/* Fanein 官网：自有品牌视觉，信息架构对齐常见物联网站（首页/产品/平台/方案/关于） */
:root {
  --ink: #0c1222;
  --ink-soft: #1a2438;
  --muted: #5c6b82;
  --paper: #f4f7fb;
  --line: rgba(12, 18, 34, 0.08);
  --accent: #0d9488;
  --accent-deep: #0f766e;
  --glow: #2dd4bf;
  --header-h: 4rem;
  --radius: 1rem;
  --font-display: "Outfit", "Noto Sans SC", system-ui, sans-serif;
  --font-body: "Noto Sans SC", system-ui, sans-serif;
  --shadow: 0 18px 50px rgba(12, 18, 34, 0.1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink);
  background: #fff;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

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

.shell {
  width: min(1120px, calc(100% - 2rem));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  backdrop-filter: blur(14px);
  background: rgba(255, 255, 255, 0.86);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s ease, background 0.25s ease;
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(255, 255, 255, 0.94);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: 0.02em;
}

.brand-mark {
  width: 1.35rem;
  height: 1.35rem;
  border-radius: 0.4rem;
  background: linear-gradient(145deg, var(--glow), var(--accent-deep));
  box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}

.brand-text {
  font-size: 1.2rem;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.site-nav > a {
  font-size: 0.92rem;
  color: var(--muted);
  font-weight: 500;
}

.site-nav > a:hover {
  color: var(--ink);
}

.nav-cta {
  display: flex;
  gap: 0.5rem;
  margin-left: 0.5rem;
}

.nav-toggle {
  display: none;
  width: 2.5rem;
  height: 2.5rem;
  border: 0;
  background: transparent;
  cursor: pointer;
  padding: 0.55rem;
}

.nav-toggle span {
  display: block;
  height: 2px;
  margin: 6px 0;
  background: var(--ink);
  transition: transform 0.2s ease;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.4rem;
  padding: 0 1rem;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 600;
  border: 1px solid transparent;
  transition: transform 0.15s ease, background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-lg {
  min-height: 2.9rem;
  padding: 0 1.35rem;
  font-size: 0.95rem;
}

.btn-solid {
  background: var(--accent);
  color: #fff;
}

.btn-solid:hover {
  background: var(--accent-deep);
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.45);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* Hero */
.hero {
  position: relative;
  min-height: min(88vh, 720px);
  display: grid;
  align-items: end;
  padding: 5rem 0 4.5rem;
  overflow: hidden;
  color: #fff;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 15% 20%, rgba(45, 212, 191, 0.35), transparent 55%),
    radial-gradient(ellipse 70% 50% at 85% 10%, rgba(56, 189, 248, 0.22), transparent 50%),
    linear-gradient(160deg, #071018 0%, #0f2740 48%, #0b3d3a 100%);
  transform: scale(1.02);
  animation: heroDrift 18s ease-in-out infinite alternate;
}

.hero-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.55), transparent 85%);
  opacity: 0.5;
}

@keyframes heroDrift {
  from {
    transform: scale(1.02) translateY(0);
  }
  to {
    transform: scale(1.06) translateY(-1.5%);
  }
}

.hero-inner {
  position: relative;
  z-index: 1;
  max-width: 40rem;
  padding-bottom: env(safe-area-inset-bottom, 0);
}

.eyebrow {
  margin: 0 0 0.75rem;
  font-size: 0.85rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.72);
}

.hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(3.2rem, 10vw, 5.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
}

.hero-lead {
  margin: 1.1rem 0 1.75rem;
  font-size: clamp(1rem, 2.4vw, 1.15rem);
  color: rgba(255, 255, 255, 0.82);
  max-width: 34rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* Sections */
.section {
  padding: 4.5rem 0;
}

.section-tint {
  background: var(--paper);
}

.section-head {
  max-width: 36rem;
  margin-bottom: 2.25rem;
}

.section-head h2 {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.5vw, 2.2rem);
  letter-spacing: -0.02em;
}

.section-head p {
  margin: 0;
  color: var(--muted);
}

.adv-grid,
.prod-grid,
.sol-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

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

.adv-grid li {
  padding: 1.25rem 1.2rem;
  border-top: 2px solid var(--accent);
  background: #fff;
  box-shadow: var(--shadow);
}

.adv-grid strong {
  display: block;
  margin-bottom: 0.4rem;
  font-size: 1.05rem;
}

.adv-grid span {
  color: var(--muted);
  font-size: 0.92rem;
}

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

.prod,
.sol {
  padding: 1.5rem 1.4rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.prod h3,
.sol h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
}

.prod p,
.sol p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.platform-layout .plat-list {
  margin: 0 0 1.75rem;
  padding-left: 1.1rem;
  columns: 2;
  gap: 2rem;
  color: var(--ink-soft);
}

.platform-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.about-layout {
  display: grid;
  grid-template-columns: 1.3fr 0.9fr;
  gap: 2rem;
  align-items: start;
}

.about-copy {
  margin: 0 0 1rem;
  color: var(--ink-soft);
  max-width: 38rem;
}

