@import url('https://fonts.googleapis.com/css2?family=Inter:wght@200;300;400;500;600;700&family=JetBrains+Mono:wght@300;400;500&display=swap');

:root {
  --bg: #0a0c10;
  --surface: #111520;
  --panel: #161b28;
  --border: rgba(255,255,255,0.08);
  --text: #c0c8e0;
  --text-muted: #5a6280;
  --white: #e8ecf8;

  /* Category colors */
  --alkali: #e63946;
  --alkaline: #f4a261;
  --transition: #457b9d;
  --post-transition: #6b7fa3;
  --metalloid: #2a9d8f;
  --nonmetal: #4cbb7a;
  --halogen: #9b5de5;
  --noble: #f72585;
  --lanthanide: #4361ee;
  --actinide: #3a0ca3;
  --unknown: #555;
}

*,*::before,*::after { box-sizing:border-box; margin:0; padding:0; }
body { font-family:'Inter',sans-serif; background:var(--bg); color:var(--text); min-height:100vh; overflow-x:auto; }

/* ── Header ── */
.header { padding:32px 28px 20px; border-bottom:1px solid var(--border); }
.header-tag { font-family:'JetBrains Mono',monospace; font-size:0.58rem; letter-spacing:4px; text-transform:uppercase; color:#4cbb7a; opacity:0.6; margin-bottom:10px; }
.header h1 { font-size:clamp(1.8rem,4vw,3rem); font-weight:700; color:var(--white); letter-spacing:-1px; }
.header p { font-size:0.88rem; color:var(--text-muted); margin-top:8px; max-width:700px; line-height:1.7; }

/* ── Legend ── */
.legend { display:flex; flex-wrap:wrap; gap:8px; padding:16px 28px; border-bottom:1px solid var(--border); }
.leg-item { display:flex; align-items:center; gap:6px; font-size:0.65rem; color:var(--text-muted); letter-spacing:0.5px; cursor:pointer; padding:4px 8px; border-radius:3px; transition:background 0.2s; }
.leg-item:hover { background:rgba(255,255,255,0.05); }
.leg-dot { width:10px; height:10px; border-radius:2px; flex-shrink:0; }
.leg-item.active { color:var(--white); }

/* ── Filter bar ── */
.filter-bar { padding:12px 28px; display:flex; gap:10px; align-items:center; flex-wrap:wrap; border-bottom:1px solid var(--border); }
.search-box { padding:7px 12px; background:var(--panel); border:1px solid var(--border); border-radius:4px; color:var(--white); font-size:0.82rem; font-family:'JetBrains Mono',monospace; width:200px; outline:none; }
.search-box::placeholder { color:var(--text-muted); }
.search-box:focus { border-color:rgba(76,187,122,0.4); }
.filter-label { font-size:0.68rem; color:var(--text-muted); letter-spacing:2px; text-transform:uppercase; }

/* ── Table container ── */
.table-wrap { padding:20px 20px 10px; overflow-x:auto; min-width:900px; }
.pt-grid { display:grid; grid-template-columns:repeat(18,minmax(54px,1fr)); gap:3px; }

/* ── Element cell ── */
.el {
  border-radius:4px;
  padding:5px 4px 4px;
  cursor:pointer;
  transition:transform 0.15s, box-shadow 0.15s, opacity 0.2s;
  border:1px solid rgba(255,255,255,0.06);
  position:relative;
  min-width:54px;
}
.el:hover { transform:scale(1.15) translateZ(0); z-index:10; box-shadow:0 4px 20px rgba(0,0,0,0.5); }
.el.dimmed { opacity:0.18; }
.el .el-num { font-family:'JetBrains Mono',monospace; font-size:0.52rem; color:rgba(255,255,255,0.4); line-height:1; }
.el .el-sym { font-size:1.2rem; font-weight:700; color:#fff; line-height:1.1; text-align:center; margin:1px 0; }
.el .el-name { font-size:0.42rem; color:rgba(255,255,255,0.55); text-align:center; white-space:nowrap; overflow:hidden; text-overflow:ellipsis; line-height:1.2; }
.el .el-mass { font-family:'JetBrains Mono',monospace; font-size:0.42rem; color:rgba(255,255,255,0.35); text-align:center; line-height:1.2; }

