/* ============================================
   长沙滔博科技有限公司 - 企业官网样式
   Design: 精致科技感 + 东方克制美学
   ============================================ */

/* --- Design Tokens --- */
:root {
  --c-bg: #060a1a;
  --c-bg-elevated: #0c1130;
  --c-bg-card: #0f1538;
  --c-bg-card-hover: #141c48;
  --c-surface: rgba(255, 255, 255, 0.03);
  --c-border: rgba(255, 255, 255, 0.06);
  --c-border-hover: rgba(59, 130, 246, 0.3);
  --c-text: #e2e8f0;
  --c-text-muted: #8892a8;
  --c-text-dim: #4a5568;
  --c-heading: #f1f5f9;
  --c-primary: #3b82f6;
  --c-primary-glow: rgba(59, 130, 246, 0.15);
  --c-accent: #f59e0b;
  --c-accent-glow: rgba(245, 158, 11, 0.12);

  --font-display: 'Sora', 'Noto Sans SC', sans-serif;
  --font-body: 'DM Sans', 'Noto Sans SC', sans-serif;
  --font-cn: 'Noto Sans SC', sans-serif;

  --nav-h: 72px;
  --container-max: 1200px;
  --radius: 12px;
  --radius-sm: 8px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-h);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.7;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.3s var(--ease-out);
}

ul { list-style: none; }

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

::selection {
  background: var(--c-primary);
  color: #fff;
}

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

/* --- Noise Texture Overlay --- */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 200px 200px;
}

/* --- Animate In (scroll triggered) --- */
.animate-in {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}

.animate-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-h);
  transition: background 0.4s var(--ease-out), box-shadow 0.4s var(--ease-out);
}

.nav.scrolled {
  background: rgba(6, 10, 26, 0.85);
  backdrop-filter: blur(20px) saturate(1.4);
  -webkit-backdrop-filter: blur(20px) saturate(1.4);
  box-shadow: 0 1px 0 var(--c-border);
}

.nav__inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav__logo-icon {
  width: 36px;
  height: 36px;
}

.nav__logo-text {
  font-family: var(--font-cn);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--c-heading);
  letter-spacing: 0.02em;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav__link {
  font-family: var(--font-cn);
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--c-text-muted);
  padding: 8px 16px;
  border-radius: 6px;
  transition: color 0.3s var(--ease-out), background 0.3s var(--ease-out);
  position: relative;
}

.nav__link:hover,
.nav__link.active {
  color: var(--c-heading);
}

.nav__link.active {
  background: var(--c-primary-glow);
  color: var(--c-primary);
}

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
}

.nav__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--c-text);
  border-radius: 2px;
  transition: transform 0.3s var(--ease-out), opacity 0.3s var(--ease-out);
}

.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 {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: radial-gradient(ellipse 80% 60% at 50% 40%, #0c1a4a 0%, var(--c-bg) 70%);
}

.hero__canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero__overlay {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 80%, var(--c-primary-glow) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, var(--c-accent-glow) 0%, transparent 50%);
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 0 24px;
  max-width: 800px;
}

.hero__tag {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.3em;
  color: var(--c-primary);
  margin-bottom: 24px;
  text-transform: uppercase;
}

.hero__title {
  font-family: var(--font-cn);
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 900;
  color: var(--c-heading);
  line-height: 1.2;
  margin-bottom: 24px;
  letter-spacing: -0.02em;
}

.hero__title-accent {
  background: linear-gradient(135deg, var(--c-primary) 0%, #60a5fa 50%, var(--c-accent) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero__subtitle {
  font-family: var(--font-cn);
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--c-text-muted);
  margin-bottom: 48px;
  font-weight: 300;
  letter-spacing: 0.08em;
}

.hero__actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.hero__scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  z-index: 2;
}

.hero__scroll-text {
  font-family: var(--font-display);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  color: var(--c-text-dim);
  text-transform: uppercase;
  writing-mode: vertical-lr;
}

.hero__scroll-line {
  width: 1px;
  height: 48px;
  background: linear-gradient(to bottom, var(--c-primary), transparent);
  animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
  0%, 100% { opacity: 0.3; transform: scaleY(0.6); }
  50% { opacity: 1; transform: scaleY(1); }
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-cn);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 14px 36px;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: all 0.3s var(--ease-out);
  position: relative;
  overflow: hidden;
}