.about-copy.muted {
  color: var(--muted);
  font-size: 0.9rem;
}

.consult {
  padding: 1.5rem;
  border-radius: var(--radius);
  background: linear-gradient(160deg, #0f2740, #0b3d3a);
  color: #fff;
  box-shadow: var(--shadow);
}

.consult h3 {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
}

.consult p {
  margin: 0 0 1rem;
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.95rem;
}

.consult-note {
  margin-top: 0.75rem !important;
  font-size: 0.8rem !important;
  opacity: 0.7;
}

.contact-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.contact-list li {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  margin-bottom: 0.85rem;
}

.contact-list span {
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.55);
}

.contact-list a {
  font-size: 1.05rem;
  font-weight: 600;
  color: #fff;
}

.footer-contact {
  margin: 0.85rem 0 0;
  font-size: 0.9rem;
}

.footer-contact a {
  display: inline;
  color: rgba(255, 255, 255, 0.85);
}

.footer-contact a:hover {
  color: #fff;
}

/* Footer */
.site-footer {
  background: var(--ink);
  color: rgba(255, 255, 255, 0.78);
  padding: 3rem 0 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand .brand-text {
  color: #fff;
}

.footer-tag {
  margin: 0.75rem 0 0;
  font-size: 0.9rem;
  max-width: 16rem;
}

.site-footer h4 {
  margin: 0 0 0.75rem;
  color: #fff;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.site-footer a {
  display: block;
  margin: 0.35rem 0;
  font-size: 0.92rem;
  color: rgba(255, 255, 255, 0.7);
}

.site-footer a:hover {
  color: #fff;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  padding-top: 1.25rem;
  font-size: 0.82rem;
  color: rgba(255, 255, 255, 0.45);
}

.icp-footer {
  flex: 1 1 auto;
  text-align: center;
  color: rgba(255, 255, 255, 0.5);
}

.icp-footer a {
  display: inline;
  margin: 0;
  color: rgba(255, 255, 255, 0.55);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.icp-footer a:hover {
  color: #fff;
}

.icp-sep {
  opacity: 0.55;
}

/* Reveal motion */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

/* Responsive */
@media (max-width: 900px) {
  .adv-grid {
    grid-template-columns: 1fr 1fr;
  }

  .platform-layout .plat-list {
    columns: 1;
  }

  .about-layout,
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .nav-toggle {
    display: block;
  }

  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.75rem 1rem 1.25rem;
    background: #fff;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-nav > a {
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--line);
  }

  .nav-cta {
    margin: 0.75rem 0 0;
    flex-direction: column;
  }

  .adv-grid,
  .prod-grid,
  .sol-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: 78vh;
    align-items: center;
    padding-top: 3.5rem;
  }
}

/* —— 私有化产品介绍分页 private.html —— */
.page-private .hero-private {
  min-height: min(82vh, 640px);
}

.page-private .hero-private .hero-lead {
  max-width: 38rem;
}

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

.mod {
  padding: 1.5rem 1.4rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.mod h3 {
  margin: 0 0 0.85rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
}

.mod ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.mod li + li {
  margin-top: 0.35rem;
}

.demo-layout {
  display: grid;
  grid-template-columns: 1.35fr 0.9fr;
  gap: 2rem;
  align-items: start;
}

.steps {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: demo-step;
}

.steps li {
  counter-increment: demo-step;
  position: relative;
  padding: 1.1rem 1.1rem 1.1rem 3.4rem;
  margin-bottom: 0.75rem;
  border-radius: var(--radius);
  background: var(--paper);
  border: 1px solid var(--line);
}

.steps li::before {
  content: counter(demo-step, decimal-leading-zero);
  position: absolute;
  left: 1rem;
  top: 1.15rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.95rem;
  color: var(--accent-deep);
}

.steps strong {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 1.02rem;
}

.steps span {
  color: var(--muted);
  font-size: 0.92rem;
}

.demo-note {
  margin: 1rem 0 0;
  font-size: 0.88rem;
  color: var(--muted);
}

.demo-code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
  padding: 0.12rem 0.4rem;
  border-radius: 0.35rem;
  background: rgba(13, 148, 136, 0.1);
  color: var(--accent-deep);
}

.demo-note a {
  color: var(--accent-deep);
  text-decoration: underline;
  text-underline-offset: 2px;
}

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

.del {
  padding: 1.35rem 1.2rem;
  border-top: 2px solid var(--accent);
  background: #fff;
  box-shadow: var(--shadow);
}

.del-step {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  color: var(--accent-deep);
}

.del h3 {
  margin: 0 0 0.45rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
}

.del p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.faq-list {
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.faq-list > div {
  padding: 1.15rem 1.25rem;
  border-radius: var(--radius);
  background: #fff;
  border: 1px solid var(--line);
}

.faq-list dt {
  margin: 0 0 0.4rem;
  font-weight: 700;
  font-size: 1rem;
}

.faq-list dd {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 900px) {
  .mod-grid,
  .demo-layout {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 720px) {
  .del-grid {
    grid-template-columns: 1fr;
  }
}