/* Design tokens — the same system already committed in the sibling phylosophr-demo app
   (Flatly navy/turquoise/amber, IBM Plex Sans/Mono, flat shapes), applied here to a
   Persuade/Read explainer page instead of an Operate tool. Same product, same family. */
:root {
  --ink-rgb: 44, 62, 80;
  --ink: #2C3E50;
  --muted: #54696A;
  --bg: #ECF0F1;
  --panel: #DEE2E6;
  --panel-strong: #CED4DA;
  --success: #18BC9C;
  --success-ink: #0E6B57;
  --success-bg: #E8F7F3;
  --warning: #F39C12;
  --warning-ink: #8A5A00;
  --warning-bg: #FDF3E3;
  --line: rgba(var(--ink-rgb), .14);
  --line-strong: #54696A;
  --shadow-card: 0 1px 2px rgba(var(--ink-rgb), .09);
  --radius-sm: 4px; --radius-md: 6px; --radius-lg: 8px;
  --measure: 68ch;
}

*, *::before, *::after { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "IBM Plex Sans", -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
}
::selection { background: var(--panel-strong); color: var(--ink); }
a { color: var(--ink); }
a:focus-visible, button:focus-visible, .btn:focus-visible { outline: 3px solid var(--ink); outline-offset: 3px; }
img { max-width: 100%; display: block; }
code, pre, .mono { font-family: "IBM Plex Mono", ui-monospace, Menlo, monospace; }

.skip-link { position: absolute; left: -9999px; top: 0; background: var(--ink); color: #fff; padding: 10px 16px; z-index: 100; }
.skip-link:focus { left: 12px; top: 12px; }

.shell { max-width: 880px; margin: 0 auto; padding: 0 28px; }
.shell--wide { max-width: 1040px; }

/* Header */
.site-header { padding: 22px 0; border-bottom: 1px solid var(--line); }
.brand-row { display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.brand-name { font-size: 19px; font-weight: 750; margin: 0; letter-spacing: -.01em; }
.header-links { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.github-link {
  display: inline-flex; align-items: center; gap: 7px;
  font-size: 14px; font-weight: 650; color: var(--ink);
  text-decoration: none; padding: 6px 12px;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
}
.github-link:hover { border-color: var(--ink); }
.header-link--cta { background: var(--ink); color: #fff; border-color: var(--ink); }
.header-link--cta:hover { background: #1c2833; border-color: #1c2833; }

/* Hero — a single centered column; the logo sits inline with the H1 as one lockup */
.hero {
  min-height: 64vh;
  display: flex;
  align-items: center;
  padding: 56px 0 48px;
}
.hero-shell {
  display: flex; flex-direction: column; align-items: center; text-align: center;
  max-width: 760px; margin: 0 auto; padding: 0 28px; width: 100%;
}
.status-tag {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 12px; font-weight: 650; letter-spacing: .02em;
  padding: 5px 11px; border-radius: var(--radius-sm);
  background: #fff; border: 1px solid var(--line); color: var(--muted);
  margin-bottom: 26px;
}
.status-tag--dot::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--warning); flex-shrink: 0; }
.hero-heading { display: flex; align-items: center; justify-content: center; gap: 20px; margin: 0 0 22px; }
.hero-logo { flex-shrink: 0; }
.hero h1 {
  font-size: clamp(30px, 4.6vw, 50px);
  line-height: 1.15;
  letter-spacing: -.03em;
  font-weight: 400;
  margin: 0;
  max-width: 14ch;
  text-align: left;
}
.hero h1 strong { font-weight: 700; }
.hero p.lede { font-size: 19px; color: var(--muted); max-width: var(--measure); margin: 0 auto 30px; }
.hero-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; align-items: center; }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px; border-radius: var(--radius-sm);
  font-size: 15px; font-weight: 650; text-decoration: none;
  border: 1px solid transparent; cursor: pointer;
  transition: background .15s, border-color .15s, transform .15s;
}
.btn-primary { background: var(--ink); color: #fff; }
.btn-primary:hover { background: #1c2833; }
.btn-outline { background: #fff; color: var(--ink); border-color: var(--line-strong); }
.btn-outline:hover { border-color: var(--ink); }

