/* ============================================================
   Dead Man Switch — Landing Page Styles
   Theme: Dark / Security / Trust
   ============================================================ */

/* ── Custom Properties ──────────────────────────────────── */
:root {
  --bg-primary:    #0d1117;
  --bg-secondary:  #161b22;
  --bg-card:       #1c2128;
  --bg-card-hover: #222a33;
  --accent:        #00d4a1;
  --accent-dark:   #009e78;
  --accent-blue:   #58a6ff;
  --text-primary:  #e6edf3;
  --text-muted:    #8b949e;
  --border:        #30363d;
  --border-accent: rgba(0,212,161,0.3);
  --glow:          rgba(0,212,161,0.12);
  --glow-blue:     rgba(88,166,255,0.1);

  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 30px;

  --shadow-card: 0 4px 24px rgba(0,0,0,0.4), 0 1px 4px rgba(0,0,0,0.3);
  --shadow-glow: 0 0 30px var(--glow), 0 4px 24px rgba(0,0,0,0.4);

  --transition: 0.25s cubic-bezier(0.4,0,0.2,1);

  --max-width: 1100px;
  --nav-height: 64px;
}

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

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

img, svg {
  display: block;
  max-width: 100%;
}

a {
  color: var(--accent-blue);
  text-decoration: none;
  transition: color var(--transition);
}

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

ul { list-style: none; }

/* ── Skip Link ───────────────────────────────────────────── */
.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  background: var(--accent);
  color: var(--bg-primary);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  z-index: 9999;
  transition: top var(--transition);
}
.skip-link:focus { top: 1rem; }

/* ── Utility ─────────────────────────────────────────────── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 600px;
  line-height: 1.7;
}

.text-center {
  text-align: center;
}
.text-center .section-subtitle {
  margin: 0 auto;
}

/* ── Scroll Animation ────────────────────────────────────── */
.animate {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.animate.visible {
  opacity: 1;
  transform: translateY(0);
}
.animate.delay-1 { transition-delay: 0.1s; }
.animate.delay-2 { transition-delay: 0.2s; }
.animate.delay-3 { transition-delay: 0.3s; }
.animate.delay-4 { transition-delay: 0.4s; }
.animate.delay-5 { transition-delay: 0.5s; }

/* Graceful degradation: no JS → everything visible */
@media (scripting: none) {
  .animate {
    opacity: 1;
    transform: none;
  }
}

/* ── Navigation ──────────────────────────────────────────── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  transition: background var(--transition), box-shadow var(--transition);
}

.nav.scrolled {
  background: rgba(13,17,23,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--border);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.01em;
}
.nav__logo:hover { color: var(--accent); }

.nav__logo-icon {
  font-size: 1.4rem;
  line-height: 1;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav__links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition);
}
.nav__links a:hover { color: var(--text-primary); }

.nav__cta {
  padding: 0.45rem 1.1rem;
  background: var(--accent);
  color: var(--bg-primary) !important;
  border-radius: var(--radius-xl);
  font-weight: 700 !important;
  font-size: 0.85rem !important;
  transition: background var(--transition), transform var(--transition) !important;
}
.nav__cta:hover {
  background: var(--accent-dark) !important;
  color: var(--bg-primary) !important;
  transform: translateY(-1px);
}

.nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}
.nav__hamburger:hover { background: var(--bg-card); }
.nav__hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
  transform-origin: center;
}

.nav__hamburger[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav__hamburger[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav__hamburger[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.nav__mobile {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: rgba(13,17,23,0.97);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 1.5rem;
  z-index: 999;
  flex-direction: column;
  gap: 1rem;
  transform: translateY(-10px);
  opacity: 0;
  transition: transform var(--transition), opacity var(--transition);
}

.nav__mobile.open {
  display: flex;
  transform: translateY(0);
  opacity: 1;
}

.nav__mobile a {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  transition: color var(--transition);
}
.nav__mobile a:last-child { border-bottom: none; }
.nav__mobile a:hover { color: var(--accent); }

/* ── Hero ────────────────────────────────────────────────── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 20%, rgba(0,212,161,0.08) 0%, transparent 70%),
    radial-gradient(ellipse 60% 40% at 80% 80%, rgba(88,166,255,0.06) 0%, transparent 60%),
    var(--bg-primary);
  z-index: 0;
}

