/* Blueprint AI — landing.
   Direction: an architect's drafting table. Light, precise, quiet — with one
   bold signature: the product shown as a real blueprint sheet.
   Type: Space Grotesk (display) · Inter (body) · Geist Mono (labels/paths). */

:root {
  --ink: #0f1115;
  --paper: #ffffff;
  --paper-2: #f6f7f9;
  --muted: #565d6b;
  --muted-2: #888f9c;
  --line: #e7e9ee;
  --line-strong: #d4d8e0;

  --blue: #1f44b8;          /* structural accent (blueprint ink) */
  --blue-soft: rgba(31, 68, 184, 0.08);
  --sheet-1: #103a86;       /* blueprint sheet gradient */
  --sheet-2: #0a2358;
  --cyan: #9cc6ff;          /* annotations on the sheet */

  --radius: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 2px rgba(15, 17, 21, 0.05);
  --shadow-md: 0 12px 34px -14px rgba(15, 17, 21, 0.22);
  --shadow-lg: 0 40px 80px -30px rgba(10, 35, 88, 0.5);

  --maxw: 1120px;
  --font-display: "Space Grotesk", "Inter", system-ui, sans-serif;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "Geist Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
.mono { font-family: var(--font-mono); }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.container--narrow { max-width: 760px; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  border: 1px solid transparent; border-radius: 999px;
  padding: 9px 18px; font-size: 14px; font-weight: 500; font-family: inherit;
  cursor: pointer; white-space: nowrap;
  transition: background-color .18s, color .18s, border-color .18s, transform .18s, box-shadow .18s;
}
.btn:active { transform: translateY(1px); }
.btn--solid { background: var(--ink); color: #fff; }
.btn--solid:hover { background: #000; box-shadow: var(--shadow-md); }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line-strong); }
.btn--ghost:hover { background: #f1f2f5; }
.btn--invert { background: #fff; color: var(--sheet-2); }
.btn--invert:hover { box-shadow: 0 10px 30px -10px rgba(0,0,0,.4); }
.btn--onblue { color: #fff; border-color: rgba(255,255,255,.45); }
.btn--onblue:hover { background: rgba(255,255,255,.12); }
.btn--lg { padding: 13px 26px; font-size: 15px; }
.btn__arrow { transition: transform .18s; }
.btn--solid:hover .btn__arrow, .btn--invert:hover .btn__arrow { transform: translateX(2px); }

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

/* ===== Nav ===== */
.nav {
  position: sticky; top: 0; z-index: 40;
  background: rgba(255,255,255,.82); backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav__inner { display: flex; align-items: center; gap: 18px; height: 64px; }
.nav__links { display: flex; gap: 22px; margin-left: 14px; flex: 1; }
.nav__links a { color: var(--muted); text-decoration: none; font-size: 14px; transition: color .15s; }
.nav__links a:hover { color: var(--ink); }
.nav__actions { display: flex; align-items: center; gap: 10px; }
.langtoggle {
  border: 1px solid var(--line-strong); background: #fff; color: var(--muted);
  border-radius: 999px; height: 32px; min-width: 42px; padding: 0 10px;
  font-family: var(--font-mono); font-size: 12px; cursor: pointer; transition: all .15s;
}
.langtoggle:hover { color: var(--ink); border-color: var(--ink); }

.brand { display: inline-flex; align-items: center; gap: 9px; text-decoration: none; color: var(--ink);
  font-family: var(--font-display); font-weight: 600; font-size: 16px; letter-spacing: -.01em; }
.brand__mark { display: inline-flex; color: var(--sheet-2); }
.brand--sm { font-size: 14px; }

