@media (max-width: 640px) {
  .terminology-board {
    font-size: 0.66rem;
    grid-template-columns: minmax(24px, auto) repeat(9, minmax(20px, 1fr));
    gap: 1px;
  }

  .term-corner,
  .term-col-label,
  .term-row-label,
  .term-cell {
    min-height: 21px;
    border-radius: 5px;
  }
}

body.manual-open,
body.account-open,
body.saved-puzzles-open {
  overflow: hidden;
}

.user-manual[hidden] {
  display: none;
}

.user-manual {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.98), rgba(239, 246, 255, 0.98));
  overflow: hidden;
  padding: max(16px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right)) max(18px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
}

.manual-shell {
  width: min(1180px, 100%);
  height: 100%;
  margin: 0 auto;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: 14px;
}

.manual-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow-soft);
}

.manual-header h2 {
  margin: 2px 0 6px;
  font-size: clamp(1.45rem, 4vw, 2.15rem);
  letter-spacing: -0.04em;
}

.manual-header p {
  margin: 0;
  color: var(--muted);
  line-height: 1.45;
  max-width: 72ch;
}

.manual-kicker,
.manual-page-kicker {
  color: var(--brand-deep);
  font-size: 0.76rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.manual-layout {
  min-height: 0;
  display: grid;
  grid-template-columns: minmax(210px, 250px) minmax(0, 1fr);
  gap: 14px;
}

.manual-toc {
  min-height: 0;
  overflow: auto;
  display: grid;
  align-content: start;
  gap: 8px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow-soft);
}

.manual-toc button {
  width: 100%;
  border: 1px solid transparent;
  border-radius: 14px;
  background: transparent;
  color: var(--muted);
  font-weight: 850;
  text-align: left;
  padding: 10px 11px;
}

.manual-toc button:hover,
.manual-toc button:focus-visible,
.manual-toc button.is-active {
  color: var(--brand-deep);
  border-color: rgba(37, 99, 235, 0.18);
  background: var(--accent-soft);
}

.manual-main {
  min-width: 0;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  display: block;
  padding-right: 2px;
}

.manual-page-status {
  display: inline-block;
  margin-bottom: 12px;
  justify-self: start;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-weight: 850;
  font-size: 0.84rem;
  padding: 7px 11px;
}

.manual-page[hidden] {
  display: none;
}

.manual-page {
  min-height: auto;
  display: grid;
  grid-template-columns: minmax(0, 0.88fr) minmax(320px, 1.12fr);
  gap: 18px;
  align-items: stretch;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--surface);
  box-shadow: var(--shadow-soft);
}

.manual-page-copy h3 {
  margin: 4px 0 10px;
  font-size: clamp(1.35rem, 3vw, 2rem);
  letter-spacing: -0.03em;
}

.manual-page-copy p {
  margin: 0;
  color: var(--muted);
  line-height: 1.58;
}

.manual-page-copy p + p {
  margin-top: 12px;
}

.manual-visual {
  min-width: 0;
  align-self: start;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface-soft);
  padding: 16px;
}

.manual-grid-visual,
.manual-assist-page {
  display: grid;
  justify-items: center;
  gap: 12px;
}

.manual-board {
  display: grid;
  grid-template-columns: repeat(9, minmax(0, 1fr));
  width: min(100%, 360px);
  aspect-ratio: 1;
  border: 3px solid var(--line-strong);
  border-radius: 14px;
  overflow: hidden;
  background: var(--line-strong);
  margin-inline: auto;
}

.manual-cell.sudoku-cell-slot {
  display: grid;
  place-items: center;
  font-size: clamp(0.7rem, 2.4vw, 1.15rem);
  font-weight: 900;
}

.manual-cell.sudoku-cell-slot.is-active {
  box-shadow: inset 0 0 0 4px var(--accent);
  z-index: 2;
}

