:root {
  color-scheme: light;
  --app-surface: #fbfaf6;
  --app-panel: #fffefa;
  --app-ink: #222824;
  --app-muted: #687069;
  --app-line: #cfd3cc;
  --app-line-strong: #9fa79f;
  --app-accent: #245b49;
  --app-accent-soft: #e2ebe5;
  --app-warm-soft: #f1e7d9;
  --app-danger: #9b2f2f;
  --app-danger-soft: #f8e9e7;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  max-width: 100%;
  overflow-x: hidden;
}

button,
input,
select {
  font: inherit;
}

a {
  color: inherit;
}

:focus-visible {
  outline: 3px solid var(--app-accent);
  outline-offset: 3px;
}

.tool-shell,
.calculator-panel,
.info-panel,
.input-row,
.result-table,
.result-details,
.unit-list,
.formula-list {
  min-width: 0;
}

.tool-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  border: 1px solid var(--app-line-strong);
  background: var(--app-surface);
}

.calculator-panel,
.info-panel {
  padding: 25px;
}

.calculator-panel {
  border-right: 1px solid var(--app-line);
}

.assumption {
  max-width: 730px;
  margin: 11px 0 0;
  padding-left: 12px;
  border-left: 3px solid var(--app-line-strong);
  color: var(--app-muted);
  font-size: 0.82rem;
  line-height: 1.6;
  overflow-wrap: anywhere;
}

.section-kicker {
  margin: 0 0 5px;
  color: var(--app-accent);
  font-size: 0.76rem;
  font-weight: 780;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h2 {
  margin: 0;
  font-size: clamp(1.2rem, 2vw, 1.48rem);
  line-height: 1.4;
}

h3 {
  margin: 0;
  font-size: 1rem;
}

fieldset {
  margin: 20px 0 0;
  padding: 0;
  border: 0;
}

legend {
  margin-bottom: 10px;
  font-weight: 760;
}

.input-grid {
  display: grid;
  gap: 18px;
}

.input-row {
  display: grid;
  gap: 5px;
}

.input-label {
  display: block;
  font-size: 0.84rem;
  font-weight: 760;
}

.value-with-unit {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(126px, auto);
  gap: 7px;
  min-width: 0;
}

.value-with-unit input,
.value-with-unit select {
  width: 100%;
  min-width: 0;
  min-height: 45px;
  padding: 8px 10px;
  border: 1px solid var(--app-line-strong);
  border-radius: 0;
  color: var(--app-ink);
  background: #fff;
}

.value-with-unit input:focus,
.value-with-unit select:focus {
  border-color: var(--app-accent);
  outline: 3px solid var(--app-accent-soft);
  outline-offset: 0;
}

.field-help {
  margin: 0;
  color: var(--app-muted);
  font-size: 0.73rem;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.form-error {
  margin: 15px 0 0;
  padding: 10px 12px;
  border-left: 4px solid var(--app-danger);
  background: var(--app-danger-soft);
  color: var(--app-danger);
  font-size: 0.84rem;
  font-weight: 700;
  overflow-wrap: anywhere;
}

.form-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 19px;
}

.button {
  min-height: 46px;
  padding: 9px 17px;
  border: 1px solid var(--app-accent);
  border-radius: 0;
  cursor: pointer;
  font-weight: 760;
}

.button-primary {
  color: #fff;
  background: var(--app-accent);
}

.button-primary:hover {
  background: #1d4d3e;
}

.button-secondary {
  color: var(--app-accent);
  background: transparent;
}

.button-secondary:hover {
  background: var(--app-accent-soft);
}

.result-box {
  margin-top: 20px;
  padding: 17px;
  border: 1px solid var(--app-line-strong);
  background: #fff;
}

.result-box[data-state="ready"] {
  border-color: var(--app-accent);
}

.result-box[data-state="error"] {
  border-color: var(--app-danger);
}

.compact-heading {
  margin-bottom: 10px;
}

.result-status,
.info-lead {
  margin: 0;
  color: var(--app-muted);
  font-size: 0.82rem;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.result-table {
  width: 100%;
  margin-top: 15px;
  border-top: 1px solid var(--app-line);
  border-left: 1px solid var(--app-line);
  border-collapse: collapse;
  font-variant-numeric: tabular-nums;
}

