#panel-periodic.panel[hidden] {
  display: none !important;
}

#panel-periodic.panel.active {
  display: block;
  padding: 0;
  margin: 0;
}

.pt-shell {
  padding: 1.25rem 1.4rem 2.5rem;
  color: var(--text);
  max-width: 100%;
}

.pt-head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.8rem 1.2rem;
  align-items: flex-end;
}

.pt-head h2 {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.7rem;
  margin: 0 0 0.3rem;
}

.pt-hint,
.pt-note,
.pt-credit,
.pt-status {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.pt-hint {
  max-width: 42rem;
}

.pt-keys {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0.9rem 0 0;
  padding: 0;
  list-style: none;
}

.pt-keys li {
  margin: 0;
  padding: 0.4rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
  font-size: 0.82rem;
  max-width: 22rem;
}

.pt-views {
  display: flex;
  gap: 0.35rem;
}

.pt-views button,
.pt-legend button,
.pt-presets button,
.pt-pair-go,
.pt-mol {
  font: inherit;
  color: var(--text);
  background: var(--bg-card);
  border: 1px solid var(--border);
  cursor: pointer;
}

.pt-views button {
  padding: 0.4rem 0.85rem;
  border-radius: 999px;
}

.pt-views button.is-on,
.pt-legend button.is-on,
.pt-presets button.is-on {
  border-color: var(--accent);
  color: var(--accent);
}

.pt-tools {
  margin-top: 0.9rem;
}

.pt-search,
.pt-pair select {
  box-sizing: border-box;
  padding: 0.45rem 0.55rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  color: var(--text);
  font: inherit;
}

.pt-search {
  width: min(22rem, 100%);
  margin-bottom: 0.55rem;
}

.pt-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.pt-legend button {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.5rem;
  border-radius: 999px;
  font-size: 0.75rem;
}

.pt-swatch {
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 2px;
}

.pt-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(16rem, 24rem);
  gap: 1rem;
  align-items: start;
  margin-top: 0.8rem;
  min-width: 0;
}

.pt-main {
  min-width: 0;
  max-width: 100%;
}

.pt-scroll {
  min-width: 0;
  overflow-x: auto;
  padding-bottom: 0.3rem;
}

.pt-grid {
  display: grid;
  grid-template-columns: repeat(18, minmax(2.55rem, 1fr));
  grid-template-rows: 1.35rem repeat(7, 2.7rem) auto repeat(2, 2.7rem);
  gap: 3px;
  min-width: 54rem;
}

.pt-ghead,
.pt-cell,
.pt-seat {
  font: inherit;
  color: var(--text-muted);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 4px;
  cursor: pointer;
  padding: 0;
}

.pt-ghead {
  font-size: 0.68rem;
}

.pt-ghead.is-on {
  color: var(--accent);
}

.pt-cell,
.pt-seat {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.pt-cell .pt-n {
  position: absolute;
  top: 1px;
  left: 3px;
  font-size: 0.58rem;
  opacity: 0.8;
}

.pt-cell .pt-sym {
  font-size: 0.92rem;
  font-weight: 600;
}

.pt-cell.is-on,
.pt-seat.is-on {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.pt-cell.is-dim,
.pt-seat.is-dim {
  opacity: 0.22;
}

.pt-seat {
  font-size: 0.62rem;
  letter-spacing: 0.01em;
  color: var(--text-muted);
  border-color: var(--border);
  background: var(--bg-card);
}

.pt-cell[data-family="alkali"] { background: #3b2426; color: #ffc1ba; }
.pt-cell[data-family="alkaline"] { background: #3b2e22; color: #ffd0a8; }
.pt-cell[data-family="transition"] { background: #33301c; color: #ffe08a; }
.pt-cell[data-family="post"] { background: #243226; color: #b7e2b4; }
.pt-cell[data-family="metalloid"] { background: #1d3333; color: #9ee0dc; }
.pt-cell[data-family="nonmetal"] { background: #1d2a3d; color: #b7d3ff; }
.pt-cell[data-family="halogen"] { background: #2a243b; color: #d2c4ff; }
.pt-cell[data-family="noble"] { background: #33243a; color: #f0c4ea; }
.pt-cell[data-family="lanthanide"] { background: #3a2432; color: #ffc0dc; }
.pt-cell[data-family="actinide"] { background: #3a2824; color: #ffc7b0; }