/* ===== Shared section bits ===== */
.section { padding: 88px 0; }
.section--muted { background: var(--paper-2); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.kicker {
  display: flex; align-items: center; gap: 8px;
  margin: 0 0 14px; color: var(--blue); font-size: 12.5px; font-weight: 500;
  letter-spacing: .08em; text-transform: uppercase;
}
.kicker::before { content: ""; width: 22px; height: 1px; background: var(--blue); display: inline-block; }
.section__title {
  margin: 0 0 48px; max-width: 22ch;
  font-family: var(--font-display); font-weight: 600; letter-spacing: -.02em;
  font-size: clamp(25px, 3.6vw, 36px); line-height: 1.15;
}

/* ===== Hero ===== */
.hero { position: relative; overflow: hidden; padding: 92px 0 78px; border-bottom: 1px solid var(--line); }
.hero__grid {
  position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(31,68,184,.07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(31,68,184,.07) 1px, transparent 1px);
  background-size: 32px 32px;
  -webkit-mask-image: radial-gradient(ellipse 78% 62% at 50% 32%, #000 28%, transparent 76%);
  mask-image: radial-gradient(ellipse 78% 62% at 50% 32%, #000 28%, transparent 76%);
}
.hero__inner { position: relative; max-width: 780px; margin: 0 auto; text-align: center; }
.eyebrow {
  display: inline-block; margin: 0 0 20px; padding: 5px 13px;
  border: 1px solid var(--line-strong); border-radius: 999px; background: #fff;
  color: var(--blue); font-family: var(--font-mono); font-size: 12.5px;
}
.hero__title {
  margin: 0; font-family: var(--font-display); font-weight: 600;
  font-size: clamp(36px, 6.2vw, 60px); line-height: 1.06; letter-spacing: -.03em;
}
.hero__subtitle { margin: 24px auto 0; max-width: 620px; font-size: clamp(15px, 2.1vw, 18px); color: var(--muted); }

.composer {
  margin: 36px auto 0; max-width: 660px; text-align: left;
  background: #fff; border: 1px solid var(--line-strong); border-radius: var(--radius-lg);
  padding: 14px 14px 12px; box-shadow: var(--shadow-md);
  transition: border-color .18s, box-shadow .18s;
}
.composer:focus-within { border-color: var(--blue); box-shadow: 0 0 0 4px var(--blue-soft), var(--shadow-md); }
.composer__input {
  width: 100%; border: 0; outline: 0; resize: none; background: transparent; color: var(--ink);
  font-family: inherit; font-size: 15.5px; line-height: 1.5; padding: 6px 8px; max-height: 180px;
}
.composer__input::placeholder { color: var(--muted-2); }
.composer__row { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-top: 8px; padding-top: 4px; }
.composer__hint { font-size: 12.5px; color: var(--muted-2); }
.composer__actions { display: flex; gap: 8px; }
.hero__note { margin: 16px 0 0; font-size: 13px; color: var(--muted-2); }

/* ===== Tools strip ===== */
.strip { padding: 26px 0; border-bottom: 1px solid var(--line); background: #fff; }
.strip__inner { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 14px 28px; }
.strip__label { font-size: 12px; color: var(--muted-2); letter-spacing: .04em; }
.strip__list { display: flex; flex-wrap: wrap; gap: 10px 26px; list-style: none; margin: 0; padding: 0; }
.strip__list li { font-family: var(--font-display); font-weight: 500; font-size: 15px; color: var(--ink); opacity: .8; }

/* ===== Contrast ===== */
.contrast { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.contrast__col { padding: 26px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
.contrast__col--good { border-color: var(--blue); box-shadow: 0 0 0 1px var(--blue) inset, var(--shadow-sm); }
.contrast__tag {
  display: inline-block; margin-bottom: 14px; padding: 3px 10px; border-radius: 999px; font-size: 12px;
}
.contrast__col--bad .contrast__tag { background: #f1f2f5; color: var(--muted); }
.contrast__col--good .contrast__tag { background: var(--blue-soft); color: var(--blue); }
.contrast__list { margin: 0; padding: 0; list-style: none; display: grid; gap: 12px; }
.contrast__list li { position: relative; padding-left: 24px; font-size: 14.5px; color: var(--muted); }
.contrast__list li::before {
  position: absolute; left: 0; top: 0; font-family: var(--font-mono); font-size: 13px; line-height: 1.5;
}
.contrast__col--bad .contrast__list li::before { content: "×"; color: var(--muted-2); }
.contrast__col--good .contrast__list li { color: var(--ink); }
.contrast__col--good .contrast__list li::before { content: "✓"; color: var(--blue); font-weight: 600; }

