/* Common Styles - 千知云官网 */
/* ============== Container ============== */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}
.section { padding: var(--space-4xl) 0; }
.section-sm { padding: var(--space-3xl) 0; }
.section-lg { padding: 120px 0; }

/* ============== Top Navigation ============== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border-light);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 20px;
  font-weight: var(--fw-bold);
  color: var(--primary);
}
.logo-mark {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 18px;
  font-weight: var(--fw-bold);
  box-shadow: 0 4px 12px rgba(44, 116, 248, 0.3);
}
.nav { display: flex; gap: 40px; }
.nav a {
  font-size: var(--fs-base);
  color: var(--text-body);
  font-weight: var(--fw-medium);
  position: relative;
  padding: 4px 0;
  transition: var(--transition-fast);
}
.nav a:hover { color: var(--primary); }
.nav a.active { color: var(--primary); }
.nav a.active::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -22px;
  transform: translateX(-50%);
  width: 24px;
  height: 3px;
  border-radius: 2px;
  background: var(--primary);
}
.header-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 40px;
  padding: 0 24px;
  border-radius: var(--radius-pill);
  background: var(--gradient-primary);
  color: #fff;
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  box-shadow: 0 4px 12px rgba(44, 116, 248, 0.3);
  transition: var(--transition-base);
}
.header-cta:hover { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(44, 116, 248, 0.4); }

/* ============== Buttons ============== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 48px;
  padding: 0 32px;
  border-radius: var(--radius-pill);
  font-size: var(--fs-base);
  font-weight: var(--fw-semibold);
  transition: var(--transition-base);
  white-space: nowrap;
}
.btn-primary {
  background: var(--gradient-primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(44, 116, 248, 0.3);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 20px rgba(44, 116, 248, 0.4); }
.btn-outline {
  background: #fff;
  color: var(--text-heading);
  border: 1.5px solid var(--border-medium);
}
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-link {
  height: auto;
  padding: 0;
  color: var(--primary);
  font-weight: var(--fw-semibold);
}
.btn-link .arrow { transition: var(--transition-fast); }
.btn-link:hover .arrow { transform: translateX(4px); }
.btn-sm { height: 36px; padding: 0 20px; font-size: var(--fs-sm); }
.btn-lg { height: 56px; padding: 0 40px; font-size: var(--fs-md); }

/* ============== Hero ============== */
.hero {
  position: relative;
  padding: 80px 0 100px;
  background: var(--gradient-hero);
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  top: -200px;
  right: -200px;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(44, 116, 248, 0.15) 0%, transparent 70%);
  pointer-events: none;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 60px;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  position: relative;
}
.hero-title {
  font-size: var(--fs-6xl);
  font-weight: var(--fw-extrabold);
  line-height: 1.15;
  margin-bottom: 24px;
}
.hero-title .accent { color: var(--primary); }
.hero-subtitle {
  font-size: var(--fs-md);
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 40px;
  max-width: 520px;
}
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }
.hero-illustration {
  display: flex;
  align-items: center;
  justify-content: center;
}
.hero-illustration img,
.hero-illustration svg { width: 100%; max-width: 560px; height: auto; }

/* ============== Section Title ============== */
.section-title {
  text-align: center;
  margin-bottom: var(--space-3xl);
}
.section-title h2 {
  font-size: var(--fs-5xl);
  font-weight: var(--fw-bold);
  margin-bottom: 16px;
}
.section-title .subtitle {
  font-size: var(--fs-md);
  color: var(--text-secondary);
}
.section-title .label {
  display: inline-block;
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  color: var(--primary);
  margin-bottom: 12px;
  letter-spacing: 0.5px;
}

/* ============== Stats ============== */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  max-width: 900px;
  margin: -60px auto 0;
  padding: 32px;
  background: #fff;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  position: relative;
  z-index: 2;
}
.stat-item { text-align: center; }
.stat-num {
  font-family: var(--font-num);
  font-size: var(--fs-4xl);
  font-weight: var(--fw-extrabold);
  color: var(--primary);
  line-height: 1;
}
.stat-num .unit {
  font-size: var(--fs-md);
  font-weight: var(--fw-medium);
  margin-left: 2px;
}
.stat-label {
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  margin-top: 8px;
}

/* ============== Card ============== */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  box-shadow: var(--shadow-card);
  transition: var(--transition-base);
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}
.card-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-lg);
  background: var(--primary-50);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--primary);
}
.card h3 {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  margin-bottom: 12px;
}
.card p {
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============== Footer ============== */
.footer {
  background: #fff;
  border-top: 1px solid var(--border-light);
  padding: 64px 0 32px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr 1.5fr;
  gap: 48px;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}
.footer-col h4 {
  font-size: var(--fs-base);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  margin-bottom: 20px;
}
.footer-col ul li {
  margin-bottom: 12px;
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition-fast);
}
.footer-col ul li:hover { color: var(--primary); }
.footer-qr {
  display: flex;
  gap: 16px;
}
.footer-qr-item { text-align: center; }
.footer-qr-item .qr-box {
  width: 92px;
  height: 92px;
  background: var(--bg-section);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 8px;
  position: relative;
  overflow: hidden;
}
.footer-qr-item .qr-label {
  font-size: var(--fs-xs);
  color: var(--text-secondary);
}
.footer-qr-item .qr-caption {
  font-size: 11px;
  color: var(--text-tertiary);
  margin-top: 4px;
  line-height: 1.5;
}
.footer-bottom {
  max-width: var(--container-width);
  margin: 48px auto 0;
  padding: 24px var(--container-padding) 0;
  border-top: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-xs);
  color: var(--text-tertiary);
  flex-wrap: wrap;
  gap: 12px;
}
.footer-bottom a { color: var(--text-tertiary); }
.footer-bottom a:hover { color: var(--primary); }
.footer-meta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-copy {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px 12px;
}
.footer-tech {
  color: var(--text-tertiary);
  opacity: 0.85;
}
.footer-tech::before {
  content: "|";
  margin-right: 12px;
  opacity: 0.4;
}