/* Animated grid */
.hero__grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(48,54,61,0.3) 1px, transparent 1px),
    linear-gradient(90deg, rgba(48,54,61,0.3) 1px, transparent 1px);
  background-size: 60px 60px;
  z-index: 0;
  mask-image: radial-gradient(ellipse 70% 70% at 50% 50%, black 0%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 70% 70% at 50% 50%, black 0%, transparent 100%);
}

.hero__content {
  position: relative;
  z-index: 1;
  width: 100%;
  text-align: center;
  padding: 4rem 0 5rem;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(0,212,161,0.1);
  border: 1px solid var(--border-accent);
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  padding: 0.35rem 0.9rem;
  border-radius: var(--radius-xl);
  margin-bottom: 1.75rem;
}

.hero__icon {
  font-size: 5rem;
  line-height: 1;
  margin-bottom: 1.5rem;
  display: block;
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-12px); }
}

.hero__title {
  font-size: clamp(2.5rem, 7vw, 4.5rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 1.25rem;
}

.hero__title .accent {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: clamp(1.05rem, 2.5vw, 1.25rem);
  color: var(--text-muted);
  max-width: 580px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.hero__actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 2rem;
  border-radius: var(--radius-xl);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  border: none;
  text-decoration: none;
  transition: all var(--transition);
  white-space: nowrap;
}

.btn--primary {
  background: var(--accent);
  color: var(--bg-primary);
  box-shadow: 0 4px 20px rgba(0,212,161,0.3);
}
.btn--primary:hover {
  background: var(--accent-dark);
  color: var(--bg-primary);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0,212,161,0.4);
}

.btn--secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border);
}
.btn--secondary:hover {
  background: var(--bg-card);
  color: var(--text-primary);
  border-color: var(--accent);
  transform: translateY(-2px);
}

.btn--lg {
  font-size: 1.1rem;
  padding: 1rem 2.5rem;
}

.hero__stats {
  display: flex;
  gap: 3rem;
  justify-content: center;
  margin-top: 3.5rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}

.hero__stat {
  text-align: center;
}

.hero__stat-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -0.02em;
}

.hero__stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ── How it Works ────────────────────────────────────────── */
.how {
  padding: 6rem 0;
  background: var(--bg-secondary);
  position: relative;
  overflow: hidden;
}

.how::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 60% 50% at 50% 0%, rgba(0,212,161,0.04) 0%, transparent 70%);
}

.how__header {
  text-align: center;
  margin-bottom: 4rem;
  position: relative;
}

.how__steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  position: relative;
}

/* Connecting line between steps */
.how__steps::before {
  content: '';
  position: absolute;
  top: 2.25rem;
  left: calc(12.5% + 1.5rem);
  right: calc(12.5% + 1.5rem);
  height: 2px;
  background: linear-gradient(90deg, var(--accent) 0%, var(--accent-blue) 100%);
  opacity: 0.3;
  z-index: 0;
}

.step {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

.step__number {
  width: 4.5rem;
  height: 4.5rem;
  border-radius: 50%;
  background: var(--bg-card);
  border: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  position: relative;
  transition: border-color var(--transition), box-shadow var(--transition);
  flex-shrink: 0;
}

.step:hover .step__number {
  border-color: var(--accent);
  box-shadow: 0 0 20px var(--glow);
}

.step__num-badge {
  position: absolute;
  top: -6px;
  right: -6px;
  width: 22px;
  height: 22px;
  background: var(--accent);
  color: var(--bg-primary);
  font-size: 0.65rem;
  font-weight: 800;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step__title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.step__desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Features ────────────────────────────────────────────── */
.features {
  padding: 6rem 0;
  background: var(--bg-primary);
}

.features__header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 2rem;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--glow) 0%, transparent 60%);
  opacity: 0;
  transition: opacity var(--transition);
}

.feature-card:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow);
  transform: translateY(-3px);
}
.feature-card:hover::before { opacity: 1; }

.feature-card__icon {
  font-size: 2.25rem;
  line-height: 1;
  margin-bottom: 1rem;
}

