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

:root {
  --primary-color: #0066cc;
  --primary-hover: #0052a3;
  --bg-light: #f4f7fa;
  --text-gray: #666;
  --border-color: #e1e4e8;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Heiti SC", "Helvetica Neue", Arial, sans-serif;
  color: #333;
  line-height: 1.6;
  background-color: #f9fafb;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.3s, background-color 0.3s;
}

ul {
  list-style: none;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section {
  padding: 80px 0;
}

.section-alt {
  background: var(--bg-light, #f4f7fa);
}

.text-center {
  text-align: center;
}

.mb-20 {
  margin-bottom: 20px;
}

.mb-40 {
  margin-bottom: 40px;
}

.mb-60 {
  margin-bottom: 60px;
}

.flex {
  display: flex;
}

.items-center {
  align-items: center;
}

.justify-between {
  justify-content: space-between;
}

.justify-center {
  justify-content: center;
}

.flex-col {
  flex-direction: column;
}

.grid {
  display: grid;
  gap: 30px;
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

header {
  background: #fff;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
}

.nav-inner {
  height: 70px;
}

.nav-logo {
  font-size: 20px;
  font-weight: bold;
  color: var(--primary-color);
  display: flex;
  align-items: center;
}

.nav-logo img {
  margin-right: 8px;
}

.nav-logo span {
  background: var(--primary-color);
  color: #fff;
  padding: 2px 8px;
  border-radius: 4px;
  margin-right: 8px;
}

.nav-links a {
  margin-left: 30px;
  font-size: 15px;
  color: #555;
  font-weight: 500;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary-color);
}

.nav-btn {
  background: var(--primary-color);
  color: #fff !important;
  padding: 8px 20px;
  border-radius: 4px;
}

.nav-btn:hover {
  background: var(--primary-hover);
}

.nav-btn.active {
  background: var(--primary-hover);
}

.nav-toggle-checkbox {
  display: none;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 26px;
  height: 18px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
}

.nav-toggle span {
  display: block;
  height: 3px;
  width: 100%;
  background: var(--primary-color);
  border-radius: 2px;
}

.section-title {
  font-size: 30px;
  margin-bottom: 14px;
  color: #222;
}

.section-subtitle {
  color: var(--text-gray);
  margin-bottom: 40px;
}

.page-hero {
  margin-top: 70px;
  padding: 90px 0 70px;
  background: linear-gradient(135deg, #004e92 0%, #0066cc 100%);
  color: #fff;
  text-align: center;
}

.page-hero h1 {
  font-size: 42px;
  line-height: 1.2;
  margin-bottom: 18px;
}

.page-hero p {
  font-size: 18px;
  opacity: 0.9;
  max-width: 780px;
  margin: 0 auto;
}

.case-card,
.metric-card,
.screen-card,
.demo-card,
.panel {
  background: #fff;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
}

.case-card,
.metric-card,
.demo-card,
.panel {
  padding: 30px;
}

.case-card h2,
.screen-card h2,
.demo-card h2,
.panel h2 {
  margin-bottom: 14px;
  color: #1f2937;
}

.case-card h2,
.panel h2 {
  font-size: 22px;
}

.screen-card h2,
.demo-card h2 {
  font-size: 20px;
}

.case-card p,
.case-card li,
.screen-card p,
.demo-card p,
.panel p,
.panel li {
  color: var(--text-gray);
  font-size: 15px;
}

.case-card ul {
  margin-top: 18px;
  padding-left: 20px;
  list-style: disc;
}

.case-card li {
  margin-bottom: 8px;
}

.metric-card strong {
  display: block;
  font-size: 30px;
  color: var(--primary-color);
  margin-bottom: 8px;
}

.metric-card span {
  color: var(--text-gray);
}

.screen-card {
  overflow: hidden;
}

.screen-card img {
  width: 100%;
  display: block;
}

.screen-card div {
  padding: 24px;
}

.panel ul,
.panel ol {
  padding-left: 20px;
  margin-top: 16px;
}

.panel ul {
  list-style: disc;
}

.panel ol {
  list-style: decimal;
}

.panel li {
  margin-bottom: 10px;
}

.contact-box {
  background: var(--primary-color);
  color: #fff;
}

.contact-box p {
  color: rgba(255, 255, 255, 0.9);
}

.cta-box {
  background: var(--primary-color);
  border-radius: 12px;
  padding: 45px;
  text-align: center;
  color: #fff;
}

.cta-btn {
  background: #fff;
  color: var(--primary-color);
  padding: 14px 34px;
  border-radius: 5px;
  font-weight: bold;
  display: inline-block;
  margin-top: 22px;
}

.cta-btn-primary {
  background: var(--primary-color);
  color: #fff;
}

footer {
  background: #fff;
  border-top: 1px solid #eee;
  padding: 30px 0;
  color: #999;
  font-size: 14px;
}

.footer-info {
  display: flex;
  justify-content: space-between;
  color: #999;
  font-size: 14px;
  border-top: 1px solid #eee;
  padding-top: 20px;
}

.footer-links > * {
  margin-left: 20px;
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: #fff;
    padding: 15px 20px 25px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    border-top: 1px solid var(--border-color);
  }

  .nav-toggle-checkbox:checked ~ .nav-links {
    display: flex;
  }

  .nav-links a {
    margin-left: 0;
    padding: 10px 0;
    border-bottom: 1px solid #f0f0f0;
  }

  .nav-links a:last-child {
    border-bottom: none;
  }

  .nav-btn {
    margin-top: 8px;
    text-align: center;
  }

  .page-hero h1 {
    font-size: 32px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .cta-box {
    padding: 30px;
  }

  .footer-info {
    flex-direction: column;
    text-align: center;
    gap: 10px;
  }
}