:root {
  color-scheme: light dark;
  --bg: #f6f6f4;
  --fg: #1c1c1c;
  --muted: #666;
  --pane: #fff;
  --border: #d0d0cc;
  --accent: #2b5d8c;
  --warn: #8a6d00;
  --error: #a4262c;
  font-family:
    system-ui,
    -apple-system,
    'Segoe UI',
    sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161616;
    --fg: #e6e6e6;
    --muted: #999;
    --pane: #1f1f1f;
    --border: #3a3a3a;
    --accent: #7db2e6;
    --warn: #e0b93b;
    --error: #ff7b81;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header,
footer {
  padding: 0.75rem 1.25rem;
}

header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.4rem;
}

header p {
  margin: 0;
  color: var(--muted);
}

main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  padding: 0 1.25rem 1rem;
}

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

.pane {
  display: flex;
  flex-direction: column;
  min-height: 24rem;
}

.pane > label {
  font-weight: 600;
  margin-bottom: 0.35rem;
}

textarea,
pre {
  flex: 1;
  margin: 0;
  padding: 0.75rem;
  background: var(--pane);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  font-size: 0.85rem;
  line-height: 1.4;
  overflow: auto;
  white-space: pre;
  tab-size: 8;
  resize: none;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: flex-end;
  margin-top: 0.75rem;
}

fieldset {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.25rem 0.6rem;
  margin: 0;
}

legend {
  color: var(--muted);
  font-size: 0.8rem;
}

.flags {
  display: flex;
  flex-direction: column;
  font-size: 0.8rem;
  color: var(--muted);
}

.flags input {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  padding: 0.35rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--pane);
  color: var(--fg);
}

button {
  padding: 0.5rem 1rem;
  border: 1px solid var(--accent);
  border-radius: 6px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

button:disabled {
  opacity: 0.5;
  cursor: default;
}

#cancel {
  background: transparent;
  color: var(--accent);
}

.diagnostics {
  margin-top: 0.5rem;
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.8rem;
}

.diagnostics .warning {
  color: var(--warn);
}

.diagnostics .error {
  color: var(--error);
}

footer {
  display: flex;
  gap: 1.5rem;
  color: var(--muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

details.source-only {
  margin: 0.5rem 0;
}
details.source-only textarea {
  width: 100%;
  min-height: 4rem;
  box-sizing: border-box;
}
[hidden] {
  display: none !important;
}