@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
  --color-primary: #1e151c;
  --color-secondary: #241a1e;
  --color-accent: #b57f84;
  --color-muted: #839196;
  --color-highlight: #6471a5;
  --color-text: #e0d8dc;
  --color-text-light: #a89da3;
  --color-white: #ffffff;
  --color-card-bg: rgba(36, 26, 30, 0.6);
  --color-card-border: rgba(181, 127, 132, 0.15);
  --color-glass: rgba(30, 21, 28, 0.75);
  --gradient-accent: linear-gradient(135deg, #b57f84, #6471a5);
  --gradient-hero: linear-gradient(160deg, #1e151c 0%, #2a1c24 40%, #1e151c 100%);
  --gradient-cta: linear-gradient(135deg, #b57f84 0%, #9b6a6f 50%, #6471a5 100%);
  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 12px 48px rgba(181, 127, 132, 0.15);
  --shadow-button: 0 4px 20px rgba(181, 127, 132, 0.3);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Noto Sans SC', 'Noto Sans TC', 'Noto Sans JP', 'Noto Sans KR', 'Microsoft YaHei', sans-serif;
  --max-width: 1200px;
}

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-main);
  background-color: var(--color-primary);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
  color: var(--color-white);
}

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

ul {
  list-style: none;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ========================
   Header / Navigation
======================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 16px 0;
  transition: all var(--transition);
  background: transparent;
}

.header.scrolled {
  background: var(--color-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: 10px 0;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

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

.header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-white);
}

.header-logo img {
  width: 32px;
  height: 32px;
  border-radius: 6px;
}

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

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

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-accent);
  border-radius: 1px;
  transition: width var(--transition);
}

.nav-menu a:hover {
  color: var(--color-white);
}

.nav-menu a:hover::after {
  width: 100%;
}

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

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

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

.lang-switcher-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: none;
  border: 1px solid var(--color-card-border);
  color: var(--color-text-light);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.85rem;
  font-family: var(--font-main);
  transition: all var(--transition);
}

.lang-switcher-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-white);
}

.lang-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--color-secondary);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-md);
  padding: 8px 0;
  min-width: 160px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--transition);
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 100;
}

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

.lang-dropdown a {
  display: block;
  padding: 8px 20px;
  color: var(--color-text-light);
  font-size: 0.85rem;
  transition: all var(--transition);
}

.lang-dropdown a:hover,
.lang-dropdown a.current {
  background: rgba(181, 127, 132, 0.1);
  color: var(--color-accent);
}

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

.btn-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(181, 127, 132, 0.4);
  color: var(--color-white);
}

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

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  background: transparent;
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-accent);
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font-main);
}

.btn-secondary:hover {
  background: rgba(181, 127, 132, 0.1);
  color: var(--color-white);
  border-color: var(--color-white);
  transform: translateY(-2px);
}

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

/* ========================
   Hero Section
======================== */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  position: relative;
  background: var(--gradient-hero);
  overflow: hidden;
  padding-top: 80px;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(181, 127, 132, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(100, 113, 165, 0.06) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero .container {
  text-align: center;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 20px;
  background: rgba(181, 127, 132, 0.1);
  border: 1px solid rgba(181, 127, 132, 0.2);
  border-radius: 50px;
  font-size: 0.85rem;
  color: var(--color-accent);
  margin-bottom: 28px;
}

.hero h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  color: var(--color-white);
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

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

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--color-text-light);
  max-width: 640px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

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

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  margin-top: 56px;
  padding-top: 40px;
  border-top: 1px solid var(--color-card-border);
}

.hero-stat {
  text-align: center;
}

.hero-stat-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-white);
}

.hero-stat-label {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-top: 4px;
}

/* ========================
   Section Common
======================== */
section {
  padding: 100px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-header h2 {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.section-header p {
  font-size: 1.05rem;
  color: var(--color-text-light);
  max-width: 600px;
  margin: 0 auto;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: 12px;
}

/* ========================
   Features
======================== */
.features {
  background: var(--color-primary);
}

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

.feature-card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-accent);
  opacity: 0;
  transition: opacity var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: rgba(181, 127, 132, 0.25);
}

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

.feature-icon {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(181, 127, 132, 0.1);
  border-radius: var(--radius-md);
  margin-bottom: 20px;
  font-size: 1.3rem;
  color: var(--color-accent);
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

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

/* ========================
   Use Cases
======================== */
.use-cases {
  background: var(--color-secondary);
}

.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.use-case-card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  text-align: center;
  transition: all var(--transition);
}

