:root {
  --bg: #ffffff;
  --surface: #f7f8fb;
  --surface-2: #eef1f7;
  --ink: #0f172a;
  --ink-soft: #475569;
  --ink-mute: #94a3b8;
  --line: #e6e9f0;
  --brand: #4f46e5;
  --brand-2: #7c3aed;
  --accent: #06b6d4;
  --radius: 16px;
  --shadow: 0 12px 40px rgba(15, 23, 42, 0.08);
  --shadow-sm: 0 4px 16px rgba(15, 23, 42, 0.06);
  --maxw: 1120px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

/* ---------- 导航 ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  gap: 20px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; }
.brand__logo { height: 30px; width: auto; display: block; }

.nav__links { display: flex; gap: 26px; margin-left: auto; }
.nav__links a { color: var(--ink-soft); font-size: 15px; font-weight: 500; transition: color .2s; }
.nav__links a:hover { color: var(--brand); }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 11px 22px;
  border-radius: 999px;
  font-size: 15px; font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .15s ease, box-shadow .2s ease, background .2s;
}
.btn--primary { background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #fff; box-shadow: 0 8px 20px rgba(79, 70, 229, 0.28); }
.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 12px 26px rgba(79, 70, 229, 0.36); }
.btn--ghost { background: #fff; color: var(--ink); border-color: var(--line); }
.btn--ghost:hover { border-color: var(--brand); color: var(--brand); }

.nav__toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav__toggle span { width: 22px; height: 2px; background: var(--ink); border-radius: 2px; transition: .25s; }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; padding: 96px 24px 72px; }
.hero__glow {
  position: absolute; inset: -20% -10% auto; height: 520px;
  background: radial-gradient(closest-side, rgba(124, 58, 237, 0.18), transparent 70%),
              radial-gradient(closest-side, rgba(6, 182, 212, 0.16), transparent 70%);
  filter: blur(20px);
  transform: translateY(-40px);
  pointer-events: none;
}
.hero__inner { max-width: var(--maxw); margin: 0 auto; text-align: center; position: relative; }
.hero__eyebrow { color: var(--brand); font-weight: 700; letter-spacing: 3px; font-size: 13px; }
.hero__title { font-size: clamp(40px, 7vw, 72px); line-height: 1.1; margin: 16px 0 18px; font-weight: 900; letter-spacing: -1px; }
.grad { background: linear-gradient(120deg, var(--brand), var(--brand-2), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero__sub { max-width: 640px; margin: 0 auto; color: var(--ink-soft); font-size: 18px; }
.hero__actions { display: flex; gap: 14px; justify-content: center; margin: 30px 0 0; flex-wrap: wrap; }

/* ---------- 通用 section ---------- */
.section { max-width: var(--maxw); margin: 0 auto; padding: 88px 24px; }
.section--alt { max-width: none; background: var(--surface); }
.section--alt > * { max-width: var(--maxw); margin-left: auto; margin-right: auto; }
.section__head { text-align: center; max-width: 680px; margin: 0 auto 48px; }
.kicker { color: var(--brand); font-weight: 700; letter-spacing: 2px; font-size: 13px; }
.section__head h2 { font-size: clamp(28px, 4vw, 40px); margin: 10px 0 14px; font-weight: 800; letter-spacing: -0.5px; }
.section__head p { color: var(--ink-soft); font-size: 17px; }

/* ---------- 方法论 steps ---------- */
.steps { list-style: none; display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.step { background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; position: relative; transition: transform .2s, box-shadow .2s; }
.step:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.step__no { font-size: 26px; font-weight: 900; background: linear-gradient(120deg, var(--brand), var(--brand-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.step h3 { margin: 8px 0 6px; font-size: 18px; }
.step p { color: var(--ink-soft); font-size: 14.5px; }

/* ---------- 能力 bars ---------- */
.skills { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px 36px; max-width: 840px; margin: 0 auto; }
.skill span { display: block; font-weight: 600; margin-bottom: 8px; font-size: 15px; }
.bar { height: 10px; background: var(--surface-2); border-radius: 999px; overflow: hidden; }
.bar i { display: block; height: 100%; width: 0; border-radius: 999px; background: linear-gradient(90deg, var(--brand), var(--accent)); transition: width 1.1s cubic-bezier(.22,1,.36,1); }

/* ---------- 联系 ---------- */
.contact { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: start; }
.contact__left .kicker { display: block; }
.contact__list { list-style: none; margin-top: 22px; display: grid; gap: 10px; color: var(--ink-soft); }
.contact__form { background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow-sm); display: grid; gap: 16px; }
.contact__form label { display: grid; gap: 6px; font-size: 14px; font-weight: 600; color: var(--ink-soft); }
.contact__form input, .contact__form textarea {
  font: inherit; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); color: var(--ink); resize: vertical;
}
.contact__form input:focus, .contact__form textarea:focus { outline: 2px solid rgba(79,70,229,.35); border-color: var(--brand); }
.form__hint { font-size: 14px; color: var(--brand); min-height: 18px; }

/* ---------- 微信公众号 ---------- */
.wechat { display: grid; grid-template-columns: 1.2fr 1fr; gap: 40px; align-items: center; max-width: 920px; margin: 0 auto; }
.wechat__text .kicker { display: block; }
.wechat__text h2 { font-size: clamp(26px, 4vw, 36px); margin: 10px 0 14px; }
.wechat__text p { color: var(--ink-soft); font-size: 17px; }
.wechat__list { list-style: none; margin-top: 22px; display: grid; gap: 10px; color: var(--ink-soft); }
.wechat__qr { text-align: center; }
.qr { width: 200px; height: 200px; margin: 0 auto; border-radius: var(--radius); border: 2px dashed var(--line); display: grid; place-items: center; text-align: center; color: var(--ink-mute); background: var(--surface); line-height: 1.5; }
.qr img { width: 100%; height: 100%; object-fit: contain; border-radius: calc(var(--radius) - 2px); }
.qr__tip { color: var(--ink-mute); font-size: 13px; margin-top: 12px; }

/* ---------- 页脚 ---------- */
.footer { border-top: 1px solid var(--line); background: var(--surface); padding: 36px 24px; }
.footer__inner { max-width: var(--maxw); margin: 0 auto; text-align: center; }
.footer__inner .footer__logo { height: 26px; display: inline-block; }
.footer__inner p { color: var(--ink-mute); font-size: 13px; margin-top: 8px; }
.footer__beian { margin-top: 6px; }
.footer__beian a { color: var(--ink-mute); }
.footer__beian a:hover { color: var(--brand); }

/* ---------- 揭示动画 ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .steps { grid-template-columns: 1fr 1fr; }
  .skills { grid-template-columns: 1fr; }
  .contact { grid-template-columns: 1fr; }
  .wechat { grid-template-columns: 1fr; }
}
@media (max-width: 680px) {
  .nav__links { display: none; position: absolute; top: 100%; left: 0; right: 0; flex-direction: column; gap: 0; background: #fff; border-bottom: 1px solid var(--line); padding: 8px 0; }
  .nav__links.open { display: flex; }
  .nav__links a { padding: 12px 24px; }
  .nav__toggle { display: flex; margin-left: auto; }
  .steps { grid-template-columns: 1fr; }
  .section { padding: 64px 20px; }
}