.manual-flow {
  display: grid;
  gap: 10px;
}

.manual-flow span {
  display: block;
  padding: 12px 14px;
  border-radius: 14px;
  background: var(--surface);
  border: 1px solid var(--line);
  color: var(--brand-deep);
  font-weight: 850;
}

.manual-control-visual {
  display: grid;
  place-items: center;
}

.manual-keypad {
  width: min(100%, 360px);
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.manual-keypad span,
.manual-note-buttons button {
  min-height: 42px;
  border-radius: 13px;
  border: 1px solid var(--line);
  background: var(--surface);
  display: grid;
  place-items: center;
  font-weight: 900;
  color: var(--brand-deep);
}

.manual-keypad .wide {
  grid-column: 1 / -1;
}

.manual-keypad .ghost {
  color: var(--muted);
  background: rgba(255, 255, 255, 0.72);
}

.manual-note-demo {
  display: grid;
  justify-items: center;
  align-content: center;
  gap: 14px;
}

.manual-note-cell {
  position: relative;
  width: min(170px, 52vw);
  aspect-ratio: 1;
  border: 3px solid var(--accent);
  border-radius: 18px;
  background: var(--surface);
  overflow: hidden;
}

.manual-note-cell .candidate-grid {
  opacity: 1;
  z-index: 1;
}

.manual-note-buttons {
  display: grid;
  grid-template-columns: repeat(9, minmax(28px, 1fr));
  gap: 6px;
  width: min(100%, 380px);
}

.manual-note-buttons button.is-on {
  background: var(--guess);
  color: var(--guess-ink);
  border-color: rgba(124, 58, 237, 0.28);
}

.manual-two-up,
.manual-whatif-demo {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.manual-two-up h4 {
  margin: 0 0 8px;
  color: var(--brand-deep);
  font-size: 0.92rem;
}

.manual-example-card {
  min-width: 0;
  display: grid;
  gap: 8px;
}

.manual-real-example-pair .manual-board {
  width: min(100%, 300px);
}

.manual-real-example-pair .manual-visual-note {
  font-size: 0.86rem;
}

.manual-step-example {
  display: grid;
  align-content: center;
  gap: 10px;
}

.manual-step-example strong {
  font-size: 1.08rem;
}

.manual-step-example p,
.manual-visual-note {
  margin: 0;
  color: var(--muted);
  line-height: 1.48;
}

.manual-mini-stat {
  justify-self: start;
  border-radius: 999px;
  padding: 7px 10px;
  background: var(--accent-soft);
  color: var(--brand-deep);
  font-weight: 850;
  font-size: 0.82rem;
}

.manual-whatif-demo .combo-option {
  width: 100%;
}

.manual-whatif-demo .manual-visual-note {
  grid-column: 1 / -1;
}

.manual-mini-cube {
  width: min(100%, 112px);
  margin-top: 4px;
}

.manual-page-nav {
  display: flex;
  margin-top: 12px;
  justify-content: space-between;
  gap: 10px;
  padding-bottom: 2px;
}

@media (max-width: 900px) {
  .manual-layout {
    grid-template-columns: 1fr;
  }

  .manual-toc {
    display: flex;
    overflow-x: auto;
    overscroll-behavior-inline: contain;
  }

  .manual-toc button {
    flex: 0 0 auto;
    width: auto;
    white-space: nowrap;
  }

  .manual-page {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .manual-header {
    align-items: stretch;
    flex-direction: column;
  }

  .manual-two-up,
  .manual-whatif-demo {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .user-manual {
    padding: max(10px, env(safe-area-inset-top)) max(8px, env(safe-area-inset-right)) max(12px, env(safe-area-inset-bottom)) max(8px, env(safe-area-inset-left));
  }

  .manual-shell {
    gap: 10px;
  }

  .manual-header,
  .manual-page,
  .manual-toc {
    border-radius: 18px;
  }

  .manual-page {
    padding: 14px;
  }

  .manual-note-buttons {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .manual-page-nav .button {
    flex: 1 1 0;
  }
}