.pt-swatch[data-family="alkali"] { background: #ffc1ba; }
.pt-swatch[data-family="alkaline"] { background: #ffd0a8; }
.pt-swatch[data-family="transition"] { background: #ffe08a; }
.pt-swatch[data-family="post"] { background: #b7e2b4; }
.pt-swatch[data-family="metalloid"] { background: #9ee0dc; }
.pt-swatch[data-family="nonmetal"] { background: #b7d3ff; }
.pt-swatch[data-family="halogen"] { background: #d2c4ff; }
.pt-swatch[data-family="noble"] { background: #f0c4ea; }
.pt-swatch[data-family="lanthanide"] { background: #ffc0dc; }
.pt-swatch[data-family="actinide"] { background: #ffc7b0; }

.pt-f-label {
  margin: 0.35rem 0;
  color: var(--text-muted);
  font-size: 0.78rem;
  align-self: end;
}

.pt-note {
  margin-top: 0.55rem;
}

.pt-detail,
.pt-bond-result,
.pt-card,
.pt-mol {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
}

.pt-detail {
  padding: 1rem 1.05rem 1.15rem;
  min-height: 16rem;
}

.pt-detail h3 {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.7rem;
  margin: 0;
}

.pt-meta,
.pt-lesson,
.pt-shells {
  margin: 0.35rem 0 0;
  font-size: 0.88rem;
}

.pt-meta,
.pt-shells {
  color: var(--text-muted);
}

.pt-lesson {
  line-height: 1.45;
}

.pt-bohr {
  display: block;
  width: min(100%, 220px);
  margin: 0.7rem auto 0.2rem;
}

.pt-nucleus { fill: var(--accent, #d7c4a3); }
.pt-ring { fill: none; stroke: var(--border); stroke-width: 1; }
.pt-electron { fill: var(--text); }

.pt-facts {
  display: grid;
  grid-template-columns: 9.5rem minmax(0, 1fr);
  gap: 0.28rem 0.6rem;
  margin: 0.8rem 0 0;
  font-size: 0.82rem;
}

.pt-facts dt {
  margin: 0;
  color: var(--text-muted);
}

.pt-facts dd {
  margin: 0;
}

.pt-pair-go {
  margin-top: 0.85rem;
  padding: 0.45rem 0.7rem;
  border-radius: 6px;
}

#pt-table-view[hidden],
#pt-bonds-view[hidden] {
  display: none !important;
}

.pt-lessons {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.7rem;
  margin-top: 0.9rem;
}

.pt-card {
  padding: 0.8rem 0.85rem 0.95rem;
}

.pt-card h3,
.pt-mol-title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.15rem;
  margin: 0 0 0.35rem;
}

.pt-card p,
.pt-mol-lesson,
.pt-type-body {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.45;
}

.pt-pair {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem 1rem;
  margin-top: 1rem;
}

.pt-pair label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.pt-pair select {
  min-width: 14rem;
}

.pt-presets {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 0.7rem;
}

.pt-presets button {
  padding: 0.28rem 0.55rem;
  border-radius: 999px;
  font-size: 0.78rem;
}

.pt-bond-result {
  margin-top: 0.8rem;
  padding: 0.9rem 1rem;
}

.pt-type {
  margin: 0 0 0.3rem;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.45rem;
}

.pt-mol-title {
  margin: 1.1rem 0 0.55rem;
}

.pt-molecules {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
  gap: 0.7rem;
}

.pt-mol {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.25rem;
  padding: 0.7rem 0.75rem 0.85rem;
  text-align: left;
}

.pt-mol svg {
  width: 100%;
  height: auto;
}

.pt-mol-kind {
  color: var(--accent);
  font-size: 0.75rem;
}

.pt-mol-name {
  font-size: 1rem;
}

.pt-atom { fill: var(--bg-elevated, #1a1a1a); stroke: var(--text); stroke-width: 1.2; }
.pt-atom-text { fill: var(--text); font-size: 11px; font-family: inherit; }
.pt-bond-line { stroke: var(--text); stroke-width: 1.6; fill: none; }
.pt-sea { fill: rgba(255, 224, 138, 0.16); stroke: none; }

