main {
  max-width: 760px;
}
h1 {
  font-size: clamp(2.3rem, 9vw, 4.2rem);
}
.cards {
  display: grid;
  gap: 22px;
  margin-top: 26px;
}
@media (min-width: 760px) {
  .cards {
    grid-template-columns: 1fr 1fr;
  }
}
.card {
  padding: 22px 20px 24px;
}
.card h2 {
  margin-top: 0;
}
.card .btn {
  width: 100%;
  margin-top: 8px;
}
.number {
  font:
    400 clamp(18px, 5.2vw, 30px)/1.35 'Gronka Mono',
    monospace;
  word-spacing: 0.1em;
  padding: 18px 16px;
  margin: 14px 0;
  letter-spacing: 0.02em;
}
.number.key {
  font-size: clamp(14px, 3.6vw, 18px);
}
.acts {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 12px;
  align-items: center;
  margin: 12px 0;
}
.err {
  color: var(--ink);
  font-weight: 600;
  padding: 10px 14px;
  margin: 10px 0;
}
.err::before {
  border-style: dashed;
}