/* ===================================================================
   OneBlockTech — dark tech style
   =================================================================== */
:root {
  --bg: #070a12;
  --bg-2: #0b1020;
  --surface: #0f1626;
  --surface-2: #131c30;
  --border: #1e2a44;
  --border-soft: #172137;
  --text: #eaf0fb;
  --text-dim: #9aa8c4;
  --text-mute: #6b7a99;
  --c1: #38bdf8;   /* cyan   */
  --c2: #818cf8;   /* indigo */
  --c3: #a78bfa;   /* violet */
  --grad: linear-gradient(115deg, var(--c1), var(--c2) 55%, var(--c3));
  --radius: 16px;
  --maxw: 1140px;
  --ease: cubic-bezier(.16,.84,.44,1);
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
}

/* ===== Light theme ===== */
:root[data-theme="light"] {
  --bg: #f6f8fc;
  --bg-2: #eef2f9;
  --surface: #ffffff;
  --surface-2: #f3f6fb;
  --border: #e2e8f2;
  --border-soft: #eaeff7;
  --text: #0e1726;
  --text-dim: #45546d;
  --text-mute: #6d7c96;
}
:root[data-theme="light"] .nav { background: rgba(255,255,255,.6); }
:root[data-theme="light"] .nav.scrolled { background: rgba(255,255,255,.85); border-bottom-color: var(--border-soft); }
:root[data-theme="light"] .bg-glow { opacity: .5; }
:root[data-theme="light"] .bg-grid {
  background-image:
    linear-gradient(rgba(80,110,170,.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(80,110,170,.08) 1px, transparent 1px);
}
:root[data-theme="light"] .section-alt {
  background: linear-gradient(180deg, transparent, var(--surface-2) 20%, var(--surface-2) 80%, transparent);
}
:root[data-theme="light"] .btn-ghost { background: rgba(15,22,40,.02); }
:root[data-theme="light"] .card:hover { box-shadow: 0 22px 50px -26px rgba(56,189,248,.28); }
:root[data-theme="light"] .btn-primary {
  background: linear-gradient(115deg, #0284c7, #4f46e5 52%, #7c3aed);
  color: #ffffff;
  box-shadow: 0 6px 20px -6px rgba(79,70,229,.4);
}
:root[data-theme="light"] .btn-primary:hover { box-shadow: 0 12px 30px -8px rgba(124,58,237,.5); }

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img, svg { display: block; }
:focus-visible { outline: 2px solid var(--c1); outline-offset: 3px; border-radius: 6px; }

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

/* ===== Background layers ===== */
.bg-grid {
  position: fixed; inset: 0; z-index: -2;
  background-image:
    linear-gradient(rgba(56,189,248,.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(56,189,248,.045) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 40%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 40%, transparent 100%);
}
.bg-glow {
  position: fixed; inset: 0; z-index: -3; pointer-events: none;
  background:
    radial-gradient(700px 420px at 15% -5%, rgba(56,189,248,.16), transparent 70%),
    radial-gradient(760px 460px at 90% 0%, rgba(167,139,250,.15), transparent 70%);
}

/* ===== Nav ===== */
.nav {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(7,10,18,.55);
  border-bottom: 1px solid transparent;
  transition: background .3s var(--ease), border-color .3s var(--ease);
}
.nav.scrolled { background: rgba(7,10,18,.82); border-bottom-color: var(--border-soft); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; gap: 24px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 19px; letter-spacing: -.02em; }
.brand-name { white-space: nowrap; }
.brand-mark { display: grid; place-items: center; filter: drop-shadow(0 3px 10px rgba(56,189,248,.35)); }
.brand-accent { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

