:root{
  --bg:#07101f; --panel:#0d192b; --panel2:#101f35; --text:#f5f7fb; --muted:#9eacc0;
  --line:#243750; --accent:#62d9ff; --gold:#f5c542;
}
*{box-sizing:border-box}
html{min-height:100%;background:#050b14}
body{margin:0;min-height:100vh;font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;color:var(--text);padding:24px;position:relative;isolation:isolate;background-color:var(--bg);background-image:linear-gradient(180deg,rgba(4,11,20,.28),rgba(4,11,20,.78)),url("assets/cosmic-space-background.png");background-size:cover;background-position:center top;background-attachment:fixed}
body::before{content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;background:linear-gradient(90deg,rgba(5,12,22,.58),rgba(5,12,22,.12) 45%,rgba(5,12,22,.46));}
.topbar{max-width:1500px;margin:0 auto 24px;display:flex;gap:20px;justify-content:space-between;align-items:end}
.eyebrow{font-size:11px;letter-spacing:.18em;color:var(--accent);font-weight:800}
h1{font-size:clamp(28px,4vw,48px);margin:6px 0}
h1 span{color:var(--accent)}
p{color:var(--muted);line-height:1.55}
.actions{display:flex;gap:10px;flex-wrap:wrap}
input,button,.share{border:1px solid var(--line);background:#0c1829;color:var(--text);border-radius:12px;padding:11px 14px;font:inherit}
input{min-width:260px;outline:none}
button{cursor:pointer}
button:hover,.filter.active{border-color:var(--accent);color:var(--accent)}
.legend{max-width:1500px;margin:0 auto 18px;display:flex;gap:8px;flex-wrap:wrap}
.filter{font-size:12px}
.periodic-table{max-width:1500px;margin:auto;display:grid;grid-template-columns:repeat(18,minmax(42px,1fr));grid-auto-rows:minmax(74px,auto);gap:7px}
.element-card{position:relative;display:flex;flex-direction:column;justify-content:space-between;padding:8px;border:1px solid var(--line);border-radius:10px;background:linear-gradient(145deg,rgba(16,34,58,.96),rgba(11,23,39,.94));backdrop-filter:blur(5px);min-height:74px;text-decoration:none;color:var(--text);transition:.18s transform,.18s border-color,.18s box-shadow}
.element-card:hover{transform:translateY(-4px) scale(1.02);border-color:var(--accent);box-shadow:0 10px 30px #0008;z-index:2}
.element-card.hidden{display:none}
.atomic{font-size:10px;color:var(--muted)}
.sym{font-size:24px;font-weight:850;line-height:1}
.ename{font-size:10px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.cat-dot{position:absolute;right:7px;top:8px;width:6px;height:6px;border-radius:50%;background:var(--accent)}
.notes{max-width:1500px;margin:18px auto;padding:16px;border:1px solid var(--line);background:#091525e8;backdrop-filter:blur(10px);border-radius:14px;display:grid;gap:6px}
code{color:#bdefff}

.viewer-page{padding:0}
.viewer-nav{height:64px;padding:0 24px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);background:#07101fe8;backdrop-filter:blur(10px);position:sticky;top:0;z-index:5}
.back{color:var(--accent);text-decoration:none;font-weight:700}.brand{font-size:12px;letter-spacing:.16em;color:var(--muted)}
.viewer-layout{max-width:1400px;margin:28px auto;padding:0 20px;display:grid;grid-template-columns:minmax(0,1.6fr) minmax(300px,.7fr);gap:22px}
.viewer-card,.info-card{border:1px solid var(--line);background:linear-gradient(145deg,#0c192b,#081321);border-radius:20px;box-shadow:0 20px 60px #0005}
.viewer-card{overflow:hidden}
.viewer-heading{padding:24px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line)}
.viewer-heading h1{margin:2px 0 0;font-size:40px}.symbol-large{font-size:18px;color:var(--muted)}
.atomic-number{font-size:64px;font-weight:900;color:#1d344e}
.scene{height:min(68vh,700px);min-height:420px;background:radial-gradient(circle at center,#122a45,#07111f 65%);touch-action:none}
.controls-hint{text-align:center;color:var(--muted);font-size:12px;padding:12px;border-top:1px solid var(--line)}
.info-card{padding:24px;height:max-content;position:sticky;top:88px}
.info-card h2{margin-top:0}.facts{display:grid;grid-template-columns:1fr 1fr;gap:10px}.facts div{padding:12px;background:#0a1728;border:1px solid var(--line);border-radius:12px}.facts span{display:block;color:var(--muted);font-size:11px;margin-bottom:5px}.facts b{font-size:14px}
.configuration{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;color:#d9f8ff;background:#091728;border:1px solid var(--line);padding:12px;border-radius:12px}
.explain{margin-top:18px;padding:14px;border-left:3px solid var(--accent);background:#091728}.explain p{font-size:12px;margin-bottom:0}
.share{display:block;text-align:center;text-decoration:none;margin-top:18px}
@media(max-width:900px){.topbar{display:block}.actions{margin-top:15px}.viewer-layout{grid-template-columns:1fr}.info-card{position:static}.scene{height:55vh;min-height:350px}.periodic-table{overflow-x:auto;grid-template-columns:repeat(18,60px);padding-bottom:8px}}
@media(max-width:600px){body{padding:12px}.topbar h1{font-size:30px}.periodic-table{grid-auto-rows:68px}.element-card{min-height:68px}.sym{font-size:20px}.ename{font-size:9px}.viewer-nav{padding:0 14px}.brand{display:none}.viewer-layout{padding:0 10px}.viewer-heading h1{font-size:30px}.atomic-number{font-size:45px}}