.ls3-sheets {
  display: grid;
  width: 100%;
  height: 100%;
  min-width: 0;
  min-height: 0;
  grid-template-rows: minmax(0, 1fr);
  background: var(--bg-primary);
  container-type: inline-size;
}

.ls3-sheets-unavailable {
  grid-row: 1;
  align-self: center;
  max-width: 32rem;
  margin: 0 auto;
  padding: 1rem;
  color: var(--text-secondary);
  line-height: 1.45;
  text-align: center;
}

.ls3-sheets-unavailable[hidden] { display: none; }

.ls3-sheets-frame {
  grid-row: 1;
  align-self: stretch;
  width: 100%;
  height: 100%;
  min-width: 0;
  min-height: 0;
  border: 0;
  background: var(--bg-primary);
  opacity: 0;
}

.ls3-sheets.is-ready .ls3-sheets-frame {
  opacity: 1;
}

.ls3-sheets.is-unavailable .ls3-sheets-frame {
  display: none;
}

.ls3-sheets-ai-message-copy > :first-child { margin-top: 0; }
.ls3-sheets-ai-message-copy > :last-child { margin-bottom: 0; }

.ls3-sheets-ai-proposal {
  margin-top: 0.8125rem;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: calc(0.875rem*var(--ls-r,1));
  background: color-mix(in srgb, var(--bg-secondary) 68%, transparent);
}

.ls3-sheets-ai-proposal > header {
  display: flex;
  min-height: 2.375rem;
  align-items: center;
  justify-content: space-between;
  gap: 0.625rem;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  color: var(--text-tertiary);
  font-size: 0.625rem;
  font-weight: 750;
  letter-spacing: 0.075em;
  text-transform: uppercase;
}

.ls3-sheets-ai-proposal > header strong {
  color: #15803d;
  letter-spacing: 0.02em;
  text-transform: none;
}

.ls3-sheets-ai-target,
.ls3-sheets-ai-more {
  margin: 0;
  padding: 0.625rem 0.75rem;
  color: var(--text-secondary);
  font-size: 0.6875rem;
}

.ls3-sheets-ai-cells {
  display: grid;
  max-height: 15rem;
  margin: 0;
  padding: 0 0.75rem 0.625rem;
  overflow: auto;
  list-style: none;
}

.ls3-sheets-ai-cells li {
  display: grid;
  grid-template-columns: minmax(2.8rem, auto) minmax(0, 1fr) auto minmax(0, 1fr);
  align-items: baseline;
  gap: 0.45rem;
  padding: 0.35rem 0;
  border-top: 1px solid var(--border-light);
  color: var(--text-tertiary);
  font-size: 0.6875rem;
}

.ls3-sheets-ai-cells span,
.ls3-sheets-ai-cells strong {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.ls3-sheets-ai-cells strong { color: var(--text-primary); }

.ls3-sheets-ai-conflict {
  margin: 0;
  padding: 0.5625rem 0.75rem;
  border-top: 1px solid color-mix(in srgb, var(--color-danger, #b3261e) 28%, var(--border));
  background: color-mix(in srgb, var(--color-danger, #b3261e) 7%, transparent);
  color: var(--color-danger, #b3261e);
  font-size: 0.6875rem;
  line-height: 1.5;
}

.ls3-sheets-ai-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4375rem;
  padding: 0.625rem 0.75rem;
  border-top: 1px solid var(--border);
}

.ls3-sheets-ai-actions button {
  min-height: 2rem;
  padding: 0 0.6875rem;
  border: 1px solid var(--border);
  border-radius: calc(0.75rem*var(--ls-r,1));
  background: var(--bg-primary);
  color: var(--text-secondary);
  cursor: pointer;
  font: 650 0.6875rem/1 var(--font-body);
}

