/* ====== 基础与变量 ====== */
:root {
  --bg: #070b14;
  --bg-soft: #0b1120;
  --bg-card: #0f1726;
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.16);
  --text: #e7eef9;
  --text-soft: #9aa9c2;
  --text-dim: #6b7894;
  --brand: #3b82f6;
  --brand-2: #22d3ee;
  --grad: linear-gradient(120deg, #3b82f6, #22d3ee);
  --radius: 16px;
  --container: 1140px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; scroll-padding-top: 90px; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.01em; font-weight: 700; }

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

/* ====== 背景光晕 ====== */
.bg-aurora { position: fixed; inset: 0; z-index: -1; overflow: hidden; pointer-events: none; }
.orb { position: absolute; border-radius: 50%; filter: blur(90px); opacity: 0.5; }
.orb-1 { width: 620px; height: 620px; top: -180px; left: -120px;
  background: radial-gradient(circle, rgba(59,130,246,0.55), transparent 70%); }
.orb-2 { width: 560px; height: 560px; top: 240px; right: -160px;
  background: radial-gradient(circle, rgba(34,211,238,0.4), transparent 70%); }
.grid-overlay {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.025) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 30%, transparent 75%);
}

/* ====== 导航 ====== */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  transition: background 0.3s var(--ease), border-color 0.3s, backdrop-filter 0.3s;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(7, 11, 20, 0.72);
  backdrop-filter: saturate(160%) blur(14px);
  border-bottom-color: var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; gap: 24px; }

.brand { display: flex; align-items: center; gap: 11px; }
.brand-mark { display: grid; place-items: center; }
.brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-text strong { font-size: 1.05rem; letter-spacing: 0.02em; }
.brand-text em { font-style: normal; font-size: 0.62rem; letter-spacing: 0.28em; color: var(--text-dim); }

.nav-links { display: flex; gap: 30px; }
.nav-links a { font-size: 0.93rem; color: var(--text-soft); position: relative; transition: color 0.2s; }
.nav-links a::after {
  content: ""; position: absolute; left: 0; bottom: -6px; width: 0; height: 2px;
  background: var(--grad); transition: width 0.25s var(--ease);
}
.nav-links a:hover, .nav-links a.active { color: var(--text); }
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 14px; }

.lang-toggle {
  background: transparent; border: 1px solid var(--line-strong); color: var(--text-soft);
  border-radius: 999px; padding: 6px 13px; font-size: 0.82rem; cursor: pointer;
  font-family: inherit; transition: all 0.2s; letter-spacing: 0.03em;
}
.lang-toggle:hover { border-color: var(--brand); color: var(--text); }
.lang-sep { opacity: 0.4; margin: 0 3px; }
body[data-lang="zh"] .lang-en, body[data-lang="zh"] .lang-sep { opacity: 0.4; }
body[data-lang="zh"] .lang-zh { color: var(--brand-2); }
body[data-lang="en"] .lang-zh, body[data-lang="en"] .lang-sep { opacity: 0.4; }
body[data-lang="en"] .lang-en { color: var(--brand-2); }

/* ====== 按钮 ====== */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  font-family: inherit; font-size: 0.95rem; font-weight: 600; cursor: pointer;
  padding: 12px 24px; border-radius: 999px; border: 1px solid transparent;
  transition: transform 0.2s var(--ease), box-shadow 0.25s, background 0.25s, border-color 0.25s;
  white-space: nowrap;
}
.btn-sm { padding: 8px 18px; font-size: 0.88rem; }
.btn-lg { padding: 15px 32px; font-size: 1.02rem; }
.btn-primary { background: var(--grad); color: #04121f; box-shadow: 0 8px 28px -10px rgba(34,211,238,0.6); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 36px -10px rgba(34,211,238,0.75); }
.btn-ghost { color: var(--text); border-color: var(--line-strong); }
.btn-ghost:hover { border-color: var(--brand); transform: translateY(-2px); background: rgba(59,130,246,0.06); }

.nav-burger { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 6px; }
.nav-burger span { width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: 0.3s; }

/* ====== 通用区块 ====== */
.section { padding: 110px 0; position: relative; }
.section-alt { background: linear-gradient(180deg, transparent, rgba(11,17,32,0.7) 12%, rgba(11,17,32,0.7) 88%, transparent); }
.section-head { max-width: 720px; margin-bottom: 56px; }
.kicker {
  display: inline-block; font-size: 0.78rem; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--brand-2); margin-bottom: 16px; font-weight: 600;
}
.section-head h2 { font-size: clamp(1.7rem, 3.6vw, 2.5rem); }

/* ====== HERO ====== */
.hero { padding: 170px 0 120px; }
.hero-inner { max-width: 880px; }
.eyebrow {
  display: inline-block; font-size: 0.85rem; letter-spacing: 0.05em; color: var(--brand-2);
  padding: 7px 16px; border: 1px solid var(--line-strong); border-radius: 999px; margin-bottom: 28px;
  background: rgba(34,211,238,0.05);
}
.hero-title { font-size: clamp(2.4rem, 6vw, 4.1rem); letter-spacing: -0.02em; margin-bottom: 24px;
  background: linear-gradient(180deg, #fff 30%, #b9c7e0); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-sub { font-size: clamp(1.05rem, 2vw, 1.28rem); color: var(--text-soft); max-width: 720px; margin-bottom: 38px; }
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 64px; }

.hero-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line);
  border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.stat { background: rgba(15,23,38,0.6); padding: 22px 24px; display: flex; flex-direction: column; gap: 4px; }
.stat strong { font-size: 1.02rem; color: var(--text); font-weight: 600; }
.stat span { font-size: 0.86rem; color: var(--text-dim); }

