:root {
  --bg: #fafafa; --fg: #1b1b1b; --muted: #5d6470; --panel: #ffffff; --border: #d3d7de;
  --accent: #0b63ce; --accent-fg: #ffffff; --ok: #1a7f37; --bad: #c62828;
}
:root[data-theme="dark"] {
  --bg: #16181d; --fg: #e6e8ec; --muted: #a0a7b4; --panel: #1e2128; --border: #343944;
  --accent: #4c9aff; --accent-fg: #0b1220; --ok: #4cc26b; --bad: #ff7b72;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #16181d; --fg: #e6e8ec; --muted: #a0a7b4; --panel: #1e2128; --border: #343944;
    --accent: #4c9aff; --accent-fg: #0b1220; --ok: #4cc26b; --bad: #ff7b72;
  }
}
* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body { display: flex; flex-direction: column; background: var(--bg); color: var(--fg); font: 15px/1.4 system-ui, sans-serif; }
header { display: flex; align-items: center; gap: 12px; padding: 8px 12px; border-bottom: 1px solid var(--border); background: var(--panel); }
header h1 { font-size: 18px; margin: 0; }
header a { color: var(--accent); }
.spacer { flex: 1; }
#status { color: var(--muted); font-size: 13px; }
main {
  flex: 1; min-height: 0; display: grid; gap: 8px; padding: 8px;
  grid-template-columns: 1fr 1fr; grid-template-rows: auto minmax(0, 1fr);
  grid-template-areas: "options options" "input output";
}
#optionsPane { grid-area: options; display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: flex-start; justify-content: space-between; }
#inputPane { grid-area: input; min-height: 0; }
#outputPane { grid-area: output; min-height: 0; display: flex; flex-direction: column; gap: 6px; }
#options { flex: 1 1 420px; background: var(--panel); border: 1px solid var(--border); border-radius: 6px; padding: 6px 10px; }
#options summary { cursor: pointer; font-weight: 600; }
#options label { display: block; padding: 3px 0; }
#options select { font: inherit; background: var(--bg); color: var(--fg); border: 1px solid var(--border); border-radius: 4px; padding: 2px 6px; }
.buttons { display: flex; gap: 8px; flex-wrap: wrap; }
button { font: inherit; padding: 8px 14px; min-height: 40px; border: 1px solid var(--border); border-radius: 6px; background: var(--panel); color: var(--fg); cursor: pointer; }
button:disabled { opacity: .5; cursor: default; }
button.primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); font-weight: 600; }
#theme { min-width: 40px; padding: 4px 10px; }
.editor { height: 100%; min-height: 160px; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; background: var(--panel); }
.editor textarea { width: 100%; height: 100%; border: 0; padding: 8px; resize: none; font: 13px/1.4 ui-monospace, Menlo, Consolas, monospace; background: var(--panel); color: var(--fg); }
#error { background: color-mix(in srgb, var(--bad) 12%, var(--panel)); border: 1px solid var(--bad); border-radius: 6px; padding: 8px 10px; white-space: pre-wrap; font: 12px/1.4 ui-monospace, Menlo, Consolas, monospace; max-height: 30%; overflow: auto; }
#verifyResult { border: 1px solid var(--border); border-radius: 6px; padding: 6px 10px; white-space: pre-wrap; }
#verifyResult.ok { border-color: var(--ok); color: var(--ok); }
#verifyResult.bad { border-color: var(--bad); color: var(--bad); }
#outputPane .editor { flex: 1; min-height: 0; }
[hidden] { display: none !important; }
@media (max-width: 760px) {
  main { grid-template-columns: 1fr; grid-template-rows: auto minmax(220px, 1fr) minmax(220px, 1fr); grid-template-areas: "options" "input" "output"; overflow-y: auto; }
  header { flex-wrap: wrap; }
  #status { order: 5; flex-basis: 100%; }
  .buttons button { flex: 1; }
}