:root {
  color-scheme: dark;
  --bg: #0b0b0d;
  --card: #141419;
  --text: #f3f3f4;
  --muted: #b1b1bb;
  --line: #272730;
  --accent: #4da3ff;
}

.tap-ripples {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.ripple {
  position: absolute;
  width: 140px;
  height: 140px;
  border-radius: 999px;
  box-shadow: 0 0 0 5px rgba(77, 163, 255, 0.18);
  transform: scale(0.2) translateZ(0);
  opacity: 0;
  animation: tapRippleWave 7s linear infinite;
}

.ripple:nth-child(1) {
  top: 8%;
  left: 12%;
  animation-delay: 0s;
}

.ripple:nth-child(2) {
  top: 22%;
  left: 72%;
  animation-delay: 1.1s;
}

.ripple:nth-child(3) {
  top: 48%;
  left: 18%;
  animation-delay: 2.3s;
}

.ripple:nth-child(4) {
  top: 58%;
  left: 78%;
  animation-delay: 3.2s;
}

.ripple:nth-child(5) {
  top: 76%;
  left: 38%;
  animation-delay: 4.4s;
}

.ripple:nth-child(6) {
  top: 30%;
  left: 45%;
  animation-delay: 5.4s;
}

@keyframes tapRippleWave {
  0% {
    transform: scale(0.2) translateZ(0);
    opacity: 0;
  }

  15% {
    opacity: 0.35;
  }

  100% {
    transform: scale(2.4) translateZ(0);
    opacity: 0;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 32px 20px 56px;
  position: relative;
  z-index: 1;
}

article {
  background: rgba(20, 20, 25, 0.4);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 20px;
  padding: 28px;
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.28);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 24px;
}

.section-nav,
.language-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.nav-item {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: border-color 0.15s ease, color 0.15s ease, background 0.15s ease;
}

.nav-item.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #08111d;
  font-weight: 600;
  pointer-events: none;
}

.nav-item.language {
  min-width: 48px;
  justify-content: center;
}

h1,
h2 {
  line-height: 1.2;
  margin: 0 0 14px;
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.1rem;
  margin-top: 28px;
}

p,
ul {
  margin: 0 0 14px;
}

ul {
  padding-left: 18px;
}

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

.muted {
  color: var(--muted);
}

strong {
  color: var(--accent);
  font-weight: 650;
}

@media (prefers-reduced-motion: reduce) {
  .ripple {
    animation: none;
    opacity: 0.08;
    transform: scale(1);
  }
}