:root {
  --bg: #0a0b0d;
  --bg-alt: #0e1013;
  --surface: #13161b;
  --line: #1f242c;
  --line-strong: #2b323c;
  --text: #e7e9ec;
  --muted: #8a93a0;
  --dim: #5d6672;
  --accent: #ff8a3d;
  --good: #4fd1a5;
  --sans: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --radius: 10px;
  --wrap: 1120px;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 72px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

html[data-lang="en"] body [lang="zh-CN"],
html[data-lang="zh"] body [lang="en"] { display: none; }

a { color: inherit; text-decoration: none; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }
.muted { color: var(--dim); }

.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(10, 11, 13, 0.82);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; font: 600 17px/1 var(--mono); letter-spacing: -0.02em; }
.brand-mark { width: 22px; height: 22px; color: var(--accent); }
.nav-links { display: flex; align-items: center; gap: 26px; font-size: 14px; color: var(--muted); }
.nav-links a:hover { color: var(--text); }
.nav-cta { color: var(--text) !important; }
.lang-toggle {
  font: 500 12px/1 var(--mono);
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  padding: 7px 10px;
  cursor: pointer;
}
.lang-toggle:hover { color: var(--text); border-color: var(--dim); }

.hero {
  position: relative;
  padding: 128px 0 150px;
  overflow: hidden;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 56px 56px;
  background-position: -1px -1px;
}
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 30% 40%, transparent 0%, var(--bg) 72%);
  pointer-events: none;
}
.hero-inner { position: relative; z-index: 1; max-width: var(--wrap); }
.eyebrow {
  margin: 0 0 24px;
  font: 500 12px/1 var(--mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}
h1 {
  margin: 0 0 24px;
  font-size: clamp(40px, 6vw, 72px);
  line-height: 1.04;
  letter-spacing: -0.035em;
  font-weight: 650;
}
.lead { margin: 0 0 38px; max-width: 600px; font-size: 19px; color: var(--muted); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }

.pulse {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 28px;
  width: 100%;
  height: 90px;
  color: var(--accent);
  opacity: 0.55;
  z-index: 1;
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  animation: draw 2.2s cubic-bezier(0.3, 0.6, 0.2, 1) 0.2s forwards;
}
@keyframes draw { to { stroke-dashoffset: 0; } }

.btn {
  display: inline-flex;
  align-items: center;
  height: 46px;
  padding: 0 20px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 550;
  transition: background 0.15s, border-color 0.15s;
}
.btn-primary { background: var(--accent); color: #140a02; }
.btn-primary:hover { background: #ff9d5c; }
.btn-ghost { border: 1px solid var(--line-strong); color: var(--text); }
.btn-ghost:hover { border-color: var(--dim); }

.pillars { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--bg-alt); }
.pillars-grid { display: grid; grid-template-columns: repeat(3, 1fr); }
.pillar { padding: 34px 28px 30px; border-left: 1px solid var(--line); }
.pillar:first-child { border-left: 0; padding-left: 0; }
.pillar h3 { margin: 0 0 8px; font: 600 18px/1.3 var(--mono); letter-spacing: -0.02em; }
.pillar p { margin: 0; font-size: 14px; color: var(--muted); }

.section { padding: 104px 0; }
.section-alt { background: var(--bg-alt); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section-head { max-width: 680px; margin-bottom: 48px; }
.kicker { margin: 0 0 14px; font: 500 12px/1 var(--mono); color: var(--accent); }
h2 { margin: 0 0 16px; font-size: clamp(30px, 3.6vw, 42px); line-height: 1.12; letter-spacing: -0.03em; font-weight: 650; }
.section-sub { margin: 0; font-size: 17px; color: var(--muted); }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.card {
  padding: 30px 28px 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.2s;
}
.card:hover { border-color: var(--line-strong); }
.card-n { font: 600 12px/1 var(--mono); color: var(--accent); }
.card h3 { margin: 14px 0 18px; font-size: 20px; letter-spacing: -0.015em; }
.card ul { margin: 0; padding: 0; list-style: none; }
.card li { position: relative; padding: 12px 0 12px 20px; border-top: 1px dashed var(--line-strong); color: var(--muted); font-size: 15px; }
.card li::before { content: ""; position: absolute; left: 0; top: 1.4em; width: 8px; height: 1px; background: var(--accent); }

.principles { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.principle { padding: 26px 24px; border-top: 2px solid var(--line-strong); }
.principle:first-child { border-top-color: var(--accent); }
.principle h3 { margin: 0 0 8px; font-size: 18px; }
.principle p { margin: 0; font-size: 14px; color: var(--muted); }

.steps { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.steps li { padding: 26px 24px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
.step-n { font: 600 13px/1 var(--mono); color: var(--accent); }
.steps h3 { margin: 12px 0 8px; font-size: 18px; }
.steps p { margin: 0; font-size: 14px; color: var(--muted); }

.contact { text-align: center; }
.contact-inner { max-width: 720px; }
.contact .section-sub { margin: 0 auto 40px; max-width: 520px; }
.contact-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.contact-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 32px 20px 28px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font: inherit;
  cursor: pointer;
  transition: border-color 0.2s, transform 0.2s;
}
.contact-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.contact-card svg { width: 30px; height: 30px; color: var(--accent); margin-bottom: 6px; }
.contact-label { font-size: 13px; color: var(--muted); }
.contact-handle { font: 600 19px/1.2 var(--mono); }
.copy-hint { font-size: 12px; color: var(--dim); }
.copy.copied .copy-hint { color: var(--good); }

.footer { border-top: 1px solid var(--line); padding: 28px 0; font-size: 13px; color: var(--muted); }
.footer-inner { display: flex; justify-content: space-between; }

a:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 6px; }

@media (max-width: 980px) {
  .cards { grid-template-columns: 1fr; }
  .principles, .steps { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .nav-links a:not(.nav-cta) { display: none; }
  .hero { padding: 80px 0 120px; }
  .section { padding: 72px 0; }
  .pillars-grid, .principles, .steps, .contact-cards { grid-template-columns: 1fr; }
  .pillar { border-left: 0; padding-left: 0; }
  .pillar + .pillar { border-top: 1px solid var(--line); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .pulse { animation: none; stroke-dashoffset: 0; }
  .contact-card { transition: none; }
}