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

:root {
  --bg: #07111f;
  --bg-soft: #0c1728;
  --panel: rgba(255, 255, 255, 0.06);
  --panel-strong: rgba(255, 255, 255, 0.08);
  --border: rgba(255, 255, 255, 0.12);
  --text: #eaf2ff;
  --text-soft: rgba(234, 242, 255, 0.72);
  --title: #ffffff;
  --primary: #4c8dff;
  --primary-soft: rgba(76, 141, 255, 0.16);
  --success: #6ce0b5;
  --shadow: 0 18px 60px rgba(0, 0, 0, 0.22);
  --radius: 20px;
  --radius-sm: 14px;
  --container: 1200px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(76, 141, 255, 0.18), transparent 28%),
    radial-gradient(circle at top right, rgba(108, 224, 181, 0.10), transparent 25%),
    linear-gradient(180deg, #07111f 0%, #0a1424 48%, #0d1829 100%);
  color: var(--text);
  line-height: 1.65;
}

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

.container {
  width: min(var(--container), calc(100% - 48px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(7, 17, 31, 0.76);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid transparent;
  transition: all 0.3s ease;
}

.site-header.scrolled {
  border-bottom-color: var(--border);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.18);
}

.header-inner {
  min-height: 82px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}

.brand-mark {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--primary), #7aa9ff);
  color: #fff;
  font-weight: 800;
  font-size: 14px;
  box-shadow: 0 12px 30px rgba(76, 141, 255, 0.35);
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-text strong {
  color: var(--title);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.2px;
}

.brand-text span {
  color: var(--text-soft);
  font-size: 12px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-menu a {
  color: var(--text-soft);
  font-size: 14px;
  transition: 0.25s ease;
}

.nav-menu a:hover {
  color: var(--title);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 22px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  transition: 0.25s ease;
  border: 1px solid transparent;
  cursor: pointer;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), #78a8ff);
  color: #fff;
  box-shadow: 0 14px 32px rgba(76, 141, 255, 0.28);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 36px rgba(76, 141, 255, 0.35);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.04);
  color: var(--title);
  border-color: var(--border);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.08);
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  background: transparent;
  border-radius: 12px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
}

.menu-toggle span {
  width: 18px;
  height: 2px;
  background: #fff;
  border-radius: 999px;
}

.mobile-menu {
  display: none;
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 10px 24px 20px;
  background: rgba(7, 17, 31, 0.94);
}

.mobile-menu a {
  display: block;
  padding: 12px 0;
  color: var(--text-soft);
}

.mobile-menu .mobile-cta {
  margin-top: 8px;
  text-align: center;
  border-radius: 999px;
  color: #fff;
  background: linear-gradient(135deg, var(--primary), #78a8ff);
  padding: 12px 18px;
}

.mobile-menu.open {
  display: block;
}

.hero-section {
  position: relative;
  overflow: hidden;
  padding: 84px 0 72px;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 25%, rgba(76, 141, 255, 0.18), transparent 25%),
    radial-gradient(circle at 78% 32%, rgba(108, 224, 181, 0.10), transparent 24%);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 44px;
  align-items: center;
}

.hero-tag,
.section-tag {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0 14px;
  border-radius: 999px;
  background: var(--primary-soft);
  border: 1px solid rgba(76, 141, 255, 0.28);
  color: #b9d1ff;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.4px;
  margin-bottom: 18px;
}

.hero-content h1 {
  font-size: clamp(34px, 5vw, 58px);
  line-height: 1.08;
  color: var(--title);
  letter-spacing: -1.2px;
  max-width: 760px;
}

.hero-desc {
  margin-top: 22px;
  max-width: 660px;
  font-size: 17px;
  color: var(--text-soft);
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 32px;
  flex-wrap: wrap;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 36px;
}

.metric-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px 16px;
  box-shadow: var(--shadow);
}

.metric-card strong {
  display: block;
  font-size: 24px;
  color: #fff;
  margin-bottom: 6px;
}

.metric-card span {
  font-size: 13px;
  color: var(--text-soft);
}

.hero-visual {
  position: relative;
}

.system-card {
  position: relative;
  background: linear-gradient(180deg, rgba(255,255,255,0.08), rgba(255,255,255,0.04));
  border: 1px solid var(--border);
  border-radius: 28px;
  box-shadow: var(--shadow);
  padding: 28px;
  min-height: 480px;
  overflow: hidden;
}

.system-card-label {
  display: inline-block;
  color: #9abfff;
  font-size: 12px;
  font-weight: 700;
  margin-bottom: 10px;
}