.nav-links { display: flex; gap: 30px; margin-left: auto; }
.nav-links a { color: var(--text-dim); font-size: 14.5px; font-weight: 500; position: relative; transition: color .2s; }
.nav-links a::after {
  content: ""; position: absolute; left: 0; bottom: -6px; height: 2px; width: 0;
  background: var(--grad); transition: width .25s var(--ease);
}
.nav-links a:hover { color: var(--text); }
.nav-links a:hover::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 14px; }
.lang-toggle {
  display: inline-flex; align-items: center; gap: 4px; cursor: pointer;
  background: var(--surface); border: 1px solid var(--border); color: var(--text-mute);
  border-radius: 9px; padding: 6px 11px; font-size: 13px; font-weight: 600; font-family: inherit;
  transition: border-color .2s, color .2s;
}
.lang-toggle:hover { border-color: var(--c2); }
.icon-btn {
  display: inline-grid; place-items: center; width: 38px; height: 36px;
  background: var(--surface); border: 1px solid var(--border); color: var(--text-dim);
  border-radius: 9px; cursor: pointer; transition: border-color .2s, color .2s;
}
.icon-btn:hover { border-color: var(--c2); color: var(--text); }
.icon-btn .moon { display: none; }
.icon-btn .sun { display: block; }
:root[data-theme="light"] .icon-btn .sun { display: none; }
:root[data-theme="light"] .icon-btn .moon { display: block; }
.lang-sep { opacity: .4; }
.lang-opt { transition: color .2s; }
.lang-opt.active { color: var(--text); }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: inherit; font-weight: 600; font-size: 15px; cursor: pointer;
  border-radius: 11px; padding: 12px 22px; border: 1px solid transparent;
  transition: transform .18s var(--ease), box-shadow .25s var(--ease), background .25s, border-color .2s;
  white-space: nowrap;
}
.btn-sm { padding: 8px 15px; font-size: 13.5px; border-radius: 9px; }
.btn-lg { padding: 15px 30px; font-size: 16px; }
.btn-primary {
  background: var(--grad); color: #060a14; box-shadow: 0 6px 22px -6px rgba(56,189,248,.5);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 30px -8px rgba(129,140,248,.6); }
.btn-ghost { background: rgba(255,255,255,.03); border-color: var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--c2); transform: translateY(-2px); background: rgba(129,140,248,.08); }

/* ===== Hero ===== */
.hero { position: relative; padding: 92px 0 64px; }
.hero-inner { display: flex; flex-direction: column; align-items: center; text-align: center; }
.badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text-dim); font-size: 13.5px; font-weight: 500;
  padding: 7px 16px; border-radius: 999px; margin-bottom: 28px;
}
.hero-title {
  font-size: clamp(38px, 6.2vw, 68px); line-height: 1.08; font-weight: 800;
  letter-spacing: -.03em; max-width: 15ch; margin-bottom: 24px;
}
.hero-title span { display: block; }
.grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-sub {
  font-size: clamp(16px, 2.2vw, 19px); color: var(--text-dim);
  max-width: 62ch; margin-bottom: 38px;
}
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; justify-content: center; margin-bottom: 60px; }
.hero-stats { display: flex; gap: 52px; flex-wrap: wrap; justify-content: center; }
.stat-num {
  font-size: 34px; font-weight: 800; letter-spacing: -.02em;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat-label { font-size: 13.5px; color: var(--text-mute); margin-top: 2px; }

/* ===== Sections ===== */
.section { padding: 88px 0; position: relative; }
.section-alt {
  background: linear-gradient(180deg, transparent, rgba(15,22,38,.5) 20%, rgba(15,22,38,.5) 80%, transparent);
  border-top: 1px solid var(--border-soft); border-bottom: 1px solid var(--border-soft);
}
.section-head { text-align: center; max-width: 640px; margin: 0 auto 54px; }
.eyebrow {
  display: inline-block; font-size: 13px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; margin-bottom: 14px;
}
.section-title { font-size: clamp(27px, 4vw, 40px); font-weight: 800; letter-spacing: -.02em; line-height: 1.15; }
.section-desc { color: var(--text-dim); font-size: 17px; margin-top: 16px; }

/* ===== Service cards ===== */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.card {
  position: relative; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 30px 28px; overflow: hidden;
  transition: transform .3s var(--ease), border-color .3s, box-shadow .3s;
}
.card::before {
  content: ""; position: absolute; inset: 0; padding: 1px; border-radius: inherit;
  background: var(--grad); opacity: 0; transition: opacity .3s;
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude;
}
.card:hover { transform: translateY(-6px); box-shadow: 0 22px 50px -22px rgba(56,189,248,.35); }
.card:hover::before { opacity: 1; }
.card-icon {
  width: 52px; height: 52px; border-radius: 13px; display: grid; place-items: center;
  color: var(--c1); background: linear-gradient(150deg, rgba(56,189,248,.14), rgba(167,139,250,.12));
  border: 1px solid var(--border); margin-bottom: 20px;
}
.card-title { font-size: 20px; font-weight: 700; margin-bottom: 10px; letter-spacing: -.01em; }
.card-desc { color: var(--text-dim); font-size: 15px; margin-bottom: 18px; }
.card-list { list-style: none; display: flex; flex-direction: column; gap: 9px; }
.card-list li { position: relative; padding-left: 22px; color: var(--text-mute); font-size: 14.5px; }
.card-list li::before {
  content: ""; position: absolute; left: 0; top: 8px; width: 8px; height: 8px; border-radius: 3px;
  background: var(--grad);
}

