:root {
  --bg: #fbfbfd; --fg: #1d1d1f; --muted: #6e6e73; --line: #e4e4e7;
  --card: #ffffff; --accent: #2563eb; --code-bg: #f3f4f6; --code-fg: #1d1d1f;
  --error: #b91c1c; --error-bg: #fef2f2;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115; --fg: #e6e6e9; --muted: #9a9aa3; --line: #25272e;
    --card: #15171d; --accent: #6ea8fe; --code-bg: #1c1f27; --code-fg: #e6e6e9;
    --error: #f87171; --error-bg: #2a1414;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--fg);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
.wrap { width: 100%; margin: 0 auto; padding: 3rem clamp(1.25rem, 5vw, 4rem) 5rem; text-align: center; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
header.hero { margin-bottom: 2.5rem; }
h1 { font-size: 2.1rem; line-height: 1.1; margin: 0 0 .6rem; letter-spacing: -0.02em; }
.tagline { font-size: 1.1rem; color: var(--muted); margin: 0 auto; max-width: 42rem; }
.pane { margin-bottom: 1.25rem; }
.pane h2 { font-size: .95rem; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); margin: 0 0 .5rem; }
textarea {
  display: block; width: 100%; min-height: 16rem; margin: 0; padding: .9rem 1.1rem;
  background: var(--code-bg); color: var(--code-fg); border: 1px solid var(--line); border-radius: 10px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: .88rem; line-height: 1.5;
  resize: vertical; overflow: auto; white-space: pre-wrap; word-break: break-word; text-align: left;
}
textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.output-scroll { width: 100%; overflow-x: auto; text-align: left; }
pre.output {
  display: inline-block; min-width: 100%; margin: 0; padding: .5rem 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: .88rem; line-height: 1.5;
  white-space: pre;
}
.controls { display: flex; flex-direction: column; align-items: center; gap: .75rem; margin: 1.25rem 0; }
.checkboxes { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.25rem; }
.controls label { display: inline-flex; align-items: center; gap: .4rem; font-size: .92rem; color: var(--fg); cursor: pointer; }
.btn {
  display: inline-block; background: var(--accent); color: #fff; border: none; cursor: pointer;
  padding: .6rem 1.3rem; border-radius: 9px; font-weight: 600; font-size: .95rem; font-family: inherit;
}
.btn:hover { opacity: .92; }
.btn:disabled { opacity: .5; cursor: default; }
.status { color: var(--muted); font-size: .88rem; }
.error { background: var(--error-bg); color: var(--error); border: 1px solid var(--error); border-radius: 10px; padding: .8rem 1rem; font-size: .9rem; margin-top: .75rem; }
footer { margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid var(--line); color: var(--muted); font-size: .85rem; }