/* ============================================
   Elements Periodic Table - Comprehensive Styles
   Light/Dark Theme Support + Responsive Design
   ============================================ */

/* ===== CSS Variables ===== */
:root {
  /* Light Theme Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #adb5bd;
  --border-color: #dee2e6;
  --shadow: rgba(0, 0, 0, 0.1);
  --shadow-lg: rgba(0, 0, 0, 0.15);
  --card-bg: #ffffff;
  --header-bg: #ffffff;
  --element-bg: #ffffff;
  --element-border: #dee2e6;
  --modal-bg: #ffffff;
  --table-stripe: #f8f9fa;
  
  /* Brand Colors */
  --brand-color: #0d6efd;
  --accent-color: #6c757d;
  
  /* Status Colors */
  --online-color: #28a745;
  --offline-color: #dc3545;
  
  /* Animation */
  --transition-speed: 0.2s;
  --transition-function: ease-in-out;
}

/* ===== Base Styles ===== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-speed) var(--transition-function),
              color var(--transition-speed) var(--transition-function);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Sticky Header ===== */
#statusBar {
  background-color: var(--header-bg);
  border-bottom: 2px solid var(--border-color);
  box-shadow: 0 2px 8px var(--shadow);
  z-index: 1000;
  transition: all var(--transition-speed) var(--transition-function);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--brand-color);
}

.brand-icon {
  font-size: 1.75rem;
}

.brand-text {
  font-family: 'Courier New', monospace;
  letter-spacing: 1px;
}

.status-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  flex-wrap: wrap;
}

.legend-compact-inline {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.legend-compact-inline .legend-item {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.75rem;
  white-space: nowrap;
  color: var(--text-secondary);
}

.legend-compact-inline .legend-color {
  width: 12px;
  height: 12px;
  border-radius: 2px;
  display: inline-block;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  transition: background-color var(--transition-speed) var(--transition-function);
}

.dot.online {
  background-color: var(--online-color);
  box-shadow: 0 0 8px var(--online-color);
}

.dot.offline {
  background-color: var(--offline-color);
}

.sep {
  color: var(--text-muted);
  margin: 0 0.25rem;
}

/* ===== Main Content ===== */
#mainContent {
  flex: 1;
  max-width: 1800px;
  margin: 0 auto;
  width: 100%;
}

/* ===== Cards ===== */
.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  transition: all var(--transition-speed) var(--transition-function);
}

.card-body {
  padding: 1.5rem;
}

/* ===== Controls Section ===== */
.form-label {
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.9rem;
}

.form-control,
.form-select {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  transition: all var(--transition-speed) var(--transition-function);
}

.form-control:focus,
.form-select:focus {
  background-color: var(--bg-secondary);
  border-color: var(--brand-color);
  color: var(--text-primary);
  box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.25);
}


/* ===== Legend ===== */
.legend-compact {
  font-size: 0.85rem;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  color: var(--text-secondary);
}

.legend-color {
  width: 12px;
  height: 12px;
  border-radius: 2px;
  display: inline-block;
}

/* ===== Periodic Table ===== */
.periodic-table-container {
  padding: 1rem;
  overflow-x: auto;
}

.periodic-table-grid {
  display: grid;
  grid-template-columns: repeat(18, 1fr);
  grid-template-rows: repeat(7, 1fr);
  gap: 4px;
  min-width: 1200px;
  margin-bottom: 2rem;
}

/* ===== Element Card ===== */
.element-card {
  background-color: var(--element-bg);
  border: 2px solid var(--element-border);
  border-radius: 8px;
  padding: 0.5rem;
  cursor: pointer;
  transition: all var(--transition-speed) var(--transition-function);
  position: relative;
  aspect-ratio: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  box-shadow: 0 2px 4px var(--shadow);
  min-height: 80px;
}

.element-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 6px;
  background: var(--category-color);
  opacity: 0.15;
  z-index: 0;
  transition: opacity var(--transition-speed) var(--transition-function);
}

