:root {
  --bg: #f6f7f9; --card: #ffffff; --text: #1b1f24; --muted: #5f6b7a;
  --accent: #0f7b5f; --accent-soft: #e3f3ee; --border: #dde2e8; --danger: #b42318;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418; --card: #1a1f25; --text: #e8ecf0; --muted: #98a3b0;
    --accent: #3fbf96; --accent-soft: #173229; --border: #2c333b; --danger: #f97066;
  }
}
* { box-sizing: border-box; }
body { margin: 0; font: 15px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif; background: var(--bg); color: var(--text); }
.app-header { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 16px; max-width: 960px; margin: 0 auto; }
.app-header h1 { font-size: 1.4rem; margin: 0; }
.currency-pick { color: var(--muted); font-size: .9rem; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; padding: 0 16px; max-width: 960px; margin: 0 auto; }
.tab { border: 1px solid var(--border); background: var(--card); color: var(--text); padding: 8px 14px; border-radius: 8px; cursor: pointer; font: inherit; }
.tab[aria-selected="true"] { background: var(--accent); border-color: var(--accent); color: #fff; }
.panel { max-width: 960px; margin: 16px auto; padding: 0 16px 40px; }

/* Shared building blocks for calculator modules */
.calc { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 20px; }
.calc h2 { margin: 0 0 4px; font-size: 1.2rem; }
.calc .hint { color: var(--muted); margin: 0 0 16px; font-size: .9rem; }
.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 12px; }
.field label { display: block; font-size: .85rem; color: var(--muted); margin-bottom: 4px; }
.field input, .field select { width: 100%; padding: 8px 10px; border: 1px solid var(--border); border-radius: 8px; background: var(--bg); color: var(--text); font: inherit; }
.btn { margin-top: 16px; background: var(--accent); color: #fff; border: 0; padding: 10px 18px; border-radius: 8px; cursor: pointer; font: inherit; }
.results { margin-top: 20px; }
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 10px; }
.stat { background: var(--accent-soft); border-radius: 10px; padding: 12px; }
.stat .label { font-size: .8rem; color: var(--muted); }
.stat .value { font-size: 1.15rem; font-weight: 600; font-variant-numeric: tabular-nums; }
.error { color: var(--danger); margin-top: 12px; }
.table-wrap { overflow-x: auto; margin-top: 16px; max-height: 360px; overflow-y: auto; }
table { border-collapse: collapse; width: 100%; font-variant-numeric: tabular-nums; font-size: .9rem; }
th, td { padding: 6px 10px; border-bottom: 1px solid var(--border); text-align: right; white-space: nowrap; }
th:first-child, td:first-child { text-align: left; }
th { position: sticky; top: 0; background: var(--card); }