/* ===== Blueprint AI vs Superpowers ===== */
.superpower {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: #fff;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}
.superpower__lead {
  margin: 0;
  padding: 28px 30px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-display);
  font-size: clamp(21px, 3vw, 30px);
  line-height: 1.18;
  letter-spacing: -.02em;
  color: var(--ink);
}
.superpower__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  padding: 18px;
  background: linear-gradient(180deg, #fff, var(--paper-2));
}
.superpower__card {
  position: relative;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: var(--shadow-sm);
}
.superpower__card--blueprint {
  border-color: var(--blue);
  box-shadow: 0 0 0 1px var(--blue) inset, var(--shadow-sm);
  background:
    linear-gradient(135deg, rgba(31,68,184,.08), transparent 54%),
    #fff;
}
.superpower__label {
  display: inline-block;
  margin-bottom: 14px;
  padding: 4px 10px;
  border-radius: 999px;
  background: #f1f2f5;
  color: var(--muted);
  font-size: 12px;
}
.superpower__card--blueprint .superpower__label {
  background: var(--blue-soft);
  color: var(--blue);
}
.superpower__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -.01em;
  color: var(--ink);
}
.superpower__desc {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.68;
}
.superpower__card--blueprint .superpower__desc {
  color: var(--ink);
}
.superpower__points {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}
.superpower__points li {
  position: relative;
  padding-left: 24px;
  font-size: 14.5px;
  color: var(--muted);
}
.superpower__points li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0;
  font-family: var(--font-mono);
  color: var(--blue);
}
.superpower__card--blueprint .superpower__points li {
  color: var(--ink);
}

/* ===== Signature: blueprint sheet ===== */
.sheet {
  position: relative; overflow: hidden; border-radius: var(--radius-lg);
  background: linear-gradient(150deg, var(--sheet-1), var(--sheet-2));
  padding: 56px 40px 88px; box-shadow: var(--shadow-lg);
}
.sheet__grid {
  position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(255,255,255,.14) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255,255,255,.14) 1px, transparent 1px);
  background-size: 30px 30px;
}
.sheet__screens { position: relative; display: flex; align-items: center; justify-content: center; gap: 26px; flex-wrap: wrap; }
.sheet__arrow { color: var(--cyan); font-size: 26px; line-height: 1; }

.screen { width: min(340px, 86vw); background: var(--paper); border-radius: 12px; overflow: hidden;
  border: 1px solid rgba(255,255,255,.6); box-shadow: 0 20px 40px -16px rgba(0,0,0,.45); }
.screen__cap {
  display: block; padding: 9px 13px; font-size: 11.5px; color: var(--muted);
  background: var(--paper-2); border-bottom: 1px solid var(--line);
}
.screen__body { padding: 16px; }
.screen__body--chat { display: flex; flex-direction: column; gap: 9px; min-height: 188px; }
.bubble { max-width: 84%; padding: 8px 11px; border-radius: 12px; font-size: 12.5px; line-height: 1.4; }
.bubble--in { align-self: flex-end; background: var(--ink); color: #fff; border-bottom-right-radius: 4px; }
.bubble--out { align-self: flex-start; background: var(--paper-2); color: var(--ink); border: 1px solid var(--line); border-bottom-left-radius: 4px; }
.screen__body--tree { min-height: 188px; display: flex; flex-direction: column; justify-content: space-between; gap: 14px; }
.tree { margin: 0; font-size: 12.5px; line-height: 1.7; color: var(--ink); white-space: pre; overflow-x: auto; }
.tree__rm { color: var(--blue); }
.chip {
  align-self: flex-start; display: inline-block; padding: 4px 10px; border-radius: 999px;
  background: var(--blue-soft); color: var(--blue); font-size: 11.5px;
}

