:root {
  --bg: #e9f2f1;
  --panel: #ffffff;
  --ink: #102a30;
  --ink-2: #3a5359;
  --rule: #c3d6d6;
  --rule-strong: #7f9ea2;
  --accent: #0b6470;
  --accent-ink: #ffffff;
  --reg-bg: #0f2f36;
  --reg-ink: #f4fbfb;
  --good: #1c6a3a;
  --bad: #a3361c;
  --if: #7a5200;
  --field: #ffffff;
  --field-line: #6f8f94;
  --focus: #d97a00;
  --note-bg: #fbf2dc;
  --r: 4px;
  --num: ui-monospace, "SF Mono", "Cascadia Mono", "Roboto Mono", Menlo, Consolas, monospace;
  --sans: "Avenir Next", "Segoe UI", "Helvetica Neue", Arial, system-ui, sans-serif;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1c1f;
    --panel: #15272b;
    --ink: #e3efef;
    --ink-2: #b3c8ca;
    --rule: #284045;
    --rule-strong: #4f6e73;
    --accent: #6fd0d8;
    --accent-ink: #062126;
    --reg-bg: #081417;
    --reg-ink: #e3f6f6;
    --good: #7fd69d;
    --bad: #ff9c80;
    --if: #f2c46a;
    --field: #0d1b1e;
    --field-line: #5f8186;
    --focus: #ffb547;
    --note-bg: #2b2414;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.55 var(--sans); }
a { color: var(--accent); text-underline-offset: 2px; }
a:focus-visible, button:focus-visible, input:focus-visible, summary:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
.vh { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--panel); padding: 8px 12px; z-index: 10; }
.skip:focus { left: 8px; }
[hidden] { display: none !important; }
main { max-width: 980px; margin: 0 auto; padding: 0 16px 48px; }

.intro { padding: 26px 0 6px; max-width: 68ch; }
h1 { font-size: clamp(1.75rem, 4.8vw, 2.6rem); line-height: 1.1; margin: 0 0 10px; font-weight: 700; letter-spacing: -0.015em; }
.lede { margin: 0; font-size: 1.08rem; color: var(--ink-2); }
h2 { font-size: 1.32rem; margin: 34px 0 10px; line-height: 1.25; }
h3 { font-size: 1.06rem; margin: 20px 0 4px; }

/* calculator */
.calc { background: var(--panel); border-top: 6px solid var(--accent); padding: 18px 20px 22px; margin-top: 18px; }
.group { border: 0; padding: 0; margin: 0 0 20px; min-width: 0; }
.group legend { font-weight: 700; font-size: 1.12rem; padding: 0; margin-bottom: 8px; }
.row2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px 20px; }
#form .row2 + .row2, .seg + .row2 { margin-top: 12px; }
.field label { display: block; font-weight: 600; margin-bottom: 4px; }
.field .hint { margin: 4px 0 0; color: var(--ink-2); font-size: 1rem; }
.field.muted label, .field.muted input { opacity: 0.7; }
.field.wide, .err.wide { grid-column: 1 / -1; }
.err { margin: 4px 0 0; color: var(--bad); font-weight: 600; font-size: 1rem; }
.err:empty { display: none; }
input { font: inherit; font-size: 17px; color: var(--ink); background: var(--field); border: 1px solid var(--field-line); border-radius: var(--r); min-height: 44px; padding: 8px 10px; width: 100%; }
input[type="date"] { min-width: 0; }
input[aria-invalid="true"] { border-color: var(--bad); border-width: 2px; }
input::placeholder { color: var(--ink-2); opacity: 1; font-style: italic; }
.money, .unit { display: flex; align-items: center; gap: 6px; }
.money span, .unit span { font-family: var(--num); color: var(--ink-2); }
.money input, .unit input { font-family: var(--num); min-width: 0; }

.seg { display: inline-flex; flex-wrap: wrap; border: 1px solid var(--field-line); border-radius: var(--r); overflow: hidden; margin-top: 14px; }
.seg label { display: flex; align-items: center; gap: 8px; min-height: 44px; padding: 6px 14px; cursor: pointer; font-weight: 600; }
.seg label + label { border-left: 1px solid var(--field-line); }
.seg input { width: auto; min-height: 0; margin: 0; accent-color: var(--accent); }
.seg label:has(input:checked) { background: color-mix(in srgb, var(--accent) 14%, transparent); }
.seg label:has(input:focus-visible) { outline: 3px solid var(--focus); outline-offset: -3px; }

