/* === Reset & Base === */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #1a6fb5;
  --primary-dark: #14578e;
  --primary-light: #e8f4fd;
  --secondary: #2c8c5a;
  --accent: #e67e22;
  --text: #2c3e50;
  --text-light: #5a6c7d;
  --text-lighter: #8a9bb0;
  --bg: #ffffff;
  --bg-light: #f5f8fb;
  --bg-dark: #1a2332;
  --border: #e2e8f0;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.1);
  --radius: 8px;
  --radius-lg: 16px;
  --transition: 0.3s ease;
  --max-width: 1200px;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

ul {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* === Header === */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition);
}

.header.scrolled {
  box-shadow: 0 2px 16px rgba(0, 0, 0, 0.08);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
}

.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--primary);
  color: #fff;
  border-radius: 8px;
  font-size: 22px;
  font-weight: 300;
}

.nav-list {
  display: flex;
  gap: 4px;
}

.nav-link {
  display: block;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-light);
  border-radius: 6px;
  transition: all var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary);
  background: var(--primary-light);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: var(--transition);
}

/* === Hero === */
.hero {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 600px;
  height: 100vh;
  max-height: 720px;
  overflow: hidden;
  margin-top: 64px;
}

.hero-bg {
  position: absolute;
  inset: 0;
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(26, 35, 50, 0.85) 0%, rgba(26, 111, 181, 0.6) 100%);
}

.hero-content {
  position: relative;
  z-index: 1;
  color: #fff;
  max-width: 720px;
}

.hero-title {
  font-size: 48px;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 16px;
  letter-spacing: 2px;
}

.hero-subtitle {
  font-size: 20px;
  font-weight: 400;
  opacity: 0.9;
  margin-bottom: 12px;
}

.hero-desc {
  font-size: 16px;
  opacity: 0.75;
  line-height: 1.8;
  margin-bottom: 32px;
}

.hero-btns {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 600;
  border-radius: 6px;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
}

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

.btn-primary:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.5);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: #fff;
}

/* === Sections === */
.section {
  padding: 88px 0;
}

.bg-light {
  background: var(--bg-light);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 56px;
}

.section-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 16px;
  position: relative;
}

.section-title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background: var(--primary);
  margin-top: 12px;
  border-radius: 2px;
}

.section-header .section-title::after {
  margin: 12px auto 0;
}

.section-desc {
  font-size: 16px;
  color: var(--text-light);
  line-height: 1.8;
}

/* Section Row (image + text) */
.section-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.section-row.reverse {
  direction: rtl;
}

.section-row.reverse .section-text {
  direction: ltr;
}

.section-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.section-img img {
  width: 100%;
  height: 340px;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.section-img:hover img {
  transform: scale(1.05);
}

.section-text .section-title::after {
  margin-left: 0;
}

.section-text p {
  font-size: 15px;
  color: var(--text-light);
  line-height: 1.8;
  margin-bottom: 20px;
}

.feature-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.feature-list li {
  position: relative;
  padding-left: 24px;
  font-size: 15px;
  color: var(--text);
  line-height: 1.6;
}

.feature-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 8px;
  height: 8px;
  background: var(--primary);
  border-radius: 50%;
}

/* === About Cards === */
.about-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.about-card {
  text-align: center;
  padding: 40px 28px;
  background: var(--bg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  transition: all var(--transition);
}

.about-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
}

.about-card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  margin: 0 auto 20px;
  background: var(--primary-light);
  border-radius: 50%;
  color: var(--primary);
}

.about-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

.about-card p {
  font-size: 14px;
  color: var(--text-light);
  line-height: 1.7;
}

/* === Device Categories === */
.device-categories {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 8px;
}

.device-cat {
  padding: 20px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.device-cat:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow);
}

.device-cat h4 {
  font-size: 15px;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 8px;
}

.device-cat p {
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 0;
}

/* === Contact === */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: 48px;
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.contact-icon {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  background: var(--primary-light);
  border-radius: var(--radius);
  color: var(--primary);
}

.contact-label {
  font-size: 13px;
  color: var(--text-lighter);
  margin-bottom: 4px;
}

.contact-value {
  font-size: 16px;
  font-weight: 500;
  color: var(--text);
}

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

.qr-placeholder {
  margin-bottom: 12px;
  display: inline-block;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.contact-qr p {
  font-size: 13px;
  color: var(--text-light);
}

/* === Footer === */
.footer {
  background: var(--bg-dark);
  color: rgba(255, 255, 255, 0.75);
  padding: 56px 0 0;
}

.footer-main {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand h3 {
  font-size: 18px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 12px;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.6;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.footer-links dt {
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 16px;
}

.footer-links dd {
  font-size: 14px;
  margin-bottom: 10px;
  line-height: 1.6;
}

.footer-links dd a {
  transition: color var(--transition);
}

.footer-links dd a:hover {
  color: var(--primary);
}

.footer-bottom {
  padding: 24px 0;
  text-align: center;
}

.footer-copy {
  font-size: 13px;
  margin-bottom: 8px;
}

.footer-icp {
  font-size: 13px;
}

.footer-icp a {
  color: var(--primary);
  transition: color var(--transition);
}

.footer-icp a:hover {
  text-decoration: underline;
}

/* === Responsive === */
@media (max-width: 1024px) {
  .section-row {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .section-row.reverse {
    direction: ltr;
  }
  .section-img img {
    height: 280px;
  }
  .footer-main {
    grid-template-columns: 1fr;
  }
  .about-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 32px;
  }
  .hero-subtitle {
    font-size: 16px;
  }
  .hero-desc {
    font-size: 14px;
  }
  .section {
    padding: 56px 0;
  }
  .section-title {
    font-size: 26px;
  }
  .section-row {
    gap: 32px;
  }
  .section-img img {
    height: 220px;
  }
  .nav {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    flex-direction: column;
    padding: 24px;
    transform: translateX(100%);
    transition: transform 0.3s ease;
    overflow-y: auto;
  }
  .nav.active {
    transform: translateX(0);
  }
  .nav-list {
    flex-direction: column;
    gap: 8px;
  }
  .nav-link {
    font-size: 16px;
    padding: 12px 16px;
  }
  .menu-toggle {
    display: flex;
  }
  .about-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .device-categories {
    grid-template-columns: 1fr;
  }
  .contact-grid {
    grid-template-columns: 1fr;
  }
  .footer-links {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .hero-btns {
    flex-direction: column;
  }
  .btn {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }
  .hero {
    min-height: 480px;
    max-height: 560px;
  }
  .hero-title {
    font-size: 26px;
  }
}