/* NextGenAI Design V2 — premium responsive base layout. */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
[hidden] { display: none !important; }

body.tng2 {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 8% -6%, rgba(141,124,246,.12), transparent 30rem),
    radial-gradient(circle at 92% 4%, rgba(242,184,75,.09), transparent 28rem),
    var(--tng-bg-dark);
  color: var(--tng-text-dark);
  font-family: var(--tng-font-body);
  font-size: var(--tng-text-body);
  line-height: var(--tng-line-height-body);
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}

.tng2 h1, .tng2 h2, .tng2 h3, .tng2 h4 {
  font-family: var(--tng-font-display);
  line-height: var(--tng-line-height-heading);
  letter-spacing: -.035em;
  font-weight: 650;
  margin: 0 0 var(--tng-space-4);
}
.tng2 p { margin-top: 0; }
:where(.tng2) a { color: inherit; }
.tng2 img { max-width: 100%; height: auto; display: block; }

.tng2 :focus-visible {
  outline: 2px solid var(--tng-focus);
  outline-offset: 3px;
  border-radius: 6px;
}

.tng2-skip-link {
  position: absolute;
  top: -100px;
  left: var(--tng-space-4);
  z-index: 1000;
  background: var(--tng-accent);
  color: #17120a;
  font-family: var(--tng-font-mono);
  font-size: var(--tng-text-small);
  font-weight: 700;
  padding: 11px 16px;
  border-radius: var(--tng-radius-control);
  text-decoration: none;
  transition: top var(--tng-transition-fast);
}
.tng2-skip-link:focus { top: var(--tng-space-4); }

.tng2-visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* Header */
.tng2-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(11,13,18,.78);
  backdrop-filter: blur(18px) saturate(145%);
  -webkit-backdrop-filter: blur(18px) saturate(145%);
  border-bottom: 1px solid rgba(255,255,255,.07);
}
.tng2-header-inner {
  max-width: var(--tng-width-site-max);
  min-height: 72px;
  margin: 0 auto;
  padding: 10px 22px;
  display: flex;
  align-items: center;
  gap: 28px;
}
.tng2-logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex: 0 0 auto;
}
.tng2-brand-mark {
  width: 34px;
  height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  color: #17120a;
  background: linear-gradient(145deg, #ffd477, var(--tng-accent));
  box-shadow: 0 8px 24px rgba(242,184,75,.18);
}
.tng2-brand-word {
  color: var(--tng-text-dark);
  font-family: var(--tng-font-display);
  font-weight: 700;
  font-size: 1.02rem;
  letter-spacing: -.025em;
}
.tng2-brand-word span { color: var(--tng-accent); }

.tng2-nav-desktop { flex: 1; min-width: 0; }
.tng2-nav-desktop ul {
  list-style: none;
  margin: 0; padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  flex-wrap: wrap;
}
.tng2-nav-desktop a {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  padding: 0 12px;
  border-radius: 10px;
  font-size: .88rem;
  font-weight: 580;
  text-decoration: none;
  color: var(--tng-text-muted-dark);
  white-space: nowrap;
  transition: color var(--tng-transition-fast), background var(--tng-transition-fast);
}
.tng2-nav-desktop a:hover,
.tng2-nav-desktop a[aria-current="page"] {
  color: var(--tng-text-dark);
  background: rgba(255,255,255,.055);
}

.tng2-header-actions { display: flex; gap: 8px; flex-shrink: 0; }
.tng2-icon-btn {
  appearance: none;
  background: rgba(255,255,255,.035);
  border: 1px solid rgba(255,255,255,.09);
  color: var(--tng-text-dark);
  border-radius: 12px;
  width: 42px; height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform var(--tng-transition-fast), border-color var(--tng-transition-fast), background var(--tng-transition-fast), color var(--tng-transition-fast);
}
.tng2-icon-btn:hover {
  transform: translateY(-1px);
  border-color: rgba(242,184,75,.45);
  background: var(--tng-accent-soft);
  color: var(--tng-accent);
}
.tng2-nav-toggle { display: none; }

@media (max-width: 899px) {
  .tng2-header-inner { min-height: 68px; padding: 10px 18px; }
  .tng2-nav-desktop { display: none; }
  .tng2-nav-toggle { display: inline-flex; }
  .tng2-header-actions { margin-left: auto; }
}
@media (max-width: 420px) {
  .tng2-brand-word { font-size: .95rem; }
  .tng2-brand-mark { width: 32px; height: 32px; }
  .tng2-header-inner { padding-inline: 14px; }
}

/* Mobile drawer */
.tng2-mobile-nav {
  position: fixed;
  inset: 0 0 0 auto;
  width: min(390px, 91vw);
  height: 100dvh;
  z-index: 60;
  transform: translateX(100%);
  transition: transform var(--tng-transition-base);
  display: flex;
  flex-direction: column;
  padding: 20px;
  overflow-y: auto;
  background:
    radial-gradient(circle at 80% 0%, rgba(141,124,246,.13), transparent 16rem),
    linear-gradient(180deg, #151923 0%, #0f1219 100%);
  border-left: 1px solid rgba(255,255,255,.08);
  box-shadow: -20px 0 60px rgba(0,0,0,.36);
}
.tng2-mobile-nav.is-open { transform: translateX(0); }
.tng2-mobile-nav-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 24px;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.tng2-logo-mobile .tng2-brand-word { font-size: .94rem; }
.tng2-mobile-nav-label {
  margin: 28px 4px 10px;
  font-family: var(--tng-font-mono);
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .14em;
  color: var(--tng-text-subtle-dark);
}
.tng2-mobile-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}
.tng2-mobile-nav li { border-bottom: 1px solid rgba(255,255,255,.06); }
.tng2-mobile-nav a {
  min-height: 58px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 4px;
  text-decoration: none;
  color: #eef1f6;
  font-family: var(--tng-font-display);
  font-size: 1.08rem;
  font-weight: 560;
  letter-spacing: -.02em;
  transition: color var(--tng-transition-fast), padding var(--tng-transition-fast);
}
.tng2-mobile-nav a span { color: var(--tng-text-subtle-dark); font-size: .9rem; }
.tng2-mobile-nav a:hover,
.tng2-mobile-nav a:focus-visible,
.tng2-mobile-nav a[aria-current="page"] {
  color: var(--tng-accent);
  padding-left: 8px;
}
.tng2-mobile-nav-foot {
  margin-top: auto;
  padding-top: 28px;
  color: var(--tng-text-subtle-dark);
  font-size: .8rem;
  line-height: 1.55;
}

