/* ===== CSS Variables ===== */
:root {
  --color-primary: #141213;
  --color-secondary: #141313;
  --color-accent: #e7496c;
  --color-accent2: #6b9fc6;
  --color-accent3: #596bb6;
  --color-white: #ffffff;
  --color-light: #f8f9fa;
  --color-gray: #6c757d;
  --color-dark-gray: #343a40;
  --color-border: rgba(255, 255, 255, 0.1);
  --gradient-accent: linear-gradient(135deg, var(--color-accent), var(--color-accent3));
  --gradient-dark: linear-gradient(180deg, #1a1718 0%, #0d0c0c 100%);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.15);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.25);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.35);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --transition: 0.3s ease;
  --font-en: 'Inter', sans-serif;
  --font-zh: 'Noto Sans SC', 'Inter', sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-en);
  background: var(--color-primary);
  color: var(--color-white);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

ul {
  list-style: none;
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Header / Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 16px 0;
  transition: background var(--transition), padding var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  background: rgba(20, 18, 19, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: 10px 0;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.4);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
}

.nav-brand img {
  width: 32px;
  height: 32px;
  border-radius: 6px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-menu a {
  font-size: 0.9rem;
  font-weight: 500;
  opacity: 0.8;
  transition: opacity var(--transition), color var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav-menu a:hover {
  opacity: 1;
  color: var(--color-accent);
}

.nav-menu a i {
  font-size: 0.8rem;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Language Switcher */
.lang-switcher {
  position: relative;
}

.lang-btn {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  color: var(--color-white);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: background var(--transition);
}

.lang-btn:hover {
  background: rgba(255, 255, 255, 0.15);
}

.lang-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: #1e1c1d;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  min-width: 160px;
  padding: 8px 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--transition);
  box-shadow: var(--shadow-md);
  z-index: 100;
}

.lang-dropdown.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.lang-dropdown a {
  display: block;
  padding: 8px 16px;
  font-size: 0.85rem;
  transition: background var(--transition);
}

.lang-dropdown a:hover {
  background: rgba(255, 255, 255, 0.08);
}

.lang-dropdown a.current {
  color: var(--color-accent);
}

/* CTA Button */
.btn-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  background: var(--gradient-accent);
  color: var(--color-white);
  border: none;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
  white-space: nowrap;
}

.btn-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(231, 73, 108, 0.4);
}

.btn-cta:active {
  transform: translateY(0);
}

.btn-cta-lg {
  padding: 16px 40px;
  font-size: 1.1rem;
  border-radius: var(--radius-md);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  background: transparent;
  color: var(--color-accent);
  border: 2px solid var(--color-accent);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition);
}

.btn-secondary:hover {
  background: var(--color-accent);
  color: var(--color-white);
  transform: translateY(-2px);
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-white);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 4px;
}

/* ===== Hero Section ===== */
.hero {
  padding: 140px 0 80px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(231, 73, 108, 0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  position: relative;
}

.hero h1 .highlight {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: rgba(255, 255, 255, 0.7);
  max-width: 640px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

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

/* ===== Section Common ===== */
.section {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-header h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  font-weight: 700;
  margin-bottom: 16px;
}

.section-header p {
  color: rgba(255, 255, 255, 0.6);
  font-size: 1.05rem;
  max-width: 600px;
  margin: 0 auto;
}

.section-alt {
  background: rgba(255, 255, 255, 0.02);
}

/* ===== Features Grid ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(231, 73, 108, 0.3);
  box-shadow: 0 8px 32px rgba(231, 73, 108, 0.1);
}

.feature-card .icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: rgba(231, 73, 108, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-card .icon i {
  font-size: 1.2rem;
  color: var(--color-accent);
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.6);
  line-height: 1.6;
}

.features-cta {
  text-align: center;
  margin-top: 48px;
}

/* ===== Use Cases ===== */
.usecases-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.usecase-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  text-align: center;
  transition: transform var(--transition), border-color var(--transition);
}

