/* Blacksea Technologies — design system */

:root {
  --bg: #ffffff;
  --bg-soft: #fafafa;
  --bg-dark: #0a0a0a;
  --bg-dark-2: #111111;
  --ink: #0a0a0a;
  --ink-2: #1d1d1f;
  --muted: #6e6e73;
  --muted-2: #86868b;
  --line: #e5e5e7;
  --line-dark: #1f1f22;
  --accent: #2a6cff;
  --r-sm: 10px;
  --r-md: 16px;
  --r-lg: 24px;
  --r-xl: 32px;
  --c: 1200px;
  --pad: 24px;
  --t-fast: 200ms cubic-bezier(.4, 0, .2, 1);
  --t-med:  450ms cubic-bezier(.22, 1, .36, 1);
  --t-slow: 800ms cubic-bezier(.22, 1, .36, 1);
  --font: "Inter", -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  line-height: 1.55;
  font-size: 17px;
  letter-spacing: -0.011em;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; transition: color var(--t-fast); }
a:hover { color: var(--accent); }
.container { max-width: var(--c); margin: 0 auto; padding: 0 var(--pad); }

h1, h2, h3, h4, h5 {
  margin: 0; font-weight: 600; letter-spacing: -0.025em; color: var(--ink);
}
.hero__title {
  font-size: clamp(44px, 7.5vw, 96px);
  line-height: 1.02; font-weight: 700; letter-spacing: -0.04em;
}
.hero__title-accent {
  background: linear-gradient(90deg, #6e6e73 0%, #0a0a0a 60%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.section__title {
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.05; font-weight: 700; letter-spacing: -0.035em;
}

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px; padding: 14px 22px; border-radius: 999px;
  font-weight: 500; font-size: 15px; letter-spacing: -0.01em;
  border: 1px solid transparent; cursor: pointer;
  transition: transform var(--t-fast), background var(--t-fast), color var(--t-fast), border-color var(--t-fast);
  white-space: nowrap;
}
.btn--primary { background: var(--ink); color: #fff; }
.btn--primary:hover { background: #1d1d1f; color: #fff; transform: translateY(-1px); }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn--ghost:hover { border-color: var(--ink); color: var(--ink); }
.btn--small { padding: 9px 16px; font-size: 14px; background: var(--ink); color: #fff; }
.btn--small:hover { background: #1d1d1f; color: #fff; }

.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t-fast), background var(--t-fast);
}
.nav.is-scrolled { border-bottom-color: var(--line); }
.nav__inner { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 32px; }
.nav__logo { display: flex; align-items: center; gap: 10px; font-weight: 600; font-size: 17px; color: var(--ink); letter-spacing: -0.02em; }
.nav__logo-mark { width: 26px; height: 26px; color: var(--ink); }
.nav__links { display: flex; gap: 36px; font-size: 14px; color: var(--ink-2); margin-left: auto; }
.nav__links a { color: var(--ink-2); font-weight: 450; }
.nav__links a:hover { color: var(--accent); }
.nav__toggle {
  display: none; background: none; border: 0; width: 36px; height: 36px;
  flex-direction: column; justify-content: center; align-items: center; gap: 5px; cursor: pointer;
}
.nav__toggle span { display: block; width: 20px; height: 1.5px; background: var(--ink); transition: transform var(--t-fast), opacity var(--t-fast); }
.nav__mobile {
  display: none; flex-direction: column; padding: 16px 24px 24px; gap: 16px;
  border-top: 1px solid var(--line); background: rgba(255,255,255,.96);
}
.nav__mobile.is-open { display: flex; }
.nav__mobile a { color: var(--ink); font-size: 18px; }
.nav__mobile .btn { align-self: start; }

