/* WILLBES AI: public introduction site.
   Native CSS, Pretendard Variable, one accent (desaturated cobalt), radius 10px everywhere.
   Dials: variance 6 / motion 4 / density 3. Theme follows prefers-color-scheme. */

:root {
  --bg: #f6f7f9;
  --bg-2: #eef0f4;
  --surface: #ffffff;
  --ink: #17181c;
  --ink-2: #454a55;
  --muted: #6b7180;
  --line: #dfe3ea;
  --line-strong: #c9cfd9;
  --accent: #2653c6;
  --accent-ink: #1b3f9c;
  --accent-tint: #e7edfb;
  --accent-tint-2: #d4dff8;
  --dark: #15171c;
  --dark-2: #1f2229;
  --on-dark: #eef0f4;
  --on-dark-muted: #a3aab7;
  --shadow: 0 24px 60px -30px rgb(23 36 74 / .35);
  --r: 10px;
  --ease: cubic-bezier(.16, 1, .3, 1);
  --nav-h: 68px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --bg-2: #14171d;
    --surface: #171a20;
    --ink: #eceef2;
    --ink-2: #c3c8d2;
    --muted: #9aa1ad;
    --line: #262a33;
    --line-strong: #353a45;
    --accent: #7c9cf0;
    --accent-ink: #a9bdf5;
    --accent-tint: #182034;
    --accent-tint-2: #1f2a47;
    --dark: #0b0d11;
    --dark-2: #13161c;
    --on-dark: #eceef2;
    --on-dark-muted: #9aa1ad;
    --shadow: 0 24px 60px -30px rgb(0 0 0 / .8);
    color-scheme: dark;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  font-family: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, system-ui, "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
  word-break: keep-all;
  overflow-wrap: anywhere;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, p { margin: 0; }

.wrap { width: min(100% - 48px, 1200px); margin-inline: auto; }
@media (max-width: 640px) { .wrap { width: min(100% - 40px, 1200px); } }

h2 {
  font-size: clamp(28px, 3.4vw, 42px);
  line-height: 1.22;
  letter-spacing: -0.02em;
  font-weight: 700;
  max-width: 22ch;
}
h3 { font-size: 20px; line-height: 1.35; letter-spacing: -0.01em; font-weight: 650; }
.lead { margin-top: 18px; color: var(--ink-2); font-size: 17px; max-width: 58ch; }
.eyebrow {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 18px;
}
.soft { color: var(--muted); }

section { padding-block: clamp(80px, 10vw, 140px); }

/* ---------- Skip link ---------- */
.skip {
  position: absolute; left: 16px; top: -60px; z-index: 100;
  padding: 10px 14px; background: var(--ink); color: var(--bg); border-radius: var(--r);
}
.skip:focus { top: 12px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  height: 46px; padding: 0 20px; border-radius: var(--r);
  font-weight: 600; font-size: 15px; white-space: nowrap;
  border: 1px solid transparent;
  transition: transform .2s var(--ease), background-color .2s var(--ease), border-color .2s var(--ease), color .2s var(--ease);
}
.btn:active { transform: translateY(1px) scale(.985); }
.btn--primary { background: var(--accent); color: #fff; }
.btn--primary:hover { background: var(--accent-ink); }
@media (prefers-color-scheme: dark) {
  .btn--primary { color: #0f1115; }
  .btn--primary:hover { background: var(--accent-ink); }
}
.btn--ghost { border-color: var(--line-strong); color: var(--ink); background: transparent; }
.btn--ghost:hover { border-color: var(--ink); }
.link { font-weight: 600; color: var(--accent); border-bottom: 1px solid transparent; }
.link:hover { border-bottom-color: currentColor; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid var(--line);
}
.nav__inner { height: var(--nav-h); display: flex; align-items: center; gap: 32px; }
.brand { display: inline-flex; align-items: center; gap: 10px; }
.brand__mark { width: 12px; height: 12px; border-radius: 3px; background: var(--accent); }
.brand__name { font-weight: 700; letter-spacing: .04em; font-size: 15px; }
.brand__name em { font-style: normal; color: var(--accent); }
.nav__links { display: flex; gap: 26px; margin-left: auto; }
.nav__links a { font-size: 14.5px; font-weight: 500; color: var(--ink-2); transition: color .2s; }
.nav__links a:hover, .nav__links a[aria-current="true"] { color: var(--ink); }
.nav__cta { height: 38px; padding: 0 16px; font-size: 14px; }
.nav__toggle {
  display: none; margin-left: auto; width: 42px; height: 42px; border: 0; background: none; cursor: pointer;
  flex-direction: column; justify-content: center; gap: 6px; align-items: center; border-radius: var(--r);
}
.nav__toggle span { width: 20px; height: 2px; background: var(--ink); transition: transform .25s var(--ease); }
.nav__toggle[aria-expanded="true"] span:first-child { transform: translateY(4px) rotate(45deg); }
.nav__toggle[aria-expanded="true"] span:last-child { transform: translateY(-4px) rotate(-45deg); }
.nav__mobile { display: none; }
@media (max-width: 900px) {
  .nav__links, .nav__cta { display: none; }
  .nav__toggle { display: flex; }
  .nav__mobile { display: flex; flex-direction: column; gap: 4px; padding: 8px 24px 20px; border-top: 1px solid var(--line); }
  .nav__mobile[hidden] { display: none; }
  .nav__mobile a { padding: 12px 4px; font-size: 17px; font-weight: 500; border-bottom: 1px solid var(--line); }
  .nav__mobile .btn { margin-top: 14px; border: 0; }
}