/* ===== Features ===== */
.features { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.feature { padding: 26px 22px; border-left: 1px solid var(--border); }
.feature-num {
  font-size: 15px; font-weight: 800; letter-spacing: .05em;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; margin-bottom: 14px;
}
.feature h3 { font-size: 17.5px; font-weight: 700; margin-bottom: 8px; }
.feature p { color: var(--text-dim); font-size: 14.5px; }

/* ===== Process steps ===== */
.steps { display: grid; grid-template-columns: repeat(5, 1fr); gap: 18px; }
.step {
  position: relative; background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 24px 20px; transition: transform .3s var(--ease), border-color .3s;
}
.step:hover { transform: translateY(-5px); border-color: var(--c2); }
.step-num {
  font-size: 22px; font-weight: 800; letter-spacing: .02em; margin-bottom: 12px;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.step h3 { font-size: 16.5px; font-weight: 700; margin-bottom: 8px; }
.step p { color: var(--text-dim); font-size: 13.5px; line-height: 1.6; }

/* ===== Technologies ===== */
.tech-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.tech-group {
  background: var(--surface); border: 1px solid var(--border); border-radius: 14px; padding: 24px 22px;
}
.tech-group h3 {
  font-size: 14px; font-weight: 700; letter-spacing: .04em; text-transform: uppercase;
  color: var(--text-mute); margin-bottom: 16px;
}
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chips span {
  font-size: 13.5px; color: var(--text-dim); padding: 6px 12px; border-radius: 8px;
  background: rgba(129,140,248,.07); border: 1px solid var(--border);
}

/* ===== FAQ ===== */
.faq-list { max-width: 820px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
  padding: 4px 22px; transition: border-color .25s;
}
.faq-item[open] { border-color: var(--c2); }
.faq-item summary {
  cursor: pointer; list-style: none; padding: 18px 34px 18px 0; position: relative;
  font-size: 16px; font-weight: 600; color: var(--text);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; position: absolute; right: 2px; top: 50%; transform: translateY(-50%);
  font-size: 22px; font-weight: 400; color: var(--c1); transition: transform .25s var(--ease);
}
.faq-item[open] summary::after { transform: translateY(-50%) rotate(45deg); }
.faq-item p { color: var(--text-dim); font-size: 14.5px; line-height: 1.7; padding: 0 0 20px; margin: 0; }

/* ===== About ===== */
.about-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px; align-items: center; }
.about-text .section-title { margin: 10px 0 20px; }
.about-text p { color: var(--text-dim); font-size: 16px; margin-bottom: 16px; }
.about-text .btn { margin-top: 10px; }
.about-panel {
  position: relative; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 12px 26px; overflow: hidden;
}
.panel-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 0; border-bottom: 1px solid var(--border-soft); font-size: 15px;
}
.panel-row:last-of-type { border-bottom: none; }
.panel-row span { color: var(--text-mute); }
.panel-row b { color: var(--text); font-weight: 600; }
.panel-glow {
  position: absolute; width: 200px; height: 200px; right: -60px; bottom: -70px;
  background: radial-gradient(circle, rgba(129,140,248,.28), transparent 70%); filter: blur(20px);
}

/* ===== CTA ===== */
.cta-box {
  position: relative; text-align: center; border-radius: 24px; padding: 66px 32px;
  background: linear-gradient(150deg, var(--surface-2), var(--surface));
  border: 1px solid var(--border); overflow: hidden;
}
.cta-box::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(500px 240px at 50% -20%, rgba(56,189,248,.2), transparent 70%);
}
.cta-title { font-size: clamp(26px, 4vw, 38px); font-weight: 800; letter-spacing: -.02em; position: relative; }
.cta-sub { color: var(--text-dim); font-size: 17px; margin: 14px auto 30px; max-width: 50ch; position: relative; }
.cta-actions { position: relative; display: flex; justify-content: center; }
.contact-info {
  position: relative; display: flex; flex-wrap: wrap; gap: 12px 30px;
  justify-content: center; margin-top: 26px;
}
.ci-item {
  display: inline-flex; align-items: center; gap: 9px;
  color: var(--text-dim); font-size: 14.5px; transition: color .2s;
}
.ci-item svg { color: var(--c1); flex-shrink: 0; }
a.ci-item:hover { color: var(--text); }
.cta-note { color: var(--text-mute); font-size: 13.5px; margin-top: 18px; position: relative; }

