/* ========== CSS Variables ========== */
:root {
  --color-primary: #050609;
  --color-secondary: #060609;
  --color-accent: #9a79e2;
  --color-muted: #77708e;
  --color-gray: #7c8486;
  --color-accent-light: rgba(154, 121, 226, 0.15);
  --color-accent-glow: rgba(154, 121, 226, 0.4);
  --color-bg-dark: #0a0a10;
  --color-bg-card: rgba(255, 255, 255, 0.04);
  --color-bg-card-hover: rgba(255, 255, 255, 0.07);
  --color-text: #e8e6f0;
  --color-text-secondary: #a9a4b8;
  --color-border: rgba(154, 121, 226, 0.12);
  --color-white: #ffffff;
  --font-heading: 'Inter', 'Noto Sans SC', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', sans-serif;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 30px rgba(154, 121, 226, 0.15);
  --transition: 0.3s ease;
}

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

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

body {
  font-family: var(--font-body);
  background-color: var(--color-bg-dark);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-white);
}

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

section {
  padding: 100px 0;
}

.section-title {
  text-align: center;
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 1.1rem;
  max-width: 640px;
  margin: 0 auto 60px;
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-accent), #7b5cc4);
  color: var(--color-white);
  box-shadow: 0 4px 20px rgba(154, 121, 226, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(154, 121, 226, 0.5);
  color: var(--color-white);
}

.btn-secondary {
  background: transparent;
  color: var(--color-accent);
  border: 1.5px solid var(--color-accent);
}

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

.btn-large {
  padding: 18px 48px;
  font-size: 1.15rem;
  border-radius: var(--radius-md);
}

/* ========== Header ========== */
.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(5, 6, 9, 0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: 10px 0;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.4);
}

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

.header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  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: 32px;
}

.header-nav a {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: color var(--transition);
}

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

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

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

.lang-switcher-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.9rem;
  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: rgba(15, 15, 25, 0.97);
  backdrop-filter: blur(20px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 8px 0;
  min-width: 160px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--transition);
  box-shadow: var(--shadow-card);
  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-secondary);
  font-size: 0.9rem;
  transition: all var(--transition);
}

.lang-dropdown a:hover,
.lang-dropdown a.current {
  color: var(--color-white);
  background: var(--color-accent-light);
}

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

/* ========== Hero ========== */
.hero {
  padding: 160px 0 100px;
  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(154, 121, 226, 0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero h1 {
  font-size: 3.5rem;
  margin-bottom: 20px;
  background: linear-gradient(135deg, var(--color-white) 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero h1 span {
  display: block;
  font-size: 1.3rem;
  font-weight: 400;
  color: var(--color-text-secondary);
  -webkit-text-fill-color: var(--color-text-secondary);
  margin-top: 12px;
}

.hero p {
  font-size: 1.2rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
}

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

/* ========== Features ========== */
.features {
  background: linear-gradient(180deg, var(--color-bg-dark) 0%, rgba(10, 10, 20, 1) 100%);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 48px;
}

.feature-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  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: linear-gradient(90deg, transparent, var(--color-accent), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}

.feature-card:hover {
  background: var(--color-bg-card-hover);
  border-color: rgba(154, 121, 226, 0.25);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

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

.feature-card .icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: var(--color-accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 1.3rem;
  color: var(--color-accent);
}

.feature-card h3 {
  font-size: 1.15rem;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.features-cta {
  text-align: center;
}

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

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

.usecase-card {
  text-align: center;
  padding: 40px 24px;
  border-radius: var(--radius-md);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  transition: all var(--transition);
}

.usecase-card:hover {
  transform: translateY(-4px);
  border-color: rgba(154, 121, 226, 0.25);
  box-shadow: var(--shadow-glow);
}

.usecase-card .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) .icon {
  background: rgba(154, 121, 226, 0.15);
  color: #9a79e2;
}

.usecase-card:nth-child(2) .icon {
  background: rgba(236, 130, 184, 0.15);
  color: #ec82b8;
}

.usecase-card:nth-child(3) .icon {
  background: rgba(100, 200, 255, 0.15);
  color: #64c8ff;
}

.usecase-card:nth-child(4) .icon {
  background: rgba(255, 180, 100, 0.15);
  color: #ffb464;
}

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

.usecase-card p {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

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

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

.pricing-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  text-align: center;
  transition: all var(--transition);
  position: relative;
}

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

.pricing-card.popular {
  border-color: var(--color-accent);
  background: rgba(154, 121, 226, 0.06);
  transform: scale(1.04);
}

.pricing-card.popular:hover {
  transform: scale(1.04) translateY(-4px);
}

.pricing-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, var(--color-accent), #7b5cc4);
  color: var(--color-white);
  padding: 6px 20px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
}

.pricing-card h3 {
  font-size: 1.3rem;
  margin-bottom: 8px;
}

.pricing-price {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-white);
  margin: 20px 0;
}

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

.pricing-features {
  text-align: left;
  margin: 28px 0 36px;
}

.pricing-features li {
  padding: 8px 0;
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.pricing-features li i {
  font-size: 0.85rem;
  width: 20px;
  text-align: center;
}

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

.pricing-features li i.fa-xmark {
  color: var(--color-gray);
}

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

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

.testimonials-header {
  text-align: center;
  margin-bottom: 48px;
}

.rating-overview {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  margin-bottom: 12px;
}

.rating-score {
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--color-white);
}

.rating-details {
  text-align: left;
}

.rating-stars {
  color: #f5a623;
  font-size: 1.2rem;
  margin-bottom: 4px;
}

.rating-count {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
}

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

.testimonial-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
  transition: all var(--transition);
}

.testimonial-card:hover {
  border-color: rgba(154, 121, 226, 0.25);
  transform: translateY(-2px);
}

.testimonial-stars {
  color: #f5a623;
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.testimonial-card p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  margin-bottom: 20px;
  font-style: italic;
  line-height: 1.7;
}

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

.testimonial-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--color-accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent);
  font-weight: 700;
  font-size: 1rem;
}

.testimonial-author-info strong {
  color: var(--color-white);
  font-size: 0.95rem;
  display: block;
}

.testimonial-author-info span {
  color: var(--color-muted);
  font-size: 0.85rem;
}

.testimonial-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 40px;
}

.testimonial-tags span {
  background: var(--color-accent-light);
  color: var(--color-accent);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
}

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

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

.comparison-table th,
.comparison-table td {
  padding: 18px 24px;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
}

.comparison-table thead th {
  background: rgba(154, 121, 226, 0.08);
  color: var(--color-white);
  font-weight: 600;
  font-size: 1rem;
}

.comparison-table tbody td {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  background: var(--color-bg-card);
}

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

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

.comparison-table .highlight {
  background: rgba(154, 121, 226, 0.06);
}

.comparison-table thead .highlight {
  background: rgba(154, 121, 226, 0.15);
  color: var(--color-accent);
}

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

.comparison-table .cross {
  color: var(--color-gray);
}

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

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

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

.faq-item:hover {
  border-color: rgba(154, 121, 226, 0.25);
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  background: transparent;
  border: none;
  color: var(--color-white);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  font-family: var(--font-body);
}

.faq-question i {
  font-size: 0.85rem;
  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 ease, padding 0.3s ease;
}

.faq-answer p {
  padding: 0 24px 20px;
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ========== Final CTA ========== */
.final-cta {
  background: linear-gradient(135deg, rgba(154, 121, 226, 0.15) 0%, rgba(123, 92, 196, 0.08) 100%);
  text-align: center;
  padding: 100px 0;
  position: relative;
  overflow: hidden;
}

.final-cta::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(154, 121, 226, 0.1) 0%, transparent 70%);
  pointer-events: none;
}

.final-cta h2 {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.final-cta p {
  font-size: 1.15rem;
  color: var(--color-text-secondary);
  margin-bottom: 40px;
}

/* ========== Footer ========== */
.footer {
  background: var(--color-primary);
  padding: 60px 0 30px;
  border-top: 1px solid var(--color-border);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand {
  max-width: 320px;
}

.footer-brand .header-logo {
  margin-bottom: 16px;
}

.footer-brand p {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-column h4 {
  font-size: 1rem;
  margin-bottom: 20px;
  color: var(--color-white);
}

.footer-column a {
  display: block;
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  padding: 4px 0;
  transition: color var(--transition);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 24px;
  text-align: center;
  color: var(--color-muted);
  font-size: 0.85rem;
}

/* ========== Back to Top ========== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), #7b5cc4);
  color: var(--color-white);
  border: none;
  cursor: pointer;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all var(--transition);
  box-shadow: 0 4px 16px rgba(154, 121, 226, 0.3);
  z-index: 999;
}

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

.back-to-top:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 24px rgba(154, 121, 226, 0.5);
}

/* ========== Animations ========== */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.animated {
  opacity: 1;
  transform: translateY(0);
}

/* ========== Mobile Nav Overlay ========== */
.mobile-nav-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(5, 6, 9, 0.97);
  backdrop-filter: blur(20px);
  z-index: 999;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
}

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

.mobile-nav-overlay a {
  color: var(--color-white);
  font-size: 1.4rem;
  font-weight: 600;
  padding: 12px 0;
}

.mobile-nav-close {
  position: absolute;
  top: 20px;
  right: 24px;
  background: transparent;
  border: none;
  color: var(--color-white);
  font-size: 2rem;
  cursor: pointer;
}

.mobile-lang-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 12px;
}

.mobile-lang-list a {
  font-size: 0.95rem !important;
  color: var(--color-text-secondary) !important;
  padding: 8px 16px !important;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.mobile-lang-list a.current {
  border-color: var(--color-accent);
  color: var(--color-accent) !important;
}

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

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

  .pricing-card.popular {
    transform: none;
  }

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

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

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

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

@media (max-width: 768px) {
  section {
    padding: 70px 0;
  }

  .header-nav {
    display: none;
  }

  .header-actions .btn-primary {
    display: none;
  }

  .header-actions .lang-switcher {
    display: none;
  }

  .menu-toggle {
    display: block;
  }

  .hero {
    padding: 130px 0 70px;
  }

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

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

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

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

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

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

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

  .comparison-table {
    font-size: 0.85rem;
  }

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

  .footer-content {
    grid-template-columns: 1fr;
    gap: 32px;
  }

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

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

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

  .section-title {
    font-size: 1.5rem;
  }

  .btn-large {
    padding: 16px 36px;
    font-size: 1rem;
  }
}