/* ==========================================================================
   12. Periodic Table Atom Picker
   ========================================================================== */
.atom-picker-control {
  margin: 12px 0 16px;
}

.control-label {
  margin-bottom: 7px;
  color: var(--text-muted);
  font-size: 12px;
  font-family: var(--font-mono);
  letter-spacing: 1px;
}

.atom-picker-button {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 4px 12px;
  align-items: center;
  width: 100%;
  min-height: 64px;
  text-align: left;
}

.selected-atom-symbol {
  grid-row: 1 / span 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  color: var(--bg-base);
  background: var(--accent-secondary);
  border-radius: 50%;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 900;
  box-shadow: 0 0 14px rgba(56, 189, 248, 0.7);
}

.selected-atom-name {
  color: var(--text-main);
  font-family: var(--font-mono);
  font-size: 13px;
}

.atom-picker-hint {
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 1px;
  text-transform: uppercase;
}

/* ==========================================================================
   MODAL & BACKDROP
   ========================================================================== */

.periodic-modal {
  position: fixed;
  inset: 0;
  z-index: 99999;
  display: grid;
  place-items: center;
}

.periodic-modal.hidden {
  display: none;
}

.periodic-backdrop {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at center, rgba(56, 189, 248, 0.12), transparent 45%),
    rgba(2, 6, 23, 0.82);
  backdrop-filter: blur(10px);
}

.periodic-panel {
  position: relative;
  z-index: 1;
  width: min(1250px, calc(100vw - 36px));
  max-height: calc(100vh - 36px);
  padding: 24px 30px;
  overflow: auto;

  background: rgba(15, 23, 42, 0.88);
  border: 1px solid rgba(56, 189, 248, 0.32);
  border-radius: 22px;

  box-shadow:
    0 0 34px rgba(56, 189, 248, 0.22),
    inset 0 0 24px rgba(56, 189, 248, 0.06);
}

/* ==========================================================================
   HEADER & CONTROLS (SEARCH + FILTERS)
   ========================================================================== */

.periodic-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 20px;
}

.periodic-header h2 {
  margin: 0;
  color: var(--accent-secondary);
  font-size: 26px;
  text-shadow: 0 0 14px rgba(56, 189, 248, 0.45);
}

.periodic-close-btn {
  width: 42px;
  height: 42px;
  color: var(--accent-danger);
  background: rgba(2, 6, 23, 0.7);
  border: 1px solid rgba(248, 113, 113, 0.45);
  border-radius: 12px;
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
  transition: all 0.2s ease;
}

.periodic-close-btn:hover {
  background: var(--accent-danger);
  color: var(--bg-base);
  box-shadow: 0 0 15px rgba(248, 113, 113, 0.5);
}

.periodic-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid rgba(56, 189, 248, 0.15);
}

/* Make search bar distinct and properly sized */
.periodic-search-wrap {
  flex: 1;
  min-width: 260px;
  max-width: 350px;
}

.periodic-search-input {
  width: 100%;
  height: 44px;
  padding: 0 16px;

  color: var(--text-main);
  background: rgba(2, 6, 23, 0.72);
  border: 1px solid rgba(56, 189, 248, 0.32);
  border-radius: 8px;
  outline: none;

  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.5px;
  transition: all 0.2s ease;

  box-shadow: inset 0 0 10px rgba(0,0,0,0.5);
}

.periodic-search-input::placeholder {
  color: rgba(148, 163, 184, 0.6);
}

.periodic-search-input:focus {
  border-color: var(--accent-primary);
  box-shadow:
    0 0 0 2px rgba(2, 6, 23, 0.9),
    0 0 15px rgba(234, 179, 8, 0.45);
}

/* Category Filters */
.periodic-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  flex: 2;
}

.legend-item {
  padding: 6px 12px;
  color: var(--text-muted);
  background: rgba(2, 6, 23, 0.6);
  border: 1px solid rgba(56, 189, 248, 0.18);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 1px;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.2s ease;
}

