/* FlyBatch landing page (SRS D-627, D-630).  Hand-written, no framework,
   no scripts, no web fonts: the page must be as checkable as the code. */

:root {
  --bg: #ffffff;
  --bg-alt: #f5f7fa;
  --ink: #1f2933;
  --muted: #52606d;
  --line: #d9e2ec;
  --accent: #b83280;
  --accent-ink: #ffffff;
  --link: #1d4ed8;
  --notice-bg: #fffbeb;
  --notice-line: #b45309;
  --card: #ffffff;
  --hero-a: #0b0d12;
  --hero-b: #1b2233;
  --hero-ink: #e6ebf5;
  --hero-muted: #9aa7c0;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --bg-alt: #111822;
    --ink: #d6deee;
    --muted: #9aa7c0;
    --line: #2a3040;
    --accent: #f472b6;
    --accent-ink: #0b0d12;
    --link: #7fb2ff;
    --notice-bg: #1f1a0e;
    --notice-line: #f59e0b;
    --card: #ffffff;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.6 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
}
a { color: var(--link); }
img { max-width: 100%; height: auto; display: block; }
figure { margin: 0; }
figcaption { color: var(--muted); font-size: 0.88rem; margin-top: 0.5rem; }
h1, h2 { line-height: 1.2; }
h2 { font-size: 1.7rem; margin: 0 0 1rem; }

.wrap { max-width: 1140px; margin: 0 auto; padding: 0 16px; }
.narrow { max-width: 820px; }

.top {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--hero-a) 92%, transparent);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid #2a3040;
}
.nav { display: flex; align-items: center; justify-content: space-between;
       gap: 1rem; min-height: 56px; flex-wrap: wrap; }
.brand { display: inline-flex; align-items: center; gap: 0.55rem;
         color: var(--hero-ink); font-weight: 800; font-size: 1.15rem;
         text-decoration: none; letter-spacing: 0.02em; }
.links { display: flex; gap: 1.1rem; flex-wrap: wrap; }
.links a { color: var(--hero-muted); text-decoration: none; font-size: 0.95rem; }
.links a:hover, .links a:focus { color: var(--hero-ink); }
.links .gh { color: var(--hero-ink); font-weight: 600; }

.hero {
  background: radial-gradient(1200px 500px at 70% 0%, var(--hero-b), var(--hero-a));
  color: var(--hero-ink);
  padding: 56px 0 48px;
}
.hero-grid { display: grid; grid-template-columns: 1fr 1.25fr; gap: 40px;
             align-items: center; }
.kicker { color: #f472b6; text-transform: uppercase; letter-spacing: 0.12em;
          font-size: 0.8rem; font-weight: 700; margin: 0 0 0.6rem; }
.hero h1 { font-size: clamp(1.8rem, 3.4vw, 2.7rem); margin: 0 0 1rem; }
.lead { color: var(--hero-ink); font-size: 1.08rem; opacity: 0.92; }
.formerly { color: var(--hero-muted); font-size: 0.9rem; margin-top: 1rem; }
.hero-fig img { border-radius: 12px; box-shadow: 0 20px 60px rgba(0,0,0,0.5); }
.hero-fig figcaption { color: var(--hero-muted); }

.cta { display: flex; flex-wrap: wrap; gap: 0.7rem; margin: 1.4rem 0 0; }
.btn {
  display: inline-block; padding: 0.6rem 1.1rem; border-radius: 8px;
  border: 1px solid var(--line); text-decoration: none; font-weight: 600;
  font-size: 0.95rem; color: inherit;
}
.hero .btn { border-color: #3a4660; color: var(--hero-ink); }
.btn.primary { background: var(--accent); border-color: var(--accent);
               color: var(--accent-ink); }
.hero .btn.primary { background: #f472b6; border-color: #f472b6; color: #0b0d12; }
.btn:hover, .btn:focus { filter: brightness(1.08); }

.notice { background: var(--notice-bg); border-top: 3px solid var(--notice-line);
          border-bottom: 1px solid var(--line); }
.notice p { margin: 0; padding: 18px 0; font-size: 1rem; }

.band { padding: 64px 0; }
.band.alt { background: var(--bg-alt); }
.two { display: grid; grid-template-columns: 1fr 1.15fr; gap: 40px;
       align-items: center; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 24px;
         margin: 1.5rem 0; }
.grid2 img, .two img, .wide img { border-radius: 10px; border: 1px solid var(--line);
                                  background: var(--card); }
.wide { margin: 1.5rem 0; }
.caveat { color: var(--muted); border-left: 3px solid var(--accent);
          padding-left: 0.9rem; }

.limits { padding-left: 1.2rem; }
.limits li { margin: 0 0 1rem; }

.foot { border-top: 1px solid var(--line); padding: 32px 0; color: var(--muted);
        font-size: 0.88rem; }

@media (max-width: 860px) {
  .hero-grid, .two, .grid2 { grid-template-columns: 1fr; }
  .band { padding: 44px 0; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}