:root {
  --blue: #48a9ca;
  --blue-dark: #137da4;
  --blue-pale: #eaf7fc;
  --blue-line: #c9e7f2;
  --ink: #263545;
  --muted: #607080;
  --border: #cfd9e1;
  --danger: #c94a43;
  --warning: #875a16;
  --warning-bg: #fff8e8;
}

* {
  box-sizing: border-box;
}

html {
  color-scheme: light;
}

body {
  margin: 0;
  background: #ffffff;
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.5;
}

.calculator-shell {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
  padding: 56px 0 48px;
}

.page-header {
  text-align: center;
}

.eyebrow {
  margin: 0 0 14px;
  color: #53667a;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.24em;
}

h1 {
  max-width: 980px;
  margin: 0 auto;
  color: var(--blue);
  font-size: clamp(34px, 4.3vw, 52px);
  font-weight: 400;
  letter-spacing: -0.025em;
  line-height: 1.16;
}

.primary-rule {
  height: 3px;
  margin: 34px 0 38px;
  background: var(--blue);
}

.variables h2 {
  margin: 0 0 26px;
  padding-bottom: 13px;
  border-bottom: 1px solid var(--blue-line);
  color: var(--blue-dark);
  font-size: 18px;
  font-weight: 700;
}

.field {
  margin-bottom: 24px;
}

label {
  display: inline-block;
  margin-bottom: 9px;
  color: #2d3a48;
  font-size: 17px;
  font-weight: 700;
}

.required {
  margin-right: 4px;
  color: var(--danger);
  font-weight: 700;
}

input,
select {
  display: block;
  width: 100%;
  min-height: 54px;
  border: 1px solid var(--border);
  border-radius: 3px;
  background: #ffffff;
  color: #152230;
  font: inherit;
  font-size: 18px;
  padding: 12px 15px;
  transition: border-color 120ms ease, box-shadow 120ms ease;
}

select {
  appearance: auto;
}

input:focus,
select:focus,
button:focus-visible {
  outline: 3px solid rgba(72, 169, 202, 0.28);
  outline-offset: 2px;
  border-color: var(--blue-dark);
}

input[aria-invalid="true"],
select[aria-invalid="true"] {
  border-color: var(--danger);
}

.field-help,
.field-error,
.form-status {
  margin: 6px 0 0;
  font-size: 14px;
}

.field-help {
  color: var(--muted);
}

.field-error,
.form-status {
  min-height: 1.2em;
  color: var(--danger);
}

.range-warnings {
  margin: 8px 0 24px;
  border-left: 4px solid #d39b37;
  background: var(--warning-bg);
  color: var(--warning);
  padding: 12px 16px;
  font-size: 14px;
}

.range-warnings ul {
  margin: 0;
  padding-left: 20px;
}

.action-row {
  margin-top: 12px;
  padding: 44px 0 38px;
  border-top: 2px solid var(--blue-line);
  text-align: center;
}

button {
  min-width: 150px;
  min-height: 54px;
  border: 0;
  border-radius: 3px;
  background: var(--blue);
  color: #ffffff;
  cursor: pointer;
  font: inherit;
  font-size: 17px;
  font-weight: 700;
  padding: 14px 26px;
  transition: background-color 120ms ease, opacity 120ms ease;
}

button:hover:not(:disabled) {
  background: var(--blue-dark);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.result-section h2,
.safety-section h2 {
  margin: 0 0 11px;
  color: #162331;
  font-size: 18px;
  font-weight: 400;
}

.result-panel {
  min-height: 78px;
  border: 1px solid #8ed0e7;
  border-radius: 3px;
  background: var(--blue-pale);
  color: #213343;
  font-size: 17px;
  padding: 20px 18px;
}

.safety-section {
  margin-top: 32px;
  padding-top: 28px;
  border-top: 1px solid #e2e8ed;
}

.safety-section p {
  margin: 0;
  color: #445464;
}

[hidden] {
  display: none !important;
}

@media (max-width: 680px) {
  .calculator-shell {
    width: min(100% - 28px, 1120px);
    padding: 34px 0 36px;
  }

  .eyebrow {
    font-size: 11px;
    letter-spacing: 0.2em;
  }

  h1 {
    font-size: 31px;
    line-height: 1.18;
  }

  .primary-rule {
    margin: 26px 0 30px;
  }

  .field {
    margin-bottom: 21px;
  }

  label,
  input,
  select {
    font-size: 16px;
  }

  .action-row {
    padding: 34px 0 30px;
  }

  button {
    width: 100%;
  }
}