:root{
  --bg:#0b1020;
  --panel:#0f1724;
  --neon1:#7c3aed;
  --neon2:#06b6d4;
  --muted: #9ca3af;
  --accent: linear-gradient(90deg,var(--neon1),var(--neon2));
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0; font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial;
  background: radial-gradient(1200px 600px at 10% 10%, rgba(12,18,35,0.6), transparent),
              radial-gradient(1000px 500px at 90% 90%, rgba(8,20,30,0.6), transparent),
              var(--bg);
  color:#e6eef8;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

/* header */
.site-header{
  display:flex; align-items:center; justify-content:space-between;
  padding:18px 28px; gap:16px;
  background: linear-gradient(90deg, rgba(0,0,0,0.25), rgba(255,255,255,0.02));
  border-bottom:1px solid rgba(255,255,255,0.03);
  position:sticky; top:0; z-index:40;
}
.logo{font-weight:800; letter-spacing:1px}
.logo span{color:var(--neon2); margin-left:6px; font-weight:900}

/* nav */
.site-header nav a{margin-left:14px; color:var(--muted); text-decoration:none}
.site-header nav a:hover{color:var(--neon1)}

/* hero */
.hero{display:flex; align-items:center; justify-content:space-between; padding:48px 28px; gap:20px}
.hero-inner{max-width:720px}
.hero h1{font-size:48px; margin:0; letter-spacing: -1px; text-shadow:0 6px 30px rgba(124,58,237,0.12)}
.hero .tag{color:var(--muted); margin-top:8px}
.cta-row{margin-top:18px; display:flex; gap:12px}
.btn{padding:10px 14px; border-radius:10px; cursor:pointer; border:1px solid rgba(255,255,255,0.04); background:transparent; color:inherit}
.btn.primary{background:linear-gradient(90deg,var(--neon1),var(--neon2)); box-shadow:0 6px 30px rgba(6,182,212,0.08); color:#021425; font-weight:700}
.btn.outline{border:1px solid rgba(255,255,255,0.06)}

/* main container */
.container{max-width:1200px; margin:20px auto; padding:0 20px}

/* panels */
.panel{background:linear-gradient(180deg, rgba(255,255,255,0.01), rgba(255,255,255,0.005)); padding:22px; margin-bottom:20px; border-radius:12px; border:1px solid rgba(255,255,255,0.02)}
.panel h2{margin:0 0 8px 0}

/* prebuilt grid */
.grid{display:grid; grid-template-columns:repeat(auto-fill,minmax(240px,1fr)); gap:12px}
.card{background:rgba(255,255,255,0.02); padding:12px; border-radius:8px; border:1px solid rgba(255,255,255,0.02)}

/* builder layout */
.builder-grid{display:grid; grid-template-columns:1fr 360px; gap:18px; align-items:start}
.catalog{background:transparent}
.catalog-controls{display:flex; gap:8px; margin-bottom:8px}
.catalog-controls input, .catalog-controls select{flex:1; padding:8px; border-radius:8px; border:1px solid rgba(255,255,255,0.04); background:transparent; color:inherit}
.parts-list{display:grid; grid-template-columns:repeat(auto-fill,minmax(280px,1fr)); gap:10px}
.part{display:flex; gap:10px; align-items:center; padding:10px; border-radius:10px; border:1px solid rgba(255,255,255,0.02); background:linear-gradient(180deg, rgba(255,255,255,0.01), transparent)}
.part img{width:84px; height:64px; object-fit:cover; border-radius:6px; background:#0b1220; border:1px solid rgba(255,255,255,0.02)}

/* summary */
.build-summary{position:sticky; top:90px; padding:16px; border-radius:10px; background:rgba(255,255,255,0.02)}
.selected-list{list-style:none; padding:0; margin:8px 0 0 0; max-height:260px; overflow:auto}
.selected-list li{display:flex; justify-content:space-between; padding:6px 8px; border-radius:8px; margin-bottom:6px; background:rgba(255,255,255,0.01); font-size:14px}
.price-block{margin-top:12px; display:flex; gap:8px; align-items:center; justify-content:space-between; flex-direction:column}
.messages{margin-top:12px}
.messages .msg{padding:8px; border-radius:8px; margin-bottom:8px}
.msg.ok{background:rgba(6,182,212,0.08); border-left:4px solid var(--neon2)}
.msg.warning{background:rgba(255,205,0,0.06); border-left:4px solid #f59e0b}
.msg.error{background:rgba(240,68,68,0.06); border-left:4px solid #ef4444}

/* responsive */
@media (max-width:900px){
  .builder-grid{grid-template-columns:1fr; }
  .hero{flex-direction:column; align-items:flex-start}
  .hero h1{font-size:32px}
}