.use-case-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.use-case-card:nth-child(1) .use-case-icon { color: var(--color-accent); background: rgba(181, 127, 132, 0.12); }
.use-case-card:nth-child(2) .use-case-icon { color: var(--color-highlight); background: rgba(100, 113, 165, 0.12); }
.use-case-card:nth-child(3) .use-case-icon { color: #7ecba1; background: rgba(126, 203, 161, 0.12); }
.use-case-card:nth-child(4) .use-case-icon { color: #d4a06a; background: rgba(212, 160, 106, 0.12); }

.use-case-icon {
  width: 60px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  margin: 0 auto 20px;
  font-size: 1.4rem;
}

.use-case-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: 10px;
}

.use-case-card p {
  font-size: 0.88rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* ========================
   Pricing
======================== */
.pricing {
  background: var(--color-primary);
}

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

.pricing-card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  transition: all var(--transition);
  position: relative;
}

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

.pricing-card.popular {
  border-color: var(--color-accent);
  background: linear-gradient(180deg, rgba(181, 127, 132, 0.08) 0%, var(--color-card-bg) 100%);
}

.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-cta);
  color: var(--color-white);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 16px;
  border-radius: 50px;
  white-space: nowrap;
}

.pricing-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: 8px;
}

.pricing-card .price {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--color-white);
  margin-bottom: 4px;
}

.pricing-card .price span {
  font-size: 1rem;
  font-weight: 400;
  color: var(--color-text-light);
}

.pricing-card .price-desc {
  font-size: 0.88rem;
  color: var(--color-text-light);
  margin-bottom: 28px;
}

.pricing-features {
  flex: 1;
  margin-bottom: 28px;
}

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

.pricing-features li i {
  font-size: 0.8rem;
  width: 18px;
  text-align: center;
}

.pricing-features li i.fa-check {
  color: #7ecba1;
}

.pricing-features li i.fa-xmark {
  color: #888;
}

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

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

/* ========================
   Testimonials
======================== */
.testimonials {
  background: var(--color-secondary);
}

.testimonials-summary {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

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

.testimonials-stars {
  font-size: 1.6rem;
  color: #f5c542;
  margin-bottom: 6px;
}

.testimonials-score {
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--color-white);
}

.testimonials-count {
  font-size: 0.88rem;
  color: var(--color-text-light);
  margin-top: 2px;
}

.testimonials-bars {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 200px;
}

.rating-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
  color: var(--color-text-light);
}

.rating-bar-fill {
  flex: 1;
  height: 6px;
  background: rgba(181, 127, 132, 0.15);
  border-radius: 3px;
  overflow: hidden;
}

.rating-bar-fill div {
  height: 100%;
  background: var(--gradient-accent);
  border-radius: 3px;
}

.testimonials-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-bottom: 40px;
}

.testimonials-tags span {
  padding: 6px 14px;
  background: rgba(181, 127, 132, 0.08);
  border: 1px solid var(--color-card-border);
  border-radius: 50px;
  font-size: 0.8rem;
  color: var(--color-text-light);
}

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

.testimonials-track {
  display: flex;
  gap: 24px;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.testimonial-card {
  min-width: calc(33.333% - 16px);
  background: var(--color-card-bg);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  flex-shrink: 0;
}

.testimonial-card .stars {
  color: #f5c542;
  font-size: 0.9rem;
  margin-bottom: 14px;
}

.testimonial-card p {
  font-size: 0.92rem;
  color: var(--color-text);
  line-height: 1.6;
  margin-bottom: 16px;
  font-style: italic;
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 12px;
}

.testimonial-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--gradient-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-white);
}

.testimonial-info .name {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--color-white);
}

.testimonial-info .role {
  font-size: 0.78rem;
  color: var(--color-text-light);
}

.carousel-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-top: 32px;
}

.carousel-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--color-card-border);
  background: var(--color-card-bg);
  color: var(--color-text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  font-size: 0.9rem;
}

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

.carousel-dots {
  display: flex;
  gap: 8px;
}

.carousel-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(181, 127, 132, 0.2);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  padding: 0;
}

.carousel-dot.active {
  background: var(--color-accent);
  width: 24px;
  border-radius: 4px;
}

/* ========================
   Comparison
======================== */
.comparison {
  background: var(--color-primary);
}

.comparison-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-card-border);
}

.comparison-table th,
.comparison-table td {
  padding: 16px 24px;
  text-align: center;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--color-card-border);
}

.comparison-table th {
  background: var(--color-secondary);
  font-weight: 600;
  color: var(--color-white);
  font-size: 0.95rem;
}

