/* ============================================================
   MAIN.CSS — Design System & Layout
   ТОВ «РЕБ-Л» Defense Tech
   ============================================================ */

/* --- Google Fonts Import --- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* --- CSS Variables --- */
:root, [data-theme="dark"] {
  color-scheme: dark;

  /* Colors — dark theme (default) */
  --color-bg:       #0A0C10;
  --color-bg-rgb:   10, 12, 16;
  --color-surface:  #111418;
  --color-card:     #1C2128;
  --color-accent:   #00D4FF;
  --color-accent-rgb: 0, 212, 255;
  --color-accent-dark: #00A8CC;
  --color-accent-glow: rgba(var(--color-accent-rgb), 0.15);
  --color-text:     #E6EDF3;
  --color-muted:    #7D8590;
  --color-border:   #30363D;
  --color-error:    #F85149;
  --color-success:  #3FB950;
  --color-warning:  #D29922;
  --shadow-strength: 0.4;
  /* Overlay tint = white on dark theme (lightens what it sits on) */
  --color-overlay-rgb: 255, 255, 255;
}

[data-theme="light"] {
  color-scheme: light;

  /* Colors — light theme */
  --color-bg:       #F4F6F9;
  --color-bg-rgb:   244, 246, 249;
  --color-surface:  #FFFFFF;
  --color-card:     #FFFFFF;
  --color-accent:   #0095C2;
  --color-accent-rgb: 0, 149, 194;
  --color-accent-dark: #006B8C;
  --color-accent-glow: rgba(0, 149, 194, 0.10);
  --color-text:     #0F1419;
  --color-muted:    #5C6770;
  --color-border:   #DCE1E6;
  --color-error:    #C5252F;
  --color-success:  #1A8043;
  --color-warning:  #B07300;
  --shadow-strength: 0.08;
  /* Overlay tint = black on light theme (darkens what it sits on) */
  --color-overlay-rgb: 0, 0, 0;
}

/* Auto-pick light theme on systems that prefer it,
   but only when no explicit data-theme is set */
@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    color-scheme: light;
    --color-bg:       #F4F6F9;
    --color-bg-rgb:   244, 246, 249;
    --color-surface:  #FFFFFF;
    --color-card:     #FFFFFF;
    --color-accent:   #0095C2;
    --color-accent-rgb: 0, 149, 194;
    --color-accent-dark: #006B8C;
    --color-accent-glow: rgba(0, 149, 194, 0.10);
    --color-text:     #0F1419;
    --color-muted:    #5C6770;
    --color-border:   #DCE1E6;
    --color-error:    #C5252F;
    --color-success:  #1A8043;
    --color-warning:  #B07300;
    --shadow-strength: 0.08;
    --color-overlay-rgb: 0, 0, 0;
  }
}

:root {

  /* Typography */
  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono:  'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;

  /* Font sizes */
  --text-xs:   0.75rem;    /* 12px */
  --text-sm:   0.875rem;   /* 14px */
  --text-base: 1rem;       /* 16px */
  --text-lg:   1.125rem;   /* 18px */
  --text-xl:   1.25rem;    /* 20px */
  --text-2xl:  1.5rem;     /* 24px */
  --text-3xl:  1.75rem;    /* 28px */
  --text-4xl:  2.5rem;     /* 40px */
  --text-5xl:  3.5rem;     /* 56px */

  /* Spacing (8px base unit) */
  --space-1:  0.25rem;   /* 4px */
  --space-2:  0.5rem;    /* 8px */
  --space-3:  0.75rem;   /* 12px */
  --space-4:  1rem;      /* 16px */
  --space-5:  1.25rem;   /* 20px */
  --space-6:  1.5rem;    /* 24px */
  --space-8:  2rem;      /* 32px */
  --space-10: 2.5rem;    /* 40px */
  --space-12: 3rem;      /* 48px */
  --space-16: 4rem;      /* 64px */
  --space-20: 5rem;      /* 80px */
  --space-24: 6rem;      /* 96px */

  /* Border radius */
  --radius-sm:  4px;
  --radius-md:  8px;
  --radius-lg:  12px;
  --radius-xl:  16px;
  --radius-full: 9999px;

  /* Shadows — strength comes from --shadow-strength so light theme gets softer shadows */
  --shadow-sm:  0 1px 3px rgba(0, 0, 0, var(--shadow-strength));
  --shadow-md:  0 4px 12px rgba(0, 0, 0, calc(var(--shadow-strength) * 1.25));
  --shadow-lg:  0 8px 32px rgba(0, 0, 0, calc(var(--shadow-strength) * 1.5));
  --shadow-accent: 0 0 20px rgba(var(--color-accent-rgb), 0.2);