.element-card:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 8px 16px var(--shadow-lg);
  border-color: var(--category-color);
  z-index: 10;
}

.element-card:hover::before {
  opacity: 0.3;
}

.element-card > * {
  position: relative;
  z-index: 1;
}

.element-number {
  font-size: 0.7rem;
  color: var(--text-muted);
  position: absolute;
  top: 4px;
  left: 6px;
  font-weight: 600;
}

.element-symbol {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  font-family: 'Courier New', monospace;
  margin-bottom: 0.1rem;
}

.element-name {
  font-size: 0.65rem;
  color: var(--text-secondary);
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 100%;
}

.element-weight {
  font-size: 0.6rem;
  color: var(--text-muted);
  margin-top: 0.1rem;
}

/* ===== Search & Filter States ===== */
.element-card.search-match {
  border-color: var(--brand-color);
  box-shadow: 0 0 12px rgba(13, 110, 253, 0.4);
  transform: scale(1.05);
}

.element-card.search-fade {
  opacity: 0.3;
  pointer-events: none;
}

.element-card.filtered-out {
  opacity: 0.2;
  pointer-events: none;
}

/* ===== Element Selection States ===== */
.element-card.selected {
  border: 3px solid var(--brand-color);
  box-shadow: 0 4px 16px rgba(13, 110, 253, 0.5);
  transform: scale(1.05);
  background-color: rgba(13, 110, 253, 0.05);
}


.element-card.selected::after {
  content: '✓';
  position: absolute;
  top: 4px;
  right: 6px;
  font-size: 1rem;
  font-weight: bold;
  color: var(--brand-color);
  z-index: 2;
}

.element-card.selectable {
  cursor: pointer;
}

/* ===== Compound Builder ===== */
.compound-builder-card {
  background: linear-gradient(135deg, var(--card-bg) 0%, var(--bg-secondary) 100%);
  border: 2px solid var(--border-color);
}

.compound-builder-card .card-title {
  color: var(--brand-color);
  font-weight: 600;
}

.selected-elements-display {
  padding: 0.5rem;
  background-color: var(--bg-secondary);
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.selected-elements-display strong {
  color: var(--text-primary);
}

.element-count-input {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
  padding: 0.5rem;
  background-color: var(--bg-primary);
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

.element-count-input .element-symbol-badge {
  font-weight: bold;
  color: var(--brand-color);
  min-width: 30px;
  font-size: 1.1rem;
}

.element-count-input input {
  width: 70px;
  padding: 0.25rem 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  background-color: var(--element-bg);
  color: var(--text-primary);
  font-size: 0.9rem;
}

.element-count-input input:focus {
  outline: none;
  border-color: var(--brand-color);
  box-shadow: 0 0 0 2px rgba(13, 110, 253, 0.25);
}

.element-count-input label {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.compound-likelihood {
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  font-weight: 600;
  text-align: center;
  font-size: 1.25rem;
}

.compound-likelihood.likely {
  background-color: rgba(40, 167, 69, 0.15);
  border: 2px solid #28a745;
  color: #28a745;
}

.compound-likelihood.possible {
  background-color: rgba(255, 193, 7, 0.15);
  border: 2px solid #ffc107;
  color: #d39e00;
}

.compound-likelihood.unlikely {
  background-color: rgba(220, 53, 69, 0.15);
  border: 2px solid #dc3545;
  color: #dc3545;
}


.compound-formula {
  font-family: 'Courier New', monospace;
  font-size: 1.5rem;
  font-weight: 600;
  text-align: center;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: 6px;
  margin-bottom: 1rem;
}

/* ===== Element Comparison Styles ===== */
.comparison-table {
  width: 100%;
  overflow-x: auto;
}

.comparison-table table {
  width: 100%;
  min-width: 600px;
}

.comparison-table th {
  background-color: var(--bg-secondary);
  position: sticky;
  top: 0;
  z-index: 10;
  padding: 0.75rem;
  font-weight: 600;
  border-bottom: 2px solid var(--border-color);
}

