.tool-intro p + p {
  margin-top: var(--space-block);
}

/* 数式ブロック。折り返しは「項（.formula-term）」単位でのみ起こるようにし、
   演算子が行末に取り残されないようにする（項の途中では折り返さない）。 */
.formula {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.2em 0.45em;
  margin: 0;
  padding: 12px 14px;
  background: var(--color-subtle);
  border: 1px solid var(--color-border-frame);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  line-height: 1.6;
  /* 項単位で折り返してもなお収まらない式（入れ子の分数を含む結論の式など）は、
     ページ全体を横に広げるのではなく、この枠の中だけを横スクロールさせる。 */
  overflow-x: auto;
}

/* 演算子と直後の項を1つの不可分な単位として扱う。 */
.formula-term {
  white-space: nowrap;
}

.formula-op {
  color: var(--color-muted);
}

.formula + .formula {
  margin-top: 8px;
}

/* 導出の結論となる式。アクセント色で他の途中式と区別する。 */
.formula--result {
  border-color: var(--color-primary);
  background: var(--color-primary-light);
}

/* 定義カード内の内訳式。主となる式より一段弱いトーンにする。 */
.formula--sub {
  justify-content: flex-start;
  margin-top: 6px;
  padding: 0 0 0 1.1em;
  background: none;
  border: none;
  font-size: 0.875rem;
  color: var(--color-muted);
}

.fraction {
  display: inline-flex;
  flex-direction: column;
  align-items: stretch;
  vertical-align: middle;
  text-align: center;
  margin: 0 0.15em;
}

.fraction-num,
.fraction-den {
  display: block;
  padding: 0 0.2em;
  white-space: nowrap;
}

.fraction-num {
  border-bottom: 1.5px solid currentColor;
}

.fraction .fraction-den {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  justify-content: center;
  gap: 0.3em;
}

.big-paren {
  display: inline-block;
  transform: scaleY(1.9);
  font-weight: 300;
  vertical-align: middle;
}

.formula-def-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 10px 0 0;
}

.formula-def {
  background: var(--color-subtle);
  border: 1px solid var(--color-border-frame);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
}

.formula-def-main {
  margin: 0;
  font-weight: 700;
  color: var(--color-text);
}

.term-common {
  color: var(--color-primary);
}

.term-common-legend {
  color: var(--color-muted);
}

.formula-result-lead {
  margin-top: 18px;
}

/* 導出過程のアコーディオン（DADSのaccordion）。結論の式は常時表示し、
   途中の代数変形は必要な人だけが開けるようにして初期表示の情報量を抑える。 */
.formula-derivation {
  margin-top: 18px;
  border-top: 1px solid var(--color-neutral-solid-gray-420);
}

.formula-derivation .dads-accordion__summary {
  font-weight: 700;
  color: var(--color-primary);
}

.formula-derivation .dads-accordion__content {
  padding-top: 0;
}

/* 式変形の各段階。左端に連番を置き、縦の流れとして追えるようにする。 */
.formula-steps {
  counter-reset: formula-step;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin: 18px 0 14px;
  padding: 0;
}

.formula-steps > li {
  counter-increment: formula-step;
  position: relative;
  padding-left: 34px;
}

.formula-steps > li::before {
  content: counter(formula-step);
  position: absolute;
  top: 0;
  left: 0;
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-size: 0.875rem;
  font-weight: 700;
}

/* 連番どうしをつなぐ縦線（最後の項目には引かない）。 */
.formula-steps > li:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 30px;
  left: 11.5px;
  bottom: -18px;
  border-left: 1px solid var(--color-border);
}

.formula-steps > li > p {
  margin: 0 0 8px;
}

.formula-steps > li > p:last-child {
  margin-bottom: 0;
}

.form-category-heading {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 26px 0 18px;
  color: var(--color-text);
  font-size: 1rem;
  white-space: nowrap;
}

.form-category-heading:first-child {
  margin-top: 0;
}

.form-category-heading::after {
  content: "";
  width: 100%;
  height: 1px;
  background: var(--color-border);
}

.eyebrow {
  color: var(--color-primary);
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.amount-field {
  margin-bottom: 20px;
}

.amount-field > label {
  display: block;
  margin-bottom: 6px;
  font-size: 1rem;
  font-weight: 700;
}

.amount-field select {
  height: 48px;
  padding-left: 34px;
  font-size: 1rem;
  text-align: center;
  text-align-last: center;
}

.staff-type-field {
  padding: 0 0 20px;
  border: 0;
}

.payment-period-field {
  padding-bottom: 20px;
}

.payment-period-options label {
  min-height: 54px;
  justify-content: center;
  text-align: center;
}

.staff-type-field[hidden] {
  display: none;
}

.regional-fields {
  margin-bottom: 4px;
  padding-top: 18px;
  border-top: 1px solid var(--color-border);
}

