:root {
  /* Design Tokens */
  /* Colors - Light Theme (Default) */
  --bg-main: #f0fbff;
  --bg-surface: rgba(255, 255, 255, 0.7);
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-button-hover: rgba(31, 139, 255, 0.08);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #64748b;
  
  --primary-color: #0ea5e9;
  --primary-hover: #0284c7;
  --primary-active: #0369a1;
  --primary-subtle: rgba(14, 165, 233, 0.1);
  
  --border-color: rgba(14, 165, 233, 0.2);
  --border-light: rgba(14, 165, 233, 0.1);
  
  /* Typography */
  --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  
  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(14, 165, 233, 0.1), 0 4px 6px -2px rgba(14, 165, 233, 0.05);
  
  /* Transitions */
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  --bg-main: #0f172a;
  --bg-surface: rgba(30, 41, 59, 0.7);
  --bg-card: rgba(30, 41, 59, 0.85);
  --bg-button-hover: rgba(56, 189, 248, 0.1);
  
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-tertiary: #94a3b8;
  
  --primary-color: #38bdf8;
  --primary-hover: #7dd3fc;
  --primary-active: #bae6fd;
  --primary-subtle: rgba(56, 189, 248, 0.15);
  
  --border-color: rgba(56, 189, 248, 0.2);
  --border-light: rgba(56, 189, 248, 0.1);
  
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
}

/* Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  background-image: 
    radial-gradient(circle at top left, var(--primary-subtle), transparent 40%),
    radial-gradient(circle at top right, var(--border-light), transparent 40%);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

html {
  scroll-behavior: smooth;
}

.container {
  width: min(1200px, 90vw);
  margin: 0 auto;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text-primary);
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  margin-bottom: var(--space-md);
}

h2 {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  margin-bottom: var(--space-lg);
}

h3 {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
}

p {
  color: var(--text-secondary);
}

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

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

/* Accessibility: Focus Styles */
:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Header & Nav */
.header-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) 0;
  position: relative;
  z-index: 10;
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: 10px 14px 10px 10px;
  border-radius: 18px;
  background: linear-gradient(135deg, var(--bg-card), var(--bg-surface));
  border: 1px solid var(--border-light);
  box-shadow: 0 14px 30px rgba(14, 165, 233, 0.08);
  text-decoration: none;
}

.brand-logo {
  width: 48px;
  height: 48px;
  object-fit: contain;
  border-radius: 14px;
  background: transparent;
  display: block;
  filter: drop-shadow(0 10px 24px rgba(14, 165, 233, 0.16));
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-title {
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.1;
}

.brand-subtitle {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary-color);
  color: #ffffff;
  box-shadow: 0 4px 14px var(--primary-subtle);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px var(--primary-subtle);
  color: #ffffff;
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-button-hover);
  border-color: var(--primary-color);
}

.btn-icon {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Icon Buttons (Theme/Lang toggle) */
.icon-btn {
  background: transparent;
  border: 1px solid var(--border-light);
  color: var(--text-secondary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.icon-btn:hover {
  background: var(--bg-button-hover);
  color: var(--primary-color);
  border-color: var(--border-color);
}

/* Hero Section */
.hero {
  padding: var(--space-3xl) 0;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.hero-content {
  max-width: 600px;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  background-color: var(--primary-subtle);
  color: var(--primary-color);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-lg);
  border: 1px solid var(--border-light);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.section-badge {
  margin-bottom: var(--space-md);
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.tag {
  padding: 4px 12px;
  border-radius: var(--radius-full);
  background-color: var(--bg-surface);
  border: 1px solid var(--border-light);
  color: var(--text-secondary);
  font-size: 0.875rem;
  backdrop-filter: blur(8px);
}

/* Hero Visual/Panel */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.visual-glow {
  position: absolute;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle, var(--primary-subtle), transparent 70%);
  filter: blur(40px);
  z-index: 0;
  animation: pulseGlow 6s ease-in-out infinite alternate;
}

@keyframes pulseGlow {
  0% { transform: scale(1); opacity: 0.8; }
  100% { transform: scale(1.1); opacity: 1; }
}

.visual-card {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 480px;
  background: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-surface) 100%);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  box-shadow: 0 24px 48px -12px rgba(14, 165, 233, 0.15), 0 0 0 1px rgba(255, 255, 255, 0.1) inset;
  overflow: hidden;
}