.btn--primary {
  background: var(--c-primary);
  color: #fff;
  box-shadow: 0 4px 24px rgba(59, 130, 246, 0.25);
}

.btn--primary:hover {
  background: #2563eb;
  box-shadow: 0 8px 32px rgba(59, 130, 246, 0.35);
  transform: translateY(-2px);
}

.btn--outline {
  background: transparent;
  color: var(--c-text);
  border: 1px solid var(--c-border);
}

.btn--outline:hover {
  border-color: var(--c-primary);
  color: var(--c-primary);
  background: var(--c-primary-glow);
}

.btn--full {
  width: 100%;
}

/* --- Section Header --- */
.section-tag {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.25em;
  color: var(--c-primary);
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-title {
  font-family: var(--font-cn);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  color: var(--c-heading);
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--c-text-muted);
  max-width: 560px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

/* --- About --- */
.about {
  padding: 120px 0;
  position: relative;
}

.about::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--c-border), transparent);
}

.about__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.about__text p {
  color: var(--c-text-muted);
  margin-bottom: 20px;
  font-size: 0.95rem;
  line-height: 1.85;
}

.about__lead {
  font-family: var(--font-cn);
  font-size: 1.15rem !important;
  color: var(--c-text) !important;
  font-weight: 500;
  line-height: 1.7 !important;
}

.about__stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.stat-card {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  transition: border-color 0.4s var(--ease-out), box-shadow 0.4s var(--ease-out);
}

.stat-card:hover {
  border-color: var(--c-border-hover);
  box-shadow: 0 8px 32px var(--c-primary-glow);
}

.stat-card__number {
  display: block;
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--c-primary);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-card__label {
  font-family: var(--font-cn);
  font-size: 0.85rem;
  color: var(--c-text-dim);
  font-weight: 400;
}

/* --- Services --- */
.services {
  padding: 120px 0;
  background: var(--c-bg-elevated);
  position: relative;
}

.services::before,
.services::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--c-border), transparent);
}

.services::before { top: 0; }
.services::after { bottom: 0; }

.services__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.service-card {
  position: relative;
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 40px 32px;
  transition: all 0.4s var(--ease-out);
  overflow: hidden;
}

.service-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-accent));
  opacity: 0;
  transition: opacity 0.4s var(--ease-out);
}

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

.service-card:hover::before {
  opacity: 1;
}

.service-card__icon {
  width: 48px;
  height: 48px;
  color: var(--c-primary);
  margin-bottom: 24px;
}

.service-card__icon svg {
  width: 100%;
  height: 100%;
}

.service-card__title {
  font-family: var(--font-cn);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--c-heading);
  margin-bottom: 12px;
}

.service-card__desc {
  font-size: 0.9rem;
  color: var(--c-text-muted);
  line-height: 1.75;
}

.service-card__index {
  position: absolute;
  top: 24px;
  right: 24px;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--c-text-dim);
  letter-spacing: 0.05em;
}

/* --- Advantages --- */
.advantages {
  padding: 120px 0;
  position: relative;
}

.advantages__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.adv-card {
  position: relative;
  padding: 40px;
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  transition: all 0.4s var(--ease-out);
  overflow: hidden;
}

.adv-card:hover {
  border-color: var(--c-border-hover);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.2);
}

.adv-card__number {
  font-family: var(--font-display);
  font-size: 3rem;
  font-weight: 800;
  color: var(--c-bg-card-hover);
  line-height: 1;
  margin-bottom: 16px;
  transition: color 0.4s var(--ease-out);
}

.adv-card:hover .adv-card__number {
  color: var(--c-primary-glow);
}

.adv-card__title {
  font-family: var(--font-cn);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--c-heading);
  margin-bottom: 12px;
}

.adv-card__desc {
  font-size: 0.9rem;
  color: var(--c-text-muted);
  line-height: 1.75;
}

.adv-card__line {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-accent));
  transition: width 0.6s var(--ease-out);
}

.adv-card:hover .adv-card__line {
  width: 100%;
}

/* --- Contact --- */
.contact {
  padding: 120px 0;
  background: var(--c-bg-elevated);
  position: relative;
}

.contact::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--c-border), transparent);
}

