/* ============================================================
   SkinAI — shared design system
   Type: Geist / Geist Mono (neutral Swiss grotesk)
   Base: warm off-white + near-black ink
   Accent: tweakable (Cobalt / Teal / Green)
   ============================================================ */

:root {
  /* base palette */
  --bg:        #fbfaf8;
  --bg-2:      #f4f2ee;   /* alternating section tint */
  --surface:   #ffffff;
  --ink:       #18181a;
  --ink-2:     #3b3b40;
  --muted:     #76757d;
  --faint:     #a8a7ad;
  --line:      #e7e4de;
  --line-2:    #d9d5cd;

  /* accent — default Cobalt, overridden by tweak via [data-accent] */
  --accent:        oklch(0.55 0.15 255);
  --accent-press:  oklch(0.48 0.15 255);
  --accent-tint:   oklch(0.96 0.03 255);
  --accent-ink:    oklch(0.42 0.13 255);

  /* semantic risk colors (independent of accent) */
  --risk-high: oklch(0.56 0.18 25);
  --risk-high-tint: oklch(0.96 0.04 25);
  --risk-mod:  oklch(0.72 0.13 65);
  --risk-mod-tint: oklch(0.96 0.04 75);
  --risk-low:  oklch(0.6 0.12 155);
  --risk-low-tint: oklch(0.96 0.03 155);

  --radius: 14px;
  --radius-sm: 9px;
  --maxw: 1180px;
  --pad: clamp(20px, 5vw, 64px);

  --shadow-sm: 0 1px 2px rgba(20,18,14,.04), 0 1px 1px rgba(20,18,14,.03);
  --shadow-md: 0 4px 14px rgba(20,18,14,.06), 0 1px 3px rgba(20,18,14,.04);
  --shadow-lg: 0 24px 60px rgba(20,18,14,.10), 0 6px 18px rgba(20,18,14,.06);

  --font: "Geist", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --mono: "Geist Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

[data-accent="teal"] {
  --accent:        oklch(0.6 0.11 200);
  --accent-press:  oklch(0.53 0.11 200);
  --accent-tint:   oklch(0.96 0.025 200);
  --accent-ink:    oklch(0.45 0.1 200);
}
[data-accent="green"] {
  --accent:        oklch(0.55 0.11 155);
  --accent-press:  oklch(0.48 0.11 155);
  --accent-tint:   oklch(0.96 0.03 155);
  --accent-ink:    oklch(0.42 0.1 155);
}

[data-accent="warm"] {
  --accent:        oklch(0.50 0.17 12);
  --accent-press:  oklch(0.43 0.17 12);
  --accent-tint:   oklch(0.96 0.03 12);
  --accent-ink:    oklch(0.40 0.15 12);
}

[data-corner="sharp"] { --radius: 4px; --radius-sm: 3px; }

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--ink);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  letter-spacing: -0.01em;
}

::selection { background: var(--accent); color: #fff; }

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

h1, h2, h3, h4 {
  margin: 0;
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.05;
  text-wrap: balance;
}

p { margin: 0; }

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

/* ---------- layout ---------- */
.wrap { max-width: var(--maxw); margin: 0 auto; padding-inline: var(--pad); }

.section { padding-block: clamp(72px, 11vw, 132px); }
.section--tint { background: var(--bg-2); }

.eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-ink);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.eyebrow::before {
  content: "";
  width: 6px; height: 6px;
  background: var(--accent);
  border-radius: 50%;
}

.section-head { max-width: 640px; margin-bottom: clamp(40px, 5vw, 64px); }
.section-head h2 {
  font-size: clamp(28px, 4vw, 44px);
  margin-top: 18px;
}
.section-head p {
  margin-top: 18px;
  font-size: 18px;
  color: var(--muted);
  max-width: 52ch;
  text-wrap: pretty;
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  font-family: var(--font);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: -0.01em;
  padding: 13px 22px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .12s ease, background .15s ease, border-color .15s ease, color .15s ease, box-shadow .15s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }

.btn--accent { background: var(--accent); color: #fff; }
.btn--accent:hover { background: var(--accent-press); }

.btn--ink { background: var(--ink); color: var(--bg); }
.btn--ink:hover { background: #000; }

.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line-2); }
.btn--ghost:hover { border-color: var(--ink); }

.btn--lg { padding: 16px 28px; font-size: 16px; }

.btn .arrow { transition: transform .18s ease; }
.btn:hover .arrow { transform: translateX(3px); }

/* ---------- nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--bg) 82%, transparent);
  backdrop-filter: saturate(140%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s ease, background .2s ease;
}
.nav.is-scrolled { border-bottom-color: var(--line); }
.nav__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 15px var(--pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand { display: inline-flex; align-items: center; gap: 11px; font-weight: 600; font-size: 17px; letter-spacing: -0.03em; }
.brand__mark { display: none; }
.nav__links { display: flex; align-items: center; gap: 4px; }
.nav__links a {
  font-size: 14.5px;
  color: var(--ink-2);
  padding: 8px 14px;
  border-radius: 8px;
  transition: color .15s ease, background .15s ease;
}
.nav__links a:hover { color: var(--ink); background: color-mix(in oklab, var(--ink) 6%, transparent); }
.nav__right { display: flex; align-items: center; gap: 12px; }

@media (max-width: 860px) {
  .nav__links { display: none; }
}

/* ---------- footer ---------- */
.footer { border-top: 1px solid var(--line); padding-block: 56px; }
.footer__top { display: flex; flex-wrap: wrap; gap: 28px 64px; justify-content: space-between; align-items: flex-start; }
.footer__note { max-width: 34ch; color: var(--muted); font-size: 14.5px; margin-top: 16px; text-wrap: pretty; }
.footer__links { display: flex; gap: 28px; flex-wrap: wrap; }
.footer__links a { font-size: 14.5px; color: var(--ink-2); }
.footer__links a:hover { color: var(--ink); }
.footer__bottom {
  margin-top: 44px; padding-top: 22px; border-top: 1px solid var(--line);
  display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between;
  color: var(--faint); font-size: 13px;
}
.footer__disclaimer { font-family: var(--mono); font-size: 12px; color: var(--muted); }

/* ---------- chips / tags ---------- */
.tag {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  padding: 4px 9px;
  border-radius: 6px;
  border: 1px solid var(--line-2);
  color: var(--muted);
  display: inline-flex; align-items: center; gap: 6px;
  white-space: nowrap;
}
.tag--high { color: var(--risk-high); border-color: color-mix(in oklab, var(--risk-high) 35%, var(--line)); background: var(--risk-high-tint); }
.tag--low  { color: var(--risk-low);  border-color: color-mix(in oklab, var(--risk-low) 30%, var(--line)); background: var(--risk-low-tint); }

/* ---------- card ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

/* ---------- focus ---------- */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

/* ---------- reveal-on-scroll ---------- */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .7s cubic-bezier(.2,.7,.2,1), transform .7s cubic-bezier(.2,.7,.2,1); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}