.regional-fields .amount-field:last-child {
  margin-bottom: 0;
}

.staff-type-field legend {
  display: block;
  margin-bottom: 6px;
  color: var(--color-text);
  font-size: 1rem;
}

.staff-type-field legend::before {
  display: none;
}

.staff-type-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.staff-type-options label {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 58px;
  padding: 9px 10px;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  text-align: center;
  cursor: pointer;
}

.staff-type-options label:has(input:checked) {
  border-color: var(--color-primary);
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
}

.staff-type-options label:has(input:disabled) {
  color: var(--color-muted);
  background: var(--color-subtle);
  cursor: not-allowed;
}

.staff-type-options input {
  accent-color: var(--color-primary);
}

.staff-type-options span,
.staff-type-options strong,
.staff-type-options small {
  display: block;
}

.staff-type-options strong {
  font-size: 0.875rem;
}

.staff-type-options small {
  margin-top: 2px;
  font-size: 0.875rem;
  font-weight: 400;
}

.currency-input {
  position: relative;
}

.currency-input input {
  width: 100%;
  height: 52px;
  padding: 10px 44px 10px 14px;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  font: 700 1.15rem/1 var(--font-hero);
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.currency-input input:focus-visible {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.currency-input span {
  position: absolute;
  top: 50%;
  right: 14px;
  transform: translateY(-50%);
  font-weight: 700;
}

.rate-fields {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.single-rate-field {
  grid-template-columns: 1fr;
}

.percent-input {
  position: relative;
}

.percent-input input {
  height: 44px;
  padding-right: 34px;
  font-weight: 700;
  text-align: right;
}

.percent-input span {
  position: absolute;
  top: 50%;
  right: 12px;
  transform: translateY(-50%);
  font-weight: 700;
}

.input-error {
  min-height: 1.25em;
  margin: 3px 0 0;
  color: var(--color-semantic-error-2);
  font-size: 0.875rem;
}

.calculate-button {
  width: 100%;
  min-height: 50px;
  border: 0;
  border-radius: var(--radius-sm);
  background: var(--color-hero-bg);
  color: #fff;
  font: 700 1rem/1 var(--font-hero);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.calculate-button:hover {
  opacity: 0.88;
}

.calculate-button:active {
  transform: scale(0.98);
}

.result-card {
  display: flex;
  min-height: 320px;
  flex-direction: column;
  margin-top: 22px;
  padding: 24px;
  border-radius: var(--radius-md);
  background: var(--color-hero-bg);
  color: #fff;
}

.result-kicker {
  margin: 0;
  font-size: 0.875rem;
  font-weight: 700;
  opacity: 0.78;
}

.empty-result {
  flex: 1;
  display: grid;
  place-content: center;
  text-align: center;
}

.empty-result[hidden] {
  display: none;
}

.empty-result-mark {
  display: block;
  font: 800 3.4rem/1 var(--font-hero);
  opacity: 0.22;
}

.empty-result p {
  margin: 14px 0 0;
  font-size: 0.875rem;
  opacity: 0.78;
}

#calculated-result {
  margin: auto 0;
  text-align: center;
}

.result-label,
.result-caption {
  margin: 0;
  font-size: 0.875rem;
  opacity: 0.82;
}

.category-result {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: 22px;
  padding: 12px 14px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.1);
  text-align: left;
}

.category-result span {
  font-size: 0.875rem;
  opacity: 0.82;
}

.category-result strong {
  font-size: 1rem;
}

.rate-result {
  margin: 8px 0 2px;
  font-family: var(--font-hero);
  line-height: 1;
}

.rate-result strong {
  font-size: clamp(2.8rem, 7vw, 4rem);
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.rate-result span {
  margin-left: 4px;
  font-size: 1.25rem;
  font-weight: 700;
}

.calculation-detail {
  margin-top: 28px;
  padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, 0.24);
}

.calculation-detail div {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.875rem;
}

.calculation-detail p {
  margin: 8px 0 0;
  font-size: 0.875rem;
  opacity: 0.72;
}

.assumption-note {
  padding: 18px 20px;
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-sm);
  background: #fff;
}

.assumption-note h2 {
  margin: 0 0 6px;
  color: var(--color-text);
  font-size: 1rem;
}

.assumption-note p {
  margin: 5px 0;
  font-size: 0.875rem;
}

@media (max-width: 680px) {
  .calculator-card,
  .result-card {
    padding: 22px 20px;
  }

  .result-card {
    min-height: 330px;
  }

  .staff-type-options {
    grid-template-columns: 1fr;
  }

  .payment-period-options,
  .rate-fields {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 420px) {
  .rate-fields {
    grid-template-columns: 1fr;
  }
}