.ls3-sheets-ai-actions button:hover,
.ls3-sheets-ai-actions button:focus-visible {
  border-color: color-mix(in srgb, var(--color-accent) 50%, var(--border));
  outline: none;
  background: var(--bg-hover);
  color: var(--text-primary);
}

.ls3-sheets-ai-actions .ls3-sheets-ai-apply-primary {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: #fff;
}

.ls3-sheets-ai-actions .ls3-sheets-ai-apply-primary:hover,
.ls3-sheets-ai-actions .ls3-sheets-ai-apply-primary:focus-visible {
  border-color: var(--color-accent-hover);
  background: var(--color-accent-hover);
  color: #fff;
}

[data-theme="dark"] .ls3-sheets-ai-proposal > header strong { color: #7bd5a5; }

.ls3-sheet-lesson-dialog {
  position: fixed;
  z-index: 1500;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 1.25rem;
  background: color-mix(in srgb, #0b1020 42%, transparent);
  backdrop-filter: blur(4px);
}

.ls3-sheet-lesson-card {
  display: grid;
  width: min(58rem, 100%);
  max-height: min(46rem, calc(100dvh - 2.5rem));
  grid-template-rows: auto auto auto minmax(10rem, 1fr) auto;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: calc(1rem*var(--ls-r,1));
  background: var(--bg-primary);
  color: var(--text-primary);
  box-shadow: var(--ls-e,var(--canvas-popout-shadow, 0 calc(20px*var(--ls-s,1)) calc(50px*var(--ls-s,1)) #0004));
}

.ls3-sheet-lesson-card > header,
.ls3-sheet-lesson-card > footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 0.875rem;
}

.ls3-sheet-lesson-card > header { border-bottom: 1px solid var(--border); }
.ls3-sheet-lesson-card > header > div { display: grid; gap: 0.15rem; }
.ls3-sheet-lesson-card > header span,
.ls3-sheet-lesson-title > span {
  color: var(--text-tertiary);
  font-size: 0.625rem;
  font-weight: 750;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.ls3-sheet-lesson-copy {
  margin: 0;
  padding: 0.75rem 0.875rem 0.25rem;
  color: var(--text-secondary);
  font-size: 0.75rem;
  line-height: 1.5;
}

.ls3-sheet-lesson-title {
  display: grid;
  gap: 0.35rem;
  padding: 0.5rem 0.875rem 0.75rem;
}

.ls3-sheet-lesson-title input {
  min-height: 2.4rem;
  padding: 0 0.7rem;
  border: 1px solid var(--border);
  border-radius: calc(0.65rem*var(--ls-r,1));
  background: var(--bg-secondary);
  color: var(--text-primary);
  font: inherit;
}

.ls3-sheet-lesson-grid-wrap { overflow: auto; border-block: 1px solid var(--border); }
.ls3-sheet-lesson-grid { border-collapse: separate; border-spacing: 0; table-layout: fixed; }
.ls3-sheet-lesson-grid th {
  padding: 0.35rem;
  background: var(--bg-secondary);
  color: var(--text-tertiary);
  font-size: 0.625rem;
  font-weight: 700;
  text-align: center;
}
.ls3-sheet-lesson-grid td { padding: 0; border-top: 1px solid var(--border-light); border-left: 1px solid var(--border-light); }
.ls3-sheet-lesson-grid td button {
  width: 100%;
  height: 100%;
  min-height: 0;
  padding: 0.35rem 0.5rem;
  overflow: hidden;
  border: 0;
  background: var(--bg-primary);
  color: var(--text-primary);
  text-align: left;
  text-overflow: ellipsis;
  white-space: nowrap;
  cursor: pointer;
}
.ls3-sheet-lesson-grid td button:hover:not(:disabled) { background: var(--bg-hover); }
.ls3-sheet-lesson-grid td button.is-selected { background: color-mix(in srgb, var(--color-accent) 14%, var(--bg-primary)); box-shadow: inset 0 0 0 2px var(--color-accent); }
.ls3-sheet-lesson-grid td button.is-formula { color: var(--text-secondary); cursor: not-allowed; font-family: var(--font-mono); font-size: 0.6875rem; }
.ls3-sheet-lesson-grid td button.is-blank { color: var(--text-tertiary); font-style: italic; }

