/* Series Number — number sequence practice */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.series-number-game .sn-sequence-display {
  margin: 0 0 20px;
  padding: 20px 24px;
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-md);
  background: var(--hub-surface-muted);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-align: center;
  color: var(--hub-ink);
  line-height: 1.6;
  word-break: break-word;
}

.series-number-game .sn-answer-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  align-items: center;
  margin-bottom: 12px;
}

.series-number-game .sn-answer-input {
  width: min(100%, 220px);
  padding: 12px 16px;
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-sm);
  font-size: 1.1rem;
  font-weight: 600;
  text-align: center;
  color: var(--hub-ink);
  background: var(--hub-input-bg);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.series-number-game .sn-answer-input:focus {
  outline: none;
  border-color: var(--hub-accent);
  box-shadow: var(--hub-focus-ring);
}

.series-number-game .sn-answer-input:disabled {
  background: var(--hub-surface-muted);
  color: var(--hub-muted);
}

.sn-resume-banner .sn-resume-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-top: 12px;
}

.sn-explanation-review {
  margin: 24px 0;
  text-align: left;
}

.sn-explanation-review h3 {
  margin: 0 0 14px;
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--hub-ink);
}

.sn-explanation-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
  max-height: min(60vh, 520px);
  overflow-y: auto;
}

.sn-explanation-item {
  padding: 14px 16px;
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-md);
  background: var(--hub-surface);
}

.sn-explanation-item.is-correct {
  border-color: color-mix(in srgb, var(--hub-good) 50%, var(--hub-border));
  background: var(--hub-good-soft);
}

.sn-explanation-item.is-wrong {
  border-color: color-mix(in srgb, var(--hub-bad) 50%, var(--hub-border));
  background: var(--hub-bad-soft);
}

.sn-explanation-item.is-skipped,
.sn-explanation-item.is-pending {
  background: var(--hub-surface-muted);
}

.sn-explanation-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 8px;
}

.sn-explanation-head strong {
  color: var(--hub-ink);
}

.sn-explanation-status {
  font-size: 12px;
  font-weight: 700;
  color: var(--hub-muted);
}

.sn-explanation-sequence {
  margin: 0 0 8px;
  font-weight: 700;
  color: var(--hub-ink);
  line-height: 1.5;
  word-break: break-word;
}

.sn-explanation-answer {
  margin: 0 0 6px;
  font-size: 14px;
  color: var(--hub-muted);
}

.sn-explanation-answer span {
  font-weight: 700;
  color: var(--hub-ink);
}

.sn-explanation-text {
  margin: 0;
  font-size: 13px;
  line-height: 1.45;
  color: var(--hub-muted);
}