* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: "Franklin Gothic Medium", "Arial Narrow", Arial, sans-serif;
}

body {
  min-height: 100vh;
  background: #f6f7fb;
  color: #1a1a1a;
  padding: 1rem;
}

.app-shell {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.controls-panel,
.challenge-panel {
  background: #fff;
  border: 1px solid #e4e8f2;
  border-radius: 12px;
  padding: 1rem;
  display: grid;
  gap: 0.75rem;
  box-shadow: 0 4px 12px rgb(12 27 82 / 6%);
}

.field {
  display: grid;
  gap: 0.25rem;
  font-size: 0.95rem;
}

input[type="number"] {
  width: 100%;
  max-width: 260px;
  font-size: 1rem;
  padding: 0.35rem 0.5rem;
  border: 1px solid #cfd6eb;
  border-radius: 8px;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.btn {
  border: 0;
  cursor: pointer;
  font-size: 0.95rem;
  padding: 0.5rem 0.9rem;
  background-color: #d9deea;
  border-radius: 8px;
  transition: transform 0.15s ease;
}

.btn:hover:enabled {
  transform: translateY(-1px);
}

.btn:disabled {
  cursor: not-allowed;
  opacity: 0.65;
}

.btn-primary {
  background-color: #3458f5;
  color: #fff;
}

.challenge-title {
  font-size: 1.05rem;
  font-weight: 600;
}

.challenge-readout {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.challenge-card {
  min-height: 90px;
  display: grid;
  place-items: center;
  font-size: clamp(1.7rem, 5vw, 2.8rem);
  border: 2px dashed #d3daf0;
  border-radius: 10px;
  text-align: center;
  padding: 0.75rem;
}

.helper-text {
  font-size: 0.88rem;
  color: #5f6b94;
}

.container {
  min-height: 300px;
  background: #fff;
  border: 1px solid #e4e8f2;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgb(12 27 82 / 6%);
  display: flex;
  justify-content: center;
  align-items: center;
  align-content: flex-start;
  flex-wrap: wrap;
  gap: 0.25rem;
  padding: 0.75rem;
}

.container span {
  padding: 0.25rem 0.3rem;
  font-size: 1.25rem;
  font-weight: 500;
}

@media (min-width: 900px) {
  .app-shell {
    grid-template-columns: 1fr 1fr;
  }

  .container {
    grid-column: span 2;
  }
}