.feature-card__title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.feature-card__desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Security ────────────────────────────────────────────── */
.security {
  padding: 6rem 0;
  background: var(--bg-secondary);
  position: relative;
  overflow: hidden;
}

.security::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 50% 60% at 80% 50%, rgba(88,166,255,0.05) 0%, transparent 70%);
  pointer-events: none;
}

.security__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.security__content .section-subtitle {
  margin-bottom: 2rem;
}

.security__points {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.5rem;
}

.security__point {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
}

.security__point-icon {
  width: 2rem;
  height: 2rem;
  background: rgba(0,212,161,0.1);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.security__point-text {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.security__point-text strong {
  color: var(--text-primary);
  display: block;
  margin-bottom: 0.2rem;
}

.security__code {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.8;
  position: relative;
  overflow: hidden;
}

.security__code::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent) 0%, var(--accent-blue) 100%);
}

.code-comment { color: #6e7681; }
.code-key     { color: #79c0ff; }
.code-value   { color: #a5d6ff; }
.code-string  { color: var(--accent); }
.code-number  { color: #f2cc60; }

.security__link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 2rem;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.6rem 1.2rem;
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.security__link:hover {
  background: var(--glow);
  color: var(--accent);
  transform: translateX(3px);
}

/* ── About ───────────────────────────────────────────────── */
.about {
  padding: 6rem 0;
  background: var(--bg-primary);
  position: relative;
  overflow: hidden;
}

.about::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 60% at 20% 60%, rgba(0,212,161,0.04) 0%, transparent 70%);
}

.about__inner {
  max-width: 780px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.about__pull-quote {
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  font-weight: 700;
  line-height: 1.5;
  color: var(--text-primary);
  border-left: 4px solid var(--accent);
  padding-left: 1.5rem;
  margin-bottom: 2.5rem;
  letter-spacing: -0.01em;
}

.about__text {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 1.5rem;
}

.about__text strong {
  color: var(--text-primary);
}

.about__russian {
  margin-top: 2.5rem;
  padding: 1.5rem 1.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  position: relative;
}

.about__russian::before {
  content: '🇷🇺';
  position: absolute;
  top: -0.75rem;
  left: 1.5rem;
  font-size: 1.2rem;
  background: var(--bg-primary);
  padding: 0 0.5rem;
}

.about__russian-text {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.8;
  font-style: italic;
}

.about__cta {
  margin-top: 2.5rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ── Footer ──────────────────────────────────────────────── */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 3.5rem 0 2rem;
}

.footer__inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.footer__brand-icon { font-size: 1.3rem; }

.footer__tagline {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
  max-width: 280px;
}

.footer__col-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer__links a {
  font-size: 0.875rem;
  color: var(--text-muted);
  transition: color var(--transition);
}
.footer__links a:hover { color: var(--accent); }

.footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 1rem;
}

.footer__copy {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer__love {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer__love .heart {
  color: #f85149;
  display: inline-block;
  animation: heartbeat 2s ease-in-out infinite;
}

@keyframes heartbeat {
  0%, 100% { transform: scale(1); }
  14%       { transform: scale(1.3); }
  28%       { transform: scale(1); }
  42%       { transform: scale(1.15); }
  56%       { transform: scale(1); }
}

.footer__version {
  font-size: 0.75rem;
  color: #444d56;
  font-family: var(--font-mono);
}

/* ── Responsive ──────────────────────────────────────────── */
@media (max-width: 1024px) {
  .features__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .security__inner {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  .security__code {
    max-width: 100%;
  }
}

@media (max-width: 768px) {
  .nav__links { display: none; }
  .nav__hamburger { display: flex; }

  .how__steps {
    grid-template-columns: 1fr;
    gap: 2.5rem;
    padding: 0 1rem;
  }
  .how__steps::before { display: none; }
  .step { flex-direction: row; align-items: flex-start; text-align: left; gap: 1.25rem; }
  .step__number { margin-bottom: 0; }

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

  .footer__inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .footer__bottom {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero__actions {
    flex-direction: column;
    align-items: center;
  }
  .btn { width: 100%; max-width: 300px; justify-content: center; }
  .hero__stats {
    gap: 2rem;
  }
  .about__cta {
    flex-direction: column;
  }
}

/* ── Reduced Motion ──────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
  .animate { opacity: 1; transform: none; }
}