/* ============================================================
   Design tokens — "Detection Overlay" system
   ============================================================ */
:root {
  /* color */
  --ink: #0b0d0c;
  --ink-raised: #101310;
  --paper: #edeae0;
  --paper-dim: #cfccc1;
  --amber: #e8a33d;
  --teal: #4fa8a0;
  --muted: #8a8f86;
  --line: rgba(237, 234, 224, 0.12);
  --line-strong: rgba(237, 234, 224, 0.24);

  /* type */
  --font-display: "Instrument Serif", "Iowan Old Style", serif;
  --font-body: "Archivo", "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "Courier New", monospace;

  /* scale (1.25 ratio, base 17px) */
  --step--1: clamp(0.75rem, 0.72rem + 0.16vw, 0.85rem);
  --step-0: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  --step-1: clamp(1.25rem, 1.18rem + 0.35vw, 1.4rem);
  --step-2: clamp(1.6rem, 1.45rem + 0.75vw, 2rem);
  --step-3: clamp(2.2rem, 1.9rem + 1.5vw, 3.1rem);
  --step-4: clamp(3rem, 2.4rem + 3vw, 5.2rem);
  --step-5: clamp(4rem, 3rem + 5vw, 8rem);

  /* layout */
  --content-max: 1180px;
  --gutter: clamp(24px, 6vw, 80px);
  --radius: 2px;
}

*, *::before, *::after { box-sizing: border-box; }

html {
  background: var(--ink);
  color-scheme: dark;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a {
  color: inherit;
  text-decoration: none;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 400;
  margin: 0;
  color: var(--paper);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--amber);
}

.section {
  width: 100%;
  padding: clamp(72px, 12vw, 140px) var(--gutter);
}

.section-inner {
  max-width: var(--content-max);
  margin: 0 auto;
}

.section-heading {
  font-size: var(--step-3);
  margin-bottom: clamp(32px, 6vw, 64px);
}

/* ---- visible keyboard focus ---- */
a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

/* ---- detection-frame corner brackets, the signature motif ---- */
.bracket-frame {
  position: relative;
}

.bracket-frame::before,
.bracket-frame::after,
.bracket-frame > .bracket-tr,
.bracket-frame > .bracket-bl {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  border: 1.5px solid var(--amber);
  opacity: 0.85;
}

.bracket-frame::before { top: -1px; left: -1px; border-right: none; border-bottom: none; }
.bracket-frame::after { bottom: -1px; right: -1px; border-left: none; border-top: none; }

.tag-readout {
  font-family: var(--font-mono);
  font-size: var(--step--1);
  letter-spacing: 0.06em;
  color: var(--teal);
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  left: 12px;
  top: -60px;
  background: var(--amber);
  color: var(--ink);
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: var(--step--1);
  z-index: 200;
  transition: top 0.15s ease;
}
.skip-link:focus { top: 12px; }