.contact__centered {
  max-width: 600px;
  margin: 0 auto;
}

.contact__info {
  display: flex;
  flex-direction: column;
  gap: 36px;
}

.contact__info-item {
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.contact__info-icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--c-primary-glow);
  border-radius: var(--radius-sm);
  color: var(--c-primary);
}

.contact__info-icon svg {
  width: 22px;
  height: 22px;
}

.contact__info-title {
  font-family: var(--font-cn);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--c-heading);
  margin-bottom: 6px;
}

.contact__info-text {
  font-size: 0.9rem;
  color: var(--c-text-muted);
  line-height: 1.7;
}


/* --- Footer --- */
.footer {
  padding: 64px 0 0;
  background: var(--c-bg);
  border-top: 1px solid var(--c-border);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
}

.footer__brand .nav__logo {
  margin-bottom: 16px;
}

.footer__desc {
  font-size: 0.9rem;
  color: var(--c-text-dim);
  line-height: 1.7;
}

.footer__heading {
  font-family: var(--font-cn);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--c-heading);
  margin-bottom: 20px;
}

.footer__links ul {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer__links a,
.footer__links li {
  font-size: 0.85rem;
  color: var(--c-text-dim);
  transition: color 0.3s var(--ease-out);
}

.footer__links a:hover {
  color: var(--c-primary);
}

.footer__bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 0;
  border-top: 1px solid var(--c-border);
  font-size: 0.8rem;
  color: var(--c-text-dim);
}

.footer__bottom a {
  color: var(--c-text-dim);
}

.footer__bottom a:hover {
  color: var(--c-primary);
}

/* --- Hero stagger --- */
.hero__content .hero__tag { transition-delay: 0.1s; }
.hero__content .hero__title { transition-delay: 0.25s; }
.hero__content .hero__subtitle { transition-delay: 0.4s; }
.hero__content .hero__actions { transition-delay: 0.55s; }

/* --- Stagger Delays for animate-in children --- */
.services__grid .service-card:nth-child(1) { transition-delay: 0s; }
.services__grid .service-card:nth-child(2) { transition-delay: 0.08s; }
.services__grid .service-card:nth-child(3) { transition-delay: 0.16s; }
.services__grid .service-card:nth-child(4) { transition-delay: 0.24s; }
.services__grid .service-card:nth-child(5) { transition-delay: 0.32s; }
.services__grid .service-card:nth-child(6) { transition-delay: 0.4s; }

.about__stats .stat-card:nth-child(1) { transition-delay: 0s; }
.about__stats .stat-card:nth-child(2) { transition-delay: 0.1s; }
.about__stats .stat-card:nth-child(3) { transition-delay: 0.2s; }
.about__stats .stat-card:nth-child(4) { transition-delay: 0.3s; }

.advantages__grid .adv-card:nth-child(1) { transition-delay: 0s; }
.advantages__grid .adv-card:nth-child(2) { transition-delay: 0.1s; }
.advantages__grid .adv-card:nth-child(3) { transition-delay: 0.2s; }
.advantages__grid .adv-card:nth-child(4) { transition-delay: 0.3s; }

/* --- Responsive --- */
@media (max-width: 1024px) {
  .services__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: 36px;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-h: 64px;
  }

  .nav__toggle {
    display: flex;
  }

  .nav__links {
    position: fixed;
    inset: 0;
    background: rgba(6, 10, 26, 0.97);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    flex-direction: column;
    justify-content: center;
    gap: 8px;
    padding: 24px;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.4s var(--ease-out), visibility 0.4s;
  }

  .nav__links.open {
    opacity: 1;
    visibility: visible;
  }

  .nav__links .nav__link {
    font-size: 1.2rem;
    padding: 14px 20px;
  }

  .about__grid {
    grid-template-columns: 1fr;
    gap: 48px;
  }

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

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

  .footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer__bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }

  .hero__scroll {
    display: none;
  }

  .section-header {
    margin-bottom: 48px;
  }

  .about, .services, .advantages, .contact {
    padding: 80px 0;
  }
}

@media (max-width: 480px) {
  .hero__actions {
    flex-direction: column;
    align-items: stretch;
    padding: 0 16px;
  }

  .stat-card {
    padding: 24px 16px;
  }

  .stat-card__number {
    font-size: 2rem;
  }

  .service-card {
    padding: 32px 24px;
  }

  .adv-card {
    padding: 32px 24px;
  }
}