:root {
  color-scheme: light;
  --page: #f3f3f3;
  --surface: #ffffff;
  --surface-soft: #f9f9f9;
  --text: #1a1a1a;
  --muted: #5d5d5d;
  --border: rgba(0, 0, 0, .09);
  --accent: #0067c0;
  --accent-hover: #005a9e;
  --dark: #161616;
  --dark-soft: #202020;
  --dark-text: #f5f5f5;
  --dark-muted: #c8c8c8;
  --green: #13a10e;
  font-family: "Segoe UI Variable Text", "Segoe UI", "Microsoft YaHei UI", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body { margin: 0; color: var(--text); background: var(--page); }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; }

.site-header {
  height: 64px;
  padding: 0 40px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  position: fixed;
  inset: 0 0 auto;
  z-index: 50;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  background: rgba(243, 243, 243, .82);
  backdrop-filter: blur(24px) saturate(130%);
  -webkit-backdrop-filter: blur(24px) saturate(130%);
}
.brand { min-width: 0; display: flex; align-items: center; gap: 10px; font-size: 15px; font-weight: 650; }
.brand img { flex: 0 0 auto; border-radius: 7px; }
.brand span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
nav { display: flex; align-items: center; gap: 8px; }
nav a { min-height: 36px; padding: 0 14px; display: inline-flex; align-items: center; border-radius: 6px; color: #4b4b4b; font-size: 14px; }
nav a:hover { color: #111; background: rgba(0, 0, 0, .05); }
.header-action { justify-self: end; min-height: 34px; padding: 0 16px; display: inline-flex; align-items: center; border: 1px solid rgba(0,0,0,.14); border-radius: 6px; background: rgba(255,255,255,.72); font-size: 14px; font-weight: 600; }
.header-action:hover { background: #fff; }

.hero {
  padding: 72px 40px;
  position: relative;
  overflow: hidden;
  color: var(--text);
  background: var(--page);
}
.hero-content { width: min(820px, 100%); margin: 0 auto; position: relative; z-index: 2; text-align: center; }
.overline { margin: 0 0 15px; color: #79b8ff; font-size: 14px; font-weight: 650; }
.overline.dark { color: var(--accent); }
h1, h2, h3, p { letter-spacing: 0; }
h1 { margin: 0; font-size: 58px; line-height: 1.08; font-weight: 650; }
.hero-summary { max-width: 700px; margin: 20px auto 0; color: var(--muted); font-size: 20px; line-height: 1.65; }
.hero-actions { margin-top: 28px; display: flex; justify-content: center; gap: 10px; }
.button { min-height: 42px; padding: 0 20px; display: inline-flex; align-items: center; justify-content: center; border: 1px solid transparent; border-radius: 6px; font-size: 14px; font-weight: 650; white-space: nowrap; }
.button.primary { color: #fff; background: var(--accent); border-color: rgba(255,255,255,.08); box-shadow: inset 0 -1px rgba(0,0,0,.12); }
.button.primary:hover { background: var(--accent-hover); }
.button.subtle { color: var(--text); border-color: rgba(0,0,0,.14); background: rgba(255,255,255,.7); }
.button.subtle:hover { background: #fff; }
.hero-window { width: min(1180px, 100%); margin: 54px auto 0; overflow: hidden; border: 1px solid rgba(0,0,0,.15); border-radius: 8px; background: #0f1926; box-shadow: 0 24px 60px rgba(0,0,0,.14); }
.hero-window > img { width: 100%; height: 440px; display: block; object-fit: cover; object-position: center top; }
.hero-caption { margin: 16px 0 0; display: flex; align-items: center; justify-content: center; gap: 9px; color: var(--muted); font-size: 13px; }
.live-dot { width: 8px; height: 8px; border-radius: 50%; background: #6ccb5f; box-shadow: 0 0 0 3px rgba(108,203,95,.16); }

.feature-section { padding: 96px 40px 108px; background: var(--page); }
.section-intro { width: min(1180px, 100%); margin: 0 auto; }
.section-intro h2, .training-copy h2, .final-section h2 { margin: 0; font-size: 40px; line-height: 1.2; font-weight: 620; }
.section-intro > p:last-child { max-width: 720px; margin: 18px 0 0; color: var(--muted); font-size: 17px; line-height: 1.7; }
.feature-grid { width: min(1180px, 100%); margin: 48px auto 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border: 1px solid var(--border); border-radius: 8px; overflow: hidden; background: var(--surface); box-shadow: 0 8px 28px rgba(0,0,0,.05); }
.feature-grid article { min-height: 250px; padding: 26px; border-right: 1px solid var(--border); }
.feature-grid article:last-child { border-right: 0; }
.feature-number { width: 36px; height: 30px; display: inline-flex; align-items: center; justify-content: center; border-radius: 6px; color: var(--accent); background: #eaf3fb; font-size: 12px; font-weight: 700; }
.feature-grid h3 { margin: 58px 0 12px; font-size: 19px; font-weight: 650; }
.feature-grid p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.75; }

