:root {
  --bg: #f8fafc;
  --text: #0f172a;
  --text-muted: #64748b;
  --text-soft: #94a3b8;
  --border: #e2e8f0;
  --border-soft: #f1f5f9;
  --card-bg: #fff;
  --primary: #2563eb;
  --primary-2: #0f766e;
  --green: #15803d;
  --red: #dc2626;
  --amber: #d97706;
  --radius: 10px;
  --radius-sm: 8px;
  --radius-xs: 6px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.06), 0 1px 2px rgba(15, 23, 42, 0.04);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background: linear-gradient(135deg, #f8fafc, #eef6ff 52%, #f0fdfa);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 14px;
}

.hidden { display: none !important; }

.container {
  max-width: 1320px;
  margin: 0 auto;
  padding: 0 24px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--primary-2));
  box-shadow: 0 8px 18px rgba(37, 99, 235, 0.22);
}

.brand-title {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
}

.brand-sub {
  margin: 2px 0 0;
  color: var(--text-muted);
  font-size: 12px;
}

.header-actions {
  display: flex;
  gap: 8px;
}

.main-area { padding-top: 24px; padding-bottom: 44px; }

.grid-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(360px, 0.8fr);
  gap: 22px;
  align-items: start;
}

.form-column, .result-column {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.card, .empty, .result-summary, .rules-panel {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.card-header { padding: 18px 22px 8px; }
.card-title {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 15px;
  font-weight: 650;
}
.card-body { padding: 12px 22px 20px; }

.form-grid-2, .form-grid-3, .form-grid-4 {
  display: grid;
  gap: 14px;
}
.form-grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.form-grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.form-grid-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text);
  font-size: 13px;
  font-weight: 550;
}

.label-sm {
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 550;
}

.help-icon {
  position: relative;
  color: var(--text-soft);
  cursor: help;
}

.help-icon[data-tip]:hover::after {
  content: attr(data-tip);
  position: absolute;
  left: 50%;
  bottom: 130%;
  transform: translateX(-50%);
  z-index: 30;
  width: 230px;
  padding: 7px 10px;
  border-radius: 6px;
  color: #fff;
  background: #1e293b;
  font-size: 11px;
  font-weight: 400;
  line-height: 1.45;
}

.input {
  width: 100%;
  height: 38px;
  padding: 0 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-xs);
  color: var(--text);
  background: #fff;
  font-family: inherit;
  font-size: 13px;
  transition: border 0.15s, box-shadow 0.15s;
}

.input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.14);
}

.input-prefix-wrap { position: relative; }
.input-prefix-wrap .input { padding-left: 34px; }
.input-prefix-wrap .input.exchange-input { padding-left: 48px; }
.input-prefix-wrap .input.with-suffix { padding-right: 34px; }
.input-prefix, .input-suffix {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-soft);
  font-size: 12px;
}
.input-prefix { left: 12px; }
.input-suffix { right: 12px; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 38px;
  padding: 0 16px;
  border-radius: var(--radius-xs);
  border: 1px solid transparent;
  background: transparent;
  color: var(--text);
  text-decoration: none;
  font-family: inherit;
  font-size: 13px;
  font-weight: 550;
  cursor: pointer;
  transition: background 0.15s, border 0.15s, opacity 0.15s;
}
.btn-sm { height: 30px; padding: 0 12px; font-size: 12px; }
.btn-lg { height: 44px; padding: 0 22px; font-size: 14px; }
.btn-outline { border-color: var(--border); background: #fff; }
.btn-outline:hover { background: #f8fafc; }
.btn-primary {
  color: #fff;
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  box-shadow: 0 8px 18px rgba(37, 99, 235, 0.2);
}
.btn-primary:hover { opacity: 0.92; }

.actions-row { display: flex; gap: 12px; }
.actions-row .btn-primary { flex: 1; }