.pt-credit {
  margin-top: 0.9rem;
  font-size: 0.75rem;
}

.pt-lab {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.95fr);
  gap: 1rem;
  align-items: start;
  margin-top: 0.9rem;
  min-width: 0;
}

.pt-stage,
.pt-shelf {
  min-width: 0;
}

.pt-stage-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 0.8rem;
  margin-bottom: 0.55rem;
}

.pt-hand {
  margin: 0;
  font-size: 0.88rem;
}

.pt-actions {
  display: flex;
  gap: 0.4rem;
}

.pt-actions button {
  font: inherit;
  color: var(--text);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.32rem 0.75rem;
  cursor: pointer;
}

.pt-actions button:disabled {
  opacity: 0.4;
  cursor: default;
}

.pt-bench {
  position: relative;
  height: min(52vh, 460px);
  min-height: 240px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #161616;
  overflow: hidden;
  touch-action: none;
}

.pt-bench.is-solid {
  background-color: #241e1a;
  background-image: radial-gradient(circle, rgba(255, 224, 138, 0.22) 1px, transparent 1.5px);
  background-size: 16px 16px;
}
.pt-bench.is-liquid {
  background-color: #1a2430;
  background-image: repeating-linear-gradient(
    180deg,
    transparent 0 12px,
    rgba(183, 211, 255, 0.14) 12px 13px
  );
  background-size: 100% 28px;
  animation: pt-waves 5s linear infinite;
}
.pt-bench.is-gas {
  background-color: #14202a;
  background-image: radial-gradient(circle, rgba(183, 211, 255, 0.28) 1px, transparent 1.6px);
  background-size: 42px 34px;
  animation: pt-drift 7s linear infinite;
}

.pt-bench-hint {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  color: var(--text-muted);
  pointer-events: none;
}

.pt-bench-hint[hidden] {
  display: none;
}

.pt-phase {
  position: absolute;
  top: 0.55rem;
  right: 0.7rem;
  z-index: 3;
  margin: 0;
  padding: 0.18rem 0.55rem;
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.4);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text);
  pointer-events: none;
}

.pt-phase:empty {
  display: none;
}

.pt-bond-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
  pointer-events: none;
}

.pt-bond-hit {
  stroke: transparent;
  stroke-width: 16;
  pointer-events: stroke;
  cursor: pointer;
}

.pt-shell-ring {
  fill: none;
  stroke: rgba(244, 241, 234, 0.35);
  stroke-width: 1.1;
  stroke-dasharray: 3 4;
}

.pt-shell-ring.is-full {
  stroke: rgba(244, 241, 234, 0.85);
  stroke-width: 1.7;
  stroke-dasharray: none;
}

.pt-electron,
.pt-shared,
.pt-sea-dot {
  fill: #f4f1ea;
  stroke: none;
}

.pt-electron.is-gained,
.pt-sea-dot {
  fill: #ffe08a;
}

.pt-shared {
  fill: #d5e4ff;
}

.pt-open {
  fill: none;
  stroke: rgba(244, 241, 234, 0.9);
  stroke-width: 1.15;
  stroke-dasharray: 2 2;
}

.pt-slot {
  fill: none;
  stroke: rgba(244, 241, 234, 0.45);
  stroke-width: 1.2;
}

.pt-sea-blob {
  fill: rgba(255, 224, 138, 0.14);
  stroke: rgba(255, 224, 138, 0.55);
  stroke-width: 1.5;
}

.pt-ion-trail {
  fill: none;
  stroke: rgba(210, 196, 255, 0.7);
  stroke-width: 1.4;
  stroke-dasharray: 2 5;
}

.pt-charge-label {
  fill: #f4f1ea;
  font-size: 16px;
  font-weight: 650;
  text-anchor: middle;
  paint-order: stroke;
  stroke: #141414;
  stroke-width: 4px;
}

