:root {
  --bg: #0a0b0d;
  --bg-2: #111317;
  --graphite: #181b20;
  --graphite-2: #22262c;
  --line: rgba(200, 206, 213, .12);
  --line-2: rgba(200, 206, 213, .22);
  --ti: #c3c8ce;
  --ti-bright: #eceef0;
  --muted: #8a9199;
  --signal: #2f80f7;
  --ti-grad: linear-gradient(135deg, #f1f3f5 0%, #a5acb4 48%, #dfe2e5 100%);
  --radius: 4px;
  --font-head: "Unbounded", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Manrope", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
  --wrap: 1200px;
  --gutter: clamp(16px, 4vw, 40px);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ti);
  font: 400 16px/1.6 var(--font-body);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, svg { display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3 { font-family: var(--font-head); font-weight: 500; color: var(--ti-bright); margin: 0; letter-spacing: -.01em; }
h1 { font-size: clamp(34px, 5.4vw, 68px); line-height: 1.05; }
h2 { font-size: clamp(26px, 3.4vw, 42px); line-height: 1.15; }
h3 { font-size: 16px; line-height: 1.3; }
p { margin: 0; }
html[lang="zh"] h1, html[lang="zh"] h2, html[lang="zh"] h3 { letter-spacing: .02em; font-weight: 600; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
.lead { color: var(--muted); font-size: clamp(16px, 1.4vw, 18px); max-width: 60ch; }
.label {
  font: 500 12px/1 var(--font-mono);
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 20px;
}

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px;
  padding: 14px 26px;
  border: 0; border-radius: var(--radius);
  background: var(--ti-grad);
  color: #0a0b0d;
  font: 600 15px/1 var(--font-body);
  cursor: pointer;
  transition: filter .2s, transform .2s;
}
.btn:hover { filter: brightness(1.08); transform: translateY(-1px); }
.btn--ghost { background: transparent; color: var(--ti-bright); box-shadow: inset 0 0 0 1px var(--line-2); }
.btn--ghost:hover { box-shadow: inset 0 0 0 1px var(--ti); }
.btn--sm { padding: 10px 16px; font-size: 14px; }
.btn--full { width: 100%; }
.btn:disabled { opacity: .6; cursor: progress; transform: none; }

/* header */
.header {
  position: sticky; top: 0; z-index: 20;
  background: rgba(10, 11, 13, .78);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.header__inner { display: flex; align-items: center; gap: 32px; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; }
.brand__emblem { height: 40px; width: auto; mix-blend-mode: lighten; }
.footer__logo img { width: 88px; height: 88px; mix-blend-mode: lighten; }
.brand__word { font: 400 15px/1 "Michroma", var(--font-head); letter-spacing: .08em; color: #f2f3f5; }
.brand__word span { margin-left: .5em; color: var(--signal); letter-spacing: .3em; font-size: .8em; }
.nav { display: flex; gap: 28px; margin-left: auto; font-size: 14px; }
.nav a { color: var(--muted); transition: color .2s; white-space: nowrap; }
.header__cta { white-space: nowrap; }
.nav a:hover { color: var(--ti-bright); }
.header__tools { display: flex; align-items: center; gap: 16px; }
.lang { display: flex; border: 1px solid var(--line-2); border-radius: var(--radius); overflow: hidden; }
.lang button {
  background: none; border: 0; color: var(--muted);
  font: 500 12px/1 var(--font-mono); padding: 8px 10px; cursor: pointer; white-space: nowrap;
}
.lang button + button { border-left: 1px solid var(--line-2); }
.lang button.is-active { background: var(--graphite-2); color: var(--ti-bright); }
.burger { display: none; background: none; border: 0; width: 36px; height: 36px; cursor: pointer; padding: 8px; }
.burger span { display: block; height: 1.5px; background: var(--ti-bright); margin: 6px 0; transition: transform .2s; }
.burger[aria-expanded="true"] span:first-child { transform: translateY(3.75px) rotate(45deg); }
.burger[aria-expanded="true"] span:last-child { transform: translateY(-3.75px) rotate(-45deg); }