.usecase-card:hover {
  transform: translateY(-4px);
}

.usecase-card:nth-child(1) { border-top: 3px solid var(--color-accent); }
.usecase-card:nth-child(2) { border-top: 3px solid var(--color-accent2); }
.usecase-card:nth-child(3) { border-top: 3px solid var(--color-accent3); }
.usecase-card:nth-child(4) { border-top: 3px solid #9b59b6; }

.usecase-card .icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  font-size: 1.4rem;
}

.usecase-card:nth-child(1) .icon { background: rgba(231, 73, 108, 0.12); color: var(--color-accent); }
.usecase-card:nth-child(2) .icon { background: rgba(107, 159, 198, 0.12); color: var(--color-accent2); }
.usecase-card:nth-child(3) .icon { background: rgba(89, 107, 182, 0.12); color: var(--color-accent3); }
.usecase-card:nth-child(4) .icon { background: rgba(155, 89, 182, 0.12); color: #9b59b6; }

.usecase-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.usecase-card p {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
  line-height: 1.6;
}

/* ===== Pricing ===== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: start;
}

.pricing-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  position: relative;
  transition: transform var(--transition), box-shadow var(--transition);
}

.pricing-card:hover {
  transform: translateY(-4px);
}

.pricing-card.popular {
  border-color: var(--color-accent);
  box-shadow: 0 0 40px rgba(231, 73, 108, 0.15);
}

.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-accent);
  color: var(--color-white);
  padding: 4px 20px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  white-space: nowrap;
}

.pricing-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.pricing-card .price {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 4px;
}

.pricing-card .price span {
  font-size: 0.9rem;
  font-weight: 400;
  color: rgba(255, 255, 255, 0.5);
}

.pricing-card .price-desc {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
  margin-bottom: 24px;
}

.pricing-features {
  margin-bottom: 28px;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 0;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.75);
}

.pricing-features li i.fa-check {
  color: var(--color-accent);
}

.pricing-features li i.fa-xmark {
  color: rgba(255, 255, 255, 0.25);
}

.pricing-features li.disabled {
  color: rgba(255, 255, 255, 0.3);
}

.pricing-card .btn-cta {
  width: 100%;
  justify-content: center;
}

.pricing-card .btn-secondary {
  width: 100%;
  justify-content: center;
}

/* ===== Testimonials ===== */
.testimonials-overview {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 40px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.testimonials-score {
  text-align: center;
}

.testimonials-score .big-score {
  font-size: 3rem;
  font-weight: 800;
}

.testimonials-score .stars {
  color: #ffc107;
  font-size: 1.1rem;
  margin: 4px 0;
}

.testimonials-score .count {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
}

.star-bars {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.star-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
}

.star-bar span:first-child {
  width: 20px;
  text-align: right;
  color: rgba(255, 255, 255, 0.6);
}

.star-bar .bar-track {
  width: 140px;
  height: 6px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
  overflow: hidden;
}

.star-bar .bar-fill {
  height: 100%;
  background: #ffc107;
  border-radius: 3px;
}

.star-bar span:last-child {
  color: rgba(255, 255, 255, 0.4);
  width: 30px;
}

.testimonials-carousel {
  position: relative;
  overflow: hidden;
}

.testimonials-track {
  display: flex;
  transition: transform 0.5s ease;
}

.testimonial-card {
  min-width: calc(33.333% - 16px);
  margin: 0 8px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius-md);
  padding: 28px;
  flex-shrink: 0;
}

.testimonial-card .stars {
  color: #ffc107;
  margin-bottom: 12px;
  font-size: 0.9rem;
}

.testimonial-card blockquote {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.75);
  line-height: 1.7;
  margin-bottom: 16px;
  font-style: italic;
}

.testimonial-card .author {
  font-size: 0.85rem;
  font-weight: 600;
}

.testimonial-card .role {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.4);
}

.carousel-controls {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 32px;
}

.carousel-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.05);
  color: var(--color-white);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
}

.carousel-btn:hover {
  background: var(--color-accent);
  border-color: var(--color-accent);
}

.testimonial-tags {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-top: 32px;
  flex-wrap: wrap;
}

.testimonial-tags span {
  padding: 6px 16px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 20px;
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.6);
}

