.signal-page {
  background:
    linear-gradient(180deg, rgba(245, 249, 255, 0.9), rgba(219, 231, 245, 0.95)),
    var(--game-art, linear-gradient(180deg, #f5f9ff, var(--page-bg-strong)));
  background-attachment: fixed;
  background-position: center;
  background-size: cover;
}

.signal-viewport {
  max-width: 1180px;
}

.signal-shell {
  width: min(100%, 1040px);
}

.signal-title-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 12px;
}

.signal-title-row h1 {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-size: clamp(2rem, 5vw, 3.2rem);
}

.signal-title-row h1 span {
  color: var(--text-strong);
}

.signal-title-row h1 strong {
  color: var(--accent-strong);
}

.signal-eyebrow,
.signal-player-pill span {
  margin-bottom: 6px;
  color: var(--text-soft);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.signal-player-pill {
  min-width: 150px;
  padding: 12px 14px;
  text-align: right;
  background: var(--surface-soft);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.signal-player-pill span,
.signal-player-pill strong {
  display: block;
}

.signal-player-pill strong {
  color: var(--text-strong);
}

.signal-intro {
  margin-bottom: 18px;
}

.signal-controls,
.signal-mode-tabs,
.signal-size-tabs,
.signal-action-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.signal-controls {
  margin: 16px 0;
}

.signal-size-tabs {
  padding: 6px;
  background: rgba(219, 234, 254, 0.55);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.signal-mode-tabs {
  padding: 6px;
  background: rgba(236, 253, 245, 0.62);
  border: 1px solid rgba(15, 159, 110, 0.18);
  border-radius: 8px;
}

.signal-size-tabs button,
.signal-mode-tabs button,
.signal-action-row button {
  width: auto;
  min-height: 40px;
  border-radius: 8px;
}

.signal-size-tabs .size-btn {
  color: var(--text-strong);
  background: transparent;
  border: 1px solid transparent;
  box-shadow: none;
}

.signal-mode-tabs .mode-btn {
  color: var(--text-strong);
  background: transparent;
  border: 1px solid transparent;
  box-shadow: none;
}

.signal-size-tabs .size-btn:hover,
.signal-size-tabs .size-btn.active {
  color: #ffffff;
  background: linear-gradient(145deg, var(--accent), var(--accent-strong));
  border-color: rgba(37, 99, 235, 0.32);
}

.signal-mode-tabs .mode-btn:hover,
.signal-mode-tabs .mode-btn.active {
  color: #ffffff;
  background: linear-gradient(145deg, var(--success), #047857);
  border-color: rgba(15, 159, 110, 0.24);
}

.signal-mode-label {
  width: fit-content;
  max-width: 100%;
  margin: -4px auto 10px;
  padding: 8px 12px;
  color: var(--success);
  background: var(--success-soft);
  border: 1px solid rgba(15, 159, 110, 0.18);
  border-radius: 8px;
  font-size: 0.86rem;
  font-weight: 800;
  text-align: center;
}

.signal-puzzle-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: fit-content;
  max-width: 100%;
  margin: 0 auto 12px;
  padding: 8px 12px;
  color: var(--text-soft);
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: var(--shadow-soft);
  font-size: 0.86rem;
}

.signal-puzzle-meta span {
  font-weight: 800;
}

.signal-puzzle-meta strong {
  color: var(--text-strong);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.82rem;
  overflow-wrap: anywhere;
}

.signal-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 18px auto;
  width: min(100%, 620px);
}

.signal-stats .summary-box span {
  font-size: 1.35rem;
}

.signal-login-note {
  width: min(100%, 680px);
  margin: 0 auto 18px;
}

.signal-board-wrap {
  width: 100%;
  overflow: visible;
  padding: 10px 0 22px;
}

.board {
  --signal-cell: 52px;
  --signal-op: 32px;
  --signal-target: 58px;
  --signal-column-target: 52px;
  --signal-gap: 6px;

  display: flex;
  flex-direction: column;
  gap: var(--signal-gap);
  width: max-content;
  margin: auto;
}

.row,
.vertical-row,
.column-targets {
  display: flex;
  align-items: center;
  gap: var(--signal-gap);
  width: max-content;
}

.cell.number,
.operator,
.vertical-operator,
.target,
.column-target {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  user-select: none;
  transition: transform 0.16s ease, background 0.16s ease, border-color 0.16s ease;
}