/* hero */
.hero { position: relative; padding: clamp(48px, 8vw, 110px) 0 56px; overflow: hidden; }
.hero__grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 70% 60% at 65% 40%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 70% 60% at 65% 40%, #000 20%, transparent 75%);
  opacity: .6;
}
.hero__inner { position: relative; display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: center; }
.hero__text { display: flex; flex-direction: column; gap: 26px; }
.hero h1 {
  background: var(--ti-grad);
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.kicker { display: flex; align-items: center; gap: 10px; font: 500 12px/1 var(--font-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); }
.dot { width: 6px; height: 6px; border-radius: 50%; background: var(--signal); box-shadow: 0 0 0 4px rgba(47, 128, 247, .2); }
.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 6px; }

.hero__visual { color: var(--ti); position: relative; display: grid; place-items: center; }
.blueprint { width: 100%; height: auto; max-width: 520px; grid-area: 1 / 1; }
.hero__logo { grid-area: 1 / 1; width: 112%; max-width: 620px; height: auto; mix-blend-mode: lighten; position: relative; }
.bp-faint { stroke-opacity: .16; stroke-width: 1; }
.bp-path { stroke: var(--signal); stroke-opacity: .7; stroke-width: 1.2; stroke-dasharray: 4 6; animation: dash 24s linear infinite; }
.bp-dim { opacity: .45; }
.bp-logo { opacity: .95; filter: drop-shadow(0 20px 40px rgba(0, 0, 0, .6)); }
.bp-marker { color: var(--signal); }
.bp-branch { stroke: var(--signal); stroke-opacity: .4; stroke-width: 1; stroke-dasharray: 2 5; animation: dash 30s linear infinite; }
.bp-nodes { color: var(--signal); opacity: .85; }
.bp-labels { color: var(--ti); opacity: .7; }
.bp-labels .bp-main { fill: var(--signal); font-weight: 500; opacity: 1; }
.bp-pulse { color: var(--signal); opacity: .8; }
@keyframes dash { to { stroke-dashoffset: -400; } }

.specs {
  display: grid; grid-template-columns: repeat(4, 1fr);
  margin: 64px 0 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
}
.specs div { padding: 20px 20px 20px 0; }
.specs div + div { padding-left: 20px; border-left: 1px solid var(--line); }
.specs dt { font: 500 11px/1 var(--font-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); margin-bottom: 10px; }
.specs dd { margin: 0; color: var(--ti-bright); font-weight: 500; }

/* sections */
.section { padding: clamp(72px, 10vw, 130px) 0; border-top: 1px solid var(--line); }
.section--alt { background: var(--bg-2); }
.section__head { display: flex; flex-direction: column; gap: 18px; margin-bottom: 56px; }

.about { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; }
.about__body { display: flex; flex-direction: column; gap: 20px; font-size: 18px; color: var(--ti); padding-top: 32px; }
.about__note { font: 400 13px/1.5 var(--font-mono); color: var(--muted); padding-top: 20px; border-top: 1px solid var(--line); }

.cards { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.card {
  position: relative;
  background: var(--bg-2);
  padding: 28px 24px 32px;
  display: flex; flex-direction: column; gap: 10px;
  min-height: 220px;
  transition: background .25s;
}
.card:hover { background: var(--graphite); }
.card p { color: var(--muted); font-size: 14px; }
.card__code { position: absolute; top: 24px; right: 22px; font: 500 11px/1 var(--font-mono); color: var(--muted); opacity: .7; }
.icon { width: 36px; height: 36px; margin-bottom: auto; fill: none; stroke: var(--ti); stroke-width: 1.4; stroke-linecap: round; stroke-linejoin: round; padding-bottom: 28px; box-sizing: content-box; }
.card--accent .icon { stroke: var(--signal); }
.card--accent::after { content: ""; position: absolute; left: 0; top: 0; width: 2px; height: 100%; background: var(--signal); opacity: .6; }

.steps { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(5, 1fr); gap: 24px; counter-reset: s; }
.steps li { position: relative; display: flex; flex-direction: column; gap: 10px; padding-top: 28px; border-top: 1px solid var(--line-2); }
.steps li::before { content: ""; position: absolute; top: -4px; left: 0; width: 7px; height: 7px; border-radius: 50%; background: var(--bg); border: 1px solid var(--ti); }
.steps li:last-child::before { background: var(--signal); border-color: var(--signal); }
.steps__n { font: 500 12px/1 var(--font-mono); color: var(--muted); }
.steps p { color: var(--muted); font-size: 14px; }