.visual-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
  z-index: 2;
}

.visual-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-light);
  position: relative;
}

.visual-header::before {
  content: '';
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: #10b981;
  animation: pulseActive 2s infinite;
}

@keyframes pulseActive {
  0% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.4); }
  70% { box-shadow: 0 0 0 6px rgba(16, 185, 129, 0); }
  100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.visual-header-text {
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.visual-header-text h3 {
  margin: 0;
  font-size: 1.5rem;
  background: linear-gradient(90deg, var(--primary-color), var(--primary-hover));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 900;
}

.visual-header-text .divider {
  color: var(--text-tertiary);
  font-size: 0.875rem;
  font-weight: 300;
}

.visual-header-text p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: 600;
}

.visual-body {
  display: grid;
  gap: var(--space-md);
}

.metric-item {
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  background: linear-gradient(90deg, var(--primary-subtle) 0%, transparent 100%);
  border-left: 3px solid var(--primary-color);
  border-top: 1px solid transparent;
  border-right: 1px solid transparent;
  border-bottom: 1px solid transparent;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.metric-item::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  height: 100%;
  width: 40px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1));
  transform: skewX(-20deg) translateX(150px);
  transition: transform 0.5s ease;
}

.metric-item:hover {
  transform: translateX(8px);
  border-color: var(--border-light);
  background: linear-gradient(90deg, rgba(14, 165, 233, 0.15) 0%, var(--bg-surface) 100%);
  box-shadow: var(--shadow-sm);
}

.metric-item:hover::after {
  transform: skewX(-20deg) translateX(-300px);
}

.metric-item strong {
  display: block;
  color: var(--text-primary);
  margin-bottom: 4px;
  font-size: 1.05rem;
}

.metric-item span {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* Sections */
.section {
  padding: var(--space-3xl) 0;
}

.section-alt {
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto var(--space-2xl);
}

.grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-lg);
}

.card {
  background: var(--bg-card);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  height: 100%;
}

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

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--primary-subtle);
  color: var(--primary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-md);
}

.card-icon svg {
  width: 24px;
  height: 24px;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-lg);
  align-items: stretch;
}

.download-card {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(248, 250, 252, 0.98));
  border: 1px solid rgba(226, 232, 240, 0.9);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.14);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  position: relative;
  overflow: hidden;
  min-height: 100%;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.download-card::before {
  content: '';
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, #38bdf8, #7dd3fc);
}

.download-card-vip {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(250, 245, 255, 0.98));
  border-color: rgba(233, 213, 255, 0.92);
}

.download-card-vip::before {
  background: linear-gradient(90deg, #a855f7, #d8b4fe);
}

.download-card:hover {
  transform: translateY(-4px);
  border-color: rgba(125, 211, 252, 0.9);
  box-shadow: 0 24px 48px rgba(15, 23, 42, 0.16);
}

.download-card-vip:hover {
  border-color: rgba(196, 181, 253, 0.92);
}

.download-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.download-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: rgba(56, 189, 248, 0.1);
  color: #0369a1;
  border: 1px solid rgba(56, 189, 248, 0.16);
  font-size: 0.875rem;
  font-weight: 700;
}

.download-chip-vip {
  background: rgba(168, 85, 247, 0.1);
  color: #7e22ce;
  border-color: rgba(168, 85, 247, 0.16);
}

.download-plan-tag {
  color: #64748b;
  font-size: 0.875rem;
  font-weight: 600;
}

.download-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.download-meta-item {
  display: inline-flex;
  align-items: center;
  padding: 7px 12px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(203, 213, 225, 0.9);
  background: rgba(248, 250, 252, 0.95);
  color: #475569;
  font-size: 0.8125rem;
  font-weight: 600;
}

.download-card-desc {
  font-size: 1rem;
  line-height: 1.7;
  min-height: 5.25rem;
  color: #475569;
}

.download-card h3 {
  margin-bottom: 0;
  font-size: 1.5rem;
  color: #0f172a;
}

.download-feature-list {
  list-style: none;
  display: grid;
  gap: 14px;
  padding: 18px;
  border-radius: 20px;
  border: 1px solid rgba(226, 232, 240, 0.96);
  background: rgba(255, 255, 255, 0.95);
}

.download-feature-list li {
  position: relative;
  padding-left: 30px;
  color: #334155;
  line-height: 1.6;
}