/* ===== Footer ===== */
.footer { border-top: 1px solid var(--border-soft); padding: 44px 0 30px; }
.footer-top {
  display: flex; align-items: flex-start; justify-content: space-between;
  gap: 30px; flex-wrap: wrap; padding-bottom: 26px; border-bottom: 1px solid var(--border-soft);
}
.footer-brand .brand-name { font-size: 18px; font-weight: 700; }
.footer-brand p { color: var(--text-mute); font-size: 13.5px; margin-top: 4px; }
.footer-contact { display: flex; flex-direction: column; gap: 11px; }
.fc-item {
  display: inline-flex; align-items: center; gap: 9px;
  color: var(--text-dim); font-size: 14px; transition: color .2s;
}
.fc-item svg { color: var(--c1); flex-shrink: 0; }
a.fc-item:hover { color: var(--text); }
.footer-links {
  display: flex; align-items: center; justify-content: space-between; gap: 18px;
  flex-wrap: wrap; padding: 22px 0 4px;
}
.footer-nav { display: flex; flex-wrap: wrap; gap: 8px 24px; }
.footer-nav a { color: var(--text-dim); font-size: 14px; transition: color .2s; }
.footer-nav a:hover { color: var(--text); }
.footer-meta { color: var(--text-mute); font-size: 13px; margin-top: 18px; }

/* ===== Legal pages ===== */
.legal { padding: 56px 0 40px; }
.legal-inner { max-width: 800px; margin: 0 auto; }
.legal h1 { font-size: clamp(28px, 4vw, 40px); font-weight: 800; letter-spacing: -.02em; margin-bottom: 10px; }
.legal .updated { color: var(--text-mute); font-size: 14px; margin-bottom: 36px; }
.legal h2 {
  font-size: 20px; font-weight: 700; margin: 34px 0 12px; padding-top: 6px;
}
.legal p, .legal li { color: var(--text-dim); font-size: 15.5px; line-height: 1.75; }
.legal p { margin-bottom: 14px; }
.legal ul { margin: 0 0 14px; padding-left: 22px; display: flex; flex-direction: column; gap: 8px; }
.legal a { color: var(--c1); }
.legal a:hover { text-decoration: underline; }
.legal .back {
  display: inline-flex; align-items: center; gap: 7px; color: var(--text-dim);
  font-size: 14.5px; margin-bottom: 30px; transition: color .2s;
}
.legal .back:hover { color: var(--text); }

/* ===== Reveal animation ===== */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* ===== Mobile menu overlay + scroll lock ===== */
.nav-overlay {
  position: fixed; inset: 0; z-index: 40; background: rgba(4,7,14,.55);
  backdrop-filter: blur(2px); opacity: 0; visibility: hidden;
  transition: opacity .3s var(--ease), visibility .3s;
}
.nav-overlay.open { opacity: 1; visibility: visible; }
body.no-scroll { overflow: hidden; }

/* ===== Mobile menu button ===== */
.menu-btn { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 6px; }
.menu-btn span { width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: .25s var(--ease); }
.menu-btn.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-btn.open span:nth-child(2) { opacity: 0; }
.menu-btn.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== Responsive ===== */
@media (max-width: 940px) {
  .cards { grid-template-columns: 1fr; }
  .features { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; gap: 34px; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .tech-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 720px) {
  .nav-links {
    position: fixed; top: 68px; right: 0; width: min(78vw, 300px); height: calc(100vh - 68px);
    flex-direction: column; gap: 4px; padding: 22px; margin: 0;
    background: var(--bg-2); border-left: 1px solid var(--border);
    transform: translateX(100%); transition: transform .3s var(--ease);
  }
  .nav-links.open { transform: none; }
  .nav-links a { padding: 14px 8px; font-size: 16px; border-bottom: 1px solid var(--border-soft); }
  .nav-links a::after { display: none; }
  .menu-btn { display: flex; }
  .nav-actions .btn-primary { display: none; }
  .brand { font-size: 16px; gap: 8px; }
  .brand-mark svg { width: 24px; height: 24px; }
  .nav-inner { gap: 12px; }
  .hero { padding: 56px 0 48px; }
  .hero-stats { gap: 10px; width: 100%; }
  .stat { flex: 1 1 0; min-width: 0; }
  .stat-num { font-size: 30px; }
  .stat-label { font-size: 12.5px; }
  .features { grid-template-columns: 1fr; }
  .feature { border-left: none; border-top: 1px solid var(--border); padding: 20px 4px; }
  .steps { grid-template-columns: 1fr; }
  .tech-grid { grid-template-columns: 1fr; }
  .footer-links { flex-direction: column; align-items: flex-start; gap: 14px; }
  .section { padding: 64px 0; }
  .cta-box { padding: 46px 22px; }
  .btn-lg { font-size: 14px; padding: 14px 20px; }
}

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