/* ── Design tokens ── */
:root {
  --bg-deep: #080c12;
  --bg-surface: #0f1623;
  --bg-card: rgba(18, 27, 42, 0.72);
  --border: rgba(148, 163, 184, 0.12);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #22d3ee;
  --accent-soft: rgba(34, 211, 238, 0.14);
  --accent-glow: rgba(34, 211, 238, 0.35);
  --violet: #818cf8;
  --radius: 16px;
  --radius-sm: 10px;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-display: "DM Sans", var(--font-sans);
  --max-width: 1120px;
  --nav-height: 72px;
  --transition: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-sans);
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

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

body.nav-open {
  overflow: hidden;
}

/* ── Background ── */
.bg-mesh {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 60% at 10% 0%, rgba(34, 211, 238, 0.08) 0%, transparent 55%),
    radial-gradient(ellipse 60% 50% at 90% 10%, rgba(129, 140, 248, 0.07) 0%, transparent 50%),
    radial-gradient(ellipse 50% 40% at 50% 100%, rgba(34, 211, 238, 0.04) 0%, transparent 50%),
    var(--bg-deep);
}

.bg-grid {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0.35;
  background-image:
    linear-gradient(rgba(148, 163, 184, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.04) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 30%, black 20%, transparent 75%);
}

/* ── Layout ── */
.container {
  width: min(100% - 2.5rem, var(--max-width));
  margin-inline: auto;
}

.section {
  padding-block: clamp(4rem, 8vw, 7rem);
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
}

.section-label::before {
  content: "";
  width: 24px;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 1rem;
}

.section-desc {
  color: var(--text-secondary);
  font-size: 1.0625rem;
  max-width: 560px;
}

/* ── Navigation ── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-height);
  transition: background var(--transition), border-color var(--transition), backdrop-filter var(--transition);
}

.nav.scrolled {
  background: rgba(8, 12, 18, 0.82);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.nav-logo img {
  height: 36px;
  width: auto;
}

.nav-logo span {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
  margin-left: auto;
}

.nav-links a {
  padding: 0.5rem 0.875rem;
  font-size: 0.9375rem;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  transition: color var(--transition), background var(--transition);
}

.nav-links a:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

.lang-switch {
  padding: 0.4375rem 0.875rem;
  font-family: var(--font-display);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid rgba(34, 211, 238, 0.25);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}

.lang-switch:hover {
  background: rgba(34, 211, 238, 0.22);
  border-color: rgba(34, 211, 238, 0.4);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  flex-shrink: 0;
  margin-left: 0.75rem;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ── Hero ── */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  padding-bottom: 4rem;
}

.hero-content {
  max-width: 780px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.375rem 0.875rem 0.375rem 0.625rem;
  background: var(--accent-soft);
  border: 1px solid rgba(34, 211, 238, 0.25);
  border-radius: 999px;
  font-size: 0.875rem;
  color: var(--accent);
  margin-bottom: 1.75rem;
  animation: fadeUp 0.8s ease both;
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 50%;
  animation: pulse 2s ease infinite;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.75rem, 7vw, 4.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 1.5rem;
}

.hero-title .line {
  display: block;
  overflow: hidden;
}

.hero-title .line:nth-child(1) {
  animation: fadeUp 0.8s 0.1s ease both;
}

.hero-title .line:nth-child(2) {
  animation: fadeUp 0.8s 0.25s ease both;
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--accent) 0%, var(--violet) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1.0625rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 620px;
  margin-bottom: 2.5rem;
  animation: fadeUp 0.8s 0.4s ease both;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  animation: fadeUp 0.8s 0.55s ease both;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.8125rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow var(--transition), background var(--transition);
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent) 0%, #0891b2 100%);
  color: var(--bg-deep);
  box-shadow: 0 0 24px var(--accent-glow);
}

.btn-primary:hover {
  box-shadow: 0 0 36px var(--accent-glow);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(148, 163, 184, 0.25);
}

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 2.5rem;
  margin-top: 4rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--border);
  animation: fadeUp 0.8s 0.7s ease both;
}

