/* AI Advertising — design system v1 (2026-07-16)
   Premium light base + AI-native dark hero. Zero external requests. */

:root {
  --ink: #101423;
  --ink-2: #3d4358;
  --ink-3: #6a7186;
  --paper: #ffffff;
  --paper-2: #f6f7fb;
  --line: #e5e7f0;
  --accent: #4f46e5;
  --accent-2: #7c3aed;
  --accent-ink: #ffffff;
  --glow-a: rgba(99, 102, 241, .28);
  --glow-b: rgba(168, 85, 247, .18);
  --night: #0a0e1a;
  --night-2: #10162b;
  --night-ink: #eef0fa;
  --night-ink-2: #a8b0cc;
  --night-line: rgba(148, 163, 216, .18);
  --ok: #0e9f6e;
  --radius: 14px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.65;
  font-size: clamp(1rem, .96rem + .2vw, 1.0625rem);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.skip {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--accent); color: #fff; padding: .6rem 1rem; border-radius: 0 0 8px 0;
}
.skip:focus { left: 0; }

.wrap { max-width: 1160px; margin: 0 auto; padding: 0 clamp(1.1rem, 4vw, 2rem); }

h1, h2, h3 { line-height: 1.15; letter-spacing: -.02em; font-weight: 750; text-wrap: balance; }
h1 { font-size: clamp(2.1rem, 1.4rem + 3.4vw, 3.6rem); }
h2 { font-size: clamp(1.55rem, 1.2rem + 1.6vw, 2.3rem); }
h3 { font-size: clamp(1.12rem, 1rem + .5vw, 1.35rem); }
p, li { max-width: 68ch; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--accent-2); }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 4px; }
strong { font-weight: 650; }

.kicker {
  display: inline-block; font-size: .78rem; font-weight: 700; letter-spacing: .12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: .9rem;
}

/* ---------- header ---------- */
.site-head {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .86);
  backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.site-head .wrap { display: flex; align-items: center; gap: 1.5rem; min-height: 66px; }
.brand { display: flex; align-items: center; gap: .6rem; font-weight: 800; font-size: 1.08rem; color: var(--ink); text-decoration: none; letter-spacing: -.01em; }
.brand svg { width: 30px; height: 30px; flex: none; }
.nav { margin-left: auto; display: flex; align-items: center; gap: clamp(.7rem, 2vw, 1.5rem); }
.nav a { color: var(--ink-2); text-decoration: none; font-weight: 550; font-size: .95rem; padding: .35rem .15rem; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--ink); }
.nav a[aria-current="page"] { box-shadow: 0 2px 0 var(--accent); }
.nav .cta { color: var(--accent-ink); background: linear-gradient(120deg, var(--accent), var(--accent-2)); padding: .55rem 1.05rem; border-radius: 999px; font-weight: 650; box-shadow: 0 4px 14px var(--glow-a); }
.nav .cta:hover { filter: brightness(1.08); color: #fff; }
@media (max-width: 760px) { .nav a:not(.cta):not(.keep) { display: none; } }

/* ---------- hero (dark) ---------- */
.hero {
  background:
    radial-gradient(1100px 520px at 15% -10%, var(--glow-a), transparent 60%),
    radial-gradient(900px 500px at 85% 0%, var(--glow-b), transparent 65%),
    linear-gradient(180deg, var(--night), var(--night-2));
  color: var(--night-ink);
  padding: clamp(4rem, 10vw, 7.5rem) 0 clamp(3.5rem, 8vw, 6rem);
  position: relative;
  overflow: hidden;
}
.hero::after {
  content: ""; position: absolute; inset: auto 0 0 0; height: 120px;
  background: linear-gradient(180deg, transparent, rgba(10, 14, 26, .55));
  pointer-events: none;
}
.hero .kicker { color: #b3b8ff; }
.hero h1 { color: #fff; max-width: 17ch; }
.hero .lede { font-size: clamp(1.08rem, 1rem + .6vw, 1.3rem); color: var(--night-ink-2); max-width: 56ch; margin: 1.3rem 0 2.2rem; }
.hero .lede strong { color: var(--night-ink); }
.hero-actions { display: flex; flex-wrap: wrap; gap: .9rem; align-items: center; }
.hero-note { font-size: .88rem; color: var(--night-ink-2); margin-top: 1.1rem; }
.hero-note a { color: #c7cbff; }