  /* Transitions */
  --transition-fast:   150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow:   400ms ease;

  /* Layout */
  --max-width: 1280px;
  --nav-height: 72px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--color-surface);
}
::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-muted);
}

/* --- Base Elements --- */
img, video, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

input, textarea, select {
  font-family: inherit;
}

/* --- Selection --- */
::selection {
  background: var(--color-accent);
  color: var(--color-bg);
}

/* --- Focus visible --- */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* --- Container --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-6);
  padding-right: var(--space-6);
}

/* --- Section --- */
.section {
  padding: var(--space-20) 0;
}

.section--alt {
  background-color: var(--color-surface);
}

/* --- Typography Scale --- */
h1, .h1 {
  font-size: var(--text-5xl);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h2, .h2 {
  font-size: var(--text-4xl);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

h3, .h3 {
  font-size: var(--text-3xl);
  font-weight: 600;
  line-height: 1.3;
}

h4, .h4 {
  font-size: var(--text-xl);
  font-weight: 600;
  line-height: 1.4;
}

h5, .h5 {
  font-size: var(--text-lg);
  font-weight: 600;
  line-height: 1.5;
}

p {
  color: var(--color-muted);
  line-height: 1.8;
}

p.lead {
  font-size: var(--text-lg);
  color: var(--color-text);
  opacity: 0.85;
}

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

/* --- Gradient Text --- */
.gradient-text {
  background: linear-gradient(135deg, var(--color-accent) 0%, #0099FF 50%, #7B61FF 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* --- Badge --- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-full);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background: rgba(var(--color-accent-rgb), 0.05);
}

.badge--muted {
  border-color: var(--color-border);
  color: var(--color-muted);
  background: transparent;
}

/* --- Grid System --- */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-auto { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* Two-column layout: title-left, body-right; collapses on mobile */
.two-col-align-center {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  align-items: center;
}

@media (max-width: 768px) {
  .two-col-align-center {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }
}

/* --- Flex Utilities --- */
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.flex-col { display: flex; flex-direction: column; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* --- Spacing Utilities --- */
.mt-4  { margin-top: var(--space-4); }
.mt-6  { margin-top: var(--space-6); }
.mt-8  { margin-top: var(--space-8); }
.mt-10 { margin-top: var(--space-10); }
.mb-4  { margin-bottom: var(--space-4); }
.mb-6  { margin-bottom: var(--space-6); }
.mb-8  { margin-bottom: var(--space-8); }
.mb-12 { margin-bottom: var(--space-12); }

/* --- Text Utilities --- */
.text-center { text-align: center; }
.text-muted   { color: var(--color-muted); }
.text-accent  { color: var(--color-accent); }
.text-mono    { font-family: var(--font-mono); }
.text-sm      { font-size: var(--text-sm); }
.text-xs      { font-size: var(--text-xs); }
.text-lg      { font-size: var(--text-lg); }

/* --- Section Header --- */
.section-header {
  margin-bottom: var(--space-12);
}

.section-header.text-center {
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
}

.section-header h2 {
  margin-bottom: var(--space-4);
}

.section-header p {
  font-size: var(--text-lg);
}

/* --- Divider --- */
hr, .divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-8) 0;
}

/* --- Breadcrumb --- */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-muted);
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--color-muted);
  transition: color var(--transition-fast);
}

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

.breadcrumb-sep {
  color: var(--color-border);
}

.breadcrumb-current {
  color: var(--color-text);
}

/* --- Page Hero --- */
.page-hero {
  padding: calc(var(--nav-height) + var(--space-16)) 0 var(--space-16);
  background: linear-gradient(180deg, rgba(var(--color-accent-rgb), 0.03) 0%, transparent 100%);
  border-bottom: 1px solid var(--color-border);
}

/* When a .page-hero has a video background */
.page-hero.has-video-bg {
  position: relative;
  overflow: hidden;
  background: none;
  border-bottom: none;
  isolation: isolate;
}

.page-hero.has-video-bg > .hero-video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
  opacity: 0.55;
}

[data-theme="light"] .page-hero.has-video-bg > .hero-video {
  opacity: 0.22;
  filter: brightness(1.10) contrast(0.95);
}

.page-hero.has-video-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 1;
  background:
    linear-gradient(90deg, rgba(0, 0, 0, 0.55) 0%, rgba(0, 0, 0, 0.10) 65%),
    linear-gradient(180deg, rgba(0, 0, 0, 0.30) 0%, rgba(0, 0, 0, 0.70) 100%);
  pointer-events: none;
}

