/* MR.Z — AI培训 · AI课程 · 智能体教学（浅色传统主题） */
:root {
  --bg: #fbfbfd;
  --panel: #ffffff;
  --ink: #1d1d1f;
  --muted: #6e6e73;
  --line: #e5e5ea;
  --brand: #0071e3;
  --brand-dark: #005bb5;
  --tint: #f0f7ff;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(0,0,0,.04), 0 8px 24px rgba(0,0,0,.05);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro SC", "SF Pro Text",
    "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  font-size: 15px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
.wrap { max-width: 960px; margin: 0 auto; padding: 0 22px; }
.br { display: none; }

/* ── 顶部导航 ── */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(251,251,253,.82);
  backdrop-filter: saturate(180%) blur(18px);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { max-width: 1024px; margin: 0 auto; padding: 0 22px; height: 52px; display: flex; align-items: center; justify-content: space-between; }
.nav-logo { font-weight: 700; font-size: 17px; letter-spacing: .5px; color: var(--ink); text-decoration: none; }
.nav-logo em { color: var(--brand); font-style: normal; }
.nav-links { display: flex; gap: 4px; list-style: none; }
.nav-links a {
  color: var(--muted); text-decoration: none; font-size: 13px;
  padding: 6px 12px; border-radius: 980px; transition: color .2s, background .2s;
}
.nav-links a:hover, .nav-links a.active { color: var(--ink); background: rgba(0,0,0,.05); }
.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 18px; height: 1.5px; background: var(--ink); margin: 5px 0; border-radius: 2px; transition: .25s; }
@media (max-width: 860px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute; top: 52px; left: 0; right: 0;
    flex-direction: column; background: var(--panel);
    border-bottom: 1px solid var(--line); padding: 10px 16px 16px; gap: 2px;
    display: none; box-shadow: var(--shadow);
  }
  .nav-links.open { display: flex; }
  .nav-links a { display: block; padding: 10px 12px; font-size: 15px; border-radius: 10px; }
  .br { display: block; }
}

/* ── Hero ── */
.hero { padding: 88px 0 64px; text-align: center; background: linear-gradient(180deg, #fff 0%, var(--bg) 100%); }
.hero-tag {
  display: inline-block; font-size: 12.5px; color: var(--brand);
  background: var(--tint); border: 1px solid #d6e9ff;
  padding: 4px 14px; border-radius: 980px; margin-bottom: 20px; letter-spacing: .5px;
}
.hero h1 { font-size: 34px; line-height: 1.3; letter-spacing: -0.5px; font-weight: 700; }
.hero-sub { color: var(--muted); font-size: 15.5px; max-width: 620px; margin: 18px auto 0; }
.hero-cta { margin-top: 30px; display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 11px 26px; border-radius: 980px;
  font-size: 14.5px; text-decoration: none; transition: .2s; font-weight: 500;
}
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-dark); }
.btn-ghost { color: var(--brand); border: 1px solid var(--line); background: var(--panel); }
.btn-ghost:hover { border-color: var(--brand); }
@media (max-width: 640px) { .hero { padding: 60px 0 46px; } .hero h1 { font-size: 26px; } }

/* ── 区块 ── */
.section { padding: 64px 0; }
.section:nth-of-type(even) { background: var(--panel); }
.sec-head { text-align: center; margin-bottom: 40px; }
.sec-head h2 { font-size: 26px; letter-spacing: -0.3px; font-weight: 700; }
.sec-desc { color: var(--muted); font-size: 14px; margin-top: 8px; }
.sec-anchor { scroll-margin-top: 70px; }