.btn {
  display: inline-block; font-weight: 680; text-decoration: none; text-align: center;
  padding: .95rem 1.7rem; border-radius: 999px; font-size: 1.02rem;
  transition: transform .15s ease, box-shadow .15s ease, filter .15s ease;
}
.btn-primary { background: linear-gradient(120deg, var(--accent), var(--accent-2)); color: #fff; box-shadow: 0 8px 26px var(--glow-a); }
.btn-primary:hover { transform: translateY(-1px); filter: brightness(1.07); color: #fff; }
.btn-ghost { color: var(--night-ink); border: 1px solid var(--night-line); background: rgba(255,255,255,.04); }
.btn-ghost:hover { border-color: rgba(199, 203, 255, .5); color: #fff; }
.btn-ghost.on-light { color: var(--ink); border-color: var(--line); background: #fff; }
.btn-ghost.on-light:hover { border-color: var(--accent); color: var(--accent); }

/* terminal card in hero */
.term {
  margin-top: 3rem; border: 1px solid var(--night-line); border-radius: var(--radius);
  background: rgba(8, 11, 22, .72); max-width: 640px;
  font-family: var(--mono); font-size: .88rem; line-height: 1.7;
  box-shadow: 0 20px 60px rgba(0, 0, 0, .45);
}
.term-bar { display: flex; gap: .42rem; padding: .7rem .9rem; border-bottom: 1px solid var(--night-line); }
.term-bar i { width: 10px; height: 10px; border-radius: 50%; background: #394059; }
.term-body { padding: 1rem 1.15rem 1.2rem; color: var(--night-ink-2); }
.term-body .q { color: #8be9c3; }
.term-body .a { color: var(--night-ink); }
.term-body .hi { color: #c7cbff; font-weight: 700; }

/* ---------- sections ---------- */
.section { padding: clamp(3.2rem, 8vw, 5.5rem) 0; }
.section.alt { background: var(--paper-2); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section-head { max-width: 760px; margin-bottom: clamp(1.8rem, 4vw, 3rem); }
.section-head p { color: var(--ink-2); margin-top: .8rem; font-size: 1.06rem; }

.grid { display: grid; gap: 1.3rem; }
.grid.c2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid.c3 { grid-template-columns: repeat(auto-fit, minmax(255px, 1fr)); }

.card {
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.7rem 1.6rem; box-shadow: 0 1px 2px rgba(16, 20, 35, .04);
}
.card h3 { margin-bottom: .55rem; }
.card p { color: var(--ink-2); font-size: .98rem; }
.card .num {
  display: inline-grid; place-items: center; width: 40px; height: 40px; border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #fff;
  font-weight: 800; margin-bottom: 1rem; font-size: 1.05rem;
}
.card ul { padding-left: 1.15rem; color: var(--ink-2); font-size: .97rem; display: grid; gap: .45rem; margin-top: .8rem; }

/* proof strip */
.proof { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 1.6rem 2rem; }
.proof .stat b { display: block; font-size: clamp(1.7rem, 1.4rem + 1.4vw, 2.4rem); font-weight: 800; letter-spacing: -.02em; color: var(--accent); }
.proof .stat span { color: var(--ink-2); font-size: .92rem; }

/* pillars */
.pillar { position: relative; overflow: hidden; }
.pillar::before {
  content: ""; position: absolute; inset: 0 0 auto 0; height: 4px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
}
.pillar .tag { font-size: .74rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-3); }
.pillar h3 { font-size: 1.45rem; margin-top: .5rem; }
.pillar .more { display: inline-block; margin-top: 1.1rem; font-weight: 650; }

/* FAQ */
.faq { display: grid; gap: .8rem; max-width: 820px; }
.faq details { border: 1px solid var(--line); border-radius: 12px; background: #fff; }
.faq summary {
  cursor: pointer; font-weight: 650; padding: 1.05rem 1.2rem; list-style: none;
  display: flex; justify-content: space-between; align-items: center; gap: 1rem;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font-size: 1.3rem; color: var(--accent); font-weight: 500; flex: none; }
.faq details[open] summary::after { content: "–"; }
.faq .faq-a { padding: 0 1.2rem 1.15rem; color: var(--ink-2); }

