/* short-term-fluency : 回答を一文ずつ伸ばしていくステップ表示 */
.stf-steps {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 20px 0 6px;
}

.stf-step {
  border: 1px solid var(--lb5);
  border-radius: 12px;
  background: var(--pw);
  padding: 16px 18px 14px;
}

.stf-step__head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 12px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--black);
  line-height: 1.4;
}

.stf-step__num {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--lb5);
  color: var(--blue2);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.stf-step__lines {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.stf-step__line {
  padding: 6px 10px 6px 14px;
  border-left: 3px solid var(--gray7);
  background: var(--white);
  border-radius: 0 6px 6px 0;
  font-size: 0.94rem;
  line-height: 1.6;
  color: var(--gray);
}

.stf-step__line--new {
  border-left-color: var(--lb);
  background: var(--lb5);
  color: var(--black);
}

.stf-step__note {
  margin: 12px 0 0;
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--gray3);
}

.stf-legend {
  margin: 6px 0 22px;
  font-size: 0.8rem;
  color: var(--gray3);
}

@media (max-width: 600px) {
  .stf-step { padding: 14px 14px 12px; }
  .stf-step__line { font-size: 0.88rem; }
}