.hint-banner {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  margin: 12px 0;
  padding: 9px 12px;
  border: 1px solid #bfdbfe;
  border-radius: var(--radius-xs);
  background: #eff6ff;
  color: #1e40af;
  font-size: 12px;
  line-height: 1.5;
}

.error-card {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  border: 1px solid #fecaca;
  border-radius: var(--radius);
  background: #fef2f2;
  color: #b91c1c;
  font-size: 13px;
}

.empty {
  padding: 58px 20px;
  text-align: center;
  border-style: dashed;
}
.empty-icon {
  width: 64px;
  height: 64px;
  display: grid;
  place-items: center;
  margin: 0 auto 16px;
  border-radius: 50%;
  background: #f1f5f9;
  color: #cbd5e1;
}
.empty-title {
  margin: 0;
  color: var(--text-muted);
  font-weight: 550;
}
.empty-sub {
  margin: 6px 0 0;
  color: var(--text-soft);
  font-size: 12px;
}

.result-summary {
  padding: 22px;
  text-align: center;
}
.result-summary.profit-positive {
  border-color: #bbf7d0;
  background: linear-gradient(135deg, #f0fdf4, #ecfdf5);
}
.result-summary.profit-negative {
  border-color: #fecaca;
  background: linear-gradient(135deg, #fef2f2, #fff1f2);
}
.result-summary .label {
  justify-content: center;
  color: var(--text-muted);
}
.result-amount {
  margin: 6px 0;
  font-size: 30px;
  font-weight: 750;
}
.green { color: var(--green); }
.red { color: var(--red); }
.amber { color: var(--amber); }
.blue { color: var(--primary); }

.result-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 8px;
  border-radius: 999px;
  border: 1px solid transparent;
  background: #0f172a;
  color: #fff;
  font-size: 11px;
  font-weight: 550;
}
.badge-outline {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}
.badge-warn {
  background: #fffbeb;
  border-color: #fcd34d;
  color: #92400e;
}

.kv-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin: 5px 0;
  font-size: 13px;
}
.kv-row .muted { color: var(--text-muted); }
.kv-row .small { color: var(--text-soft); font-size: 12px; }
.kv-row .value { font-weight: 650; }
.divider {
  height: 1px;
  margin: 10px 0;
  border: 0;
  background: var(--border);
}

.fee-item {
  padding: 7px 0;
  border-bottom: 1px solid var(--border-soft);
}
.fee-item:last-child { border-bottom: 0; }
.fee-name { font-size: 13px; font-weight: 550; }
.fee-amount { font-size: 13px; font-weight: 650; }
.fee-formula {
  margin: 4px 0 0;
  color: var(--text-soft);
  font-size: 11px;
  line-height: 1.45;
}

.rules-panel {
  margin-bottom: 22px;
  padding: 18px 22px;
  background: rgba(239, 246, 255, 0.68);
  border-color: #bfdbfe;
}
.rules-panel h2 {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-size: 15px;
}
.rules-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 14px;
}
.rules-grid h4 {
  margin: 0 0 5px;
  font-size: 13px;
}
.rules-grid p {
  margin: 0;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.55;
}

.tier-table-wrap {
  overflow-x: auto;
  margin-top: 14px;
}
.tier-table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  font-size: 12px;
}
.tier-table th, .tier-table td {
  padding: 7px 9px;
  border: 1px solid #bfdbfe;
  text-align: left;
  white-space: nowrap;
}
.tier-table thead { background: #dbeafe; }

.site-footer {
  margin-top: 24px;
  padding: 16px 0;
  border-top: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.62);
  text-align: center;
}
.site-footer p {
  margin: 0;
  color: var(--text-soft);
  font-size: 12px;
}

@media (max-width: 980px) {
  .grid-layout { grid-template-columns: 1fr; }
  .form-grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .rules-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  .container { padding: 0 16px; }
  .header-inner { align-items: flex-start; flex-direction: column; }
  .form-grid-2, .form-grid-3, .form-grid-4, .rules-grid { grid-template-columns: 1fr; }
  .actions-row { flex-direction: column; }
}