*{box-sizing:border-box}
:root{
  --bg:#05070d;
  --bg2:#0d1527;
  --panel:#0a1020;
  --panel2:#101833;
  --text:#f7fbff;
  --muted:#bfd0f3;
  --border:#23304f;
  --shadow:0 14px 40px rgba(0,0,0,.38);
  --radius:18px;
}
a {
  display: inline-block;
  padding: 10px 20px;
  background: rgb(0, 0, 0, .31);
  color: rgb(255, 255, 255);
  text-decoration: none;
  border-radius: 8px;
  margin: 5px;
}
body{
  margin:0;
  font-family:Inter,Arial,sans-serif;
  color:var(--text);
  background:
    radial-gradient(circle at top left, rgba(0,194,168,.12), transparent 22%),
    radial-gradient(circle at top right, rgba(155,93,229,.14), transparent 26%),
    linear-gradient(145deg,#02040a,#091126 38%,#050a17 100%);
}
.app{max-width:1700px;margin:0 auto;padding:18px}
.hero,.panel,.popup-card{
  background:rgba(10,16,32,.94);
  border:1px solid var(--border);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
}
.hero{
  padding:20px;
  display:grid;
  grid-template-columns:1.5fr 1fr;
  gap:18px;
  align-items:start;
  margin-bottom:18px;
}
.hero h1{margin:0 0 10px;font-size:clamp(28px,4vw,48px)}
.hero p{margin:0;color:var(--muted);line-height:1.7}
.tabs{display:flex;flex-wrap:wrap;gap:10px;justify-content:flex-end}
button,input,select{
  border:1px solid #2d3a5c;
  background:#09111f;
  color:#fff;
  border-radius:14px;
  padding:12px 14px;
  font-size:14px;
}
button{cursor:pointer;font-weight:700}
button:hover{background:#12203b}
.tab-btn.active,.quick-btn.active{outline:2px solid #7dd3fc}
.toolbar{
  padding:14px;
  display:grid;
  grid-template-columns:2fr 1.2fr 1.2fr 1fr auto;
  gap:10px;
  margin-bottom:18px;
}
.main-grid{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:18px}
.view{display:none}
.active-view{display:block}
.legend-grid,.quick-grid,.mini-grid,.revision-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(150px,1fr));
  gap:10px;
}
.legend-item,.mini-card,.revision-card{
  background:#0d1527;
  border:1px solid #243250;
  border-radius:14px;
  padding:10px 12px;
}
.legend-item{display:flex;align-items:center;gap:10px;color:var(--muted)}
.swatch{width:14px;height:14px;border-radius:50%}
.table-panel{padding:14px;overflow:auto}
.periodic-table{
  display:grid;
  grid-template-columns:repeat(18,minmax(58px,1fr));
  gap:8px;
  min-width:1180px;
}
.blank,.element{min-height:82px;border-radius:15px}
.blank{opacity:0}
.element{
  position:relative;
  padding:8px;
  border:1px solid rgba(255,255,255,.12);
  color:#fff;
  display:flex;
  flex-direction:column;
  justify-content:space-between;
  cursor:pointer;
  overflow:hidden;
  transition:.2s ease;
}
.element::after{
  content:"";
  position:absolute;inset:0;
  background:linear-gradient(to top right, rgba(255,255,255,.05), transparent 55%);
  pointer-events:none;
}
.element:hover{transform:translateY(-4px) scale(1.02)}
.element.active{outline:3px solid rgba(255,255,255,.42)}
.element.dim{opacity:.14;filter:grayscale(.45)}
.num{font-size:11px;font-weight:700}
.symbol{font-size:22px;font-weight:900;line-height:1}
.name{font-size:10px;font-weight:700}
.meta{font-size:10px;opacity:.92}
.sidebar{display:grid;gap:18px;align-content:start}
.info-block{line-height:1.75;color:var(--muted)}
.quick-grid{grid-template-columns:1fr 1fr}
#atomCanvas,#trendCanvas{
  width:100%;
  background:radial-gradient(circle at center, rgba(77,171,247,.08), rgba(0,0,0,.04));
  border-radius:18px;
  border:1px solid rgba(255,255,255,.1);
}
.flash-toolbar{display:flex;gap:10px;flex-wrap:wrap}
.flash-wrap{min-height:420px;display:grid;place-items:center}
.flashcard{
  width:min(560px,94vw);
  height:320px;
  position:relative;
  transform-style:preserve-3d;
  transition:transform .7s ease;
  cursor:pointer;
}
.flashcard.flipped{transform:rotateY(180deg)}
.flash-side{
  position:absolute;inset:0;
  background:linear-gradient(135deg,#101833,#0a1020);
  border:1px solid #2b3b61;
  border-radius:24px;
  display:grid;
  place-items:center;
  padding:24px;
  text-align:center;
  backface-visibility:hidden;
  box-shadow:var(--shadow);
}
.flash-front .flash-symbol{font-size:72px;font-weight:900}
.flash-front .flash-name{font-size:24px;margin-top:8px}
.flash-back{transform:rotateY(180deg);line-height:1.8;color:var(--muted);font-size:16px}
.split-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.chart-controls,.revision-header,.revision-actions{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.revision-header{justify-content:space-between;margin-bottom:14px}
.revision-card h3{margin:0 0 8px}
.popup{
  position:fixed;inset:0;background:rgba(0,0,0,.78);
  display:grid;place-items:center;padding:16px;
}
.hidden{display:none!important}
.popup-card{
  width:min(860px,96vw);
  max-height:90vh;
  overflow:auto;
  padding:20px;
  position:relative;
}
.close-btn{position:absolute;top:12px;right:12px;width:42px;height:42px;padding:0;font-size:22px}
.popup-title{display:flex;gap:14px;align-items:center;margin-bottom:14px}
.popup-badge{
  width:72px;height:72px;border-radius:18px;
  display:grid;place-items:center;font-size:28px;font-weight:900;
  border:1px solid rgba(255,255,255,.18)
}
.popup-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.popup-chip{
  background:#0d1527;border:1px solid #243250;border-radius:14px;padding:12px
}
.orbital-boxes{display:grid;gap:8px;margin-top:12px}
.orbital-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.boxset{display:flex;gap:6px;flex-wrap:wrap}
.orbital-box{
  width:28px;height:28px;border:1px solid #445a82;border-radius:6px;
  display:grid;place-items:center;background:#07101d;font-size:14px
}
@media print{
  body{background:#fff;color:#000}
  .hero,.toolbar,.sidebar,.tabs,.popup,.flash-toolbar,.revision-actions,.legend-grid{display:none!important}
  .view{display:none!important}
  #revisionView{display:block!important}
  .panel,.revision-card{box-shadow:none;border:1px solid #aaa;background:#fff;color:#000}
}
@media (max-width:1100px){
  .main-grid,.hero,.split-grid{grid-template-columns:1fr}
}
@media (max-width:760px){
  .toolbar{grid-template-columns:1fr}
  .quick-grid{grid-template-columns:1fr 1fr}
}