/* ── 服务卡 ── */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 860px) { .cards { grid-template-columns: 1fr; } }
.card {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 24px; box-shadow: var(--shadow); transition: transform .2s, box-shadow .2s;
}
.card:hover { transform: translateY(-3px); box-shadow: 0 2px 4px rgba(0,0,0,.05), 0 14px 34px rgba(0,0,0,.08); }
.card-icon {
  width: 40px; height: 40px; border-radius: 11px; background: var(--tint); color: var(--brand);
  display: flex; align-items: center; justify-content: center; margin-bottom: 16px;
}
.card h3 { font-size: 17px; font-weight: 600; margin-bottom: 6px; }
.card .card-kicker { font-size: 12.5px; color: var(--brand); font-weight: 500; margin-bottom: 10px; }
.card p { color: var(--muted); font-size: 13.5px; }
.card ul { margin-top: 12px; list-style: none; }
.card ul li { color: var(--muted); font-size: 13px; padding: 4px 0 4px 18px; position: relative; }
.card ul li::before { content: ""; position: absolute; left: 2px; top: 13px; width: 5px; height: 5px; border-radius: 50%; background: var(--brand); }

/* ── 适合谁学 ── */
.who { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 860px) { .who { grid-template-columns: 1fr; } }
.who-card { background: var(--tint); border: 1px solid #d6e9ff; border-radius: var(--radius); padding: 22px; }
.who-card strong { display: block; font-size: 15px; margin-bottom: 6px; }
.who-card p { color: var(--muted); font-size: 13.5px; }

/* ── 答疑 / FAQ ── */
.qa-module { margin-bottom: 34px; }
.qa-module h3 { font-size: 16.5px; font-weight: 600; margin-bottom: 14px; padding-left: 12px; border-left: 3px solid var(--brand); }
.faq-list { display: flex; flex-direction: column; gap: 10px; }
details.faq {
  background: var(--panel); border: 1px solid var(--line); border-radius: 12px;
  overflow: hidden; transition: border-color .2s;
}
details.faq:hover { border-color: #d0d0d6; }
details.faq summary {
  cursor: pointer; list-style: none; padding: 15px 18px;
  font-size: 14.5px; font-weight: 500; display: flex; align-items: center; gap: 10px;
}
details.faq summary::-webkit-details-marker { display: none; }
details.faq summary::after {
  content: ""; margin-left: auto; flex-shrink: 0;
  width: 8px; height: 8px; border-right: 1.6px solid var(--muted); border-bottom: 1.6px solid var(--muted);
  transform: rotate(45deg); transition: transform .2s;
}
details.faq[open] summary::after { transform: rotate(-135deg); }
details.faq[open] summary { border-bottom: 1px solid var(--line); }
details.faq .faq-body { padding: 14px 18px 16px; color: var(--muted); font-size: 13.5px; }
details.faq .faq-body p + p { margin-top: 8px; }

/* ── 关于 ── */
.about { display: flex; gap: 36px; align-items: flex-start; }
@media (max-width: 860px) { .about { flex-direction: column; } }
.about-text { flex: 1; }
.about-text p { color: var(--muted); font-size: 14.5px; margin-bottom: 12px; }
.about-facts { flex-shrink: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 860px) { .about-facts { width: 100%; } }
.fact { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; min-width: 130px; }
.fact b { display: block; font-size: 20px; color: var(--brand); font-weight: 700; }
.fact span { font-size: 12.5px; color: var(--muted); }

/* ── 联系 ── */
.contact-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 860px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-card {
  display: flex; align-items: center; gap: 14px; background: var(--panel);
  border: 1px solid var(--line); border-radius: var(--radius); padding: 20px;
  text-decoration: none; color: var(--ink); box-shadow: var(--shadow); transition: transform .2s;
}
.contact-card:hover { transform: translateY(-2px); }
.contact-icon {
  width: 40px; height: 40px; border-radius: 50%; background: var(--tint); color: var(--brand);
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.contact-card strong { display: block; font-size: 13.5px; }
.contact-card span { font-size: 13px; color: var(--muted); }

/* ── 页脚 ── */
footer { border-top: 1px solid var(--line); padding: 28px 0 36px; text-align: center; }
footer p { color: var(--muted); font-size: 12.5px; }
footer nav { margin-top: 8px; display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }
footer nav a { color: var(--muted); font-size: 12.5px; text-decoration: none; }
footer nav a:hover { color: var(--brand); }

/* ── 进场动画 ── */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .5s ease, transform .5s ease; }
.reveal.visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } }