:root {
  --bg: #f5f6f8;
  --card: #ffffff;
  --ink: #1a1d21;
  --muted: #5c6470;
  --accent: #0070f2;
  --accent-soft: #e8f1ff;
  --border: #e2e6ea;
  --po: #c9400a;
  --bdcc: #0a6e54;
  --ok: #0a6e54;
  --warn: #a05a00;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
}

.app-header {
  padding: 2rem 1.25rem 1rem;
  max-width: 1080px;
  margin: 0 auto;
}

.app-header h1 { margin: 0; font-size: 1.75rem; }
.subtitle { color: var(--muted); margin: 0.35rem 0 0; max-width: 60ch; }

main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 1.25rem 3rem;
  display: grid;
  gap: 1rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.04);
}

.card h2 { margin: 0 0 0.75rem; font-size: 1.05rem; }

.fields { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; }
.field { display: flex; flex-direction: column; gap: 0.4rem; font-size: 0.9rem; color: var(--muted); }
.input-row { display: flex; align-items: center; gap: 0.5rem; }
input[type="number"] {
  width: 140px;
  padding: 0.5rem 0.6rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
}
.unit { color: var(--muted); font-size: 0.85rem; }

.presets { margin-top: 1rem; display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }
.presets-label { color: var(--muted); font-size: 0.85rem; }
.preset {
  border: 1px solid var(--border);
  background: var(--card);
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.85rem;
}
.preset:hover { background: var(--accent-soft); border-color: var(--accent); }

.results { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1rem; }
.result-card { display: flex; flex-direction: column; }
.card-head { display: flex; align-items: center; justify-content: space-between; gap: 0.5rem; }
.badge {
  font-size: 0.72rem;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  white-space: nowrap;
}
.badge-po { background: var(--po); color: #fff; }
.badge-bdcc { background: var(--bdcc); color: #fff; }

.big-number { font-size: 2.4rem; font-weight: 700; margin-top: 0.5rem; }
.unit { margin-bottom: 0.75rem; }
.formula { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.82rem; color: var(--muted); margin-bottom: 0.75rem; }

.tier-table { font-size: 0.82rem; }
.tier-row {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.3rem 0;
  border-bottom: 1px solid var(--border);
}
.tier-row:last-child { border-bottom: none; }
.tier-row .label { color: var(--muted); }
.tier-row .value { font-variant-numeric: tabular-nums; font-weight: 600; }

.delta p { margin: 0.25rem 0; }
.note { color: var(--muted); font-size: 0.85rem; }
#recommendation { color: var(--warn); font-weight: 600; }

.chart-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: -0.2rem 0 0.75rem;
  font-size: 0.85rem;
}

.legend-item { display: inline-flex; align-items: center; gap: 0.4rem; }
.legend-swatch { width: 0.85rem; height: 0.85rem; display: inline-block; border-radius: 2px; }
.legend-po { background: var(--po); }
.legend-bdcc { background: var(--bdcc); }

.chart-card canvas { width: 100%; height: auto; }

.assumptions ul { margin: 0.5rem 0; padding-left: 1.2rem; }
.assumptions li { margin: 0.25rem 0; font-size: 0.9rem; }