:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-border: #262b36;
  --text: #e7e9ee;
  --text-dim: #9aa2b1;
  --accent: #5b8cff;
  --accent-text: #0f1115;
  --ok: #3ecf8e;
  --fail: #ef5b5b;
  --mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.5;
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 20px 80px;
}

.nav {
  display: flex;
  gap: 4px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--panel-border);
  padding-bottom: 4px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.nav a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.85rem;
  padding: 8px 12px;
  border-radius: 8px 8px 0 0;
  white-space: nowrap;
  flex: 0 0 auto;
}

.nav a:hover {
  color: var(--text);
}

.nav a[aria-current="page"] {
  color: var(--text);
  background: var(--panel);
  font-weight: 600;
}

header h1 {
  font-size: 1.6rem;
  margin: 0 0 8px;
}

.subtitle {
  color: var(--text-dim);
  font-size: 0.95rem;
  max-width: 62ch;
}

.subtitle code {
  font-family: var(--mono);
  background: #1f2430;
  padding: 1px 5px;
  border-radius: 4px;
  color: var(--text);
}

.input-card, .results-card {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  padding: 20px;
  margin-top: 20px;
}

label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 8px;
}

textarea {
  width: 100%;
  resize: vertical;
  background: #0d0f14;
  color: var(--text);
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  padding: 12px;
  font-family: var(--mono);
  font-size: 0.95rem;
}

textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.controls {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 14px;
}

button {
  font: inherit;
  cursor: pointer;
  border-radius: 8px;
  padding: 9px 16px;
  border: 1px solid transparent;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 600;
}

.btn-primary:hover:not(:disabled) { filter: brightness(1.08); }

.btn-secondary {
  background: transparent;
  color: var(--text);
  border-color: var(--panel-border);
}

.btn-secondary:hover:not(:disabled) { border-color: var(--accent); }

.status {
  color: var(--text-dim);
  font-size: 0.9rem;
}

.error {
  color: var(--fail);
  font-size: 0.9rem;
  margin: 12px 0 0;
}

.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.results-header h2 {
  margin: 0;
  font-size: 1.15rem;
}

.badge {
  font-size: 0.8rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 999px;
}

.badge-ok {
  background: rgba(62, 207, 142, 0.15);
  color: var(--ok);
}

.badge-fail {
  background: rgba(239, 91, 91, 0.15);
  color: var(--fail);
}

.solver-detail {
  margin-top: 14px;
  color: var(--text-dim);
  font-size: 0.85rem;
}

.solver-detail summary {
  cursor: pointer;
}

.mono-block {
  display: block;
  margin-top: 8px;
  padding: 10px;
  background: #0d0f14;
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--text);
  word-break: break-word;
  white-space: pre-wrap;
}

.steps-list {
  margin: 16px 0;
  padding-left: 0;
  list-style: none;
  counter-reset: step;
  border-top: 1px solid var(--panel-border);
}

.steps-list li {
  counter-increment: step;
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 7px 0;
  border-bottom: 1px solid var(--panel-border);
  font-family: var(--mono);
  font-size: 0.9rem;
}

.steps-list li::before {
  content: counter(step) '.';
  color: var(--text-dim);
  width: 2.2em;
  flex-shrink: 0;
  text-align: right;
}

.step-move {
  color: var(--text-dim);
  width: 3.5em;
  flex-shrink: 0;
}

.step-arrow {
  color: var(--text-dim);
}

.step-actions {
  color: var(--text);
  font-weight: 600;
}

.search-log {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-dim);
  margin: -4px 0 16px;
}

.summary-row {
  display: flex;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 16px 24px;
  margin-top: 8px;
}

.tally-table {
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 0.9rem;
}

.tally-table th, .tally-table td {
  padding: 6px 16px 6px 0;
  text-align: left;
}

.tally-table th {
  color: var(--text-dim);
  font-weight: 500;
  border-bottom: 1px solid var(--panel-border);
}

.total-box {
  background: #0d0f14;
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  padding: 10px 20px;
  text-align: center;
}

.total-label {
  font-size: 0.75rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.total-value {
  font-size: 1.6rem;
  font-weight: 700;
  font-family: var(--mono);
}

.converter-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.panel-title {
  font-size: 1.05rem;
  margin: 0 0 4px;
}

.panel-hint {
  color: var(--text-dim);
  font-size: 0.82rem;
  margin: 0 0 14px;
}

.output-block {
  margin-top: 14px;
}

.output-row {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.notice {
  color: var(--text-dim);
  font-size: 0.8rem;
  margin: 10px 0 0;
}

.field-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.field-row label {
  margin: 0;
  white-space: nowrap;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 10px 0 0;
  font-size: 0.85rem;
  color: var(--text-dim);
  cursor: pointer;
}

.checkbox-row input {
  margin: 0;
  cursor: pointer;
}

.field-row input[type="number"] {
  width: 80px;
  background: #0d0f14;
  color: var(--text);
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  padding: 8px 10px;
  font-family: var(--mono);
}

@media (max-width: 600px) {
  .wrap {
    padding: 20px 14px 56px;
  }

  header h1 {
    font-size: 1.32rem;
  }

  .subtitle {
    font-size: 0.88rem;
  }

  .input-card, .results-card {
    padding: 14px;
    margin-top: 16px;
  }

  .controls, .field-row {
    gap: 10px;
  }

  .controls button, .field-row button {
    flex: 1 1 auto;
  }

  .steps-list li {
    gap: 6px;
    padding: 8px 0;
    font-size: 0.82rem;
    flex-wrap: wrap;
  }

  .steps-list li::before {
    width: 1.6em;
  }

  .step-move {
    width: auto;
    min-width: 2.6em;
  }

  .summary-row {
    gap: 14px;
  }

  .total-box {
    padding: 8px 16px;
  }

  .output-row, .results-header {
    gap: 10px;
  }
}