/* 周周信息咨询 · 科技风 · Mobile-first */
:root {
  --bg: #050816;
  --bg-card: rgba(10, 22, 40, 0.78);
  --border: rgba(56, 189, 248, 0.14);
  --border-hover: rgba(56, 189, 248, 0.42);
  --text: #f1f5f9;
  --muted: #94a3b8;
  --accent: #0ea5e9;
  --accent-2: #22d3ee;
  --violet: #818cf8;
  --radius: 14px;
  --max: 1080px;
  --section: clamp(3rem, 9vw, 5rem);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 1rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: rgba(5, 8, 22, 0.72);
  border-bottom: 1px solid transparent;
  transition: background 0.3s, border-color 0.3s, box-shadow 0.3s;
}

.site-header.is-scrolled {
  background: rgba(5, 8, 22, 0.92);
  border-bottom-color: var(--border);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--text);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.brand:hover {
  color: var(--accent-2);
  text-decoration: none;
}

.brand img {
  width: 36px;
  height: 36px;
}

.nav-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: rgba(14, 165, 233, 0.08);
  color: var(--text);
  cursor: pointer;
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
}

.nav {
  display: none;
  position: absolute;
  left: 0;
  right: 0;
  top: 100%;
  flex-direction: column;
  padding: 0.5rem 1.25rem 1rem;
  background: rgba(5, 8, 22, 0.97);
  border-bottom: 1px solid var(--border);
}

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

.nav a {
  padding: 0.8rem 0.75rem;
  color: var(--muted);
  font-weight: 500;
  border-radius: 8px;
  text-decoration: none;
}

.nav a:hover {
  color: var(--accent-2);
  background: rgba(14, 165, 233, 0.1);
}

@media (min-width: 768px) {
  .nav {
    display: flex;
    position: static;
    flex-direction: row;
    gap: 0.25rem;
    padding: 0;
    background: transparent;
    border: 0;
  }

  .nav a {
    padding: 0.5rem 0.85rem;
  }
}

/* Hero */
.hero {
  position: relative;
  min-height: min(88vh, 760px);
  display: flex;
  align-items: center;
  padding: 2.5rem 0 3rem;
  overflow: hidden;
}

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

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

.hero-overlay {
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(180deg, rgba(5, 8, 22, 0.35) 0%, rgba(5, 8, 22, 0.88) 85%);
}

.hero-content {
  position: relative;
  z-index: 2;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  margin: 0 0 1rem;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--accent-2);
}

.hero-tag::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent);
}

.hero h1 {
  margin: 0 0 1rem;
  max-width: 12em;
  font-size: clamp(1.85rem, 5vw, 2.85rem);
  line-height: 1.22;
  letter-spacing: -0.02em;
}

.hero h1 span {
  background: linear-gradient(105deg, var(--accent) 0%, var(--accent-2) 45%, var(--violet) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub {
  margin: 0 0 1.75rem;
  max-width: 36em;
  color: var(--muted);
  font-size: 1.05rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.78rem 1.45rem;
  font: inherit;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.25s var(--ease), box-shadow 0.25s, border-color 0.25s;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-2) 100%);
  color: #042028;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 36px rgba(14, 165, 233, 0.38);
  text-decoration: none;
}

.btn-outline {
  background: rgba(14, 165, 233, 0.08);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--border-hover);
  color: var(--accent-2);
  text-decoration: none;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  max-width: 480px;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
}

.hero-stat strong {
  display: block;
  font-size: 1.5rem;
  line-height: 1.2;
}

.hero-stat span {
  font-size: 0.75rem;
  color: var(--muted);
}

/* Sections */
.section {
  padding: var(--section) 0;
}

.section-alt {
  background: linear-gradient(180deg, transparent 0%, rgba(14, 165, 233, 0.04) 50%, transparent 100%);
}

.section-head {
  margin-bottom: 2rem;
  max-width: 40em;
}

.section-kicker {
  margin: 0 0 0.45rem;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--accent);
}