.titleblock {
  position: absolute; right: 18px; bottom: 18px; z-index: 2;
  border: 1px solid rgba(255,255,255,.35); border-radius: 6px; overflow: hidden;
  color: var(--cyan); font-size: 10.5px; background: rgba(10,35,88,.35); backdrop-filter: blur(2px);
}
.titleblock__row { display: flex; gap: 12px; justify-content: space-between; padding: 5px 10px; }
.titleblock__row + .titleblock__row { border-top: 1px solid rgba(255,255,255,.2); }
.titleblock__row b { color: #fff; letter-spacing: .04em; }

/* ===== Steps ===== */
.steps { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.step { position: relative; padding: 30px 24px 26px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff;
  transition: transform .2s, box-shadow .2s, border-color .2s; }
.step:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--line-strong); }
.step__bubble {
  position: absolute; top: -16px; left: 24px;
  width: 32px; height: 32px; display: grid; place-items: center;
  border-radius: 50%; background: var(--ink); color: #fff; font-size: 13px; font-weight: 500;
  box-shadow: 0 0 0 4px #fff;
}
.step__title { margin: 8px 0 8px; font-family: var(--font-display); font-size: 18px; font-weight: 600; }
.step__desc { margin: 0; font-size: 14.5px; color: var(--muted); }

/* ===== Feature cards ===== */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.card { position: relative; padding: 24px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff;
  transition: border-color .2s, box-shadow .2s, transform .2s; }
.card:hover { border-color: var(--line-strong); box-shadow: var(--shadow-sm); transform: translateY(-2px); }
.card__id { display: block; margin-bottom: 12px; font-size: 12px; color: var(--blue); letter-spacing: .06em; }
.card__title { margin: 0 0 8px; font-family: var(--font-display); font-size: 16.5px; font-weight: 600; }
.card__desc { margin: 0; font-size: 14.5px; color: var(--muted); }

/* ===== Export ===== */
.export { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: center; }
.export__title { margin: 8px 0 16px; max-width: 16ch; font-family: var(--font-display); font-weight: 600;
  font-size: clamp(22px, 3vw, 30px); letter-spacing: -.02em; line-height: 1.2; }
.export__desc { margin: 0 0 20px; color: var(--muted); font-size: 15px; }
.export__points { margin: 0; padding: 0; list-style: none; display: grid; gap: 10px; }
.export__points li { position: relative; padding-left: 24px; font-size: 14.5px; }
.export__points li::before { content: "✓"; position: absolute; left: 0; color: var(--blue); font-family: var(--font-mono); }
.export__file { border: 1px solid var(--line-strong); border-radius: var(--radius); overflow: hidden; background: #fff; box-shadow: var(--shadow-md); }
.filehead { display: flex; align-items: center; padding: 11px 14px; background: var(--paper-2); border-bottom: 1px solid var(--line);
  font-size: 12.5px; color: var(--muted); }
.filehead .dot { width: 10px; height: 10px; border-radius: 50%; background: var(--line-strong); margin-right: 6px; }
.tree--lg { padding: 18px; font-size: 13px; }
.tree--lg b { color: var(--ink); font-weight: 500; }

/* ===== FAQ ===== */
.faq { display: grid; gap: 0; border-top: 1px solid var(--line); }
.faq__item { border-bottom: 1px solid var(--line); }
.faq__item summary {
  list-style: none; cursor: pointer; padding: 20px 40px 20px 2px; position: relative;
  font-family: var(--font-display); font-weight: 500; font-size: 16.5px; color: var(--ink);
}
.faq__item summary::-webkit-details-marker { display: none; }
.faq__item summary::after {
  content: "+"; position: absolute; right: 6px; top: 50%; transform: translateY(-50%);
  font-family: var(--font-mono); font-size: 20px; color: var(--muted-2); transition: transform .2s;
}
.faq__item[open] summary::after { content: "−"; color: var(--blue); }
.faq__item p { margin: 0; padding: 0 40px 22px 2px; color: var(--muted); font-size: 14.5px; max-width: 64ch; }