.training-section { padding: 96px max(40px, calc((100% - 1180px) / 2)); display: grid; grid-template-columns: 360px minmax(0, 1fr); align-items: center; gap: 64px; color: var(--dark-text); background: var(--dark-soft); }
.training-copy > p:not(.overline) { margin: 20px 0 0; color: var(--dark-muted); line-height: 1.75; }
.training-copy dl { margin: 32px 0 0; }
.training-copy dl div { padding: 16px 0; border-top: 1px solid rgba(255,255,255,.12); }
.training-copy dt { margin-bottom: 5px; font-size: 14px; font-weight: 650; }
.training-copy dd { margin: 0; color: #aaa; font-size: 13px; line-height: 1.5; }
.training-window { min-width: 0; margin: 0; overflow: hidden; border: 1px solid rgba(255,255,255,.16); border-radius: 8px; background: #0f1926; box-shadow: 0 24px 56px rgba(0,0,0,.28); }
.window-titlebar { height: 46px; padding-left: 14px; display: flex; align-items: center; justify-content: space-between; color: #ddd; background: #2b2b2b; border-bottom: 1px solid rgba(255,255,255,.1); font-size: 13px; }
.window-app { display: flex; align-items: center; gap: 9px; }
.window-app img { border-radius: 5px; }
.window-controls { height: 100%; display: grid; grid-template-columns: repeat(3, 46px); }
.window-controls span { display: grid; place-items: center; color: #c5c5c5; }
.training-window > img { width: 100%; height: auto; display: block; }

.security-section { padding: 96px 40px; background: #fafafa; }
.section-intro.compact { display: flex; align-items: flex-end; justify-content: space-between; gap: 30px; }
.section-intro.compact .overline { margin-bottom: 8px; }
.security-list { width: min(1180px, 100%); margin: 42px auto 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.security-list article { padding: 26px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface); }
.security-list h3 { margin: 0 0 10px; font-size: 17px; }
.security-list p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.7; }

.final-section { width: min(1180px, calc(100% - 80px)); margin: 96px auto 0; padding: 32px; display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 22px; border: 1px solid var(--border); border-radius: 8px; background: rgba(255,255,255,.78); box-shadow: 0 8px 28px rgba(0,0,0,.05); backdrop-filter: blur(20px); }
.final-section > img { border-radius: 8px; }
.final-section h2 { font-size: 24px; }
.final-section p { margin: 9px 0 0; color: var(--muted); font-size: 14px; }
footer { min-height: 80px; padding: 24px 40px; display: flex; align-items: center; justify-content: space-between; border-top: 1px solid var(--border); color: var(--muted); background: #ededed; font-size: 13px; }

@media (max-width: 980px) {
  .site-header { padding: 0 22px; grid-template-columns: 1fr auto; }
  nav { display: none; }
  h1 { font-size: 52px; }
  .feature-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .feature-grid article { border-bottom: 1px solid var(--border); }
  .feature-grid article:nth-child(2) { border-right: 0; }
  .feature-grid article:nth-child(n+3) { border-bottom: 0; }
  .training-section { padding: 80px 30px; grid-template-columns: 1fr; gap: 42px; }
}

@media (max-width: 640px) {
  .site-header { height: 58px; padding: 0 14px; }
  .brand { font-size: 13px; }
  .header-action { min-height: 32px; padding: 0 11px; font-size: 12px; }
  .hero { padding: 54px 16px; }
  h1 { font-size: 42px; }
  .hero-summary { font-size: 17px; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .button { width: 100%; }
  .hero-window { margin-top: 36px; }
  .hero-window > img { height: 280px; }
  .feature-section, .security-section { padding: 72px 16px; }
  .section-intro h2, .training-copy h2 { font-size: 32px; }
  .feature-grid { grid-template-columns: 1fr; }
  .feature-grid article { min-height: 210px; border-right: 0; border-bottom: 1px solid var(--border) !important; }
  .feature-grid article:last-child { border-bottom: 0 !important; }
  .feature-grid h3 { margin-top: 38px; }
  .training-section { padding: 72px 16px; }
  .window-controls { grid-template-columns: repeat(3, 36px); }
  .security-list { grid-template-columns: 1fr; }
  .final-section { width: calc(100% - 32px); margin: 78px auto 0; padding: 24px; grid-template-columns: auto 1fr; }
  .final-section .button { grid-column: 1 / -1; }
  .final-section h2 { font-size: 20px; }
  footer { padding: 22px 16px; align-items: flex-start; flex-direction: column; gap: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}