/* ---------- Hero ---------- */
.hero { padding-block: 0; }
.hero__grid {
  display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(32px, 6vw, 96px); align-items: center;
  padding-block: clamp(40px, 5vw, 56px);
}
.hero__title {
  font-size: clamp(34px, 4.3vw, 58px);
  line-height: 1.12; letter-spacing: -0.03em; font-weight: 750;
  padding-bottom: 4px;
}
.hero__title em { font-style: italic; color: var(--accent); font-weight: 750; }
.hero__sub { margin-top: 24px; font-size: clamp(17px, 1.4vw, 20px); color: var(--ink-2); max-width: 30ch; }
.hero__cta { margin-top: 36px; display: flex; gap: 12px; flex-wrap: wrap; }
.hero__visual { position: relative; border-radius: var(--r); overflow: hidden; box-shadow: var(--shadow); height: clamp(440px, calc(100dvh - var(--nav-h) - 112px), 720px); justify-self: end; width: 100%; }
.hero__visual picture { display: block; height: 100%; }
.hero__visual img { width: 100%; height: 100%; object-fit: cover; }
.hero__visual::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: linear-gradient(180deg, transparent 60%, rgb(23 36 74 / .28));
}
@media (max-width: 900px) {
  .hero__grid { grid-template-columns: 1fr; min-height: 0; padding-top: 40px; padding-bottom: 56px; }
  .hero__visual { aspect-ratio: 4 / 3; height: auto; order: -1; }
  .hero__sub { max-width: 40ch; }
}

/* ---------- Now ---------- */
.now { background: var(--surface); border-block: 1px solid var(--line); }
.now__title { max-width: 26ch; }
.now__body { margin-top: 28px; max-width: 64ch; display: grid; gap: 16px; font-size: 17px; color: var(--ink-2); }
.now__figure { margin: 56px 0 0; border-radius: var(--r); overflow: hidden; }
.now__figure img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; max-height: 560px; }
.assets {
  margin-top: 56px; display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px;
  padding-top: 32px; border-top: 1px solid var(--line);
}
.assets strong { display: block; font-size: 19px; font-weight: 650; letter-spacing: -0.01em; }
.assets p { margin-top: 10px; color: var(--ink-2); max-width: 36ch; }
.assets__main strong { font-size: 24px; }
@media (max-width: 900px) { .assets { grid-template-columns: 1fr 1fr; } .assets__main { grid-column: 1 / -1; } }
@media (max-width: 640px) { .assets { grid-template-columns: 1fr; gap: 28px; } }

/* ---------- Layers ---------- */
.stack { margin-top: 56px; display: grid; gap: 10px; }
.stack__band {
  display: grid; grid-template-columns: 56px 1fr; gap: 20px; align-items: start;
  padding: 26px 28px; border-radius: var(--r); border: 1px solid var(--line);
  background: var(--surface);
  transition: transform .5s var(--ease);
}
.stack__band p { margin-top: 8px; color: var(--ink-2); max-width: 64ch; }
.stack__band--3 { margin-inline: 14% 0; }
.stack__band--2 { margin-inline: 7% 0; background: var(--accent-tint); border-color: transparent; }
.stack__band--1 { background: var(--accent); border-color: transparent; color: #fff; }
.stack__band--1 p { color: rgb(255 255 255 / .82); }
@media (prefers-color-scheme: dark) { .stack__band--1 { color: #0f1115; } .stack__band--1 p { color: rgb(15 17 21 / .78); } }
.stack__num { font-size: 30px; font-weight: 700; letter-spacing: -0.03em; line-height: 1; padding-top: 2px; opacity: .7; }

@media (max-width: 640px) {
  .stack__band { grid-template-columns: 1fr; gap: 8px; padding: 22px; }
  .stack__band--3, .stack__band--2 { margin-inline: 0; }
}

/* ---------- Loop ---------- */
.loop { background: var(--bg-2); border-block: 1px solid var(--line); }
.cycle {
  margin-top: 56px; display: grid; grid-template-columns: repeat(5, 1fr); gap: 28px;
  position: relative; counter-reset: step;
}
.cycle::before {
  content: ""; position: absolute; left: 0; right: 0; top: 13px; height: 1px; background: var(--line-strong);
}
.cycle li { position: relative; padding-top: 42px; }
.cycle li::before {
  content: ""; position: absolute; top: 8px; left: 0; width: 11px; height: 11px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 0 5px var(--bg-2);
}
.cycle__step { display: block; font-size: 12px; letter-spacing: .12em; font-weight: 600; color: var(--accent); text-transform: uppercase; }
.cycle h3 { margin-top: 10px; font-size: 17px; }
.cycle p { margin-top: 10px; font-size: 14.5px; color: var(--ink-2); }
@media (max-width: 1024px) { .cycle { grid-template-columns: repeat(3, 1fr); row-gap: 40px; } .cycle::before { display: none; } }
@media (max-width: 640px) {
  .cycle { grid-template-columns: 1fr; gap: 0; padding-left: 26px; }
  .cycle::before { display: block; left: 5px; top: 8px; bottom: 8px; width: 1px; height: auto; right: auto; }
  .cycle li { padding: 0 0 36px; }
  .cycle li::before { left: -26px; }
  .cycle li:last-child { padding-bottom: 0; }
}

/* ---------- Products / bento ---------- */
.bento { margin-top: 56px; display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.tile {
  border-radius: var(--r); overflow: hidden; border: 1px solid var(--line); background: var(--surface);
  display: flex; flex-direction: column;
}
.tile__img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; }
.tile > *:not(picture) { margin-inline: 28px; }
.tile picture { display: block; }
.tile__tag { margin-top: 26px; font-size: 12.5px; font-weight: 600; letter-spacing: .04em; color: var(--muted); }
.tile h3 { margin-top: 8px; font-size: 26px; letter-spacing: -0.02em; }
.tile p { margin-top: 12px; color: var(--ink-2); }
.tile__list { margin-top: 18px; margin-bottom: 28px; display: grid; gap: 8px; font-size: 14.5px; color: var(--ink-2); padding-top: 16px; border-top: 1px solid var(--line); }
.tile__list li { padding-left: 14px; position: relative; }
.tile__list li::before { content: ""; position: absolute; left: 0; top: .72em; width: 5px; height: 1px; background: var(--accent); }
.tile--dark { background: var(--dark); border-color: transparent; color: var(--on-dark); }
.tile--dark p, .tile--dark .tile__list { color: var(--on-dark-muted); }
.tile--dark .tile__tag { color: var(--on-dark-muted); }
.tile--dark .tile__list { border-top-color: rgb(255 255 255 / .12); }
.tile--tint { background: var(--accent-tint); border-color: transparent; }
.tile--wide {
  grid-column: 1 / -1; flex-direction: row; align-items: flex-start; gap: 40px; padding: 28px;
  background: var(--surface);
}
.tile--wide > * { margin: 0; }
.tile--wide > div { flex: 0 0 280px; }
.tile--wide h3 { margin-top: 6px; }
.tile--wide p { margin-top: 4px; max-width: 60ch; }
@media (max-width: 900px) {
  .bento { grid-template-columns: 1fr; }
  .tile--wide { flex-direction: column; gap: 8px; }
  .tile--wide > div { flex: none; }
}
@media (max-width: 640px) { .tile > *:not(picture) { margin-inline: 22px; } .tile--wide { padding: 22px; } }