/* ===== Final CTA band ===== */
.ctaband { position: relative; overflow: hidden; padding: 84px 0; color: #fff;
  background: linear-gradient(150deg, var(--sheet-1), var(--sheet-2)); }
.ctaband__grid {
  position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(255,255,255,.1) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255,255,255,.1) 1px, transparent 1px);
  background-size: 32px 32px;
  -webkit-mask-image: radial-gradient(ellipse 70% 80% at 50% 50%, #000 30%, transparent 78%);
  mask-image: radial-gradient(ellipse 70% 80% at 50% 50%, #000 30%, transparent 78%);
}
.ctaband__inner { position: relative; text-align: center; }
.ctaband__title { margin: 0 0 12px; font-family: var(--font-display); font-weight: 600;
  font-size: clamp(26px, 4vw, 38px); letter-spacing: -.02em; }
.ctaband__sub { margin: 0 0 28px; color: rgba(255,255,255,.75); font-size: 16px; }
.ctaband__actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* ===== Footer ===== */
.footer { border-top: 1px solid var(--line); padding: 48px 0 28px; }
.footer__inner { display: flex; justify-content: space-between; gap: 36px; flex-wrap: wrap; }
.footer__brand { display: flex; flex-direction: column; gap: 10px; max-width: 280px; }
.footer__copy { font-size: 13px; color: var(--muted-2); }
.footer__cols { display: flex; gap: 56px; flex-wrap: wrap; }
.footer__col { display: flex; flex-direction: column; gap: 9px; }
.footer__h { font-size: 11px; color: var(--muted-2); letter-spacing: .08em; text-transform: uppercase; }
.footer__col a { color: var(--muted); text-decoration: none; font-size: 14px; transition: color .15s; }
.footer__col a:hover { color: var(--ink); }
.footer__legal { margin-top: 28px; padding-top: 18px; border-top: 1px solid var(--line); font-size: 12.5px; color: var(--muted-2); }

/* ===== Scroll reveal ===== */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s cubic-bezier(.22,1,.36,1), transform .6s cubic-bezier(.22,1,.36,1); }
.reveal.is-visible { opacity: 1; transform: none; }

/* Hero entrance */
@keyframes rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
.hero__inner > * { animation: rise .6s cubic-bezier(.22,1,.36,1) both; }
.eyebrow { animation-delay: .02s; }
.hero__title { animation-delay: .08s; }
.hero__subtitle { animation-delay: .16s; }
.composer { animation-delay: .24s; }
.hero__note { animation-delay: .32s; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero__inner > * { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ===== Responsive ===== */
@media (max-width: 920px) {
  .nav__links { display: none; }
  .steps, .cards { grid-template-columns: 1fr 1fr; }
  .export { grid-template-columns: 1fr; gap: 28px; }
}
@media (max-width: 680px) {
  .section { padding: 60px 0; }
  .hero { padding: 64px 0 54px; }
  .contrast { grid-template-columns: 1fr; }
  .superpower__grid { grid-template-columns: 1fr; }
  .steps, .cards { grid-template-columns: 1fr; }
  .sheet { padding: 36px 18px 78px; }
  .sheet__arrow { transform: rotate(90deg); }
  .footer__inner { flex-direction: column; gap: 28px; }
}
@media (max-width: 520px) {
  .composer__row { flex-direction: column; align-items: stretch; }
  .composer__hint { display: none; }
  .composer__actions { justify-content: stretch; }
  .composer__actions .btn { flex: 1; }
}