/* =============================================
   Flave.ai — Global Styles
   ============================================= */

/* CSS Variables */
:root {
  --color-primary: #272033;
  --color-secondary: #2d2435;
  --color-accent: #c598a4;
  --color-accent2: #6264d9;
  --color-accent3: #909c94;
  --color-bg: #1a1525;
  --color-bg-light: #312840;
  --color-text: #e8e0f0;
  --color-text-muted: #a89bb8;
  --color-white: #ffffff;
  --color-card: rgba(45, 36, 53, 0.7);
  --color-border: rgba(197, 152, 164, 0.15);
  --gradient-hero: linear-gradient(135deg, #272033 0%, #1a1525 40%, #2d2435 100%);
  --gradient-cta: linear-gradient(135deg, #6264d9 0%, #c598a4 100%);
  --gradient-accent: linear-gradient(135deg, #6264d9 0%, #8b6dd4 50%, #c598a4 100%);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 30px rgba(98, 100, 217, 0.2);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --font-main: 'Inter', 'Noto Sans SC', 'Noto Sans JP', 'Noto Sans KR', sans-serif;
  --transition: 0.3s ease;
  --max-width: 1200px;
}

/* Reset & Base */
*,
*::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-bg);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

html[lang="zh-TW"] body {
  font-family: 'Inter', 'Noto Sans TC', sans-serif;
}

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

a:hover {
  color: var(--color-accent2);
}

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

ul, ol {
  list-style: none;
}

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

/* Utility */
.section-title {
  font-size: 2.2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-muted);
  font-size: 1.1rem;
  margin-bottom: 48px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

section {
  padding: 80px 0;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

.fade-in-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

.fade-in-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

/* =============================================
   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: rgba(39, 32, 51, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: 10px 0;
  box-shadow: var(--shadow-md);
}

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

.header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--color-white);
}

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

.header-nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-nav a {
  color: var(--color-text-muted);
  font-size: 0.92rem;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
}

.header-nav a:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.06);
}

.header-nav a i {
  font-size: 0.85rem;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

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

.lang-switcher-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: 0.88rem;
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font-main);
}

.lang-switcher-btn:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.1);
}

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

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

.lang-dropdown a {
  display: block;
  padding: 10px 16px;
  color: var(--color-text-muted);
  font-size: 0.88rem;
  transition: all var(--transition);
}

.lang-dropdown a:hover,
.lang-dropdown a.current {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.06);
}

.lang-dropdown a.current {
  color: var(--color-accent2);
}

/* CTA Button */
.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: 0.95rem;
  border-radius: var(--radius-xl);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(98, 100, 217, 0.4);
  color: var(--color-white);
}

.btn-cta-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  background: transparent;
  color: var(--color-accent2);
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--radius-xl);
  border: 2px solid var(--color-accent2);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-cta-outline:hover {
  background: var(--color-accent2);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(98, 100, 217, 0.3);
}

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

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-white);
  border-radius: 2px;
  transition: all var(--transition);
}

.menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* =============================================
   Hero Section
   ============================================= */
.hero {
  position: relative;
  min-height: 85vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: var(--gradient-hero);
  padding-top: 100px;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 30% 40%, rgba(98, 100, 217, 0.08) 0%, transparent 50%),
              radial-gradient(circle at 70% 60%, rgba(197, 152, 164, 0.06) 0%, transparent 50%);
  animation: heroBgFloat 20s ease-in-out infinite;
}

@keyframes heroBgFloat {
  0%, 100% { transform: translate(0, 0) rotate(0deg); }
  33% { transform: translate(2%, -1%) rotate(1deg); }
  66% { transform: translate(-1%, 1%) rotate(-1deg); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 750px;
  padding: 0 24px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  background: rgba(98, 100, 217, 0.15);
  border: 1px solid rgba(98, 100, 217, 0.3);
  border-radius: 50px;
  font-size: 0.85rem;
  color: var(--color-accent2);
  margin-bottom: 24px;
}

.hero-badge i {
  font-size: 0.75rem;
}

.hero h1 {
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  color: var(--color-white);
}

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

.hero-desc {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  margin-bottom: 36px;
  line-height: 1.8;
}

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

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  margin-top: 56px;
  padding-top: 32px;
  border-top: 1px solid var(--color-border);
}

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

.hero-stat-num {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-white);
}

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

/* =============================================
   Features Section
   ============================================= */
.features {
  background: var(--color-bg);
  position: relative;
}

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

.feature-card {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: all var(--transition);
  backdrop-filter: blur(10px);
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(98, 100, 217, 0.3);
  box-shadow: var(--shadow-glow);
}

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: rgba(98, 100, 217, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 1.3rem;
  color: var(--color-accent2);
}

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

.feature-card p {
  font-size: 0.93rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

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

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

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

.usecase-card {
  background: rgba(39, 32, 51, 0.6);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  text-align: center;
  transition: all var(--transition);
}

.usecase-card:hover {
  transform: translateY(-4px);
  border-color: rgba(197, 152, 164, 0.3);
}

.usecase-icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  font-size: 1.5rem;
}

.usecase-card:nth-child(1) .usecase-icon {
  background: rgba(98, 100, 217, 0.15);
  color: var(--color-accent2);
}

.usecase-card:nth-child(2) .usecase-icon {
  background: rgba(197, 152, 164, 0.15);
  color: var(--color-accent);
}

.usecase-card:nth-child(3) .usecase-icon {
  background: rgba(144, 156, 148, 0.15);
  color: var(--color-accent3);
}

.usecase-card:nth-child(4) .usecase-icon {
  background: rgba(98, 100, 217, 0.15);
  color: #8b6dd4;
}

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

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

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

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

.pricing-card {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: all var(--transition);
  position: relative;
  backdrop-filter: blur(10px);
}

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

.pricing-card.popular {
  border-color: var(--color-accent2);
  box-shadow: var(--shadow-glow);
}

.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  padding: 4px 20px;
  background: var(--gradient-cta);
  color: var(--color-white);
  font-size: 0.78rem;
  font-weight: 600;
  border-radius: 50px;
  white-space: nowrap;
}

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

.pricing-price {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--color-white);
  margin-bottom: 6px;
}

.pricing-price span {
  font-size: 0.95rem;
  font-weight: 400;
  color: var(--color-text-muted);
}

.pricing-desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  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: var(--color-text-muted);
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.pricing-features li:last-child {
  border-bottom: none;
}

.pricing-features li i.fa-check {
  color: var(--color-accent2);
  font-size: 0.8rem;
}

.pricing-features li i.fa-xmark {
  color: rgba(168, 155, 184, 0.4);
  font-size: 0.8rem;
}

.pricing-features li.disabled {
  color: rgba(168, 155, 184, 0.4);
}

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

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

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

.testimonials-header {
  display: flex;
  justify-content: center;
  gap: 48px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

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

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

.testimonial-stat-label {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.testimonial-stars {
  color: #fbbf24;
  font-size: 1.2rem;
  margin-bottom: 4px;
}

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

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

.testimonial-card {
  min-width: calc(33.333% - 16px);
  background: rgba(39, 32, 51, 0.6);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  margin: 0 12px;
  flex-shrink: 0;
}

.testimonial-card-stars {
  color: #fbbf24;
  font-size: 0.9rem;
  margin-bottom: 14px;
}

.testimonial-card p {
  font-size: 0.93rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-bottom: 18px;
  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: 700;
  font-size: 0.85rem;
  color: var(--color-white);
}

.testimonial-info strong {
  display: block;
  font-size: 0.9rem;
  color: var(--color-white);
}

.testimonial-info span {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.testimonials-dots {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 32px;
}

.testimonials-dots button {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: none;
  background: rgba(255, 255, 255, 0.2);
  cursor: pointer;
  transition: all var(--transition);
  padding: 0;
}

.testimonials-dots button.active {
  background: var(--color-accent2);
  width: 28px;
  border-radius: 5px;
}

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

.testimonial-tag {
  padding: 6px 16px;
  background: rgba(98, 100, 217, 0.1);
  border: 1px solid rgba(98, 100, 217, 0.2);
  border-radius: 50px;
  font-size: 0.82rem;
  color: var(--color-accent2);
}

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

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

.comparison-table thead th {
  background: var(--color-secondary);
  padding: 18px 20px;
  text-align: center;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--color-white);
  border-bottom: 1px solid var(--color-border);
}

.comparison-table thead th:first-child {
  text-align: left;
}

.comparison-table thead th.highlight {
  background: rgba(98, 100, 217, 0.15);
  color: var(--color-accent2);
}

.comparison-table tbody td {
  padding: 16px 20px;
  text-align: center;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  background: var(--color-card);
}

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

.comparison-table tbody td.highlight {
  background: rgba(98, 100, 217, 0.06);
}

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

.comparison-table .check {
  color: var(--color-accent2);
  font-weight: 700;
}

.comparison-table .cross {
  color: rgba(168, 155, 184, 0.4);
}

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

.faq-list {
  max-width: 780px;
  margin: 0 auto;
}

.faq-item {
  background: rgba(39, 32, 51, 0.6);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: all var(--transition);
}

.faq-item:hover {
  border-color: rgba(197, 152, 164, 0.25);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  background: none;
  border: none;
  color: var(--color-white);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-main);
  transition: all var(--transition);
  gap: 16px;
}

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

.faq-question i {
  font-size: 0.85rem;
  transition: transform var(--transition);
  color: var(--color-accent2);
  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-inner {
  padding: 0 24px 18px;
  font-size: 0.93rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.faq-answer-inner a {
  color: var(--color-accent2);
  font-weight: 600;
}

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

.final-cta::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.05) 0%, transparent 60%);
}

.final-cta-content {
  position: relative;
  z-index: 1;
}

.final-cta h2 {
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 16px;
}

.final-cta p {
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 36px;
}

.final-cta .btn-cta {
  background: var(--color-white);
  color: var(--color-accent2);
  font-weight: 700;
}

.final-cta .btn-cta:hover {
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 6px 25px rgba(0, 0, 0, 0.2);
}

/* =============================================
   Footer
   ============================================= */
.footer {
  background: var(--color-primary);
  padding: 48px 0 24px;
  border-top: 1px solid var(--color-border);
}

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

.footer-brand {
  max-width: 300px;
}

.footer-brand .header-logo {
  margin-bottom: 12px;
}

.footer-brand p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.footer-links {
  display: flex;
  gap: 48px;
}

.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-muted);
  padding: 4px 0;
  transition: all var(--transition);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 20px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

/* Back to Top */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-cta);
  color: var(--color-white);
  border: none;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  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(-3px);
  box-shadow: 0 6px 25px rgba(98, 100, 217, 0.5);
}

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

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

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

  .pricing-card:last-child {
    grid-column: 1 / -1;
    max-width: 400px;
    margin: 0 auto;
  }

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

@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  section {
    padding: 60px 0;
  }

  .section-title {
    font-size: 1.8rem;
  }

  .header-nav {
    display: none;
  }

  .header-nav.mobile-active {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(39, 32, 51, 0.98);
    backdrop-filter: blur(20px);
    justify-content: center;
    align-items: center;
    z-index: 1000;
    gap: 8px;
  }

  .header-nav.mobile-active a {
    font-size: 1.2rem;
    padding: 14px 32px;
  }

  .menu-toggle {
    display: flex;
  }

  .hero {
    min-height: 75vh;
    padding-top: 80px;
  }

  .hero h1 {
    font-size: 2.2rem;
  }

  .hero-stats {
    gap: 24px;
    flex-wrap: wrap;
  }

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

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

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

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

  .comparison-table {
    font-size: 0.82rem;
  }

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

  .testimonial-card {
    min-width: calc(100% - 24px);
  }

  .testimonials-header {
    gap: 24px;
  }

  .footer-content {
    flex-direction: column;
  }

  .footer-links {
    flex-direction: column;
    gap: 24px;
  }

  .final-cta h2 {
    font-size: 1.8rem;
  }

  .lang-switcher {
    order: -1;
  }

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

  .header-nav.mobile-active + .header-right .btn-cta,
  .mobile-cta {
    display: inline-flex;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.8rem;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .pricing-price {
    font-size: 2.2rem;
  }
}