:root{
  --bg: #0b0e14;
  --panel: #11151f;
  --panel-2: #0e1420;
  --text: #e6eaf2;
  --muted: #a6b0cf;
  --accent: #6ae3ff;
  --accent-2:#8aff80;
  --border: #20283a;
  --focus: #ffd166;
  --link: #7cc7ff;
  --error: #ff6b6b;

  --radius: 16px;
  --shadow: 0 8px 24px rgba(0,0,0,.35);
  --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
}

@media (prefers-color-scheme: light){
  :root{
    --bg: #f6f7fb;
    --panel:#ffffff;
    --panel-2:#f0f3fa;
    --text:#0f172a;
    --muted:#475569;
    --accent:#0077ff;
    --accent-2:#008a4b;
    --border:#e5e7eb;
    --focus:#b45309;
    --link:#0057c2;
  }
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:var(--font);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

a{ color: var(--link); text-decoration: underline; text-underline-offset: 2px; }
a:focus{ outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 6px; }
a:hover{ text-decoration-thickness: 2px; }

/* Skip link */
.skip-link{
  position:absolute; left:-9999px; top:auto; width:1px; height:1px; overflow:hidden;
}
.skip-link:focus{
  position:fixed; left:1rem; top:1rem; width:auto; height:auto; padding:.5rem .75rem;
  background: var(--panel); color: var(--text); border:2px solid var(--focus); z-index:9999;
  border-radius:10px;
}

/* Layout */
.layout{
  display:grid;
  grid-template-columns: 300px 1fr;
  min-height:100vh;
}

.sidebar{
  position:sticky; top:0; align-self:start;
  background: linear-gradient(180deg, var(--panel) 0%, var(--panel-2) 100%);
  border-right:1px solid var(--border);
  min-height:100vh; padding:1rem;
}

.brand{
  display:flex; align-items:center; gap:.75rem; margin-bottom:1rem;
}
.brand-logo{
  width:36px; height:36px; border-radius:12px;
  background: radial-gradient(60% 60% at 30% 30%, var(--accent) 0%, transparent 60%),
              radial-gradient(70% 70% at 70% 70%, var(--accent-2) 0%, transparent 50%),
              linear-gradient(135deg, rgba(255,255,255,.08), rgba(0,0,0,.08));
  border:1px solid var(--border);
  box-shadow: var(--shadow);
}
.brand h1{
  font-size:1.125rem; margin:0;
}

.controls{
  display:flex; gap:.5rem; align-items:center; margin:.5rem 0 1rem 0;
}
.button{
  border:1px solid var(--border); background:var(--panel); color:var(--text);
  padding:.5rem .75rem; border-radius:999px;
  cursor:pointer;
}
.button:focus{ outline:3px solid var(--focus); outline-offset:2px; }
.button[aria-pressed="true"]{ background:var(--panel-2); }

.search{
  position:relative; margin:.5rem 0 1rem 0;
}
.search input{
  width:100%; padding:.75rem 2.5rem .75rem .875rem; border-radius:12px;
  border:1px solid var(--border); background:var(--bg); color:var(--text);
}
.search input:focus{ outline:3px solid var(--focus); }
.search .icon{
  position:absolute; right:.75rem; top:50%; transform:translateY(-50%); pointer-events:none;
}

.nav{
  margin-top:.75rem;
}
.nav h2{
  font-size:.875rem; text-transform:uppercase; letter-spacing:.08em; color:var(--muted);
  margin:1rem 0 .25rem 0;
}
.nav ul{ list-style:none; padding:0; margin:0; }
.nav a{
  display:flex; align-items:center; gap:.5rem;
  padding:.5rem .75rem; border-radius:10px; text-decoration:none;
  color:var(--text); border:1px solid transparent;
}
.nav a[aria-current="page"], .nav a:hover{
  background:var(--panel-2); border-color:var(--border);
}
.nav a:focus{ outline:3px solid var(--focus); }

.main{
  padding:2rem clamp(1rem, 4vw, 3rem);
}

.hero{
  background: linear-gradient(180deg, rgba(106,227,255,0.12), transparent 55%);
  border:1px solid var(--border);
  border-radius: var(--radius);
  padding:1.25rem 1.25rem 1rem;
  box-shadow: var(--shadow);
}
.hero h1{ margin-top:0; font-size: clamp(1.5rem, 2vw + 1rem, 2.25rem); }
.hero p{ color: var(--muted); margin-bottom:.75rem; }

.card-grid{
  display:grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap:1rem; margin-top:1rem;
}
.card{
  background:var(--panel); border:1px solid var(--border); border-radius: var(--radius);
  padding:1rem; box-shadow: var(--shadow);
}
.card h3{ margin-top:0; font-size:1.125rem; }
.card p{ color:var(--muted); }
.card a.cta{
  display:inline-block; margin-top:.5rem; text-decoration:none; font-weight:600;
  padding:.5rem .75rem; border-radius:10px; background: var(--accent);
  color:#04141d;
}
.card a.cta:focus{ outline:3px solid var(--focus); }

.section h2{ font-size:1.25rem; margin-top:2rem; }

footer{
  margin-top:2rem; padding:1.25rem; color:var(--muted);
  border-top:1px solid var(--border);
}

/* Mobile: collapsible sidebar */
.topbar{
  display:none;
}

@media (max-width: 900px){
  .layout{
    grid-template-columns: 1fr;
  }
  .sidebar{
    position:fixed; inset:0 0 auto 0; height:auto; max-height:70vh; overflow:auto;
    transform: translateY(-110%); transition: transform .25s ease;
    border-right:none; border-bottom:1px solid var(--border); border-top:none;
    z-index:900;
  }
  .sidebar.open{ transform: translateY(0); }
  .topbar{
    display:flex; align-items:center; justify-content:space-between;
    padding: .75rem 1rem; border-bottom:1px solid var(--border);
    background: var(--panel);
    position:sticky; top:0; z-index:950;
  }
  .main{ padding-top:1rem; }
}