.result-table th,
.result-table td {
  padding: 9px 10px;
  border-right: 1px solid var(--app-line);
  border-bottom: 1px solid var(--app-line);
  text-align: left;
}

.result-table thead th {
  color: var(--app-muted);
  background: var(--app-surface);
  font-size: 0.75rem;
}

.result-table tbody th {
  width: 62%;
  color: var(--app-muted);
  font-size: 0.78rem;
  font-weight: 760;
}

.result-table tbody td {
  color: var(--app-accent);
  font-size: 0.86rem;
  font-weight: 780;
  overflow-wrap: anywhere;
  text-align: right;
}

.result-details {
  display: grid;
  margin: 16px 0 0;
  border-top: 1px solid var(--app-line);
  border-left: 1px solid var(--app-line);
}

.result-details div {
  display: grid;
  grid-template-columns: minmax(125px, 0.42fr) minmax(0, 1fr);
  gap: 10px;
  min-width: 0;
  padding: 9px 10px;
  border-right: 1px solid var(--app-line);
  border-bottom: 1px solid var(--app-line);
}

.result-details dt {
  color: var(--app-muted);
  font-size: 0.73rem;
  font-weight: 700;
}

.result-details dd {
  min-width: 0;
  margin: 0;
  font-size: 0.78rem;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.info-lead {
  margin-top: 17px;
  color: var(--app-ink);
  font-size: 0.88rem;
}

.unit-list {
  display: grid;
  margin: 19px 0 0;
  border-top: 1px solid var(--app-line);
  border-left: 1px solid var(--app-line);
}

.unit-list div {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 9px;
  min-width: 0;
  padding: 9px 12px;
  border-right: 1px solid var(--app-line);
  border-bottom: 1px solid var(--app-line);
}

.unit-list dt {
  color: var(--app-muted);
  font-size: 0.75rem;
  font-weight: 760;
}

.unit-list dd {
  margin: 0;
  font-size: 0.81rem;
  line-height: 1.5;
  overflow-wrap: anywhere;
}

.scope-note {
  margin-top: 20px;
  padding: 16px 17px;
  border: 1px solid var(--app-line);
  background: var(--app-warm-soft);
}

.scope-note p {
  margin: 8px 0 0;
  font-size: 0.8rem;
  line-height: 1.6;
  overflow-wrap: anywhere;
}

.content-section {
  margin-top: 43px;
}

.formula-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 17px;
  border-top: 1px solid var(--app-line);
  border-left: 1px solid var(--app-line);
}

.formula-list article {
  display: grid;
  gap: 4px;
  min-width: 0;
  padding: 14px 15px;
  border-right: 1px solid var(--app-line);
  border-bottom: 1px solid var(--app-line);
}

.formula-list strong {
  font-size: 1rem;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.formula-list span {
  color: var(--app-muted);
  font-size: 0.81rem;
  line-height: 1.55;
}

.proof-guide {
  margin-top: 20px;
  padding: 17px 18px;
  border: 1px solid var(--app-line);
  background: var(--app-surface);
}

.proof-guide ul {
  margin: 10px 0 0;
  padding-left: 1.25em;
}

.proof-guide li {
  margin-top: 5px;
  overflow-wrap: anywhere;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 760px) {
  .tool-shell {
    grid-template-columns: 1fr;
  }

  .calculator-panel {
    border-right: 0;
    border-bottom: 1px solid var(--app-line);
  }
}

@media (max-width: 520px) {
  .calculator-panel,
  .info-panel {
    padding: 19px 14px;
  }

  .value-with-unit {
    grid-template-columns: minmax(0, 1fr) minmax(108px, auto);
  }

  .result-table th,
  .result-table td {
    padding: 8px 7px;
  }

  .result-table tbody th {
    width: 58%;
    font-size: 0.72rem;
  }

  .result-table tbody td {
    font-size: 0.78rem;
  }

  .result-details div {
    grid-template-columns: 1fr;
    gap: 3px;
  }

  .formula-list {
    grid-template-columns: 1fr;
  }

  .form-actions .button {
    flex: 1 1 140px;
  }
}

@media (max-width: 360px) {
  .value-with-unit {
    grid-template-columns: 1fr;
  }
}