/* Category backgrounds */
.cat-alkali      { background:rgba(230,57,70,0.2);   border-color:rgba(230,57,70,0.35); }
.cat-alkaline    { background:rgba(244,162,97,0.2);  border-color:rgba(244,162,97,0.35); }
.cat-transition  { background:rgba(69,123,157,0.2);  border-color:rgba(69,123,157,0.35); }
.cat-post-trans  { background:rgba(107,127,163,0.2); border-color:rgba(107,127,163,0.35); }
.cat-metalloid   { background:rgba(42,157,143,0.2);  border-color:rgba(42,157,143,0.35); }
.cat-nonmetal    { background:rgba(76,187,122,0.2);  border-color:rgba(76,187,122,0.35); }
.cat-halogen     { background:rgba(155,93,229,0.2);  border-color:rgba(155,93,229,0.35); }
.cat-noble       { background:rgba(247,37,133,0.2);  border-color:rgba(247,37,133,0.35); }
.cat-lanthanide  { background:rgba(67,97,238,0.2);   border-color:rgba(67,97,238,0.35); }
.cat-actinide    { background:rgba(58,12,163,0.25);  border-color:rgba(58,12,163,0.4); }
.cat-unknown     { background:rgba(80,80,80,0.2);    border-color:rgba(80,80,80,0.35); }

/* Placeholder cells */
.el-blank { opacity:0; pointer-events:none; }
.el-gap   { opacity:0; pointer-events:none; }

/* ── Tooltip (detail panel) ── */
#detail-panel {
  position:fixed; right:24px; top:50%; transform:translateY(-50%);
  width:260px; background:var(--panel); border:1px solid var(--border);
  border-radius:8px; padding:20px; z-index:100;
  box-shadow:0 10px 40px rgba(0,0,0,0.5);
  display:none;
  transition:opacity 0.2s;
}
#detail-panel.visible { display:block; }
.dp-num { font-family:'JetBrains Mono',monospace; font-size:0.65rem; color:var(--text-muted); margin-bottom:4px; }
.dp-sym { font-size:4rem; font-weight:700; color:#fff; line-height:1; margin-bottom:4px; }
.dp-name { font-size:1.1rem; font-weight:600; color:var(--white); margin-bottom:14px; }
.dp-row { display:flex; justify-content:space-between; padding:6px 0; border-bottom:1px solid var(--border); font-size:0.76rem; }
.dp-row:last-child { border-bottom:none; }
.dp-key { color:var(--text-muted); }
.dp-val { color:var(--white); font-family:'JetBrains Mono',monospace; font-size:0.72rem; }
.dp-close { position:absolute; top:10px; right:10px; cursor:pointer; color:var(--text-muted); font-size:1.2rem; line-height:1; }
.dp-close:hover { color:var(--white); }

/* ── Lanthanide/Actinide separator ── */
.series-label { font-family:'JetBrains Mono',monospace; font-size:0.55rem; color:var(--text-muted); letter-spacing:2px; text-transform:uppercase; display:flex; align-items:center; padding:3px 6px; }

/* ── Info sections ── */
.info-sections { max-width:1200px; margin:0 auto; padding:40px 28px 60px; display:grid; grid-template-columns:1fr 1fr; gap:24px; }
.info-card { background:var(--panel); border:1px solid var(--border); border-radius:6px; padding:24px; }
.info-card h2 { font-size:1rem; font-weight:700; color:var(--white); margin-bottom:14px; text-transform:uppercase; letter-spacing:1px; }
.info-card p { font-size:0.84rem; line-height:1.75; color:var(--text-muted); font-weight:300; }

/* ── Period/group labels ── */
.period-label { font-family:'JetBrains Mono',monospace; font-size:0.55rem; color:var(--text-muted); display:flex; align-items:center; justify-content:center; min-width:54px; }

@media(max-width:900px){ .info-sections{grid-template-columns:1fr;} }