.system-card h3 {
  font-size: 24px;
  color: #fff;
  margin-bottom: 28px;
}

.system-nodes {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
  padding-top: 12px;
}

.node {
  min-height: 92px;
  padding: 20px;
  border-radius: 20px;
  border: 1px solid rgba(255,255,255,0.14);
  background: rgba(255,255,255,0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #fff;
  font-weight: 600;
}

.node-main {
  grid-column: span 2;
  min-height: 110px;
  background: linear-gradient(135deg, rgba(76,141,255,0.22), rgba(108,224,181,0.12));
  border-color: rgba(76, 141, 255, 0.36);
  box-shadow: 0 14px 32px rgba(76, 141, 255, 0.20);
}

.system-lines .line {
  position: absolute;
  background: linear-gradient(90deg, rgba(76,141,255,0.0), rgba(76,141,255,0.4), rgba(76,141,255,0.0));
  border-radius: 999px;
}

.line-1 {
  width: 180px;
  height: 1px;
  top: 152px;
  right: 44px;
}

.line-2 {
  width: 1px;
  height: 130px;
  top: 200px;
  left: 50%;
}

.line-3 {
  width: 120px;
  height: 1px;
  bottom: 112px;
  left: 48px;
}

.line-4 {
  width: 120px;
  height: 1px;
  bottom: 112px;
  right: 48px;
}

.section-block {
  padding: 92px 0;
}

.section-heading {
  max-width: 880px;
  margin-bottom: 42px;
}

.section-heading h2 {
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1.15;
  color: #fff;
  letter-spacing: -0.8px;
}

.section-desc {
  margin-top: 18px;
  color: var(--text-soft);
  font-size: 16px;
}

.diagnosis-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}

.diagnosis-card {
  background: linear-gradient(180deg, rgba(255,255,255,0.06), rgba(255,255,255,0.035));
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 28px;
  box-shadow: var(--shadow);
}

.accent-card {
  border-color: rgba(76, 141, 255, 0.28);
  background: linear-gradient(180deg, rgba(76,141,255,0.12), rgba(255,255,255,0.04));
}

.card-icon {
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  background: rgba(255,255,255,0.08);
  color: #fff;
  font-size: 14px;
  font-weight: 800;
  margin-bottom: 18px;
}

.diagnosis-card h3 {
  font-size: 24px;
  color: #fff;
  margin-bottom: 18px;
}

.diagnosis-card ul {
  list-style: none;
}

.diagnosis-card li {
  position: relative;
  padding-left: 20px;
  color: var(--text-soft);
  margin-bottom: 12px;
}

.diagnosis-card li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 0 6px rgba(76, 141, 255, 0.14);
}

.card-note {
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid rgba(255,255,255,0.08);
  color: #cfe0ff;
  font-size: 14px;
}

.diagnosis-summary {
  margin-top: 26px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.summary-item {
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px 20px;
  background: rgba(255,255,255,0.04);
}

.summary-label {
  display: block;
  font-size: 12px;
  color: #93b9ff;
  margin-bottom: 6px;
}

.summary-item strong {
  color: #fff;
  font-size: 16px;
}

.placeholder-section {
  padding-top: 0;
}

.placeholder-box {
  background: rgba(255,255,255,0.04);
  border: 1px dashed rgba(255,255,255,0.18);
  border-radius: 24px;
  padding: 32px;
}

.placeholder-box h2 {
  font-size: 28px;
  color: #fff;
  margin-bottom: 10px;
}

.placeholder-box p {
  color: var(--text-soft);
}

@media (max-width: 1080px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero-visual {
    order: -1;
  }
}

@media (max-width: 860px) {
  .nav-menu,
  .header-inner > .btn-primary {
    display: none;
  }

  .menu-toggle {
    display: inline-flex;
  }

  .hero-section {
    padding-top: 56px;
  }

  .hero-metrics,
  .diagnosis-grid,
  .diagnosis-summary {
    grid-template-columns: 1fr;
  }

  .system-card {
    min-height: auto;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(var(--container), calc(100% - 32px));
  }

  .header-inner {
    min-height: 74px;
  }

  .brand-text span {
    display: none;
  }

  .hero-content h1 {
    font-size: 34px;
  }

  .hero-desc {
    font-size: 15px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-actions .btn {
    width: 100%;
  }

  .diagnosis-card,
  .placeholder-box,
  .system-card {
    padding: 22px;
  }

  .node {
    min-height: 80px;
    font-size: 14px;
  }

  .node-main {
    min-height: 96px;
  }
}