/* Variables */
:root{
  --bg: #ffffff;
  --card: #f7f7fb;
  --text: #111827;
  --muted: #6b7280;
  --accent: #2563eb;
  --radius: 10px;
  --glass: rgba(255,255,255,0.6);
}

[data-theme="dark"]{
  --bg: #0b1220;
  --card: #0f1724;
  --text: #e6eef8;
  --muted: #9aa6b2;
  --accent: #60a5fa;
  --glass: rgba(255,255,255,0.03);
}

/* Base */
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:Inter, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  background:linear-gradient(180deg,var(--bg), color-mix(in srgb, var(--bg) 95%, #000 5%));
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  transition:background .25s ease, color .25s ease;
}

/* Topbar */
.topbar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:14px 20px;
  backdrop-filter: blur(6px);
  background:var(--glass);
  border-bottom:1px solid rgba(0,0,0,0.04);
}
.brand strong{font-size:1.05rem}
.brand small{display:block;color:var(--muted);font-size:.75rem}

/* Controls */
.controls{display:flex;gap:10px;align-items:center}
.lang-switch select{
  padding:6px 8px;border-radius:8px;border:1px solid rgba(0,0,0,0.06);
  background:transparent;color:var(--text);
}
.theme-btn{
  display:inline-flex;align-items:center;gap:8px;padding:6px 10px;border-radius:8px;border:1px solid rgba(0,0,0,0.06);
  background:transparent;color:var(--text);cursor:pointer;
}

/* Layout */
.container{max-width:980px;margin:28px auto;padding:0 18px}
.hero{margin-bottom:18px}
.hero h1{margin:0 0 6px;font-size:1.6rem}
.hero p{margin:0;color:var(--muted)}

/* Cards */
.demo-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}
.card{
  background:linear-gradient(180deg,var(--card), color-mix(in srgb, var(--card) 90%, #000 2%));
  padding:16px;border-radius:var(--radius);box-shadow:0 6px 18px rgba(2,6,23,0.06);
}
.card h2{margin:0 0 8px}
.card p{margin:0 0 12px;color:var(--muted)}

/* Form */
label{display:block;font-size:.85rem;margin:8px 0 6px}
input,select,textarea{
  width:100%;padding:8px 10px;border-radius:8px;border:1px solid rgba(0,0,0,0.06);
  background:transparent;color:var(--text);
}
textarea{resize:vertical}

/* Buttons */
.actions{display:flex;gap:8px;margin-top:12px}
.btn{padding:8px 12px;border-radius:8px;border:1px solid rgba(0,0,0,0.06);background:transparent;color:var(--text);cursor:pointer}
.btn.primary{background:var(--accent);color:white;border:none;box-shadow:0 6px 12px rgba(37,99,235,0.12)}

/* Series list */
.series-list{list-style:none;padding:0;margin:12px 0 0;display:flex;flex-direction:column;gap:8px}
.series-item{display:flex;justify-content:space-between;align-items:flex-start;padding:10px;border-radius:8px;background:rgba(0,0,0,0.03)}
[data-theme="dark"] .series-item{background:rgba(255,255,255,0.02)}
.series-item .meta{font-size:.9rem;color:var(--muted)}
.series-item .title{font-weight:600}
.series-item button.small{padding:6px 8px;font-size:.85rem;border-radius:6px}

/* Footer */
.footer{margin-top:18px;color:var(--muted);text-align:center}

/* Accessibility helpers */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

/* Responsive */
@media (max-width:520px){
  .topbar{padding:12px}
  .brand strong{font-size:1rem}
}