/* ===== Comparison ===== */
.comparison-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.comparison-table th,
.comparison-table td {
  padding: 16px 24px;
  text-align: center;
  font-size: 0.9rem;
}

.comparison-table thead th {
  background: rgba(255, 255, 255, 0.06);
  font-weight: 600;
  font-size: 0.95rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.comparison-table tbody tr {
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  transition: background var(--transition);
}

.comparison-table tbody tr:hover {
  background: rgba(255, 255, 255, 0.03);
}

.comparison-table tbody td:first-child {
  text-align: left;
  font-weight: 500;
}

.comparison-table .highlight-col {
  background: rgba(231, 73, 108, 0.06);
}

.comparison-table thead .highlight-col {
  background: rgba(231, 73, 108, 0.15);
  color: var(--color-accent);
}

.comparison-table .check {
  color: var(--color-accent);
}

.comparison-table .cross {
  color: rgba(255, 255, 255, 0.2);
}

.comparison-wrapper {
  overflow-x: auto;
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.faq-question {
  width: 100%;
  background: none;
  border: none;
  color: var(--color-white);
  padding: 20px 0;
  font-size: 1rem;
  font-weight: 500;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  transition: color var(--transition);
  font-family: inherit;
}

.faq-question:hover {
  color: var(--color-accent);
}

.faq-question i {
  font-size: 0.85rem;
  transition: transform var(--transition);
  flex-shrink: 0;
}

.faq-item.active .faq-question i {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-answer p {
  padding: 0 0 20px;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.6);
  line-height: 1.7;
}

/* ===== Final CTA ===== */
.final-cta {
  padding: 100px 0;
  background: var(--gradient-accent);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.final-cta::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 30% 50%, rgba(255, 255, 255, 0.1) 0%, transparent 50%);
  pointer-events: none;
}

.final-cta h2 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 800;
  margin-bottom: 16px;
  position: relative;
}

.final-cta p {
  font-size: 1.1rem;
  opacity: 0.9;
  margin-bottom: 36px;
  position: relative;
}

.final-cta .btn-cta-lg {
  background: var(--color-white);
  color: var(--color-accent);
  position: relative;
}

.final-cta .btn-cta-lg:hover {
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

/* ===== Footer ===== */
.footer {
  padding: 48px 0 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 40px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.1rem;
}

.footer-brand img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.footer-links {
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
}

.footer-links a {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--color-accent);
}

.footer-bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.35);
}

/* ===== Back to Top ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-accent);
  color: var(--color-white);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition);
  z-index: 999;
  box-shadow: var(--shadow-md);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 24px rgba(231, 73, 108, 0.4);
}

/* ===== Animate on Scroll ===== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

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

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

  .testimonial-card {
    min-width: calc(50% - 16px);
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    max-width: 320px;
    height: 100vh;
    background: #1a1718;
    flex-direction: column;
    align-items: flex-start;
    padding: 80px 32px 32px;
    gap: 8px;
    transition: right var(--transition);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.5);
  }

  .nav-menu.active {
    right: 0;
  }

  .nav-menu a {
    font-size: 1.1rem;
    padding: 12px 0;
    width: 100%;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  }

  .menu-toggle {
    display: block;
  }

  .menu-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    z-index: 998;
  }

  .menu-overlay.active {
    display: block;
  }

  .hero {
    padding: 120px 0 60px;
  }

  .hero h1 {
    font-size: 2rem;
  }

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

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

  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 400px;
    margin: 0 auto;
  }

  .testimonial-card {
    min-width: calc(100% - 16px);
  }

  .testimonials-overview {
    flex-direction: column;
    gap: 24px;
  }

  .comparison-table th,
  .comparison-table td {
    padding: 12px 14px;
    font-size: 0.8rem;
  }

  .footer-content {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .footer-links {
    justify-content: center;
  }

  .final-cta {
    padding: 60px 0;
  }

  .section {
    padding: 60px 0;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .hero h1 {
    font-size: 1.7rem;
  }

  .hero .subtitle {
    font-size: 0.95rem;
  }

  .nav-right .btn-cta {
    display: none;
  }
}