/* CTA band */
.band {
  background:
    radial-gradient(800px 380px at 80% -20%, var(--glow-b), transparent 60%),
    radial-gradient(700px 420px at 10% 120%, var(--glow-a), transparent 60%),
    linear-gradient(160deg, var(--night), var(--night-2));
  color: var(--night-ink); border-radius: calc(var(--radius) + 6px);
  padding: clamp(2.4rem, 6vw, 4rem); text-align: center;
}
.band h2 { color: #fff; }
.band p { color: var(--night-ink-2); margin: .9rem auto 1.8rem; max-width: 54ch; }

/* forms */
.form { display: grid; gap: 1.05rem; max-width: 560px; }
.form label { font-weight: 620; font-size: .93rem; display: grid; gap: .38rem; }
.form input, .form select, .form textarea {
  font: inherit; color: var(--ink); background: #fff;
  border: 1px solid #cfd3e4; border-radius: 10px; padding: .78rem .9rem; width: 100%;
}
.form input:focus, .form select:focus, .form textarea:focus { border-color: var(--accent); outline: 2px solid var(--glow-a); }
.form input::placeholder, .form textarea::placeholder { color: #5d6478; opacity: 1; }
.form textarea { min-height: 130px; resize: vertical; }
.form button { border: 0; cursor: pointer; }
.form button[aria-busy="true"] { opacity: .65; pointer-events: none; }
.form .fine { font-size: .84rem; color: var(--ink-3); }
.hp { position: absolute !important; left: -9999px !important; height: 0; overflow: hidden; }

/* article / prose */
.prose { max-width: 720px; }
.prose > * + * { margin-top: 1.1rem; }
.prose h2 { margin-top: 2.6rem; }
.prose h3 { margin-top: 1.9rem; }
.prose ul, .prose ol { padding-left: 1.3rem; display: grid; gap: .5rem; }
.prose .tldr {
  background: rgba(79, 70, 229, .05); border: 1px solid rgba(79, 70, 229, .25);
  border-radius: 10px; padding: 1.1rem 1.3rem; font-size: 1rem;
}
.prose .meta { color: var(--ink-3); font-size: .9rem; }
.prose blockquote { padding-left: 1.1rem; color: var(--ink-2); font-style: italic; }
.prose code { font-family: var(--mono); font-size: .88em; background: var(--paper-2); border: 1px solid var(--line); border-radius: 6px; padding: .1em .4em; }

/* footer */
.site-foot { background: var(--night); color: var(--night-ink-2); margin-top: clamp(3rem, 7vw, 5rem); }
.site-foot .wrap { padding-top: clamp(2.5rem, 6vw, 4rem); padding-bottom: 2.2rem; }
.foot-grid { display: grid; gap: 2.2rem; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); }
.site-foot h4 { color: var(--night-ink); font-size: .95rem; margin-bottom: .8rem; }
.site-foot a { color: var(--night-ink-2); text-decoration: none; }
.site-foot a:hover { color: #fff; }
.site-foot ul { list-style: none; display: grid; gap: .5rem; font-size: .95rem; }
.foot-legal { border-top: 1px solid var(--night-line); margin-top: 2.4rem; padding-top: 1.4rem; font-size: .82rem; display: grid; gap: .5rem; }
.foot-legal .tm { max-width: 90ch; }

/* reveal — hidden ONLY when JS is running (html.js), so no-JS users and crawlers see everything */
html.js .reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
html.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { html.js .reveal { opacity: 1; transform: none; } }

/* misc */
.crumbs { font-size: .88rem; color: var(--ink-3); margin: 1.6rem 0 0; }
.crumbs a { color: var(--ink-3); }
.pagehead { padding: clamp(2.6rem, 6vw, 4rem) 0 clamp(1.4rem, 3vw, 2rem); }
.pagehead p.lede { color: var(--ink-2); font-size: 1.12rem; max-width: 62ch; margin-top: 1rem; }
table { border-collapse: collapse; width: 100%; font-size: .95rem; }
th, td { text-align: left; padding: .7rem .8rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-weight: 700; }