:root {
  --bg: #f6f5f1;
  --surface: #ffffff;
  --ink: #1d2226;
  --ink-2: #4a545c;
  --muted: #6b757d;
  --line: #dcd9d0;
  --grid: #e8e6df;
  --a: #2f6db5;      /* Loan A */
  --b: #c2581a;      /* Loan B */
  --neutral: #8b949b; /* interest in split charts */
  --good: #2c7a4b;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14181b;
    --surface: #1c2226;
    --ink: #e8eaeb;
    --ink-2: #b4bcc1;
    --muted: #8e989e;
    --line: #333c42;
    --grid: #2a3237;
    --a: #6da8ec;
    --b: #ee9a5c;
    --neutral: #7c868d;
    --good: #6cc48d;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.page-header, main { max-width: 1100px; margin: 0 auto; padding: 0 16px; }
.page-header { padding-top: 24px; }
h1 { font-size: 1.6rem; margin: 0 0 4px; }
h2 { font-size: 1.15rem; margin: 28px 0 10px; }
.lede { color: var(--ink-2); margin: 0; }
main { padding-bottom: 48px; }

.verdict, .panel, .card, .chart, .table-wrap {
  background: var(--surface); border: 1px solid var(--line); border-radius: 8px;
}
.verdict { padding: 16px 20px; margin-top: 20px; border-left: 5px solid var(--neutral); }
.verdict.win-a { border-left-color: var(--a); }
.verdict.win-b { border-left-color: var(--b); }
.verdict h2 { margin: 0 0 4px; font-size: 1.3rem; }
.verdict p { margin: 4px 0; color: var(--ink-2); }

.panel { padding: 8px 16px 16px; margin-top: 20px; }
.panel-head { display: flex; justify-content: space-between; align-items: center; }
.panel-head h2 { margin: 12px 0 4px; }
.button {
  font: inherit; padding: 6px 14px; border-radius: 6px; cursor: pointer;
  background: transparent; color: var(--ink); border: 1px solid var(--ink-2);
}
.button:hover { background: var(--grid); }
.group { border: 1px solid var(--line); border-radius: 6px; margin: 12px 0 0; padding: 8px 12px 12px; min-width: 0; }
.group legend { padding: 0 6px; font-weight: 600; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 10px 14px; }
label { display: flex; flex-direction: column; gap: 3px; font-size: 0.85rem; color: var(--ink-2); }
label.check { flex-direction: row; align-items: center; gap: 8px; align-self: end; padding-bottom: 8px; }
input[type="number"], input[type="text"], select {
  font: inherit; color: var(--ink); background: var(--bg);
  border: 1px solid var(--line); border-radius: 5px; padding: 6px 8px; width: 100%;
}
input:focus-visible, select:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--a); outline-offset: 2px;
}
.loans { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.swatch { display: inline-block; width: 12px; height: 12px; border-radius: 3px; margin-right: 6px; }
.swatch-a { background: var(--a); }
.swatch-b { background: var(--b); }
.loan-summary { margin: 10px 0 0; font-size: 0.9rem; color: var(--ink-2); }
.badge {
  display: inline-block; padding: 1px 8px; border-radius: 10px; font-size: 0.75rem; font-weight: 600;
  border: 1px solid var(--ink-2); color: var(--ink);
}
.badge.jumbo { background: var(--ink); color: var(--surface); }

.cards { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.card { padding: 12px 16px; }
.card.win-a { border-top: 4px solid var(--a); }
.card.win-b { border-top: 4px solid var(--b); }
.card h3 { margin: 0 0 8px; font-size: 1rem; }
.card .big { font-size: 1.6rem; font-weight: 650; margin: 0 0 8px; }
.card dl { margin: 0; display: grid; grid-template-columns: 1fr auto; gap: 4px 12px; font-size: 0.9rem; }
.card dt { color: var(--ink-2); }
.card dd { margin: 0; text-align: right; font-variant-numeric: tabular-nums; }
.card dl.calc .subtotal { color: var(--ink); font-weight: 600; border-top: 1px solid var(--line); padding-top: 3px; margin-bottom: 6px; }
.card dl.facts { margin-top: 10px; padding-top: 8px; border-top: 1px dashed var(--line); font-size: 0.85rem; }
.sanity { color: var(--muted); font-size: 0.85rem; margin: 8px 0 0; }

.charts { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.chart { margin: 0; padding: 12px; min-width: 0; }
.chart.wide { grid-column: 1 / -1; }
.chart figcaption { font-weight: 600; font-size: 0.95rem; margin-bottom: 6px; }
.canvas-box { position: relative; height: 280px; }
.chart.wide .canvas-box { height: 340px; }

.table-wrap { margin-top: 20px; padding: 10px 16px; }
.table-wrap summary { cursor: pointer; font-weight: 600; }
.scroll { overflow-x: auto; margin-top: 10px; }
table { border-collapse: collapse; width: 100%; font-size: 0.85rem; font-variant-numeric: tabular-nums; }
th, td { padding: 4px 10px; text-align: right; border-bottom: 1px solid var(--grid); white-space: nowrap; }
th { color: var(--ink-2); font-weight: 600; }
th:first-child, td:first-child { text-align: left; }
.assumptions p { color: var(--ink-2); margin: 6px 0; }

@media (max-width: 720px) {
  .loans, .cards, .charts { grid-template-columns: 1fr; }
  .canvas-box, .chart.wide .canvas-box { height: 260px; }
}
.advanced summary { cursor: pointer; font-weight: 600; padding: 2px 0; }
.advanced[open] summary { margin-bottom: 8px; }
/* Advanced section: two titled sub-groups; inputs line up even if a label wraps. */
.advanced .sub + .sub { margin-top: 14px; padding-top: 12px; border-top: 1px solid var(--line); }
.advanced .sub h3 { margin: 0 0 8px; font-size: 0.75rem; font-weight: 600; letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-2); }
.advanced label.check { align-self: auto; padding: 0 0 10px; }
.grid label > input, .grid label > select { margin-top: auto; }
.chart-totals { margin: 2px 0 8px; font-size: 0.82rem; color: var(--ink-2); font-variant-numeric: tabular-nums; }