.stat-item strong {
  display: block;
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  line-height: 1.2;
}

.stat-item span {
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* ── Cards ── */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin-top: 3rem;
}

.about-quote {
  margin-top: 1.5rem;
  font-family: var(--font-display);
  font-style: italic;
  font-size: 1.0625rem;
  color: var(--accent);
  opacity: 0.85;
}

.strengths-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-top: 2.5rem;
}

.strength-item {
  padding: 1.125rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
  position: relative;
  padding-left: 2.5rem;
  transition: border-color var(--transition);
}

.strength-item::before {
  content: "✦";
  position: absolute;
  left: 1rem;
  top: 1.125rem;
  color: var(--accent);
  font-size: 0.75rem;
}

.strength-item:hover {
  border-color: rgba(34, 211, 238, 0.25);
}

.tech-categories {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  margin-top: 2.5rem;
}

.tech-group-title {
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.875rem;
  padding-left: 0.75rem;
  border-left: 3px solid var(--accent);
}

.tech-group .tags-wrap {
  margin-top: 0;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  backdrop-filter: blur(12px);
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  border-color: rgba(34, 211, 238, 0.3);
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.3);
}

.card-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-soft);
  border-radius: var(--radius-sm);
  font-size: 1.25rem;
  margin-bottom: 1.25rem;
}

.card h3 {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.625rem;
}

.card p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ── Tech tags ── */
.tags-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 0.625rem;
  margin-top: 2.5rem;
}

.tag {
  padding: 0.4375rem 1rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  border-radius: 999px;
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}

.tag:hover {
  color: var(--accent);
  border-color: rgba(34, 211, 238, 0.35);
  background: var(--accent-soft);
}

/* ── Industries ── */
.industries-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1rem;
  margin-top: 2.5rem;
}

.industry-item {
  text-align: center;
  padding: 1.5rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color var(--transition);
}

.industry-item:hover {
  border-color: rgba(129, 140, 248, 0.35);
}

.industry-item .icon {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

.industry-item span {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
}

/* ── Contact ── */
.contact-box {
  margin-top: 2.5rem;
  padding: 2.5rem;
  background: linear-gradient(135deg, rgba(34, 211, 238, 0.06) 0%, rgba(129, 140, 248, 0.06) 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.contact-info h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  margin-bottom: 0.375rem;
}

.contact-info p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

.contact-email {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--accent);
  transition: opacity var(--transition);
}

.contact-email:hover {
  opacity: 0.8;
}

/* ── Footer ── */
.footer {
  padding-block: 2.5rem 2rem;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  text-align: center;
}

.footer-logo img {
  height: 40px;
  width: auto;
  margin-inline: auto;
  opacity: 0.85;
}

.footer-beian {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.5rem 1rem;
}

.footer-beian a {
  font-size: 0.8125rem;
  color: var(--text-muted);
  transition: color var(--transition);
}

.footer-beian a:hover {
  color: var(--text-secondary);
}

.footer-beian img {
  width: 18px;
  height: 18px;
}

.footer-copy {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ── Scroll reveal ── */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Animations ── */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ── Responsive ── */
@media (max-width: 900px) {
  .nav-logo span {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-controls {
    margin-left: auto;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    z-index: 99;
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
    margin-left: 0;
    padding: 0.75rem 1rem 1rem;
    background: rgba(8, 12, 18, 0.98);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
    transform: translateY(calc(-100% - var(--nav-height)));
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: transform var(--transition), opacity var(--transition), visibility var(--transition);
    max-height: calc(100dvh - var(--nav-height));
    overflow-y: auto;
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .nav-links li {
    width: 100%;
  }

  .nav-links a {
    display: block;
    width: 100%;
    text-align: center;
    padding: 0.875rem 1rem;
  }

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

  .strengths-list {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 640px) {
  .hero-stats {
    gap: 1.5rem;
  }

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

  .cards-grid {
    grid-template-columns: 1fr;
  }

  .contact-box {
    flex-direction: column;
    align-items: flex-start;
  }
}