/* Sections */
section { padding: 52px 0; border-top: 1px solid var(--line); }
.hero + section { border-top: none; }
h2 { font-size: clamp(24px, 3vw, 32px); letter-spacing: -.02em; font-weight: 650; margin: 0 0 18px; max-width: 22ch; }
h3 { font-size: 19px; font-weight: 650; margin: 28px 0 8px; }
p { margin: 0 0 16px; max-width: var(--measure); }
.section-intro { font-size: 17px; color: var(--muted); max-width: var(--measure); }
ul.plain, ol.plain { margin: 0 0 16px; padding-left: 22px; max-width: var(--measure); }
ul.plain li, ol.plain li { margin-bottom: 8px; }

.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; margin: 28px 0; }
.stat-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius-md); padding: 20px 22px; box-shadow: var(--shadow-card); }
.stat-card .num { font-size: 30px; font-weight: 700; letter-spacing: -.02em; display: block; margin-bottom: 4px; }
.stat-card p { font-size: 14px; color: var(--muted); margin: 0; max-width: none; }

/* Mechanism steps */
.step-list { list-style: none; margin: 30px 0 0; padding: 0; display: grid; gap: 14px; }
.step {
  display: grid; grid-template-columns: 40px 1fr; gap: 16px;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-md);
  padding: 18px 20px; box-shadow: var(--shadow-card);
}
.step .n { font-family: "IBM Plex Mono", monospace; font-size: 13px; font-weight: 650; color: var(--success-ink); background: var(--success-bg); border-radius: var(--radius-sm); width: 32px; height: 32px; display: grid; place-items: center; }
.step h3 { margin: 0 0 4px; font-size: 16px; }
.step p { margin: 0; font-size: 14.5px; color: var(--muted); max-width: none; }

/* Callouts */
.callout { border-radius: var(--radius-md); padding: 20px 22px; margin: 24px 0; border: 1px solid; }
.callout--note { background: var(--success-bg); border-color: rgba(24, 188, 156, .4); }
.callout--status { background: var(--warning-bg); border-color: rgba(243, 156, 18, .5); }
.callout p:last-child { margin-bottom: 0; }
.callout .callout-label { display: block; font-size: 12px; font-weight: 700; letter-spacing: .04em; text-transform: uppercase; margin-bottom: 6px; }
.callout--note .callout-label { color: var(--success-ink); }
.callout--status .callout-label { color: var(--warning-ink); }

/* Annotation demo card */
.annotation-demo { background: var(--ink); color: #fff; border-radius: var(--radius-lg); padding: 26px 28px; margin: 30px 0; }
.annotation-demo .demo-label { font-size: 12px; letter-spacing: .06em; text-transform: uppercase; color: #9fb3c8; margin-bottom: 14px; display: block; }
.annotation-demo .source-sentence { font-size: 16px; line-height: 1.7; margin-bottom: 18px; }
.annotation-demo mark { background: var(--success); color: #0b2d26; border-radius: 3px; padding: 1px 4px; box-decoration-break: clone; }
.annotation-demo .tag-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 10px; }
.annotation-demo .tag { background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.15); border-radius: var(--radius-sm); padding: 9px 12px; }
.annotation-demo .tag .k { font-size: 11px; color: #9fb3c8; display: block; margin-bottom: 3px; }
.annotation-demo .tag .v { font-family: "IBM Plex Mono", monospace; font-size: 13px; color: #fff; }

.chip-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0 26px; }
.chip { background: #fff; border: 1px solid var(--line); border-radius: 30px; padding: 6px 14px; font-size: 13.5px; color: var(--ink); }

/* Footer / contact */
.contact { text-align: left; }
.contact .btn { margin-top: 6px; }
footer.site-footer { padding: 36px 0 48px; }
footer.site-footer p { font-size: 13px; color: var(--muted); }

@media (max-width: 640px) {
  .shell, .shell--wide { padding: 0 20px; }
  .hero { min-height: 0; padding: 40px 0 36px; }
  .hero-shell { padding: 0 20px; }
  .hero-heading { flex-direction: column; gap: 14px; }
  .hero h1 { text-align: center; }
  .hero-logo { width: 56px; height: 56px; }
  section { padding: 40px 0; }
  .step { grid-template-columns: 32px 1fr; }
}