.tng2-overlay-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(2,4,8,.68);
  backdrop-filter: blur(3px);
  z-index: 50;
}

/* Search */
.tng2-search-overlay {
  position: fixed;
  inset: 0;
  z-index: 70;
  padding: 12vh 18px 30px;
  display: flex;
  align-items: flex-start;
  justify-content: center;
}
.tng2-search-overlay-inner {
  position: relative;
  width: min(720px, 100%);
  padding: 26px;
  background: rgba(18,22,32,.97);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 24px;
  box-shadow: var(--tng-shadow-md);
}
.tng2-search-heading {
  font-family: var(--tng-font-display);
  font-size: 1.2rem;
  font-weight: 650;
  margin: 0 48px 18px 0;
}
.tng2-search-close { position: absolute; right: 20px; top: 20px; }
.tng2-search-form { display: flex; gap: 10px; min-width: 0; }
.tng2-search-form input {
  flex: 1; min-width: 0;
  background: #0c0f15;
  border: 1px solid var(--tng-border-dark-strong);
  color: var(--tng-text-dark);
  border-radius: 12px;
  padding: 14px 15px;
  font: inherit;
}
.tng2-search-form input::placeholder { color: #707988; }
.tng2-search-form button {
  background: var(--tng-accent);
  color: #17120a;
  border: 0;
  border-radius: 12px;
  padding: 0 20px;
  font-weight: 700;
  cursor: pointer;
}
@media (max-width: 520px) {
  .tng2-search-overlay-inner { padding: 22px 16px 16px; }
  .tng2-search-form { flex-direction: column; }
  .tng2-search-form button { min-height: 48px; }
}

/* Main shell */
.tng2-shell {
  width: min(100%, calc(var(--tng-width-site-max) + 44px));
  margin: 0 auto;
  padding: 42px 22px 72px;
}
@media (min-width: 768px) {
  .tng2-shell { padding: 64px 28px 96px; }
}
@media (max-width: 480px) {
  .tng2-shell { padding: 34px 18px 68px; }
}

/* Article layout */
.tng2-article-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--tng-space-8);
  max-width: var(--tng-width-reading);
  margin: 0 auto;
}
@media (min-width: 1024px) {
  .tng2-article-layout {
    max-width: none;
    grid-template-columns: minmax(0,var(--tng-width-reading)) 280px;
    justify-content: center;
  }
}
@media (min-width: 1280px) {
  .tng2-article-layout { grid-template-columns: 220px minmax(0,var(--tng-width-reading)) 280px; }
}
.tng2-toc-rail { order: -1; }
@media (min-width: 1280px) {
  .tng2-toc-rail { order: 0; position: sticky; top: 94px; align-self: start; }
}
.tng2-related-rail { position: static; }
@media (min-width: 1024px) {
  .tng2-related-rail { position: sticky; top: 94px; align-self: start; }
}
.tng2-reading-column { min-width: 0; }
.tng2-reading-column img,
.tng2-reading-column figure { max-width: 100%; }
.tng2-reading-column pre { max-width: 100%; overflow-x: auto; }
.tng2-reading-column table { display: block; max-width: 100%; overflow-x: auto; }

/* Footer */
.tng2-footer {
  border-top: 1px solid rgba(255,255,255,.07);
  background: rgba(7,9,13,.6);
}
.tng2-footer-inner {
  max-width: var(--tng-width-site-max);
  margin: 0 auto;
  padding: 54px 22px 42px;
  display: grid;
  grid-template-columns: minmax(0,1fr) minmax(320px,.9fr);
  gap: 64px;
}
.tng2-footer-brand p {
  max-width: 470px;
  margin: 18px 0 0;
  color: var(--tng-text-muted-dark);
  font-size: .9rem;
  line-height: 1.65;
}
.tng2-footer-label {
  margin-bottom: 14px;
  color: var(--tng-text-subtle-dark);
  font-family: var(--tng-font-mono);
  font-size: .68rem;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.tng2-footer-links { display: flex; flex-wrap: wrap; gap: 10px 22px; }
.tng2-footer-links a { color: var(--tng-text-muted-dark); text-decoration: none; font-size: .88rem; }
.tng2-footer-links a:hover { color: var(--tng-text-dark); }
.tng2-footer-bottom {
  max-width: var(--tng-width-site-max);
  margin: 0 auto;
  padding: 18px 22px 26px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  border-top: 1px solid rgba(255,255,255,.055);
  color: var(--tng-text-subtle-dark);
  font-family: var(--tng-font-mono);
  font-size: .69rem;
}
@media (max-width: 760px) {
  .tng2-footer-inner { grid-template-columns: 1fr; gap: 34px; padding-top: 42px; }
  .tng2-footer-bottom { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .tng2-mobile-nav { transition: none; }
}