.legend-item:hover {
  color: var(--bg-base);
  background: var(--accent-secondary);
  border-color: var(--accent-secondary);
  transform: translateY(-1px);
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.55);
}

.legend-item.active {
  color: var(--bg-base);
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  box-shadow:
    0 0 12px rgba(234, 179, 8, 0.65),
    0 0 24px rgba(234, 179, 8, 0.22);
}

/* ==========================================================================
   THE GRID & ELEMENTS
   ========================================================================== */

.periodic-grid {
  display: grid;
  grid-template-columns: repeat(18, minmax(46px, 1fr));
  grid-template-rows: repeat(9, 64px);
  gap: 7px;
  min-width: 980px;
}

.periodic-element {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2px;
  padding: 6px;

  color: var(--text-main);
  background: rgba(2, 6, 23, 0.72);
  border: 1px solid rgba(56, 189, 248, 0.22);
  border-radius: 10px;

  font-family: var(--font-mono);
  text-align: left;
  cursor: pointer;

  transition: all 0.2s ease;
}

.periodic-element:hover {
  transform: translateY(-3px) scale(1.04);
  border-color: var(--accent-primary);
  box-shadow:
    0 0 14px rgba(234, 179, 8, 0.4),
    0 0 24px rgba(56, 189, 248, 0.18);
  z-index: 5;
}

.periodic-element.selected {
  border-color: var(--accent-primary);
  background: rgba(234, 179, 8, 0.15);
  box-shadow:
    0 0 0 1px rgba(234, 179, 8, 0.5),
    0 0 18px rgba(234, 179, 8, 0.5);
}

.element-symbol {
  font-size: 18px;
  font-weight: 900;
}

.element-name {
  max-width: 100%;
  overflow: hidden;
  color: var(--text-muted);
  font-size: 9px;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.element-valence {
  position: absolute;
  top: 5px;
  right: 6px;
  color: var(--accent-primary);
  font-size: 9px;
}

/* --- Element Categories (Colors) --- */
.periodic-element.nonmetal { border-color: rgba(56, 189, 248, 0.38); }
.periodic-element.halogen { border-color: rgba(34, 197, 94, 0.42); }
.periodic-element.noble-gas { border-color: rgba(148, 163, 184, 0.45); }
.periodic-element.alkali-metal, .periodic-element.alkaline-earth-metal { border-color: rgba(249, 115, 22, 0.45); }
.periodic-element.metal { border-color: rgba(100, 116, 139, 0.55); }
.periodic-element.transition-metal { border-color: rgba(96, 165, 250, 0.45); }
.periodic-element.metalloid { border-color: rgba(20, 184, 166, 0.45); }
.periodic-element.lanthanide { border-color: rgba(192, 132, 252, 0.45); }
.periodic-element.actinide { border-color: rgba(244, 114, 182, 0.45); }

/* --- Filtering & Search states --- */
.periodic-element.filtered-out {
  opacity: 0.18;
  filter: grayscale(0.9);
  transform: scale(0.96);
  pointer-events: none; /* Prevents hovering disabled items */
}

.periodic-element.filtered-in {
  box-shadow:
    0 0 12px rgba(56, 189, 248, 0.22),
    inset 0 0 10px rgba(56, 189, 248, 0.06);
}

.periodic-element.search-match {
  border-color: var(--accent-primary);
  box-shadow:
    0 0 0 1px rgba(234, 179, 8, 0.36),
    0 0 16px rgba(234, 179, 8, 0.36),
    inset 0 0 12px rgba(234, 179, 8, 0.05);
}

/* ==========================================================================
   MOBILE RESPONSIVENESS
   ========================================================================== */
@media (max-width: 900px) {
  .periodic-controls {
    flex-direction: column;
    align-items: stretch;
  }
  .periodic-search-wrap {
    max-width: 100%;
  }
  .periodic-close-btn {
    position: absolute;
    top: 16px;
    right: 16px;
  }
}