.more { margin-top: 12px; }
.more summary { cursor: pointer; font-weight: 600; color: var(--accent); min-height: 44px; display: flex; align-items: center; }
.more .row2 { margin-top: 6px; }
.store-note, .link-note { background: var(--note-bg); padding: 10px 12px; border-radius: var(--r); margin: 0 0 14px; }
.link-box { margin-top: 6px; overflow-wrap: anywhere; }
.empty { padding-top: 14px; border-top: 1px dashed var(--rule-strong); color: var(--ink-2); }
.empty p { margin: 0; }

/* the answer: a meter register */
.answer { border-top: 1px solid var(--rule); padding-top: 16px; margin-bottom: 22px; }
.answer-label { margin: 0 0 6px; font-weight: 700; }
.register { display: inline-block; margin: 0 0 10px; padding: 6px 16px 8px; background: var(--reg-bg); color: var(--reg-ink); border-radius: var(--r); font: 700 clamp(2.1rem, 8vw, 3rem)/1.15 var(--num); letter-spacing: 0.04em; box-shadow: inset 0 0 0 3px color-mix(in srgb, var(--reg-ink) 18%, transparent); }
.answer-how { margin: 0 0 8px; max-width: 72ch; }
.answer-how span { display: block; }
.verdict { margin: 0; font-weight: 700; max-width: 72ch; }
.verdict[data-kind="yes"] { color: var(--good); }
.verdict[data-kind="no"] { color: var(--bad); }

.checklist { list-style: none; margin: 0; padding: 0; }
.checklist li { border-bottom: 1px solid var(--rule); padding: 10px 0; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 6px 16px; align-items: center; }
.tri { display: inline-flex; border: 1px solid var(--field-line); border-radius: var(--r); overflow: hidden; }
.tri label { display: flex; align-items: center; gap: 6px; min-height: 44px; padding: 4px 10px; cursor: pointer; font-weight: 600; white-space: nowrap; }
.tri label + label { border-left: 1px solid var(--field-line); }
.tri input { width: auto; min-height: 0; margin: 0; accent-color: var(--accent); }
.tri label:has(input:checked) { background: color-mix(in srgb, var(--accent) 14%, transparent); }
.tri label:has(input[value="no"]:checked) { background: color-mix(in srgb, var(--bad) 14%, transparent); }
.tri label:has(input:focus-visible) { outline: 3px solid var(--focus); outline-offset: -3px; }
.c-note { grid-column: 1 / -1; color: var(--ink-2); font-size: 1rem; }
.mode { margin: 0 0 16px; }
.where { margin: 4px 0 0; padding-left: 20px; }
.where li { margin: 0 0 6px; }
.part { margin: 0 0 20px; }
.part .row2 { margin-top: 6px; }
.letter-kind { margin: 4px 0 10px; color: var(--ink-2); }
#out { display: flex; flex-direction: column; }
#out > * { min-width: 0; }
#out .answer { order: -2; }
#calc[data-mode="nobill"] #dates { order: -1; }
.note { background: var(--note-bg); padding: 10px 12px; border-radius: var(--r); margin: 12px 0 0; }
.timing { list-style: none; margin: 12px 0 0; padding: 0; }
.timing:empty { display: none; }
.timing li { margin: 0 0 4px 1.2em; list-style: disc; }
.timing li.good { color: var(--good); }
.timing li.bad { color: var(--bad); font-weight: 600; }

.actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 6px; }
.btn { font: inherit; font-weight: 600; min-height: 44px; padding: 8px 16px; border-radius: var(--r); border: 1px solid var(--accent); background: transparent; color: var(--accent); cursor: pointer; }
.btn.primary { background: var(--accent); color: var(--accent-ink); }
.btn.quiet { border-color: var(--rule-strong); color: var(--ink-2); }
.btn.small { padding: 6px 12px; }
.btn:hover { filter: brightness(1.08); }
.letter-opts { border-top: 1px solid var(--rule); margin-top: 18px; padding-top: 4px; }
.letter-opts .seg { margin: 4px 0 12px; }

.kept { margin-top: 22px; border-top: 1px solid var(--rule); }
.kept h2 { font-size: 1.1rem; margin: 14px 0 6px; }
.kept ul { list-style: none; margin: 0; padding: 0; }
.kept li { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 8px; padding: 6px 0; border-bottom: 1px solid var(--rule); }
.kept-btns { display: flex; gap: 8px; }
.dim { color: var(--ink-2); }