.cell.number {
  width: var(--signal-cell);
  height: var(--signal-cell);
  color: var(--text-strong);
  background: linear-gradient(180deg, #ffffff, #f6fbff);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  box-shadow: var(--shadow-soft);
  font-size: clamp(1.05rem, 3vw, 1.55rem);
  font-weight: 900;
  cursor: pointer;
  position: relative;
}

.cell.number:hover,
.operator:hover,
.vertical-operator:hover {
  transform: translateY(-1px);
}

.cell.number.disabled {
  color: var(--danger);
  background: var(--danger-soft);
  border-color: rgba(220, 38, 38, 0.26);
}

.cell.number.disabled::after {
  content: "";
  position: absolute;
  width: 82%;
  height: 4px;
  background: var(--danger);
  border-radius: 999px;
  transform: rotate(-30deg);
}

.operator,
.vertical-operator {
  color: var(--text-soft);
  background: rgba(219, 234, 254, 0.52);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-weight: 900;
}

.operator {
  width: var(--signal-op);
  height: var(--signal-op);
  font-size: 1.25rem;
}

.vertical-operator {
  width: var(--signal-cell);
  height: calc(var(--signal-op) * 0.82);
  font-size: 1.12rem;
}

.plus {
  color: var(--accent-strong);
  background: var(--accent-soft);
  border-color: rgba(37, 99, 235, 0.32);
}

.minus {
  color: #9a3412;
  background: #ffedd5;
  border-color: rgba(217, 119, 6, 0.25);
}

.empty {
  color: var(--text-soft);
}

.target,
.column-target {
  color: var(--text-strong);
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: var(--shadow-soft);
  font-weight: 900;
}

.target {
  width: var(--signal-target);
  height: var(--signal-cell);
  margin-left: 4px;
  font-size: clamp(1rem, 2.4vw, 1.35rem);
}

.column-target {
  width: var(--signal-column-target);
  height: calc(var(--signal-cell) * 0.76);
  font-size: clamp(0.95rem, 2.3vw, 1.22rem);
}

.target.correct,
.column-target.correct {
  color: var(--success);
  background: var(--success-soft);
  border-color: rgba(15, 159, 110, 0.24);
}

.target.wrong,
.column-target.wrong {
  color: var(--danger);
  background: var(--danger-soft);
  border-color: rgba(220, 38, 38, 0.22);
}

.target-bottom-spacer {
  width: calc(var(--signal-target) + 4px);
  flex-shrink: 0;
}

.column-gap,
.row-leading-gap {
  width: var(--signal-op);
  flex-shrink: 0;
}

.signal-save-status {
  min-height: 1.4em;
  text-align: center;
}

.signal-ranking {
  margin-top: 18px;
}

.signal-ranking h2 {
  margin-bottom: 10px;
  text-align: center;
}

.signal-howto {
  margin-top: 10px;
}

.signal-instruction-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.signal-instruction-grid article {
  padding: 16px;
  background: var(--surface-soft);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.signal-instruction-grid span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  margin-bottom: 10px;
  color: var(--accent-strong);
  background: var(--accent-soft);
  border-radius: 8px;
  font-weight: 900;
}

.signal-instruction-grid h2 {
  margin-bottom: 6px;
  font-size: 1rem;
}

@media (max-width: 720px) {
  .signal-title-row,
  .signal-player-pill {
    text-align: left;
  }

  .signal-title-row {
    flex-direction: column;
  }

  .signal-player-pill {
    width: 100%;
  }

  .signal-stats {
    grid-template-columns: 1fr;
  }

  .signal-action-row,
  .signal-action-row button,
  .signal-mode-tabs,
  .signal-size-tabs {
    width: 100%;
  }

  .signal-size-tabs,
  .signal-mode-tabs {
    display: grid;
  }

  .signal-size-tabs {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .signal-mode-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .board {
    --signal-gap: 2px;
    --signal-op: 18px;
    --signal-target: 26px;
    --signal-column-target: var(--signal-cell);
  }

  .board-size-3 {
    --signal-cell: clamp(34px, 11vw, 42px);
  }

  .board-size-5 {
    --signal-cell: clamp(30px, 9.4vw, 38px);
  }

  .board-size-7 {
    --signal-cell: clamp(22px, 7vw, 30px);
    --signal-op: max(13px, calc(var(--signal-cell) * 0.52));
  }

  .cell.number {
    font-size: clamp(0.86rem, 4.6vw, 1.18rem);
    border-radius: 6px;
  }

  .operator,
  .vertical-operator,
  .target,
  .column-target {
    border-radius: 5px;
    font-size: clamp(0.72rem, 3.5vw, 0.95rem);
  }

  .target {
    margin-left: 2px;
  }
}