:root {
  --paper: #fbfaf6;
  --card: #ffffff;
  --ink: #1b2430;
  --soft: #55616f;
  --line: #dcd8cd;
  --brand: #0f5c4f;
  --brand-deep: #0a4439;
  --human: #1f7a4d;
  --unsure: #a36a00;
  --ai: #b3382c;
  --wrap: 740px;
  --font: Charter, 'Bitstream Charter', 'Iowan Old Style', Georgia, serif;
  --ui: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.65 var(--ui); }
a { color: var(--brand); text-underline-offset: 3px; }
:focus-visible { outline: 3px solid var(--brand); outline-offset: 2px; }
[hidden] { display: none !important; }

.top {
  max-width: 1000px; margin: 0 auto; padding: 16px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px 20px; flex-wrap: wrap;
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 800; font-size: 19px; text-decoration: none; letter-spacing: -0.01em; }
.top nav { display: flex; flex-wrap: wrap; gap: 4px 18px; font-size: 15px; }
.top nav a { color: var(--soft); text-decoration: none; font-weight: 600; }
.top nav a:hover, .top nav a[aria-current='page'] { color: var(--ink); }

.hero { max-width: var(--wrap); margin: 0 auto; padding: 26px 20px 40px; }
h1 { margin: 0; font: 700 clamp(30px, 6vw, 44px)/1.12 var(--font); letter-spacing: -0.02em; text-wrap: balance; }
.lead { margin: 12px 0 0; color: var(--soft); font-size: 18px; max-width: 620px; text-wrap: pretty; }
.notice {
  margin: 16px 0 22px; padding: 10px 14px; border-left: 4px solid var(--brand); background: #eef4f1;
  font-size: 15px; border-radius: 0 8px 8px 0;
}
.cta { display: inline-block; margin-top: 20px; background: var(--brand); color: #fff; font-weight: 700; text-decoration: none; padding: 12px 22px; border-radius: 10px; }
.cta:hover { background: var(--brand-deep); }

/* Tool */
.tool { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 18px; box-shadow: 0 1px 2px rgba(27, 36, 48, 0.05); }
.tool label.field { display: block; font-weight: 700; margin-bottom: 8px; }
textarea {
  display: block; width: 100%; min-height: 260px; resize: vertical; padding: 14px;
  font: 16px/1.6 var(--font); color: var(--ink); background: var(--paper);
  border: 1px solid var(--line); border-radius: 10px;
}
.tool-row { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 10px 16px; margin-top: 12px; }
.count { font-size: 14.5px; color: var(--soft); font-variant-numeric: tabular-nums; }
.count.is-bad { color: var(--ai); font-weight: 700; }
button { font: inherit; cursor: pointer; }
.btn { background: var(--brand); color: #fff; border: 0; border-radius: 10px; padding: 12px 22px; font-weight: 700; min-height: 46px; }
.btn:hover { background: var(--brand-deep); }
.btn:disabled { opacity: 0.5; cursor: default; }
.btn-quiet { background: transparent; color: var(--soft); border: 1px solid var(--line); }
.btn-quiet:hover { background: var(--paper); color: var(--ink); }
.turnstile { margin-top: 12px; min-height: 0; }
.turnstile:empty { display: none; }
.status { margin: 14px 0 0; font-size: 15px; color: var(--soft); }
.status.is-error { color: var(--ai); font-weight: 600; }

.result { margin-top: 18px; padding-top: 18px; border-top: 1px solid var(--line); }
.score-row { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; }
.score { font: 700 clamp(46px, 12vw, 68px)/1 var(--ui); letter-spacing: -0.03em; font-variant-numeric: tabular-nums; }
.verdict { font-weight: 700; font-size: 19px; }
.is-human .score, .is-human .verdict { color: var(--human); }
.is-unsure .score, .is-unsure .verdict { color: var(--unsure); }
.is-ai .score, .is-ai .verdict { color: var(--ai); }
.meter { height: 10px; border-radius: 999px; background: #ece9e0; overflow: hidden; margin: 12px 0 10px; }
.meter span { display: block; height: 100%; width: 0; border-radius: 999px; background: currentColor; }
.is-human .meter { color: var(--human); }
.is-unsure .meter { color: var(--unsure); }
.is-ai .meter { color: var(--ai); }
.explain { margin: 0 0 14px; font-size: 15.5px; color: var(--soft); }
.result h2 { font: 700 15px/1.3 var(--ui); text-transform: uppercase; letter-spacing: 0.06em; color: var(--soft); margin: 18px 0 8px; }
.passages { font: 16px/1.7 var(--font); white-space: pre-wrap; overflow-wrap: anywhere; background: var(--paper); border: 1px solid var(--line); border-radius: 10px; padding: 14px; max-height: 420px; overflow-y: auto; }
.passages mark { color: inherit; padding: 2px 0; border-radius: 3px; }
.p-human { background: transparent; }
.p-unsure { background: #fbeccb; }
.p-ai { background: #f8d3ce; }
.legend { display: flex; flex-wrap: wrap; gap: 6px 16px; margin: 10px 0 0; padding: 0; list-style: none; font-size: 13.5px; color: var(--soft); }
.legend i { display: inline-block; width: 12px; height: 12px; border-radius: 3px; margin-right: 6px; vertical-align: -1px; border: 1px solid var(--line); }
.legend .p-human { background: var(--paper); }
.fine { font-size: 13.5px; color: var(--soft); margin: 12px 0 0; }

/* Content */
.block { max-width: var(--wrap); margin: 0 auto; padding: 30px 20px; }
.block + .block { border-top: 1px solid var(--line); }
h2 { margin: 0 0 14px; font: 700 clamp(22px, 4vw, 27px)/1.22 var(--font); letter-spacing: -0.01em; }
h3 { margin: 0 0 4px; font-size: 17.5px; }
.prose p { margin: 0 0 14px; }
.prose p:last-child { margin-bottom: 0; }
.prose ul, .prose ol { margin: 0 0 14px; padding-left: 22px; }
.prose li { margin-bottom: 8px; }
table { width: 100%; border-collapse: collapse; margin: 0 0 14px; font-size: 15.5px; }
th, td { text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-size: 13px; text-transform: uppercase; letter-spacing: 0.05em; color: var(--soft); }

.faq details { border-bottom: 1px solid var(--line); }
.faq details:first-child { border-top: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 15px 30px 15px 0; font-weight: 700; list-style: none; position: relative; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: '+'; position: absolute; right: 4px; top: 50%; transform: translateY(-50%); font-size: 22px; font-weight: 400; color: var(--brand); }
.faq details[open] summary::after { content: '–'; }
.faq p { margin: 0 0 16px; color: var(--soft); }

.doc h1 { margin-bottom: 18px; }
.doc h2 { font-size: 21px; margin: 26px 0 10px; }

.foot { border-top: 1px solid var(--line); margin-top: 26px; padding: 28px 20px 34px; }
.foot nav { max-width: var(--wrap); margin: 0 auto; display: flex; flex-wrap: wrap; gap: 8px 22px; font-size: 15px; }
.foot nav a { color: var(--soft); text-decoration: none; }
.foot nav a:hover { color: var(--brand); }
.foot .fine { max-width: var(--wrap); margin: 16px auto 0; }

@media (max-width: 480px) {
  body { font-size: 16px; }
  .tool { padding: 14px; }
  textarea { min-height: 220px; }
  .btn { flex: 1; }
}
@media (prefers-reduced-motion: no-preference) { .meter span { transition: width 0.4s; } }