:root {
  --paper: #f7f2ea;
  --ink: #15171c;
  --muted: #667085;
  --blue: #1b5cff;
  --red: #e13d4f;
  --gold: #f0b23c;
  --green: #14a06f;
  --line: #ded6c9;
  --card: #fffaf1;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(27,92,255,.08) 0 1px, transparent 1px 80px),
    linear-gradient(180deg, rgba(225,61,79,.06) 0 1px, transparent 1px 80px),
    var(--paper);
  letter-spacing: 0;
}

a { color: inherit; text-decoration: none; }
p { margin: 0; color: var(--muted); font-size: 18px; line-height: 1.7; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 78px;
  padding: 0 clamp(18px, 5vw, 70px);
  border-bottom: 1px solid var(--line);
  background: rgba(247,242,234,.9);
  backdrop-filter: blur(18px);
}

.brand {
  font-size: 23px;
  font-weight: 950;
  color: var(--ink);
}

.brand::after {
  content: "";
  display: inline-block;
  width: 9px;
  height: 9px;
  margin-left: 8px;
  border-radius: 50%;
  background: var(--blue);
}

.nav { display: flex; align-items: center; gap: 6px; }
.nav a {
  padding: 11px 13px;
  border-radius: 999px;
  color: #323844;
  font-weight: 850;
}
.nav a:hover { background: #fff; color: var(--blue); }

.menu-button {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fffaf1;
}
.menu-button span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: var(--ink);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, .96fr) minmax(360px, .82fr);
  gap: clamp(26px, 4vw, 58px);
  align-items: center;
  padding: clamp(44px, 6vw, 86px) clamp(20px, 7vw, 112px);
  min-height: calc(100vh - 78px);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 950;
  text-transform: uppercase;
  letter-spacing: .08em;
}
.eyebrow::before {
  content: "";
  width: 28px;
  height: 3px;
  background: var(--red);
}

h1 {
  max-width: 880px;
  margin: 16px 0 24px;
  font-size: clamp(48px, 6.2vw, 88px);
  line-height: .96;
  letter-spacing: 0;
}

.lead {
  max-width: 790px;
  font-size: clamp(20px, 2vw, 26px);
  color: #4d5562;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}
.primary,
.secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  padding: 0 22px;
  border-radius: 14px;
  font-weight: 950;
}
.primary { background: var(--blue); color: #fff; }
.secondary { background: #fff; border: 1px solid var(--line); }

.ru-panel {
  max-width: 640px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 30px;
  background: #181b22;
  color: #fff;
  box-shadow: 0 32px 80px rgba(32,38,49,.22);
}

.choice-section {
  padding-top: clamp(52px, 7vw, 92px);
  background: #fff;
}

.choice-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.choice-card {
  position: relative;
  display: grid;
  gap: 12px;
  min-height: 310px;
  padding: clamp(24px, 4vw, 38px);
  border-radius: 30px;
  overflow: hidden;
  box-shadow: 0 24px 70px rgba(33,37,45,.08);
}

.choice-card::after {
  content: "→";
  position: absolute;
  right: 28px;
  bottom: 20px;
  font-size: 46px;
  font-weight: 950;
}

.choice-card span {
  color: currentColor;
  font-size: 13px;
  font-weight: 950;
  text-transform: uppercase;
  letter-spacing: .08em;
}

.choice-card h3 {
  max-width: 620px;
  font-size: clamp(34px, 4vw, 58px);
  line-height: .96;
}

.choice-card small {
  font-size: 18px;
  font-weight: 950;
  opacity: .72;
}

.choice-card p {
  max-width: 660px;
  font-size: 20px;
}

.choice-card.official {
  background: #111827;
  color: #fff;
}
.choice-card.official p { color: #d7deeb; }

.choice-card.multi {
  background: linear-gradient(135deg, #1b5cff, #7c4dff 55%, #e13d4f);
  color: #fff;
}
.choice-card.multi p { color: #eef3ff; }
.panel-header {
  padding: 14px 16px;
  border-radius: 16px;
  background: linear-gradient(90deg, var(--blue), var(--red));
  font-weight: 950;
  text-transform: uppercase;
  letter-spacing: .08em;
}
.chat-line {
  margin-top: 16px;
  padding: 18px;
  border-radius: 18px;
  line-height: 1.55;
  font-weight: 800;
}
.chat-line.user { background: rgba(255,255,255,.08); }
.chat-line.bot { background: rgba(27,92,255,.22); }
.model-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-top: 18px;
}
.model-row span {
  padding: 12px;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 14px;
  color: #dce4f2;
  font-weight: 850;
}

.section {
  padding: clamp(58px, 8vw, 104px) clamp(20px, 7vw, 112px);
}
.section h2 {
  max-width: 900px;
  margin: 12px 0 20px;
  font-size: clamp(38px, 5vw, 74px);
  line-height: .98;
  letter-spacing: 0;
}
.section h3 {
  margin: 0 0 10px;
  font-size: 25px;
  line-height: 1.12;
}
.section-head { max-width: 900px; margin: 0 auto 34px; text-align: center; }
.section-head.left { margin-left: 0; text-align: left; }

