:root {
  --bg: #0b1020;
  --panel: #121a31;
  --panel-2: #182341;
  --text: #ecf2ff;
  --muted: #9fb0d3;
  --line: rgba(255,255,255,0.09);
  --tile-shadow: 0 16px 32px rgba(0,0,0,0.28);
  --accent: #78a8ff;
  --table-size: clamp(32px, 3.15vw, 72px);
  --gap: 6px;
}
body.light {
  --bg: #f3f6fc;
  --panel: #ffffff;
  --panel-2: #eef3ff;
  --text: #10203e;
  --muted: #5b6e92;
  --line: rgba(16,32,62,0.09);
  --tile-shadow: 0 10px 22px rgba(25, 60, 120, 0.12);
  --accent: #2f66ff;
}
* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; background: radial-gradient(circle at top, rgba(80,120,255,0.22), transparent 28%), var(--bg); color: var(--text); font-family: Inter, system-ui, sans-serif; }
button, input { font: inherit; }
.app-shell { max-width: min(1800px, 100vw); margin: 0 auto; padding: 18px; }
.topbar, .control-panel, .table-panel, .detail-panel, .legend-wrap {
  background: color-mix(in srgb, var(--panel) 90%, transparent);
  border: 1px solid var(--line);
  box-shadow: var(--tile-shadow);
  border-radius: 24px;
}
.topbar { padding: 22px 24px; display: flex; justify-content: space-between; gap: 20px; align-items: end; flex-wrap: wrap; }
.eyebrow { color: var(--accent); font-size: 12px; font-weight: 800; text-transform: uppercase; letter-spacing: .16em; margin-bottom: 8px; }
h1 { margin: 0; font-size: clamp(1.8rem, 4vw, 3rem); }
.subline { margin: 8px 0 0; color: var(--muted); max-width: 900px; }
.topbar-actions { display: flex; gap: 14px; align-items: end; flex-wrap: wrap; }
.search-wrap { display: grid; gap: 6px; color: var(--muted); font-size: 13px; }
.search-wrap input {
  background: var(--panel-2); color: var(--text); border: 1px solid var(--line); border-radius: 14px; padding: 12px 14px; min-width: min(320px, 74vw);
}
.ghost-btn, .segmented button, .legend-chip {
  border: 1px solid var(--line); background: var(--panel-2); color: var(--text); border-radius: 14px; padding: 11px 14px; cursor: pointer;
  transition: transform .18s ease, border-color .18s ease, background .18s ease, opacity .18s ease, box-shadow .18s ease;
}
.ghost-btn:hover, .segmented button:hover, .legend-chip:hover { transform: translateY(-1px); border-color: color-mix(in srgb, var(--accent) 58%, var(--line)); }
.control-panel { margin-top: 18px; padding: 18px; display: grid; gap: 12px; }
.segmented { display: flex; gap: 10px; flex-wrap: wrap; }
.segmented.hidden { display: none; }
.segmented button.active, .legend-chip.active {
  background: color-mix(in srgb, var(--accent) 22%, var(--panel-2));
  border-color: color-mix(in srgb, var(--accent) 58%, var(--line));
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--accent) 35%, transparent) inset;
}
.context-help { color: var(--muted); font-size: 14px; }

.table-panel { margin-top: 18px; padding: 18px; overflow: hidden; }
.table-grid {
  display: grid;
  grid-template-columns: 34px repeat(18, minmax(0, 1fr));
  gap: var(--gap);
  align-items: stretch;
  width: 100%;
}
.axis-label, .group-label {
  color: var(--muted); display: flex; align-items: center; justify-content: center; font-size: clamp(10px, 1vw, 14px); min-height: var(--table-size);
}
.element-tile {
  position: relative;
  min-width: 0;
  aspect-ratio: 1 / 1;
  border-radius: clamp(10px, 1vw, 18px);
  border: 1px solid rgba(255,255,255,0.18);
  padding: clamp(3px, .45vw, 7px);
  color: #07101f;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, filter .18s ease, opacity .18s ease, outline-color .18s ease;
  outline: 2px solid transparent;
  overflow: hidden;
}
.element-tile:hover { transform: translateY(-2px); box-shadow: 0 10px 22px rgba(0,0,0,.16); }
.element-tile.selected { outline-color: white; box-shadow: 0 0 0 2px rgba(255,255,255,0.24) inset, 0 14px 28px rgba(0,0,0,.22); }
.element-tile.faded { opacity: .18; filter: grayscale(.4); }
.element-tile.highlighted { outline-color: color-mix(in srgb, var(--accent) 72%, white); transform: translateY(-2px); }
.tile-top { display: flex; justify-content: space-between; align-items: start; gap: 4px; font-size: clamp(8px, .8vw, 12px); opacity: .9; }
.tile-symbol { font-size: clamp(1rem, 2vw, 2.2rem); font-weight: 800; line-height: 1; text-align: center; margin-top: auto; }
.tile-name { font-size: clamp(8px, .78vw, 12px); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; text-align: center; }
.tile-extra { font-size: clamp(8px, .72vw, 11px); text-align: center; opacity: .92; min-height: 1em; }
.empty-cell { min-height: var(--table-size); }

