/* Konstruct Landing - Professional Privacy-First Design */

:root {
  /* Professional dark palette */
  --bg: #0a0a0a;
  --bg-elevated: #141414;
  --fg: #f5f5f5;
  --fg-secondary: #b8b8b8;
  --fg-muted: #7a7a7a;
  --accent: #4d9eff;
  --accent-hover: #6fb0ff;
  --border: #2a2a2a;
  --border-subtle: #1a1a1a;
  --success: #00c853;
  --warning: #ffa726;
  
  /* Typography scale */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'IBM Plex Mono', 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
  
  /* Spacing scale */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;
  --space-3xl: 6rem;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

/* Import Inter font for professional typography */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: 'liga' 1, 'calt' 1;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

strong {
  font-weight: 600;
  color: var(--fg);
}

.container {
  max-width: 1024px;
  padding: 0 var(--space-lg);
  margin: 0 auto;
}

/* Skip to content link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--accent);
  color: var(--bg);
  padding: 8px 16px;
  text-decoration: none;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
}

/* Header - Professional & Clear */
header {
  padding: var(--space-3xl) 0 var(--space-2xl);
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, var(--bg) 0%, var(--bg-elevated) 100%);
}

header h1 {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  margin: 0 0 var(--space-md);
  letter-spacing: -0.025em;
  font-weight: 700;
  line-height: 1.1;
  background: linear-gradient(135deg, var(--fg) 0%, var(--fg-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

header p {
  font-size: 1.125rem;
  color: var(--fg-secondary);
  max-width: 700px;
  line-height: 1.8;
  font-weight: 400;
}

.badges {
  margin-top: var(--space-lg);
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.badge {
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 0.875rem;
  color: var(--fg-secondary);
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: all 0.2s ease;
}

.badge:hover {
  border-color: var(--accent);
  background: rgba(77, 158, 255, 0.1);
  color: var(--accent);
}

/* Sections - Professional Spacing */
section {
  padding: var(--space-3xl) 0;
  border-bottom: 1px solid var(--border-subtle);
}

section:last-of-type {
  border-bottom: none;
}

h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  margin: 0 0 var(--space-lg);
  letter-spacing: -0.02em;
  font-weight: 700;
  color: var(--fg);
  line-height: 1.2;
}

h3 {
  font-size: 1.5rem;
  margin: var(--space-xl) 0 var(--space-md);
  font-weight: 600;
  color: var(--fg);
}

p {
  max-width: 760px;
  color: var(--fg-secondary);
  margin-bottom: var(--space-md);
  line-height: 1.8;
}

ul {
  padding-left: 1.5rem;
  max-width: 760px;
  color: var(--fg-secondary);
}

li {
  margin-bottom: var(--space-sm);
  line-height: 1.7;
}

li strong {
  color: var(--fg);
}

code {
  background: rgba(77, 158, 255, 0.1);
  border: 1px solid rgba(77, 158, 255, 0.2);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.875em;
  color: var(--accent);
  font-weight: 500;
}

/* Table - Professional & Clean */
table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin-top: var(--space-lg);
  font-size: 0.9375rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: var(--bg-elevated);
}

th, td {
  padding: 1rem 1.25rem;
  text-align: left;
  border-bottom: 1px solid var(--border-subtle);
}

th {
  background: var(--bg);
  color: var(--fg-secondary);
  font-weight: 600;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

tbody tr {
  transition: background 0.15s ease;
}

tbody tr:hover {
  background: rgba(77, 158, 255, 0.05);
}

tbody th {
  background: transparent;
  color: var(--fg);
  font-weight: 600;
  text-transform: none;
  letter-spacing: 0;
  font-size: 0.9375rem;
}

tbody th strong {
  color: var(--accent);
}

/* Footer - Minimal & Professional */
footer {
  padding: var(--space-2xl) 0;
  color: var(--fg-muted);
  font-size: 0.875rem;
  text-align: center;
  border-top: 1px solid var(--border-subtle);
}

footer p {
  max-width: none;
  color: var(--fg-muted);
}

/* Mission Statement - Special Styling */
section[aria-labelledby="about-heading"] {
  background: var(--bg-elevated);
  border-radius: 12px;
  padding: var(--space-2xl);
  margin: var(--space-xl) 0;
  border: 1px solid var(--border);
}

/* Feature List Enhancement */
section[aria-labelledby="features-heading"] ul li {
  position: relative;
  padding-left: 1.5rem;
}

section[aria-labelledby="features-heading"] ul li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--success);
  font-weight: bold;
}

/* Responsive */
@media (max-width: 768px) {
  :root {
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
  }

  header {
    padding: var(--space-2xl) 0 var(--space-xl);
  }

  section {
    padding: var(--space-xl) 0;
  }
  
  .container {
    padding: 0 var(--space-md);
  }

  table {
    font-size: 0.875rem;
  }

  th, td {
    padding: 0.75rem;
  }
}

@media (max-width: 640px) {
  .badges {
    gap: 0.5rem;
  }

  .badge {
    font-size: 0.8125rem;
    padding: 0.4rem 0.8rem;
  }
}

/* Print styles */
@media print {
  body {
    background: white;
    color: black;
  }
  
  a {
    color: #0066cc;
  }
  
  header, section {
    border: none;
  }
}


/* Language Switcher */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 4px;
}
.lang-switcher button {
  background: none;
  border: 1px solid var(--border);
  color: var(--fg-muted);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: var(--font-sans);
  letter-spacing: 0.04em;
}
.lang-switcher button:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.lang-switcher button.active {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(77, 158, 255, 0.08);
}
.lang-sep {
  color: var(--border);
  user-select: none;
}
/* Page nav bar (for FAQ and other pages) */
.page-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 56px;
  background: rgba(10, 10, 10, 0.95);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
  display: flex;
  align-items: center;
}
.page-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 0;
  padding-bottom: 0;
}
.nav-logo {
  font-weight: 700;
  font-size: 1rem;
  color: var(--fg);
  letter-spacing: -0.01em;
}
.nav-logo:hover { color: var(--accent); }

/* Language visibility — hides inactive language content */
html[data-lang="en"] .ru,
html[data-lang="ru"] .en {
  display: none !important;
}