:root{
  --bg:#0b0f14;
  --card:#121a23;
  --text:#e7eef7;
  --muted:#b8c4d4;
  --line:rgba(231,238,247,.12);
  --accent:#7dd3fc;
  --accent2:#a7f3d0;
  --max:1280px;
  --radius:18px;
}

*{box-sizing:border-box}

html,body{
  margin:0;
  padding:0;
}

body{
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(125,211,252,.20), transparent 60%),
    radial-gradient(1200px 600px at 90% 0%, rgba(167,243,208,.14), transparent 55%),
    var(--bg);
  color:var(--text);
  line-height:1.6;
}

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

a:hover{
  text-decoration:underline;
}

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

.container{
  max-width:var(--max);
  margin:0 auto;
  padding:0 18px;
}

.skip-link{
  position:absolute;
  left:-999px;
  top:0;
  background:#fff;
  color:#000;
  padding:10px 12px;
  border-radius:10px;
}

.skip-link:focus{
  left:12px;
  top:12px;
  z-index:9999;
}

header{
  position:sticky;
  top:0;
  z-index:50;
  backdrop-filter:blur(10px);
  background:rgba(11,15,20,.70);
  border-bottom:1px solid var(--line);
}

.navbar{
  display:flex;
  align-items:center;
  justify-content:flex-start;
  padding:14px 0;
  gap:36px;
}

.brand{
  display:flex;
  align-items:center;
  gap:10px;
  font-weight:700;
  letter-spacing:.2px;
  white-space:nowrap;
}

.brand-badge{
  width:34px;
  height:34px;
  border-radius:12px;
  background:linear-gradient(135deg, rgba(125,211,252,.85), rgba(167,243,208,.75));
  box-shadow:0 10px 26px rgba(0,0,0,.30);
}

.logo{
  width:60px;
  height:60px;
  object-fit:contain;
  flex:0 0 auto;
}

.nav-toggle{
  display:none;
  border:1px solid var(--line);
  background:rgba(255,255,255,.06);
  color:var(--text);
  padding:10px 12px;
  border-radius:12px;
  cursor:pointer;
}

nav ul{
  list-style:none;
  display:flex;
  gap:8px;
  margin:0;
  padding:0;
  flex-wrap:nowrap;
  justify-content:flex-start;
}

nav a{
  display:inline-block;
  padding:10px 10px;
  border-radius:12px;
  color:var(--text);
  white-space:nowrap;
}

nav a[aria-current="page"]{
  background:rgba(125,211,252,.14);
  border:1px solid rgba(125,211,252,.25);
}

.hero{
  padding:46px 0 18px;
}

.hero-grid{
  display:grid;
  grid-template-columns:1.15fr .85fr;
  gap:18px;
  align-items:stretch;
}

.card{
  background:rgba(18,26,35,.88);
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:18px;
  box-shadow:0 18px 40px rgba(0,0,0,.35);
}

.hero h1{
  margin:0 0 10px;
  font-size:clamp(1.65rem, 3vw, 2.4rem);
  line-height:1.2;
}

.hero p{
  color:var(--muted);
  margin:0 0 14px;
}

.pills{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  margin-top:12px;
}

.pill{
  font-size:.92rem;
  padding:8px 12px;
  border-radius:999px;
  border:1px solid var(--line);
  background:rgba(255,255,255,.05);
  color:var(--text);
}

.hero-img{
  border-radius:var(--radius);
  border:1px solid var(--line);
  overflow:hidden;
  position:relative;
}

.hero-img img{
  height:100%;
  width:100%;
  object-fit:cover;
  opacity:.92;
}

.hero-img .img-caption{
  position:absolute;
  left:12px;
  right:12px;
  bottom:12px;
  background:rgba(11,15,20,.72);
  border:1px solid var(--line);
  border-radius:14px;
  padding:10px 12px;
  color:var(--muted);
  font-size:.95rem;
}

.grid{
  display:grid;
  grid-template-columns:repeat(3, 1fr);
  gap:14px;
  margin:18px 0 10px;
}

.feature h3{
  margin:0 0 8px;
  font-size:1.06rem;
}

.feature p{
  margin:0;
  color:var(--muted);
}

.feature a{
  display:inline-block;
  margin-top:10px;
}

.section{
  padding:10px 0 30px;
}

.section h1,
.section h2{
  line-height:1.25;
}

.section h2{
  font-size:1.35rem;
  margin:18px 0 10px;
}

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

.callout{
  border-left:4px solid rgba(125,211,252,.55);
  background:rgba(125,211,252,.08);
  padding:14px 14px;
  border-radius:14px;
  border:1px solid rgba(125,211,252,.18);
  color:var(--text);
}

.callout p{
  margin:0;
  color:var(--text);
}

.small{
  font-size:.95rem;
}

.kbd{
  font-family:ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  background:rgba(255,255,255,.07);
  border:1px solid var(--line);
  padding:2px 6px;
  border-radius:8px;
}

.two-col{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:14px;
}

.list{
  margin:0;
  padding-left:18px;
  color:var(--muted);
}

.list li{
  margin:6px 0;
}

/* References list (APA-like hanging indent) */
.references{
  list-style:none;
  margin:0;
  padding:0;
  color:var(--muted);
}

.references li{
  margin:12px 0;
  padding-left:1.5em;
  text-indent:-1.5em;
  line-height:1.7;
}

.references a{
  margin-left:6px;
  white-space:nowrap;
}

.footer{
  border-top:1px solid var(--line);
  padding:22px 0 26px;
  color:var(--muted);
  font-size:.95rem;
}

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

.footer a:hover{
  color:var(--text);
}

@media (max-width: 920px){
  .hero-grid{
    grid-template-columns:1fr;
  }

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

  .two-col{
    grid-template-columns:1fr;
  }

  nav ul{
    display:none;
  }

  nav ul.open{
    display:flex;
    flex-direction:column;
    align-items:flex-start;
    width:100%;
  }

  .navbar{
    flex-wrap:wrap;
    gap:16px;
  }

  .nav-toggle{
    display:inline-block;
  }

  .logo{
    width:48px;
    height:48px;
  }
}