.multiple-section {
  background: #111827;
  color: #fff;
}
.multiple-section p { color: #cbd5e1; }
.multiple-section .eyebrow { color: #8ab2ff; }
.multiple-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}
.multiple-grid article {
  min-height: 255px;
  padding: 24px;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 24px;
  background: linear-gradient(180deg, rgba(255,255,255,.08), rgba(255,255,255,.03));
}
.multiple-grid span {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 24px;
  border-radius: 14px;
  background: #fff;
  color: var(--blue);
  font-weight: 950;
}

.split {
  display: grid;
  grid-template-columns: 1fr .72fr;
  gap: 34px;
  align-items: center;
}
.note-card {
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: #fff;
}

.tool-grid,
.prompt-grid,
.usecase-grid,
.safety-grid,
.related-grid,
.neutral-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}
.tool-grid a,
.prompt-grid article,
.usecase-grid article,
.safety-grid article,
.related-grid a,
.neutral-grid a,
.faq-list details {
  border: 1px solid var(--line);
  border-radius: 22px;
  background: #fff;
  box-shadow: 0 18px 44px rgba(33,37,45,.06);
}
.tool-grid a {
  display: grid;
  gap: 8px;
  min-height: 190px;
  padding: 22px;
}
.tool-grid strong { font-size: 22px; }
.tool-grid small { color: #98a2b3; font-weight: 850; }
.tool-grid span { color: #667085; line-height: 1.55; }

.related-section {
  background: #eef4ff;
}

.neutral-grid {
  grid-template-columns: repeat(5, 1fr);
  margin-bottom: clamp(40px, 6vw, 72px);
}

.neutral-grid a {
  display: grid;
  gap: 8px;
  min-height: 160px;
  padding: 20px;
  background: #111827;
  color: #fff;
  border-color: rgba(17,24,39,.18);
}

.neutral-grid strong { font-size: 20px; }
.neutral-grid small { color: #9fb3d9; font-weight: 850; overflow-wrap: anywhere; }
.neutral-grid span { color: #d7deeb; line-height: 1.46; }

.related-grid {
  grid-template-columns: repeat(4, 1fr);
}

.related-grid a {
  display: grid;
  gap: 8px;
  min-height: 176px;
  padding: 22px;
}

.related-grid strong { font-size: 21px; }
.related-grid small { color: #98a2b3; font-weight: 850; }
.related-grid span { color: #667085; line-height: 1.5; }

.directory-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.directory-strip a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  border: 1px solid #cbd7ef;
  border-radius: 999px;
  background: #fff;
  color: #323844;
  font-weight: 850;
}

.directory-strip small {
  color: #98a2b3;
  font-weight: 800;
}

.usecases-section {
  background: #fffaf1;
}
.usecase-grid {
  grid-template-columns: repeat(3, 1fr);
}
.usecase-grid article,
.safety-grid article {
  min-height: 210px;
  padding: 24px;
}

.quality-section {
  background: #eef4ff;
}

.checklist {
  display: grid;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}
.checklist li {
  padding: 14px 16px;
  border-left: 4px solid var(--blue);
  border-radius: 12px;
  background: #fff;
  color: #323844;
  font-weight: 800;
}

.prompt-section { background: #fff6e6; }
.prompt-grid article { padding: 24px; }

.safety-section {
  background: #15171c;
  color: #fff;
}
.safety-section p { color: #cbd5e1; }
.safety-section .eyebrow { color: #8ab2ff; }
.safety-grid {
  grid-template-columns: repeat(3, 1fr);
}
.safety-grid article {
  background: rgba(255,255,255,.06);
  border-color: rgba(255,255,255,.14);
}

.faq-list {
  display: grid;
  gap: 12px;
  max-width: 980px;
  margin: 0 auto;
}
.faq-list details { overflow: hidden; }
.faq-list summary {
  cursor: pointer;
  padding: 20px 24px;
  font-size: 21px;
  font-weight: 950;
}
.faq-list p { padding: 0 24px 22px; }

.footer {
  padding: 64px clamp(20px, 7vw, 112px) 32px;
  background: #15171c;
  color: #fff;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: 28px;
}
.footer p { color: #cbd5e1; }
.footer h2,
.footer h3 { margin: 0 0 14px; }
.footer a {
  display: block;
  margin: 9px 0;
  color: #dce4f2;
  font-weight: 750;
}
.smallprint {
  margin-top: 38px;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,.12);
  font-size: 15px;
}

@media (max-width: 1080px) {
  .hero,
  .split { grid-template-columns: 1fr; }
  .hero { min-height: auto; }
  .multiple-grid,
  .tool-grid,
  .prompt-grid,
  .choice-grid,
  .usecase-grid,
  .safety-grid,
  .related-grid,
  .neutral-grid,
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .topbar { min-height: 70px; padding-inline: 16px; }
  .brand { font-size: 19px; }
  .menu-button { display: block; }
  .nav {
    position: absolute;
    top: 70px;
    left: 12px;
    right: 12px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 12px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: #fffaf1;
    box-shadow: 0 24px 70px rgba(33,37,45,.18);
  }
  .topbar.nav-open .nav { display: flex; }
  .nav a { padding: 14px; }
  h1 { font-size: clamp(42px, 13vw, 64px); }
  .hero { padding-top: 44px; }
  .hero-actions a { width: 100%; }
  .multiple-grid,
  .tool-grid,
  .prompt-grid,
  .choice-grid,
  .usecase-grid,
  .safety-grid,
  .related-grid,
  .neutral-grid,
  .footer-grid,
  .model-row { grid-template-columns: 1fr; }
  .choice-card { min-height: 250px; }
}