:root {
  --gradient-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --main-card-bg: #f8f9fa;
  --text-dark: #1f2937;
  --text-muted: #6b7280;
  --accent-blue: #4a6cf7;
  --accent-teal: #10b981;
  --card-bg: #ffffff;
  --install-card-bg: #eef2ff;
  --font-main: 'Inter', -apple-system, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 40px 20px;
  background: var(--gradient-bg);
  background-attachment: fixed;
  font-family: var(--font-main);
  color: var(--text-dark);
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
}

.main-container {
  background-color: var(--main-card-bg);
  width: 100%;
  max-width: 900px;
  border-radius: 24px;
  padding: 60px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  position: relative;
}

.lang-switch {
  position: absolute;
  top: 20px;
  right: 20px;
  background: white;
  padding: 8px 16px;
  border-radius: 50px;
  font-size: 0.85rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  color: var(--text-muted);
  z-index: 100;
}

.lang-switch a {
  text-decoration: none;
  color: var(--text-muted);
  margin: 0 2px;
}

.lang-switch a.active {
  color: var(--accent-blue);
  font-weight: bold;
}

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

h1 {
  font-size: 2.5rem;
  margin-bottom: 12px;
  color: var(--text-dark);
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
}

.section-title {
  font-size: 1.5rem;
  font-weight: bold;
  margin: 40px 0 24px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--card-bg);
  padding: 24px;
  border-radius: 12px;
  border-left: 4px solid var(--accent-teal);
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.feature-card h3 {
  font-size: 1.1rem;
  margin: 0 0 12px;
  color: var(--text-dark);
}

.feature-card ul {
  padding-left: 0;
  list-style: none;
  margin: 0;
}

.feature-card li {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 8px;
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.feature-card li::before {
  content: "✓";
  color: var(--accent-teal);
  font-weight: bold;
}

.install-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
  background-color: var(--install-card-bg);
  padding: 30px;
  border-radius: 16px;
  margin-top: 40px;
}

.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 14px 24px;
  background-color: var(--accent-blue);
  color: white;
  text-decoration: none;
  border-radius: 12px;
  font-weight: bold;
  transition: opacity 0.2s;
}

.btn:hover {
  opacity: 0.9;
}

.btn-secondary {
  background-color: #374151;
}

.footer {
  text-align: center;
  margin-top: 60px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

@media (max-width: 640px) {
  .main-container { padding: 30px 20px; }
  h1 { font-size: 1.8rem; }
  .features-grid { grid-template-columns: 1fr; }
}