flex;
  justify-content: space-between;
  font-size: 14px;
  padding: 8px 0;
}

.result-card .label { color: var(--text-tertiary); }
.result-card .value { font-weight: 600; }

.status-paid { color: var(--success); }
.status-pending { color: #d97706; }
.status-failed { color: var(--danger); }

@media (max-width: 520px) {
  .checkout-intro { padding: 24px 20px 4px; }
  .section { padding: 18px 20px; }
  .summary-bar { padding: 18px 20px 22px; }
}