.pt-dot {
  position: absolute;
  z-index: 2;
  width: 2.55rem;
  height: 2.55rem;
  margin: 0;
  padding: 0;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  font: inherit;
  cursor: grab;
  touch-action: none;
}

.pt-bench.has-hand .pt-dot.has-room {
  box-shadow: 0 0 0 7px rgba(215, 196, 163, 0.28);
}

.pt-dot.is-on {
  outline: 2px solid var(--accent, #d7c4a3);
  outline-offset: 3px;
}

.pt-dot-sym {
  font-size: 1rem;
  font-weight: 650;
  pointer-events: none;
}

.pt-dot[data-family="alkali"] { background: #3b2426; color: #ffc1ba; }
.pt-dot[data-family="alkaline"] { background: #3b2e22; color: #ffd0a8; }
.pt-dot[data-family="transition"] { background: #33301c; color: #ffe08a; }
.pt-dot[data-family="post"] { background: #243226; color: #b7e2b4; }
.pt-dot[data-family="metalloid"] { background: #1d3333; color: #9ee0dc; }
.pt-dot[data-family="nonmetal"] { background: #1d2a3d; color: #b7d3ff; }
.pt-dot[data-family="halogen"] { background: #2a243b; color: #d2c4ff; }
.pt-dot[data-family="noble"] { background: #33243a; color: #f0c4ea; }
.pt-dot[data-family="lanthanide"] { background: #3a2432; color: #ffc0dc; }
.pt-dot[data-family="actinide"] { background: #3a2824; color: #ffc7b0; }

.pt-cell.is-armed {
  outline: 2px solid var(--accent, #d7c4a3);
  outline-offset: -2px;
  box-shadow: inset 0 0 0 1px var(--accent, #d7c4a3);
}

@keyframes pt-waves {
  from { background-position: 0 0; }
  to { background-position: 0 28px; }
}

@keyframes pt-drift {
  from { background-position: 0 0; }
  to { background-position: 42px -34px; }
}

@media (prefers-reduced-motion: reduce) {
  .pt-bench.is-liquid,
  .pt-bench.is-gas {
    animation: none;
  }
}

.pt-formula {
  margin: 0.65rem 0 0.2rem;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.55rem;
  letter-spacing: 0.02em;
}

.pt-formula sub {
  font-size: 0.65em;
}

.pt-key {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 0.7rem;
  margin: 0.15rem 0 0.35rem;
  padding: 0;
  list-style: none;
  color: var(--text-muted);
  font-size: 0.75rem;
}

.pt-key li {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.pt-key i {
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 50%;
  box-sizing: border-box;
}

.pt-key-dot {
  background: #f4f1ea;
}

.pt-key-open {
  border: 1px dashed #f4f1ea;
}

.pt-key-share {
  background: #d5e4ff;
  box-shadow: 8px 0 0 #d5e4ff;
  margin-right: 8px;
}

.pt-key-sea {
  background: rgba(255, 224, 138, 0.35);
  border: 1px solid rgba(255, 224, 138, 0.8);
}

.pt-result {
  min-height: 2.6rem;
  margin: 0;
  color: var(--text-muted);
  font-size: 0.88rem;
  line-height: 1.4;
}

.pt-heat {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-top: 0.75rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.pt-heat input {
  flex: 1;
  min-width: 0;
  accent-color: var(--accent, #d7c4a3);
}

.pt-heat span {
  min-width: 4.5rem;
  text-align: right;
  color: var(--text);
}

.pt-shelf .pt-scroll {
  max-height: min(68vh, 620px);
  overflow: auto;
}

@media (max-width: 800px) {
  .pt-shell {
    padding: 1rem 0.75rem 2rem;
  }

  .pt-layout,
  .pt-lessons,
  .pt-lab {
    grid-template-columns: minmax(0, 1fr);
  }

  .pt-stage {
    order: -1;
  }

  .pt-bench {
    height: 280px;
    min-height: 220px;
  }

  .pt-shelf .pt-scroll {
    max-height: 240px;
  }

  .pt-pair select {
    min-width: 0;
    width: 100%;
  }
}