/* ============== CTA Banner ============== */
.cta-banner {
  background: var(--gradient-blue-deep);
  padding: 80px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-banner::before,
.cta-banner::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.15) 0%, transparent 70%);
  pointer-events: none;
}
.cta-banner::before { top: -100px; left: -100px; width: 300px; height: 300px; }
.cta-banner::after { bottom: -150px; right: -150px; width: 400px; height: 400px; }
.cta-banner h2 {
  color: #fff;
  font-size: var(--fs-4xl);
  font-weight: var(--fw-bold);
  margin-bottom: 12px;
  position: relative;
}
.cta-banner p {
  color: rgba(255, 255, 255, 0.9);
  font-size: var(--fs-md);
  margin-bottom: 32px;
  position: relative;
}
.cta-banner .btn {
  background: #fff;
  color: var(--primary);
  position: relative;
  height: 52px;
  padding: 0 40px;
  font-size: var(--fs-md);
}
.cta-banner .btn:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15); }

/* ============== Page Banner (non-homepage hero) ============== */
.page-banner {
  background: var(--gradient-hero);
  padding: 100px 0 80px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-banner::before {
  content: "";
  position: absolute;
  top: -100px;
  right: -100px;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(44, 116, 248, 0.12) 0%, transparent 70%);
}
.page-banner h1 {
  font-size: var(--fs-6xl);
  font-weight: var(--fw-extrabold);
  margin-bottom: 16px;
  position: relative;
}
.page-banner .subtitle {
  font-size: var(--fs-md);
  color: var(--text-secondary);
  position: relative;
}

/* ============== Forms ============== */
.form-input {
  width: 100%;
  height: 48px;
  padding: 0 16px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  font-size: var(--fs-base);
  background: #fff;
  transition: var(--transition-fast);
}
.form-input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(44, 116, 248, 0.1); }
.form-textarea {
  width: 100%;
  min-height: 120px;
  padding: 12px 16px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  font-size: var(--fs-base);
  background: #fff;
  resize: vertical;
}
.form-textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(44, 116, 248, 0.1); }

/* ============== Decorative background ============== */
.bg-deco-blur {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
  z-index: 0;
}

/* ============== Utilities ============== */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-heading { color: var(--text-heading); }
.text-secondary { color: var(--text-secondary); }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }
.mt-5 { margin-top: 48px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }
.mb-5 { margin-bottom: 48px; }
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.gap-2 { gap: 16px; }
.gap-3 { gap: 24px; }

/* ============== Responsive ============== */
@media (max-width: 1024px) {
  :root { --container-padding: 20px; }
  .hero { padding: 60px 0 80px; }
  .hero-title { font-size: var(--fs-5xl); }
  .hero-inner { gap: 40px; }
  .section { padding: 80px 0; }
  .section-title h2 { font-size: var(--fs-4xl); }
  .footer-grid { grid-template-columns: repeat(3, 1fr); gap: 32px; }
}
@media (max-width: 768px) {
  .nav { display: none; }
  .header-cta { height: 36px; padding: 0 18px; font-size: 13px; }
  .hero { padding: 48px 0 60px; }
  .hero-inner { grid-template-columns: 1fr; gap: 32px; text-align: center; }
  .hero-title { font-size: var(--fs-4xl); }
  .hero-subtitle { margin-left: auto; margin-right: auto; }
  .hero-actions { justify-content: center; }
  .hero-illustration { order: -1; max-width: 360px; margin: 0 auto; }
  .stats { grid-template-columns: repeat(2, 1fr); margin-top: -32px; padding: 24px; gap: 16px; }
  .stat-num { font-size: var(--fs-3xl); }
  .section { padding: 60px 0; }
  .section-title h2 { font-size: var(--fs-3xl); }
  .section-title .subtitle { font-size: var(--fs-base); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 32px; }
  .footer-qr { flex-direction: column; }
  .cta-banner { padding: 60px 0; }
  .cta-banner h2 { font-size: var(--fs-2xl); }
  .page-banner { padding: 70px 0 50px; }
  .page-banner h1 { font-size: var(--fs-4xl); }
  .btn-lg { height: 48px; padding: 0 28px; font-size: var(--fs-base); }
}
@media (max-width: 480px) {
  :root { --container-padding: 16px; }
  .header-inner { height: 60px; }
  .hero-title { font-size: var(--fs-3xl); }
  .section-title h2 { font-size: var(--fs-2xl); }
  .stats { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}