.ls3-sheet-lesson-card > footer { min-height: 3.75rem; }
.ls3-sheet-lesson-card > footer > div { display: flex; gap: 0.5rem; }
.ls3-sheet-lesson-count { color: var(--text-secondary); font-size: 0.75rem; }
.ls3-sheet-lesson-card > footer button {
  min-height: 2.25rem;
  padding: 0 0.8rem;
  border: 1px solid var(--border);
  border-radius: calc(0.7rem*var(--ls-r,1));
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  font: 650 0.75rem/1 var(--font-body);
}
.ls3-sheet-lesson-card > footer button.is-primary { border-color: var(--color-accent); background: var(--color-accent); color: #fff; }

.ls3-sheet-refresh-card { grid-template-rows: auto auto auto minmax(8rem, 1fr) auto; }
.ls3-sheet-refresh-status {
  margin: 0;
  padding: 0.625rem 0.875rem;
  border-top: 1px solid var(--border-light);
  background: color-mix(in srgb, var(--color-accent) 6%, var(--bg-secondary));
  color: var(--text-secondary);
  font-size: 0.75rem;
}
.ls3-sheet-refresh-status[data-tone="error"] {
  background: color-mix(in srgb, var(--color-danger, #b3261e) 7%, var(--bg-secondary));
  color: var(--color-danger, #b3261e);
}
.ls3-sheet-refresh-body { min-height: 0; overflow: auto; }
.ls3-sheet-refresh-table-wrap { min-height: 100%; }
.ls3-sheet-refresh-table { width: 100%; border-collapse: collapse; table-layout: fixed; }
.ls3-sheet-refresh-table th,
.ls3-sheet-refresh-table td {
  padding: 0.55rem 0.7rem;
  border-bottom: 1px solid var(--border-light);
  text-align: left;
  vertical-align: top;
  overflow-wrap: anywhere;
}
.ls3-sheet-refresh-table thead th {
  position: sticky;
  z-index: 1;
  top: 0;
  background: var(--bg-secondary);
  color: var(--text-tertiary);
  font-size: 0.625rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.ls3-sheet-refresh-table tbody th { width: 5rem; color: var(--text-secondary); font-size: 0.6875rem; }
.ls3-sheet-refresh-table tbody td { font-family: var(--font-mono); font-size: 0.6875rem; }
.ls3-sheet-refresh-table tbody td:last-child { background: color-mix(in srgb, var(--color-accent) 7%, transparent); }
.ls3-sheet-refresh-empty,
.ls3-sheet-refresh-more {
  margin: 0;
  padding: 1rem 0.875rem;
  color: var(--text-secondary);
  font-size: 0.75rem;
  line-height: 1.5;
}

.lesson-composer-preview-sheet {
  width: 100%;
  height: 100%;
  border-collapse: collapse;
  background: var(--bg-primary);
}

span.lesson-composer-preview-sheet {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(2, 1fr);
}

span.lesson-composer-preview-sheet > i,
.lesson-composer-preview-sheet td {
  border: 1px solid var(--border-light);
  color: var(--text-secondary);
  font-size: 0.625rem;
  text-align: center;
}

.lesson-composer-preview-sheet td.is-input {
  background: color-mix(in srgb, var(--color-accent) 12%, var(--bg-primary));
  box-shadow: inset 0 0 0 1px var(--color-accent);
}

@media (max-width: 620px) {
  .ls3-sheet-lesson-dialog { padding: 0.5rem; }
  .ls3-sheet-lesson-card { max-height: calc(100dvh - 1rem); }
  .ls3-sheet-lesson-card > footer { align-items: flex-start; flex-direction: column; }
}