.series-row {
  display: grid;
  grid-template-columns: 150px repeat(15, minmax(0, 1fr));
  gap: var(--gap);
  margin-top: 12px;
}
.series-title {
  color: var(--accent); font-weight: 700; display: flex; align-items: center; justify-content: flex-start; padding-left: 8px;
}
.legend-wrap { margin-top: 18px; padding: 18px; }
.legend-title { font-weight: 700; margin-bottom: 10px; }
.legend-grid { display: flex; flex-wrap: wrap; gap: 10px; }
.legend-chip { display: inline-flex; align-items: center; gap: 10px; }
.legend-swatch { width: 16px; height: 16px; border-radius: 999px; border: 1px solid rgba(0,0,0,.15); }

.detail-panel { margin-top: 18px; padding: 22px; }
.detail-grid { display: grid; grid-template-columns: minmax(260px, 420px) 1fr; gap: 20px; align-items: start; }
.detail-card {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 18px;
}
.detail-header { display: flex; justify-content: space-between; gap: 16px; align-items: start; }
.big-symbol { font-size: 4rem; font-weight: 800; line-height: .9; }
.muted { color: var(--muted); }
.info-list { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 10px; margin-top: 14px; }
.info-item { background: color-mix(in srgb, var(--panel) 65%, transparent); border: 1px solid var(--line); border-radius: 16px; padding: 12px; }
.info-item strong { display: block; font-size: 12px; color: var(--muted); margin-bottom: 5px; }

.model-stage {
  background: radial-gradient(circle at 50% 35%, rgba(255,255,255,.06), transparent 55%), color-mix(in srgb, var(--panel) 85%, black 5%);
  border: 1px solid var(--line);
  border-radius: 22px;
  min-height: 360px;
  padding: 10px;
  display: grid;
  place-items: center;
}
.model-stage svg { width: min(100%, 560px); height: auto; overflow: visible; }
.nucleus-label { font-size: 42px; font-weight: 800; fill: var(--text); }
.nucleus-small { font-size: 14px; fill: var(--muted); }
.shell-stroke { stroke: color-mix(in srgb, var(--text) 75%, transparent); stroke-width: 3; fill: none; opacity: .88; }
.electron-guide { fill: rgba(255,255,255,.18); }
.electron-dot { fill: #ff5363; stroke: rgba(255,255,255,.8); stroke-width: 2; filter: drop-shadow(0 2px 4px rgba(0,0,0,.35)); }
.lewis-wrap { display: grid; place-items: center; min-height: 360px; }
.lewis-box {
  position: relative;
  width: min(280px, 74vw);
  aspect-ratio: 1 / 1;
  border: 3px solid color-mix(in srgb, var(--text) 72%, transparent);
  border-radius: 24px;
  display: grid;
  place-items: center;
  background: rgba(255,255,255,.02);
}
.lewis-symbol { font-size: clamp(3rem, 9vw, 5.5rem); font-weight: 800; line-height: 1; }
.lewis-mark {
  position: absolute;
  background: var(--text);
  box-shadow: 0 0 0 1px rgba(255,255,255,.08);
}
.lewis-mark.dot {
  width: 12px;
  height: 12px;
  border-radius: 999px;
}
.lewis-mark.line.top,
.lewis-mark.line.bottom {
  width: 42px;
  height: 4px;
  border-radius: 999px;
  left: 50%;
  transform: translateX(-50%);
}
.lewis-mark.line.left,
.lewis-mark.line.right {
  width: 4px;
  height: 42px;
  border-radius: 999px;
  top: 50%;
  transform: translateY(-50%);
}
.lewis-mark.dot.top { top: 20px; left: 50%; transform: translateX(-50%); }
.lewis-mark.dot.right { right: 20px; top: 50%; transform: translateY(-50%); }
.lewis-mark.dot.bottom { bottom: 20px; left: 50%; transform: translateX(-50%); }
.lewis-mark.dot.left { left: 20px; top: 50%; transform: translateY(-50%); }
.lewis-mark.line.top { top: 24px; }
.lewis-mark.line.right { right: 24px; }
.lewis-mark.line.bottom { bottom: 24px; }
.lewis-mark.line.left { left: 24px; }

.pill-list { display: flex; flex-wrap: wrap; gap: 10px; }
.pill {
  background: color-mix(in srgb, var(--panel) 60%, transparent);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 10px 14px;
}
.formula-grid { display: grid; gap: 10px; }
.formula-card {
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 58%, transparent);
  border-radius: 18px;
  padding: 14px 16px;
}
.formula-big { font-size: 1.6rem; font-weight: 800; margin-bottom: 6px; }
.helper-note { color: var(--muted); font-size: 14px; }

@media (max-width: 1100px) {
  .detail-grid { grid-template-columns: 1fr; }
  .series-row { grid-template-columns: 110px repeat(15, minmax(0, 1fr)); }
}
@media (max-width: 740px) {
  .app-shell { padding: 10px; }
  .topbar, .control-panel, .table-panel, .detail-panel, .legend-wrap { border-radius: 18px; }
  .table-grid { grid-template-columns: 24px repeat(18, minmax(0, 1fr)); gap: 4px; }
  .series-row { grid-template-columns: 80px repeat(15, minmax(0, 1fr)); gap: 4px; }
  .tile-top { font-size: 7px; }
  .tile-symbol { font-size: clamp(.82rem, 2.5vw, 1.2rem); }
  .tile-name, .tile-extra { font-size: 7px; }
}