.hero { position: relative; padding: 180px 0 120px; overflow: hidden; }
.hero__inner { position: relative; z-index: 2; max-width: 1000px; }
.hero__eyebrow {
  display: inline-block; font-size: 13px; font-weight: 500; color: var(--muted);
  padding: 6px 14px; border: 1px solid var(--line); border-radius: 999px; margin-bottom: 28px;
}
.hero__sub {
  max-width: 640px; margin: 28px 0 36px;
  font-size: clamp(18px, 2vw, 22px); line-height: 1.45; color: var(--muted); font-weight: 400;
}
.hero__cta { display: flex; gap: 12px; flex-wrap: wrap; }
.hero__glow {
  position: absolute; top: -200px; right: -200px;
  width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(42,108,255,.12) 0%, rgba(42,108,255,0) 65%);
  pointer-events: none; z-index: 1;
}

.trust { padding: 32px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--bg-soft); }
.trust__inner { text-align: center; font-size: 14px; color: var(--muted); letter-spacing: 0; }

.section { padding: 140px 0; }
.section__head { max-width: 760px; margin-bottom: 80px; }
.section__kicker {
  display: block; font-size: 13px; font-weight: 500; color: var(--accent);
  margin-bottom: 16px; letter-spacing: 0.02em; text-transform: uppercase;
}
.section__lede {
  font-size: clamp(18px, 1.8vw, 22px); color: var(--muted);
  margin: 24px 0 0; max-width: 640px; line-height: 1.5; font-weight: 400;
}
.section--dark { background: var(--bg-dark); color: #f5f5f7; }
.section--dark .section__title, .section--dark h3 { color: #f5f5f7; }
.section--dark .section__lede, .section--dark p { color: var(--muted-2); }
.section--dark .section__kicker { color: #5a8bff; }

.cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; margin-bottom: 96px; }
.card {
  background: var(--bg-soft); border: 1px solid var(--line);
  border-radius: var(--r-xl); padding: 48px 40px;
  transition: transform var(--t-med), border-color var(--t-med), background var(--t-med);
}
.card:hover { transform: translateY(-4px); border-color: var(--ink); background: #fff; }
.card__num { font-size: 14px; font-weight: 500; color: var(--muted); margin-bottom: 24px; }
.card__title { font-size: clamp(24px, 2.6vw, 32px); font-weight: 600; letter-spacing: -0.025em; margin-bottom: 16px; }
.card__body { color: var(--muted); margin: 0 0 24px; font-size: 16px; }
.card__list { list-style: none; padding: 0; margin: 0; border-top: 1px solid var(--line); }
.card__list li {
  padding: 14px 0; border-bottom: 1px solid var(--line);
  font-size: 15px; color: var(--ink-2); position: relative; padding-left: 20px;
}
.card__list li::before {
  content: ""; position: absolute; left: 0; top: 22px;
  width: 6px; height: 6px; border-radius: 50%; background: var(--accent);
}

.process { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; padding-top: 64px; border-top: 1px solid var(--line); }
.process__item h4 { font-size: 18px; margin: 16px 0 8px; font-weight: 600; }
.process__item p { color: var(--muted); font-size: 14px; margin: 0; line-height: 1.5; }
.process__step { font-size: 12px; font-weight: 500; color: var(--accent); letter-spacing: 0.05em; }

.work { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.work__item {
  border-radius: var(--r-xl); overflow: hidden;
  background: var(--bg-dark-2); border: 1px solid var(--line-dark);
  transition: transform var(--t-med);
}
.work__item:hover { transform: translateY(-4px); }
.work__media { aspect-ratio: 16 / 10; position: relative; overflow: hidden; }
.work__media--1 { background: linear-gradient(135deg, #1a1a2e 0%, #2a6cff 100%); }
.work__media--2 { background: linear-gradient(135deg, #0f3460 0%, #16213e 100%); }
.work__media--3 { background: linear-gradient(135deg, #2c1810 0%, #ff6b35 100%); }
.work__media--4 { background: linear-gradient(135deg, #1f1f22 0%, #6e6e73 100%); }
.work__media::after {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(circle at 20% 30%, rgba(255,255,255,.08) 0%, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(255,255,255,.06) 0%, transparent 40%);
}
.work__body { padding: 32px; }
.work__tag {
  display: inline-block; font-size: 12px; font-weight: 500; color: #5a8bff;
  letter-spacing: 0.04em; text-transform: uppercase; margin-bottom: 12px;
}
.work__body h3 { font-size: 24px; font-weight: 600; letter-spacing: -0.02em; margin-bottom: 12px; }
.work__body p { color: var(--muted-2); margin: 0; font-size: 15px; }
.work__note { margin-top: 64px; text-align: center; color: var(--muted-2); font-size: 15px; }
.work__note a { color: #5a8bff; text-decoration: underline; text-underline-offset: 4px; }

