:root {
  --bg: #f4f1ea;
  --card: #fff;
  --text: #1c1917;
  --muted: #57534e;
  --line: #d6d3d1;
  --warn: #fff7d6;
  --warn-border: #e6c200;
  --err: #fef2f2;
  --err-text: #b91c1c;
  --btn: #1d4ed8;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 40px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font: 15px/1.5 "Songti SC", "Songti", "SimSun", serif;
  color: var(--text);
  background: var(--bg);
}

main {
  max-width: 1520px;
  margin: 0 auto;
  padding: var(--space-5) 20px 64px;
}

.page-head { margin-bottom: var(--space-5); }
h1 { font-size: 22px; margin: 0 0 var(--space-1); }
h2 { font-size: 16px; margin: 0 0 var(--space-2); }
.lead { color: var(--muted); margin: 0; max-width: 42em; }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

form {
  max-width: 760px;
  background: var(--card);
  border: 1px solid var(--line);
  padding: var(--space-5) var(--space-4) var(--space-4);
  display: grid;
  gap: var(--space-5);
}

.group { display: grid; gap: var(--space-2); }
.group-label {
  margin: 0;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.pair {
  display: grid;
  gap: var(--space-3);
}

@media (min-width: 640px) {
  .pair { grid-template-columns: 1fr 1fr; align-items: end; }
}

.group-target { gap: var(--space-3); }

.group-run {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  gap: var(--space-3) var(--space-4);
  padding-top: var(--space-2);
  border-top: 1px solid var(--line);
}

.band-field {
  flex: 1;
  min-width: 160px;
  max-width: 240px;
}

label { display: grid; gap: var(--space-1); font-weight: 600; }

fieldset.target-mode {
  border: 0;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-5);
  align-items: center;
}

label.mode-opt {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: var(--space-2);
  font-weight: 600;
}

label.mode-opt input[type="radio"] {
  margin: 0;
  padding: 0;
  width: auto;
  height: auto;
}

.hint {
  color: var(--muted);
  font-weight: 400;
  margin: 0;
  font-size: 13px;
}

.target-wrap { display: grid; gap: var(--space-1); }
.target-wrap > label { font-weight: 600; }

.target-row {
  display: flex;
  align-items: stretch;
}

.target-row input {
  flex: 1;
  min-width: 0;
  margin: 0;
  border: 1px solid var(--line);
  border-right: none;
  border-radius: 0;
}

.unit {
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  padding: 0 12px;
  border: 1px solid var(--line);
  background: #e7e5e4;
  font-weight: 600;
  min-width: 2.5em;
}

input, select, button {
  font: inherit;
  padding: 8px 10px;
}

button {
  background: var(--btn);
  color: #fff;
  border: 0;
  cursor: pointer;
  width: max-content;
}

button:disabled { opacity: 0.5; cursor: not-allowed; }

.error {
  background: var(--err);
  color: var(--err-text);
  padding: 10px 12px;
  margin-top: var(--space-3);
}

#preview { margin-top: var(--space-6); }

.preview-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.echo {
  font-size: 18px;
  font-weight: 700;
  margin: 0;
  flex: 1 1 16em;
}

.warning {
  background: var(--warn);
  border: 1px solid var(--warn-border);
  padding: 8px 10px;
  margin: 0 0 var(--space-3);
}

.kpis {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

@media (max-width: 639px) {
  .kpis { grid-template-columns: 1fr; }
}

.kpi {
  display: grid;
  gap: 2px;
  padding: var(--space-3) 0;
  border-top: 1px solid var(--line);
}

.kpi-label {
  color: var(--muted);
  font-size: 13px;
}

.kpi-value {
  font-variant-numeric: tabular-nums;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.stats {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: var(--space-1) var(--space-4);
  padding: var(--space-3) 0 var(--space-5);
  border-top: 1px solid var(--line);
}

.stats dt { color: var(--muted); }
.stats dd { margin: 0; font-variant-numeric: tabular-nums; }

.ledger-tables {
  display: grid;
  gap: var(--space-5);
}

@media (min-width: 1200px) {
  .ledger-tables { grid-template-columns: 1fr 1fr; align-items: start; }
}

.table-wrap { overflow-x: auto; }

table {
  border-collapse: collapse;
  width: max-content;
  min-width: 100%;
  background: var(--card);
}

th, td {
  border: 1px solid var(--line);
  padding: 6px 8px;
  text-align: left;
  white-space: nowrap;
}

th { background: #e7e5e4; }

.download {
  display: inline-block;
  padding: 8px 14px;
  background: #0f766e;
  color: #fff;
  text-decoration: none;
  width: max-content;
}

.download[hidden] { display: none; }