[data-theme="light"] .page-hero.has-video-bg::after {
  background:
    linear-gradient(90deg, rgba(244, 246, 249, 0.85) 0%, rgba(244, 246, 249, 0.55) 65%),
    linear-gradient(180deg, rgba(244, 246, 249, 0.75) 0%, rgba(244, 246, 249, 0.95) 100%);
}

.page-hero.has-video-bg > .container {
  position: relative;
  z-index: 2;
}

/* Text-shadow safety net for inner-page hero headlines on video bg */
.page-hero.has-video-bg h1,
.page-hero.has-video-bg p,
.page-hero.has-video-bg .section-label,
.page-hero.has-video-bg .breadcrumb {
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.45);
}

[data-theme="light"] .page-hero.has-video-bg h1,
[data-theme="light"] .page-hero.has-video-bg p,
[data-theme="light"] .page-hero.has-video-bg .section-label,
[data-theme="light"] .page-hero.has-video-bg .breadcrumb {
  text-shadow: none;
}

@media (prefers-reduced-motion: reduce) {
  .page-hero.has-video-bg > .hero-video {
    display: none;
  }
}

@media (max-width: 640px) {
  .page-hero.has-video-bg > .hero-video {
    display: none;
  }
}

.page-hero h1 {
  margin-bottom: var(--space-4);
}

.page-hero p {
  font-size: var(--text-lg);
  max-width: 680px;
}

/* --- Skip to content link (Accessibility P0) --- */
.skip-to-content {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  z-index: 9999;
  padding: var(--space-3) var(--space-6);
  background: var(--color-accent);
  color: var(--color-bg);
  font-weight: 700;
  font-size: var(--text-base);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-to-content:focus {
  top: var(--space-2);
  outline: 2px solid var(--color-bg);
  outline-offset: 2px;
}

/* --- Fade-in Animation --- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 0 0 rgba(var(--color-accent-rgb), 0.1); }
  50%       { box-shadow: 0 0 0 8px rgba(var(--color-accent-rgb), 0); }
}

.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.fade-in-delay-1 { transition-delay: 0.1s; }
.fade-in-delay-2 { transition-delay: 0.2s; }
.fade-in-delay-3 { transition-delay: 0.3s; }
.fade-in-delay-4 { transition-delay: 0.4s; }

/* --- Stagger children --- */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.stagger-children.visible > *:nth-child(1) { transition-delay: 0s;    opacity: 1; transform: none; }
.stagger-children.visible > *:nth-child(2) { transition-delay: 0.1s;  opacity: 1; transform: none; }
.stagger-children.visible > *:nth-child(3) { transition-delay: 0.2s;  opacity: 1; transform: none; }
.stagger-children.visible > *:nth-child(4) { transition-delay: 0.3s;  opacity: 1; transform: none; }
.stagger-children.visible > *:nth-child(5) { transition-delay: 0.4s;  opacity: 1; transform: none; }
.stagger-children.visible > *:nth-child(6) { transition-delay: 0.5s;  opacity: 1; transform: none; }

/* --- prefers-reduced-motion (Performance + Accessibility P0) --- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .fade-in,
  .stagger-children > * {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }

  .fade-in.visible,
  .stagger-children.visible > * {
    opacity: 1 !important;
    transform: none !important;
  }

  .nav-logo-dot {
    animation: none !important;
  }
}

/* ============================================================
   RESPONSIVE BREAKPOINTS
   ============================================================ */

/* Tablet — 1024px */
@media (max-width: 1024px) {
  h1, .h1 { font-size: 3rem; }
  h2, .h2 { font-size: 2.25rem; }
  h3, .h3 { font-size: 1.5rem; }

  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }

  .section { padding: var(--space-16) 0; }
}

/* Mobile — 768px */
@media (max-width: 768px) {
  :root {
    --nav-height: 64px;
  }

  h1, .h1 { font-size: 2.25rem; letter-spacing: -0.01em; }
  h2, .h2 { font-size: 1.875rem; }
  h3, .h3 { font-size: 1.375rem; }

  .container {
    padding-left: var(--space-4);
    padding-right: var(--space-4);
  }

  .section { padding: var(--space-10) 0; }

  .grid-2 { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: 1fr; }

  .section-header { margin-bottom: var(--space-8); }

  .page-hero {
    padding: calc(var(--nav-height) + var(--space-10)) 0 var(--space-10);
  }
}

/* Small Mobile — 480px */
@media (max-width: 480px) {
  h1, .h1 { font-size: 1.875rem; }
  h2, .h2 { font-size: 1.625rem; }
}