.contact { display: grid; grid-template-columns: .9fr 1.1fr; gap: 64px; align-items: start; }
.contact__info { display: flex; flex-direction: column; gap: 18px; }
.contact__info .label { margin-bottom: 2px; }
.channels { list-style: none; padding: 0; margin: 20px 0 0; border-top: 1px solid var(--line); }
.channels li { display: flex; justify-content: space-between; align-items: baseline; gap: 16px; padding: 16px 0; border-bottom: 1px solid var(--line); }
.channels span { font: 500 11px/1 var(--font-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); }
.channels a { color: var(--ti-bright); font-weight: 500; transition: color .2s; }
.channels a:hover { color: var(--signal); }

.form { display: flex; flex-direction: column; gap: 16px; padding: 32px; background: var(--graphite); border: 1px solid var(--line); border-radius: var(--radius); }
.form__row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form__row--wide { grid-template-columns: 2fr 1fr; }
.form label { display: flex; flex-direction: column; gap: 8px; min-width: 0; }
.form label span { font: 500 11px/1 var(--font-mono); letter-spacing: .12em; text-transform: uppercase; color: var(--muted); }
.form input, .form textarea {
  width: 100%;
  background: var(--bg); color: var(--ti-bright);
  border: 1px solid var(--line-2); border-radius: var(--radius);
  padding: 12px 14px; font: 400 15px/1.4 var(--font-body);
  transition: border-color .2s;
}
.form textarea { resize: vertical; }
.form input::placeholder { color: #565c63; }
.form input:focus, .form textarea:focus { outline: none; border-color: var(--ti); }
.form .btn { margin-top: 8px; }
.form__status { min-height: 1.4em; font-size: 14px; color: var(--muted); }
.form__status.is-ok { color: var(--signal); }
.form__status.is-err { color: #e0a39a; }
.hp { position: absolute; left: -9999px; }

.footer { border-top: 1px solid var(--line); padding: 32px 0; font-size: 13px; color: var(--muted); }
.footer__inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; }

:focus-visible { outline: 1px solid var(--signal); outline-offset: 3px; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .bp-path, .bp-branch { animation: none; }
  .bp-pulse { display: none; }
  .bp-marker { display: none; }
}

@media (max-width: 1080px) {
  .cards { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(3, 1fr); row-gap: 40px; }
}

@media (max-width: 1140px) {
  .nav {
    position: absolute; top: 68px; left: 0; right: 0;
    flex-direction: column; gap: 0;
    background: var(--bg); border-bottom: 1px solid var(--line);
    padding: 8px var(--gutter) 16px;
    display: none;
  }
  .nav.is-open { display: flex; }
  .nav a { padding: 12px 0; font-size: 16px; border-bottom: 1px solid var(--line); }
  .burger { display: block; }
  .header__tools { margin-left: auto; }
}

@media (max-width: 900px) {
  .hero__inner, .about, .contact { grid-template-columns: 1fr; gap: 40px; }
  .hero__visual { order: -1; max-width: 340px; margin: 0 auto; width: 100%; }
  .about__body { padding-top: 0; }
  .specs { grid-template-columns: repeat(2, 1fr); }
  .specs div:nth-child(3) { padding-left: 0; border-left: 0; }
  .specs div:nth-child(n+3) { border-top: 1px solid var(--line); }
}

@media (max-width: 600px) {
  .header__cta { display: none; }
  .brand__word { font-size: 11px; }
  .brand__word span { margin-left: .35em; letter-spacing: .2em; }
  .brand { gap: 6px; min-width: 0; }
  .brand__emblem { height: 28px; }
  .header__inner { gap: 8px; }
  .header__tools { gap: 6px; }
  .lang button { padding: 7px 6px; font-size: 11px; }
  .burger { width: 32px; padding: 6px; }
  .cards { grid-template-columns: 1fr; }
  .card { min-height: 0; }
  .steps { grid-template-columns: 1fr; }
  .form { padding: 20px; }
  .form__row, .form__row--wide { grid-template-columns: 1fr; }
  .channels li { flex-direction: column; gap: 8px; }
  .hero__actions .btn { flex: 1 1 100%; }
}

@media (max-width: 400px) {
  .header .brand__word { display: none; }
}