:root {
  color-scheme: dark;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: #101820;
  color: #f7fbff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 18% 6%, rgba(42, 171, 238, .22), transparent 34rem),
    radial-gradient(circle at 84% 60%, rgba(92, 111, 223, .16), transparent 30rem),
    linear-gradient(160deg, #0d141b, #17212b 58%, #111a23);
  line-height: 1.55;
}

.page { width: min(100%, 720px); margin: 0 auto; padding: 40px 16px 56px; }

.hero, .block {
  padding: clamp(26px, 6vw, 48px);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 24px;
  background: rgba(23, 33, 43, .82);
  box-shadow: 0 24px 70px rgba(0,0,0,.3);
}
.hero { text-align: center; }
.block { margin-top: 18px; }

.mark {
  display: grid; place-items: center;
  width: 76px; height: 76px; margin: 0 auto 22px;
  border-radius: 22px;
  background: linear-gradient(145deg, #39b9f3, #168acb);
  box-shadow: 0 18px 42px rgba(34, 158, 217, .34);
}
.mark svg { width: 44px; height: 44px; fill: #fff; }

.eyebrow { margin: 0 0 10px; color: #7fd6ff; font-size: 13px; font-weight: 750; letter-spacing: .1em; text-transform: uppercase; }
h1 { margin: 0; font-size: clamp(32px, 7vw, 48px); line-height: 1.06; letter-spacing: -.035em; }
h2 { margin: 0 0 16px; font-size: clamp(21px, 4.5vw, 26px); letter-spacing: -.02em; }
.lead { margin: 20px auto 28px; color: #c3ced8; font-size: clamp(16px, 3.5vw, 19px); }
p { margin: 0 0 12px; color: #c3ced8; }
b { color: #f7fbff; }

.button {
  display: flex; align-items: center; justify-content: center;
  width: 100%; min-height: 56px; margin-top: 8px; padding: 14px 24px;
  border-radius: 16px;
  background: #229ed9; color: #fff;
  font-size: 17px; font-weight: 750; text-decoration: none;
  box-shadow: 0 12px 28px rgba(34, 158, 217, .28);
  transition: transform .18s ease, background .18s ease;
}
.button:hover { background: #32abe1; transform: translateY(-1px); }
.button:focus-visible { outline: 3px solid #fff; outline-offset: 4px; }
.hint { margin: 14px 0 0; color: #8e9cab; font-size: 14px; }

.topics, .steps { margin: 0; padding-left: 20px; color: #c3ced8; }
.topics li, .steps li { margin-bottom: 8px; }

.example {
  margin-bottom: 14px; padding: 16px 18px;
  border-radius: 16px; background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.07);
}
.q { margin: 0 0 8px; color: #7fd6ff; font-weight: 700; }
.q::before { content: "Вопрос: "; color: #8e9cab; font-weight: 500; }
.a { margin: 0; }
.note, .small { color: #8e9cab; font-size: 14px; }

.footer a, .block a:not(.button) { color: #7fd6ff; }
.block .button { margin-top: 20px; }

/* Кнопка внизу экрана появляется, когда верхняя кнопка ушла из вида. */
.sticky-cta {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 10;
  padding: 12px 16px calc(12px + env(safe-area-inset-bottom));
  background: rgba(16, 24, 32, .92);
  border-top: 1px solid rgba(255,255,255,.1);
  backdrop-filter: blur(14px);
  transform: translateY(110%);
  transition: transform .22s ease;
}
.sticky-cta .button { width: min(100%, 688px); margin: 0 auto; }
.sticky-cta.visible { transform: none; }
body.has-sticky .page { padding-bottom: 110px; }

@media (prefers-reduced-motion: reduce) { .button, .sticky-cta { transition: none; } }
@media (max-width: 420px) { .page { padding-top: 16px; } .hero, .block { border-radius: 20px; } }