/* ---------- Roadmap ---------- */
.roadmap { background: var(--surface); border-block: 1px solid var(--line); }
.timeline { margin-top: 56px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border-top: 1px solid var(--line-strong); }
.timeline li { padding: 28px 28px 0 0; border-right: 1px solid var(--line); margin-right: 28px; }
.timeline li:last-child { border-right: 0; margin-right: 0; }
.timeline__when { display: inline-block; font-size: 13px; font-weight: 650; color: var(--accent); padding: 4px 10px; border-radius: 6px; background: var(--accent-tint); }
.timeline h3 { margin-top: 16px; }
.timeline p { margin-top: 10px; font-size: 15px; color: var(--ink-2); }
@media (max-width: 900px) {
  .timeline { grid-template-columns: 1fr 1fr; row-gap: 32px; }
  .timeline li:nth-child(2) { border-right: 0; margin-right: 0; }
}
@media (max-width: 640px) {
  .timeline { grid-template-columns: 1fr; border-top: 0; }
  .timeline li { border-right: 0; margin-right: 0; padding: 22px 0; border-top: 1px solid var(--line); }
}

/* ---------- Principles ---------- */
.principles__grid { margin-top: 48px; display: grid; grid-template-columns: 1fr 1fr; gap: 64px; }
.principles__col h3 { font-size: 15px; letter-spacing: .02em; color: var(--muted); font-weight: 600; padding-bottom: 14px; border-bottom: 1px solid var(--line-strong); }
.rules { margin-top: 8px; counter-reset: rule; display: grid; }
.rules li { counter-increment: rule; padding: 16px 0 16px 44px; position: relative; font-size: 17px; font-weight: 500; }
.rules li + li { border-top: 1px solid var(--line); }
.rules li::before {
  content: counter(rule, decimal-leading-zero); position: absolute; left: 0; top: 18px;
  font-size: 13px; font-weight: 600; color: var(--accent); letter-spacing: .04em;
}
.metrics { margin-top: 8px; display: grid; }
.metrics li { display: grid; gap: 4px; padding: 16px 0; }
.metrics li + li { border-top: 1px solid var(--line); }
.metrics strong { font-size: 17px; font-weight: 650; }
.metrics span { font-size: 14.5px; color: var(--muted); }
.metrics__note { margin-top: 20px; padding: 14px 16px; border-radius: var(--r); background: var(--accent-tint); color: var(--accent-ink); font-size: 14.5px; font-weight: 500; }
@media (max-width: 900px) { .principles__grid { grid-template-columns: 1fr; gap: 48px; } }

/* ---------- Partner ---------- */
.partner { background: var(--dark); color: var(--on-dark); }
.partner__inner { display: grid; grid-template-columns: 1.3fr 1fr; gap: 64px; align-items: center; }
.partner h2 { color: var(--on-dark); }
.partner p { margin-top: 18px; color: var(--on-dark-muted); font-size: 17px; max-width: 56ch; }
.partner__cta { margin-top: 32px; display: flex; align-items: center; gap: 24px; flex-wrap: wrap; }
.partner .btn--primary { background: #fff; color: #15171c; }
.partner .btn--primary:hover { background: #dfe3ea; }
.partner .link { color: var(--on-dark); }
.partner__logo { display: grid; gap: 14px; justify-items: start; padding: 32px; border-radius: var(--r); background: var(--dark-2); border: 1px solid rgb(255 255 255 / .08); }
.partner__logo img { width: min(100%, 320px); height: auto; }
.partner__logo span { font-size: 13.5px; color: var(--on-dark-muted); }
@media (max-width: 900px) { .partner__inner { grid-template-columns: 1fr; gap: 40px; } }

/* ---------- Footer ---------- */
.footer { padding: 48px 0 40px; border-top: 1px solid var(--line); }
.footer__inner { display: grid; grid-template-columns: 1fr 1.6fr; gap: 48px; align-items: start; }
.footer__brand p { margin-top: 10px; font-size: 14px; color: var(--muted); }
.footer__notice { font-size: 13.5px; color: var(--muted); line-height: 1.7; }
.footer__copy { grid-column: 1 / -1; font-size: 13px; color: var(--muted); padding-top: 24px; border-top: 1px solid var(--line); }
@media (max-width: 900px) { .footer__inner { grid-template-columns: 1fr; gap: 24px; } }

/* ---------- Reveal on scroll (IntersectionObserver, motion 4) ---------- */
@media (prefers-reduced-motion: no-preference) {
  .reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
  .reveal.is-in { opacity: 1; transform: none; }
  .hero__copy > * { animation: rise .8s var(--ease) both; }
  .hero__copy > :nth-child(2) { animation-delay: .06s; }
  .hero__copy > :nth-child(3) { animation-delay: .12s; }
  .hero__copy > :nth-child(4) { animation-delay: .18s; }
  .hero__visual { animation: rise 1s var(--ease) .1s both; }
  @keyframes rise { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: none; } }
}