/* ====== ABOUT ====== */
.about-grid { display: grid; grid-template-columns: 1.4fr 1fr; gap: 64px; align-items: start; }
.lead { font-size: 1.15rem; color: var(--text-soft); }
.about-points { display: flex; flex-direction: column; gap: 26px; }
.point { display: flex; gap: 16px; align-items: flex-start; }
.point .dot { width: 10px; height: 10px; border-radius: 50%; background: var(--grad); margin-top: 9px; flex-shrink: 0;
  box-shadow: 0 0 0 4px rgba(59,130,246,0.12); }
.point strong { display: block; font-size: 1.05rem; margin-bottom: 2px; }
.point p { font-size: 0.92rem; color: var(--text-dim); line-height: 1.5; }

/* ====== SERVICES ====== */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card {
  background: var(--bg-card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 36px 30px; transition: transform 0.3s var(--ease), border-color 0.3s, background 0.3s;
  position: relative; overflow: hidden;
}
.card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--grad); transform: scaleX(0); transform-origin: left; transition: transform 0.4s var(--ease);
}
.card:hover { transform: translateY(-6px); border-color: var(--line-strong); background: #121b2d; }
.card:hover::before { transform: scaleX(1); }
.card-num { font-size: 0.9rem; font-weight: 700; letter-spacing: 0.1em; color: var(--brand-2);
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; margin-bottom: 18px; }
.card h3 { font-size: 1.22rem; margin-bottom: 14px; }
.card p { font-size: 0.95rem; color: var(--text-soft); }

/* ====== APPROACH ====== */
.approach-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 70px; align-items: center; }
.approach-copy h2 { font-size: clamp(1.7rem, 3.6vw, 2.5rem); margin-bottom: 20px; }
.approach-copy p { color: var(--text-soft); margin-bottom: 28px; font-size: 1.05rem; }
.checklist { list-style: none; display: flex; flex-direction: column; gap: 16px; }
.checklist li {
  display: flex; gap: 14px; align-items: flex-start; padding: 18px 22px;
  background: var(--bg-card); border: 1px solid var(--line); border-radius: 12px;
  font-size: 0.95rem; color: var(--text-soft); transition: border-color 0.25s, transform 0.25s;
}
.checklist li:hover { border-color: var(--line-strong); transform: translateX(4px); }
.checklist li::before {
  content: "✓"; flex-shrink: 0; width: 22px; height: 22px; border-radius: 50%;
  background: rgba(34,211,238,0.12); color: var(--brand-2); font-size: 0.8rem; font-weight: 700;
  display: grid; place-items: center; margin-top: 1px;
}

/* ====== CTA ====== */
.section-cta { padding: 100px 0; }
.cta-box {
  background: radial-gradient(120% 140% at 50% 0%, rgba(59,130,246,0.14), transparent 60%), var(--bg-card);
  border: 1px solid var(--line-strong); border-radius: 24px; padding: 64px 48px; text-align: center;
}
.cta-box h2 { font-size: clamp(1.7rem, 3.6vw, 2.5rem); margin-bottom: 18px; }
.cta-box > p { color: var(--text-soft); max-width: 620px; margin: 0 auto 36px; font-size: 1.08rem; }
.cta-actions { display: flex; gap: 22px; align-items: center; justify-content: center; flex-wrap: wrap; }
.cta-mail { color: var(--brand-2); font-size: 1rem; border-bottom: 1px solid transparent; transition: border-color 0.2s; }
.cta-mail:hover { border-bottom-color: var(--brand-2); }

/* ====== FOOTER ====== */
.footer { border-top: 1px solid var(--line); padding: 54px 0 30px; margin-top: 20px; }
.footer-inner { display: flex; justify-content: space-between; align-items: flex-start; gap: 30px; flex-wrap: wrap; padding-bottom: 30px; }
.footer-brand { display: flex; flex-direction: column; gap: 4px; }
.footer-brand strong { font-size: 1.02rem; }
.footer-brand span { font-size: 0.82rem; color: var(--text-dim); }
.footer-meta { display: flex; gap: 26px; flex-wrap: wrap; font-size: 0.9rem; color: var(--text-soft); }
.footer-meta a:hover { color: var(--brand-2); }
.footer-bottom { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  padding-top: 24px; border-top: 1px solid var(--line); font-size: 0.82rem; color: var(--text-dim); }
.footer-beian { display: flex; justify-content: center; align-items: center; gap: 22px; flex-wrap: wrap;
  padding-top: 16px; font-size: 0.78rem; color: var(--text-dim); }
.footer-beian a { display: inline-flex; align-items: center; gap: 6px; color: var(--text-dim); }
.footer-beian a:hover { color: var(--brand-2); }

/* ====== 滚动入场动画 ====== */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* ====== 响应式 ====== */
@media (max-width: 900px) {
  .about-grid, .approach-grid { grid-template-columns: 1fr; gap: 40px; }
  .cards { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: 1fr; }
}
@media (max-width: 720px) {
  .nav-links {
    position: fixed; top: 72px; left: 0; right: 0; flex-direction: column; gap: 0;
    background: rgba(7,11,20,0.96); backdrop-filter: blur(14px); border-bottom: 1px solid var(--line);
    padding: 8px 24px 18px; transform: translateY(-130%); transition: transform 0.35s var(--ease); visibility: hidden;
  }
  .nav-links.open { transform: translateY(0); visibility: visible; }
  .nav-links a { padding: 13px 0; border-bottom: 1px solid var(--line); }
  .nav-burger { display: flex; }
  .nav-actions .btn { display: none; }
  .nav-burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav-burger.open span:nth-child(2) { opacity: 0; }
  .nav-burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
  .section { padding: 80px 0; }
  .hero { padding: 140px 0 90px; }
  .cta-box { padding: 44px 26px; }
}

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