:root {
  color-scheme: light;
  --ink: #111;
  --muted: #777;
  --line: #e2e2e2;
  --error: #b3261e;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: #fff;
  color: var(--ink);
  font: 14px/1.4 system-ui, -apple-system, "Segoe UI", sans-serif;
}

main {
  width: min(760px, 100%);
  margin: 0 auto;
  padding: clamp(24px, 12vh, 120px) 16px 32px;
  display: grid;
  gap: 12px;
}

textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: inherit;
  font: 14px/1.5 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  resize: vertical;
}

textarea:focus { outline: none; border-color: var(--ink); }

.output {
  display: flex;
  gap: 12px;
  align-items: stretch;
}

.preview {
  flex: 1;
  min-width: 0;
  min-height: 180px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  overflow: auto;
  /* Checkerboard: makes the PNG's transparency visible. */
  background: repeating-conic-gradient(#f3f3f3 0 25%, #fff 0 50%) 0 0 / 16px 16px;
}

.preview img { display: block; max-width: 100%; height: auto; }
.preview img[hidden] { display: none; }
.preview.stale img { opacity: 0.25; }

#message { margin: 0; color: var(--muted); text-align: center; }
#message:empty { display: none; }
.preview.stale #message { color: var(--error); }

.actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 96px;
}

button {
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: inherit;
  font: inherit;
  cursor: pointer;
}

button:hover:not(:disabled) { border-color: var(--ink); }
button:focus-visible { outline: 2px solid var(--ink); outline-offset: 1px; }
button:disabled { color: #bbb; cursor: default; }

.option {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  justify-self: start;
  cursor: pointer;
  user-select: none;
}

.option input { margin: 0; accent-color: var(--ink); }

@media (max-width: 520px) {
  .output { flex-direction: column; }
  .actions { flex-direction: row; width: 100%; }
  .actions button { flex: 1; }
}