.video-practice {
  border: 2px solid rgba(60, 122, 137, .22);
  background: linear-gradient(145deg, var(--surface, #fff), #f4faf9);
}
.practice-kicker {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin-bottom: 8px;
  padding: 5px 10px;
  border-radius: 999px;
  background: #e4f1ef;
  color: #315e66;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .04em;
}
.practice-steps {
  margin: 14px 0 18px;
  padding-left: 22px;
  color: var(--text-dim);
}
.practice-steps li + li { margin-top: 6px; }
.practice-player {
  position: relative;
  overflow: hidden;
  margin: 16px 0 12px;
  border-radius: 16px;
  background: #142c34;
  box-shadow: 0 14px 34px rgba(31, 66, 72, .16);
}
.practice-player video {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #142c34;
}
.audio-mask {
  position: absolute;
  inset: 0 0 48px;
  display: none;
  place-items: center;
  padding: 24px;
  background: radial-gradient(circle at center, #31545d, #142c34 70%);
  color: #fff;
  text-align: center;
  pointer-events: none;
}
.practice-player.audio-only .audio-mask { display: grid; }
.audio-mask-icon {
  display: block;
  margin-bottom: 8px;
  font-size: 42px;
}
.practice-controls,
.layered-hints {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}
.practice-controls { margin-bottom: 18px; }
.layered-hints { margin-top: 18px; }
.practice-btn {
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface, #fff);
  color: var(--text);
  font: inherit;
  font-size: 14px;
  font-weight: 750;
  cursor: pointer;
}
.practice-btn:hover,
.practice-btn[aria-pressed="true"] {
  border-color: var(--accent);
  background: #e4f1ef;
  color: #285b65;
}
.practice-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-top: 16px;
}
.practice-field {
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: rgba(255, 255, 255, .82);
}
.practice-field.full { grid-column: 1 / -1; }
.practice-field label {
  display: block;
  font-weight: 800;
  line-height: 1.5;
}
.practice-field .field-help {
  display: block;
  margin-top: 4px;
  color: var(--text-dim);
  font-size: 13px;
}
.practice-field .exercise-answer {
  min-height: 104px;
  margin: 10px 0 0;
}
.practice-hint {
  display: none;
  margin-top: 10px;
  padding: 13px 15px;
  border-radius: 10px;
  background: #e4f1ef;
  color: #315e66;
  font-size: 14px;
}
.practice-hint.show { display: block; }
.practice-reference {
  margin-top: 16px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface, #fff);
}
.practice-reference.source-note { margin: 0 0 18px; }
.practice-reference summary {
  padding: 14px 16px;
  color: var(--accent);
  font-weight: 800;
  cursor: pointer;
}
.practice-reference-body { padding: 0 16px 16px; }
.practice-reference-line {
  margin: 8px 0;
  padding: 10px 12px;
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  background: var(--bg);
  font-variant-numeric: tabular-nums;
}
.practice-self-check {
  margin-top: 16px;
  padding: 16px;
  border-radius: 13px;
  background: #eff6f3;
}
.practice-self-check label {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  margin-top: 9px;
  cursor: pointer;
}
.practice-self-check input {
  margin-top: 4px;
  accent-color: var(--accent);
}
.practice-check-progress {
  margin-top: 12px;
  color: #315e66;
  font-size: 13px;
  font-weight: 800;
}
@media (max-width: 700px) {
  .practice-grid { grid-template-columns: 1fr; }
  .practice-field.full { grid-column: auto; }
  .video-practice { padding: 20px 14px; }
}