.toast { position: fixed; left: 50%; bottom: 16px; transform: translateX(-50%); max-width: min(560px, calc(100% - 32px)); background: var(--ink); color: var(--bg); padding: 10px 14px; border-radius: var(--r); box-shadow: 0 6px 24px rgb(0 0 0 / 0.25); display: flex; gap: 12px; align-items: center; z-index: 20; pointer-events: none; }
.toast .btn { pointer-events: auto; background: var(--bg); color: var(--ink); border-color: var(--bg); }

/* reading part */
.prose { max-width: 70ch; }
.prose p { margin: 0 0 12px; }
.faq h3 { margin-top: 18px; }
.sources { margin-top: 28px !important; color: var(--ink-2); overflow-wrap: anywhere; }
.disclaimer { font-weight: 600; }

/* footer */
.site-foot { border-top: 1px solid var(--rule); padding: 18px 16px 28px; color: var(--ink-2); }
.sb-footer { max-width: 980px; margin: 0 auto; font-size: 1rem; }
.sb-more { line-height: 1.9; }
.sb-privacy, .sb-credit { margin: 6px 0 0; }

.print-root { display: none; }

@media (max-width: 560px) {
  .calc { padding: 14px 14px 18px; margin-left: -4px; margin-right: -4px; }
  .row2 { grid-template-columns: 1fr; }
  .seg { display: grid; }
  .seg.mode, #bill-fs > .seg { display: flex; }
  .seg.mode label, #bill-fs > .seg label { flex: 1 1 auto; justify-content: center; padding: 6px 8px; white-space: nowrap; }
  .seg.mode label + label, #bill-fs > .seg label + label { border-top: 0; border-left: 1px solid var(--field-line); }
  .checklist li { grid-template-columns: 1fr; }
  .tri { display: flex; }
  .tri label { flex: 1 1 0; justify-content: center; padding: 4px 6px; }
  .seg label + label { border-left: 0; border-top: 1px solid var(--field-line); }
  .actions .btn { flex: 1 1 auto; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }

/* print: only the statement (and letter) */
@media print {
  @page { size: auto; margin: 0.6in 0.65in 0.65in; }
  body { background: #fff; color: #000; font: 10.5pt/1.4 var(--sans); }
  main, .site-foot, .toast, .skip { display: none !important; }
  .print-root { display: block !important; }
  .p-sheet { break-after: page; }
  .p-sheet:last-child { break-after: auto; }
  .p-title { font-size: 16pt; font-weight: 700; margin: 0 0 8pt; padding-bottom: 4pt; border-bottom: 2pt solid #0b6470; print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  .p-meta { display: flex; flex-wrap: wrap; gap: 4pt 28pt; margin: 0 0 5pt; overflow-wrap: anywhere; }
  .p-blank { display: inline-block; min-width: 1.9in; border-bottom: 0.75pt solid #000; height: 1em; vertical-align: bottom; }
  .p-blank.wide { min-width: 3.4in; }
  .p-table { width: calc(100% - 2px); margin: 8pt 1px 6pt; border-collapse: collapse; font-variant-numeric: tabular-nums; }
  .p-table th, .p-table td { border: 0.75pt solid #777; padding: 3pt 5pt; text-align: left; vertical-align: top; }
  .p-table th { width: 32%; font-weight: 700; background: #e8f1f1; print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  .p-table tr { break-inside: avoid; }
  .p-blankrows td { height: 20pt; }
  .p-keep { break-inside: avoid; }
  .p-sum { font-size: 14pt; margin: 6pt 0 3pt; }
  .p-sub { font-weight: 700; margin: 8pt 0 2pt; }
  .p-text { margin: 0 0 6pt; }
  .p-checks { list-style: none; margin: 0 0 6pt; padding: 0; }
  .p-checks li { display: flex; gap: 8pt; align-items: baseline; padding: 1pt 0; }
  .p-box { display: inline-block; width: 11pt; height: 11pt; border: 0.9pt solid #000; text-align: center; line-height: 10pt; font-size: 10pt; flex: none; }
  .p-small { font-size: 8pt; line-height: 1.35; color: #333; margin-top: 8pt; break-inside: avoid; }
  .p-letter { font-size: 11.5pt; line-height: 1.5; max-width: 6.4in; }
  .p-letter p { margin: 0 0 10pt; }
  .p-list { margin: -4pt 0 10pt; padding-left: 18pt; }
  .p-right { text-align: right; }
  .p-sign { margin-top: 34pt !important; }
}