:root {
  --bg: #f4f5f8;
  --surface: #fcfcfb;
  --text: #0b0b0b;
  --muted: #52514e;
  --border: #e3e5ea;
  --grid: #ebebe8;
  --primary: #1c5cab;
  --primary-text: #ffffff;
  --danger: #c62828;
  --good-bg: #e6f4ea;
  --good-text: #14532d;
  --warn-bg: #fff4d6;
  --warn-text: #6b4a00;
  /* chart series, reference palette slots 1-4 (validated) */
  --s-current: #2a78d6;
  --s-tracker: #eb6834;
  --s-fixed:   #1baf7a;
  --s-flex:    #eda100;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111110;
    --surface: #1a1a19;
    --text: #f0efec;
    --muted: #c3c2b7;
    --border: #2f2f2c;
    --grid: #2a2a28;
    --primary: #256abf;
    --danger: #ef7a7a;
    --good-bg: #13301e;
    --good-text: #bfe8cc;
    --warn-bg: #3a2e0c;
    --warn-text: #f3dc9c;
    --s-current: #3987e5;
    --s-tracker: #d95926;
    --s-fixed:   #199e70;
    --s-flex:    #c98500;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-tap-highlight-color: transparent;
}

[hidden] { display: none !important; }

.topbar {
  position: sticky; top: 0; z-index: 5;
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 16px;
  padding-top: max(12px, env(safe-area-inset-top));
  background: var(--primary);
  color: var(--primary-text);
}
.topbar h1 { margin: 0; font-size: 1.3rem; letter-spacing: .02em; }
.topbar .btn.ghost { color: var(--primary-text); border-color: rgba(255,255,255,.5); }

main { max-width: 720px; margin: 0 auto; padding: 12px 12px 48px; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  margin-bottom: 12px;
}
.card h2 { margin: 0 0 12px; font-size: 1.1rem; }

.muted, .hint { color: var(--muted); }
.hint { font-size: .85rem; margin: 8px 0 0; }
.error { color: var(--danger); }
.status { text-align: center; color: var(--muted); }

form label, .whatif label, details label {
  display: block; margin-bottom: 12px; font-size: .9rem; color: var(--muted);
}
input, select {
  display: block; width: 100%; margin-top: 4px;
  font: inherit; color: var(--text);
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px;
}
input[type=range] { padding: 0; accent-color: var(--primary); background: none; border: 0; height: 32px; }
label.check { display: flex; align-items: center; gap: 8px; }
label.check input { width: auto; margin: 0; }
output { float: right; color: var(--text); font-variant-numeric: tabular-nums; }
.money-input { display: flex; align-items: center; gap: 6px; color: var(--text); }
.money-input input { width: 8em; margin: 0; }
a { color: var(--primary); }

.btn {
  font: inherit; cursor: pointer;
  border-radius: 10px; padding: 12px 16px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
}
.btn.primary { width: 100%; background: var(--primary); color: var(--primary-text); border-color: var(--primary); }
.btn.ghost { background: transparent; }
.btn.small { padding: 6px 10px; font-size: .85rem; }
#demo-btn { width: 100%; margin-top: 8px; }

/* Verdict */
.verdict h2 { font-size: 1.5rem; margin-bottom: 4px; }
.verdict .big { font-size: 1.05rem; margin: 0 0 12px; }
.verdict.switch { background: var(--good-bg); color: var(--good-text); }
.verdict.switch .muted, .verdict.switch .hint { color: var(--good-text); }
.fuel-verdicts { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin: 8px 0; }
.fuel-verdicts div { border: 1px solid var(--border); border-radius: 10px; padding: 10px; }
.fuel-verdicts strong { display: block; }
.caveat { background: var(--warn-bg); color: var(--warn-text); border-radius: 8px; padding: 8px 10px; font-size: .85rem; margin: 8px 0 0; }

.whatif { display: grid; grid-template-columns: 1fr 1fr; gap: 0 20px; }
@media (max-width: 560px) { .whatif, .fuel-verdicts { grid-template-columns: 1fr; } }

/* Tables */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: .9rem; }
th, td { padding: 8px 6px; border-bottom: 1px solid var(--border); text-align: left; white-space: nowrap; }
table.nums td:not(:first-child), table.nums th:not(:first-child) { text-align: right; font-variant-numeric: tabular-nums; }
tr.current td { font-weight: 600; }
tr.best td:first-child::after { content: " ★ cheapest"; font-weight: 400; color: var(--muted); font-size: .8rem; }
.swatch { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 6px; vertical-align: baseline; }

/* Filters */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 10px; }
.filters select { width: auto; margin: 0; padding: 6px 10px; font-size: .85rem; }
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.seg button { font: inherit; font-size: .85rem; border: 0; background: transparent; color: var(--text); padding: 6px 10px; cursor: pointer; }
.seg button.on { background: var(--primary); color: var(--primary-text); }

/* Chart */
.legend { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: .85rem; color: var(--muted); margin-bottom: 4px; }
.chart svg { display: block; width: 100%; height: auto; touch-action: pan-y; }
.chart .grid line { stroke: var(--grid); stroke-width: 1; }
.chart .axis text { fill: var(--muted); font-size: 11px; }
.chart .series { fill: none; stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; }
.chart .end-label { font-size: 11px; fill: var(--text); }
.chart .cross { stroke: var(--muted); stroke-width: 1; }
.chart .dot { stroke: var(--surface); stroke-width: 2; }

.tooltip {
  position: fixed; z-index: 10; pointer-events: none;
  background: var(--surface); color: var(--text);
  border: 1px solid var(--border); border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0,0,0,.15);
  padding: 8px 10px; font-size: .8rem; min-width: 160px;
}
.tooltip .row { display: flex; justify-content: space-between; gap: 12px; font-variant-numeric: tabular-nums; }
.tooltip .head { font-weight: 600; margin-bottom: 4px; }

.details { display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; font-size: .9rem; margin: 12px 0; }
.details dt { color: var(--muted); }
.details dd { margin: 0; word-break: break-all; }
summary { cursor: pointer; color: var(--primary); }

/* Export */
.btn-row { display: flex; gap: 8px; margin-top: 8px; }
.btn-row .btn { flex: 1; width: auto; }
#x-text { width: 100%; height: 160px; margin-top: 8px; font: 12px/1.3 ui-monospace, monospace; color: var(--text); background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 8px; }