.team { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.team__card {
  background: var(--bg-soft); border: 1px solid var(--line);
  border-radius: var(--r-lg); padding: 32px;
  transition: transform var(--t-med), border-color var(--t-med);
}
.team__card:hover { transform: translateY(-3px); border-color: var(--ink); }
.team__avatar { width: 72px; height: 72px; border-radius: 50%; margin-bottom: 24px; }
.team__avatar--1 { background: linear-gradient(135deg, #2a6cff, #1a1a2e); }
.team__avatar--2 { background: linear-gradient(135deg, #0a0a0a, #6e6e73); }
.team__avatar--3 { background: linear-gradient(135deg, #1d1d1f, #2a6cff); }
.team__card h4 { font-size: 19px; font-weight: 600; margin-bottom: 4px; letter-spacing: -0.015em; }
.team__role { display: block; color: var(--accent); font-size: 13px; font-weight: 500; margin-bottom: 12px; letter-spacing: 0.02em; }
.team__card p { color: var(--muted); font-size: 15px; margin: 0; }

.section--book { background: linear-gradient(180deg, #fafafa 0%, #ffffff 100%); }
.book { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.book__card { background: var(--ink); color: #fff; border-radius: var(--r-xl); padding: 48px; }
.book__card h3 { color: #fff; font-size: 28px; margin-bottom: 12px; font-weight: 600; letter-spacing: -0.02em; }
.book__card p { color: var(--muted-2); margin: 0 0 28px; font-size: 16px; }
.book__card .btn--primary { background: #fff; color: var(--ink); }
.book__card .btn--primary:hover { background: #f5f5f7; color: var(--ink); }
.book__alt { margin-top: 24px !important; font-size: 14px !important; }
.book__alt a { color: #fff; text-decoration: underline; text-underline-offset: 4px; }

.footer { background: var(--bg-dark); color: #f5f5f7; padding: 80px 0 32px; }
.footer__inner { display: grid; grid-template-columns: 1.2fr 2fr; gap: 64px; padding-bottom: 64px; border-bottom: 1px solid var(--line-dark); }
.footer__logo { display: flex; align-items: center; gap: 10px; font-weight: 600; font-size: 18px; color: #fff; margin-bottom: 16px; }
.footer__logo svg { width: 28px; height: 28px; color: #fff; }
.footer__brand p { color: var(--muted-2); margin: 0; font-size: 15px; max-width: 280px; }
.footer__cols { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.footer__cols h5 { font-size: 13px; color: var(--muted-2); font-weight: 500; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 20px; }
.footer__cols a, .footer__cols span { display: block; color: #f5f5f7; font-size: 15px; margin-bottom: 12px; }
.footer__cols a:hover { color: #5a8bff; }
.footer__base { display: flex; justify-content: space-between; padding-top: 32px; color: var(--muted-2); font-size: 13px; }

.reveal { opacity: 0; transform: translateY(24px); transition: opacity var(--t-slow), transform var(--t-slow); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }

@media (max-width: 900px) {
  .nav__links { display: none; }
  .nav__toggle { display: flex; }
  .nav .btn--small { display: none; }
  .hero { padding: 140px 0 80px; }
  .section { padding: 96px 0; }
  .section__head { margin-bottom: 48px; }
  .cards, .work, .team, .process, .book, .footer__inner { grid-template-columns: 1fr; gap: 24px; }
  .process { padding-top: 48px; gap: 40px; }
  .book__card { padding: 32px; }
  .footer__cols { grid-template-columns: repeat(2, 1fr); }
  .footer__base { flex-direction: column; gap: 8px; }
}
@media (max-width: 540px) {
  .footer__cols { grid-template-columns: 1fr; }
  .card { padding: 36px 28px; }
  .work__body { padding: 24px; }
}