.comparison-table th.highlight {
  background: rgba(181, 127, 132, 0.12);
  color: var(--color-accent);
}

.comparison-table td:first-child {
  text-align: left;
  font-weight: 500;
  color: var(--color-text);
}

.comparison-table td.highlight {
  background: rgba(181, 127, 132, 0.05);
}

.comparison-table tbody tr {
  background: var(--color-card-bg);
  transition: background var(--transition);
}

.comparison-table tbody tr:hover {
  background: rgba(36, 26, 30, 0.8);
}

.comparison-table tbody tr:last-child td {
  border-bottom: none;
}

.comparison-table .check {
  color: var(--color-accent);
  font-weight: 600;
}

.comparison-table .cross {
  color: #666;
}

/* ========================
   FAQ
======================== */
.faq {
  background: var(--color-secondary);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: all var(--transition);
}

.faq-item:hover {
  border-color: rgba(181, 127, 132, 0.3);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  background: transparent;
  border: none;
  color: var(--color-white);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-main);
  gap: 16px;
  transition: color var(--transition);
}

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

.faq-question i {
  font-size: 0.8rem;
  color: var(--color-accent);
  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 cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-answer-inner {
  padding: 0 24px 20px;
  font-size: 0.92rem;
  color: var(--color-text-light);
  line-height: 1.7;
}

/* ========================
   Final CTA
======================== */
.final-cta {
  background: var(--gradient-cta);
  padding: 80px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.final-cta::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.05) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.final-cta h2 {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 12px;
}

.final-cta p {
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 32px;
}

.final-cta .btn-cta-lg {
  background: var(--color-white);
  color: var(--color-primary);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.final-cta .btn-cta-lg:hover {
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.3);
}

/* ========================
   Footer
======================== */
.footer {
  background: var(--color-secondary);
  padding: 60px 0 0;
  border-top: 1px solid var(--color-card-border);
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
}

.footer-brand p {
  font-size: 0.88rem;
  color: var(--color-text-light);
  margin-top: 12px;
  line-height: 1.6;
  max-width: 280px;
}

.footer-col h4 {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: 16px;
}

.footer-col a {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-light);
  padding: 5px 0;
  transition: color var(--transition);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-card-border);
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--color-text-light);
}

.footer-social {
  display: flex;
  gap: 16px;
}

.footer-social a {
  color: var(--color-text-light);
  font-size: 1.1rem;
}

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

/* ========================
   Back to Top
======================== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-cta);
  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(16px);
  transition: all var(--transition);
  box-shadow: var(--shadow-button);
  z-index: 999;
}

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

.back-to-top:hover {
  transform: translateY(-4px);
}

/* ========================
   Animations
======================== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.fade-in-delay-1 { transition-delay: 0.1s; }
.fade-in-delay-2 { transition-delay: 0.2s; }
.fade-in-delay-3 { transition-delay: 0.3s; }
.fade-in-delay-4 { transition-delay: 0.4s; }
.fade-in-delay-5 { transition-delay: 0.5s; }

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

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

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

  .pricing-card:last-child {
    grid-column: span 2;
    max-width: 400px;
    margin: 0 auto;
  }

  .footer-top {
    grid-template-columns: 1fr 1fr;
  }

  .testimonial-card {
    min-width: calc(50% - 12px);
  }
}

@media (max-width: 768px) {
  section {
    padding: 64px 0;
  }

  .nav-menu {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: var(--color-primary);
    flex-direction: column;
    justify-content: center;
    gap: 24px;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
    z-index: 999;
  }

  .nav-menu.active {
    opacity: 1;
    visibility: visible;
  }

  .nav-menu a {
    font-size: 1.2rem;
  }

  .mobile-toggle {
    display: flex;
    z-index: 1001;
  }

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

  .hero {
    min-height: auto;
    padding: 120px 0 60px;
  }

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

  .hero-stats {
    gap: 24px;
  }

  .hero-stat-number {
    font-size: 1.5rem;
  }

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

  .use-cases-grid {
    grid-template-columns: 1fr;
  }

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

  .pricing-card:last-child {
    grid-column: auto;
    max-width: none;
  }

  .testimonial-card {
    min-width: calc(100% - 0px);
  }

  .comparison-table {
    font-size: 0.8rem;
  }

  .comparison-table th,
  .comparison-table td {
    padding: 12px 10px;
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

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

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

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

  .hero-buttons {
    flex-direction: column;
    gap: 12px;
  }

  .hero-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }

  .lang-switcher {
    display: none;
  }
}