.section-head h2 {
  margin: 0 0 0.65rem;
  font-size: clamp(1.45rem, 3vw, 2rem);
  letter-spacing: -0.02em;
}

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

/* About */
.about-grid {
  display: grid;
  gap: 1.25rem;
}

@media (min-width: 768px) {
  .about-grid {
    grid-template-columns: 1.4fr 1fr;
    align-items: start;
  }
}

.about-card {
  padding: 1.65rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.about-card p {
  margin: 0;
  color: var(--muted);
}

.about-card p + p {
  margin-top: 0.85rem;
}

.about-highlight {
  padding: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: linear-gradient(145deg, rgba(14, 165, 233, 0.12), rgba(99, 102, 241, 0.08));
}

.about-highlight p {
  margin: 0;
  font-weight: 500;
  color: var(--text);
}

.about-highlight small {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.8125rem;
  color: var(--muted);
}

/* Services */
.service-grid {
  display: grid;
  gap: 1.15rem;
}

@media (min-width: 640px) {
  .service-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .service-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.service-card {
  position: relative;
  padding: 1.45rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform 0.3s var(--ease), border-color 0.3s, box-shadow 0.3s;
  overflow: hidden;
}

.service-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-hover);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.3);
}

.service-icon {
  width: 44px;
  height: 44px;
  margin-bottom: 0.85rem;
}

.service-card h3 {
  margin: 0 0 0.35rem;
  font-size: 1.05rem;
}

.service-card .subtitle {
  display: block;
  margin-bottom: 0.55rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--accent-2);
}

.service-card p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted);
  line-height: 1.6;
}

/* Why */
.why-grid {
  display: grid;
  gap: 1rem;
}

@media (min-width: 768px) {
  .why-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.why-card {
  text-align: center;
  padding: 1.65rem 1.1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform 0.3s var(--ease), border-color 0.3s;
}

.why-card:hover {
  transform: translateY(-3px);
  border-color: rgba(129, 140, 248, 0.35);
}

.why-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  margin-bottom: 0.75rem;
  border-radius: 10px;
  background: rgba(14, 165, 233, 0.15);
  color: var(--accent-2);
  font-weight: 700;
  font-size: 0.875rem;
}

.why-card h3 {
  margin: 0 0 0.45rem;
  font-size: 1.05rem;
}

.why-card p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--muted);
}

/* CTA */
.cta {
  margin: 0 0 var(--section);
}

.cta-box {
  padding: 2.25rem 1.5rem;
  text-align: center;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: rgba(10, 22, 40, 0.85);
}

.cta-box h2 {
  margin: 0 0 0.55rem;
  font-size: clamp(1.2rem, 2.5vw, 1.55rem);
}

.cta-box p {
  margin: 0 auto 1.25rem;
  max-width: 34em;
  color: var(--muted);
  font-size: 0.95rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2.25rem 0 2rem;
  background: #03050c;
  text-align: center;
}

.footer-brand {
  margin: 0 0 0.35rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.footer-contact {
  margin: 0 0 1rem;
  font-size: 0.875rem;
  color: var(--muted);
}

.footer-icp {
  margin: 0 0 0.85rem;
}

.footer-icp a {
  font-size: 0.8125rem;
  color: var(--muted);
  text-decoration: none;
}

.footer-icp a:hover {
  color: var(--accent);
  text-decoration: underline;
}

.footer-copy {
  margin: 0;
  font-size: 0.75rem;
  color: #64748b;
}

/* Reveal */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.65s var(--ease), transform 0.65s var(--ease);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

[data-reveal-delay="1"] { transition-delay: 0.08s; }
[data-reveal-delay="2"] { transition-delay: 0.14s; }
[data-reveal-delay="3"] { transition-delay: 0.2s; }
[data-reveal-delay="4"] { transition-delay: 0.26s; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}