.download-feature-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: #7dd3fc;
  box-shadow: 0 0 0 6px rgba(56, 189, 248, 0.12);
}

.download-card-vip .download-feature-list li::before {
  background: #d8b4fe;
  box-shadow: 0 0 0 6px rgba(168, 85, 247, 0.14);
}

.download-card-footer {
  margin-top: auto;
  display: grid;
  gap: var(--space-md);
}

.download-note {
  font-size: 0.875rem;
  color: #64748b;
  min-height: 2.8em;
}

.download-action {
  width: 100%;
  min-height: 52px;
  border-radius: 14px;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  justify-content: center;
  padding: 0.9rem 1.2rem;
  border: 1px solid transparent;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast), background-color var(--transition-fast), color var(--transition-fast);
}

.download-action span {
  text-align: center;
}

.download-action-primary {
  background: #0f172a;
  color: #ffffff;
  box-shadow: 0 10px 20px rgba(15, 23, 42, 0.16);
}

.download-action-primary:hover {
  color: #ffffff;
  background: #020617;
  transform: translateY(-1px);
  box-shadow: 0 14px 26px rgba(15, 23, 42, 0.2);
}

.download-action-secondary {
  background: #ffffff;
  color: #0f172a;
  border-color: rgba(203, 213, 225, 0.9);
  box-shadow: none;
}

.download-action-secondary:hover {
  color: #0f172a;
  background: rgba(168, 85, 247, 0.16);
  border-color: rgba(216, 180, 254, 0.28);
  transform: translateY(-1px);
}

.steps-list {
  list-style: none;
  counter-reset: step-counter;
  display: grid;
  gap: var(--space-lg);
  max-width: 800px;
  margin: 0 auto;
}

.step-item {
  position: relative;
  padding-left: 60px;
  background: var(--bg-card);
  padding: var(--space-lg) var(--space-lg) var(--space-lg) 70px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
}

.step-item::before {
  counter-increment: step-counter;
  content: counter(step-counter);
  position: absolute;
  left: var(--space-lg);
  top: var(--space-lg);
  width: 32px;
  height: 32px;
  background: var(--primary-color);
  color: #fff;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 0.875rem;
}

/* CTA Panel */
.cta-panel {
  background: linear-gradient(135deg, var(--primary-subtle), var(--bg-surface));
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
  flex-wrap: wrap;
}

.cta-content h2 {
  margin-bottom: var(--space-sm);
}

.cta-content p {
  font-size: 1.125rem;
}

/* Footer */
.footer {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--border-light);
  background-color: var(--bg-main);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 0;
}

.footer-text {
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

/* Animations */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* Modal Component */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.modal-overlay.show {
  opacity: 1;
  visibility: visible;
}

.modal-container {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  width: min(400px, 90vw);
  box-shadow: var(--shadow-lg);
  position: relative;
  transform: scale(0.95) translateY(10px);
  transition: transform var(--transition-normal);
}

.modal-overlay.show .modal-container {
  transform: scale(1) translateY(0);
}

.modal-close {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: var(--bg-button-hover);
  color: var(--text-primary);
}

.modal-close svg {
  width: 20px;
  height: 20px;
}

.modal-header {
  text-align: center;
  margin-bottom: var(--space-lg);
}

.modal-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--space-md);
  background: var(--primary-subtle);
  color: var(--primary-color);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-icon svg {
  width: 24px;
  height: 24px;
}

.modal-body {
  text-align: center;
}

.progress-bar {
  height: 6px;
  background: var(--border-light);
  border-radius: var(--radius-full);
  margin-top: var(--space-lg);
  overflow: hidden;
  position: relative;
}

.progress-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 50%;
  background: var(--primary-color);
  border-radius: var(--radius-full);
  animation: progress 2s ease-in-out infinite;
}

@keyframes progress {
  0% { left: -50%; }
  100% { left: 100%; }
}

/* Responsive Design */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .hero-content {
    margin: 0 auto;
  }
  
  .hero-actions, .hero-tags {
    justify-content: center;
  }

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

@media (max-width: 768px) {
  :root {
    --space-3xl: 48px;
    --space-2xl: 32px;
  }
  
  .cta-panel {
    flex-direction: column;
    text-align: center;
    justify-content: center;
  }

  .download-card {
    padding: var(--space-lg);
  }

  .download-card-desc {
    min-height: auto;
  }
  
  .footer-inner {
    flex-direction: column;
    text-align: center;
  }
}