.comparison-table .element-header {
  text-align: center;
  vertical-align: middle;
}

.comparison-table .element-symbol-header {
  font-size: 1.5rem;
  font-weight: bold;
  display: block;
  margin-bottom: 0.25rem;
}

.comparison-table .element-name-header {
  font-size: 0.9rem;
  font-weight: normal;
  color: var(--text-secondary);
}

.comparison-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border-color);
  vertical-align: top;
}

.comparison-table .property-label {
  font-weight: 600;
  color: var(--text-secondary);
  white-space: nowrap;
}

.comparison-table .property-value {
  text-align: center;
}

.comparison-table tr:hover {
  background-color: var(--bg-secondary);
}

/* ===== F-Block (Lanthanides & Actinides) ===== */
.f-block-container {
  margin-top: 2rem;
}

.f-block-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.f-block-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  min-width: 100px;
  text-align: right;
}

.f-block-elements {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  flex: 1;
}

.f-block-elements .element-card {
  width: 80px;
  min-height: 90px;
}

/* ===== Modal Styles ===== */
.modal-content {
  background-color: var(--modal-bg);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.modal-header {
  border-bottom-color: var(--border-color);
}

.modal-footer {
  border-top-color: var(--border-color);
}

.modal-title {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.element-symbol-large {
  font-size: 2.5rem;
  font-weight: 700;
  font-family: 'Courier New', monospace;
}

.element-details {
  color: var(--text-primary);
}

.detail-section {
  margin-bottom: 1.5rem;
}

.detail-section h5 {
  color: var(--brand-color);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border-color);
}

.detail-section table {
  color: var(--text-primary);
}

.detail-section .table {
  margin-bottom: 0;
}

.table {
  --bs-table-bg: transparent;
  --bs-table-striped-bg: var(--table-stripe);
  --bs-table-hover-bg: var(--bg-tertiary);
  color: var(--text-primary);
}

.table td {
  border-color: var(--border-color);
}

.element-description {
  text-align: justify;
  line-height: 1.7;
  color: var(--text-secondary);
}

/* ===== Historical Timeline ===== */
.horizontal-timeline {
  margin: 1.5rem 0 2rem 0;
  padding: 1rem 0;
  background: var(--bg-secondary);
  border-radius: 8px;
  overflow-x: auto;
}

.horizontal-timeline-track {
  position: relative;
  height: 80px;
  margin: 0 2rem;
  background: linear-gradient(to right, 
    var(--border-color) 0%, 
    var(--brand-color) 50%, 
    var(--border-color) 100%);
  border-radius: 4px;
  height: 4px;
  margin-top: 40px;
}

.century-marker {
  position: absolute;
  top: -8px;
  transform: translateX(-50%);
}

.century-marker::before {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 2px;
  height: 16px;
  background: var(--border-color);
  top: 0;
}

.century-label {
  position: absolute;
  top: -30px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.75rem;
  color: var(--text-secondary);
  white-space: nowrap;
  font-weight: 500;
}

.event-marker {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
  z-index: 2;
}

.event-line {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 3px;
  height: 30px;
  top: -30px;
  background: linear-gradient(to bottom, var(--accent-color), var(--brand-color));
  border-radius: 2px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.event-line::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 50%;
  transform: translateX(-50%);
  width: 8px;
  height: 8px;
  background: var(--accent-color);
  border-radius: 50%;
  border: 2px solid var(--bg-secondary);
  box-shadow: 0 0 0 2px var(--accent-color);
}

.event-label {
  position: absolute;
  top: -50px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent-color);
  white-space: nowrap;
  background: var(--bg-primary);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--accent-color);
}

.timeline {
  position: relative;
  padding: 1rem 0;
}

.timeline-item {
  display: flex;
  gap: 1rem;
  position: relative;
  margin-bottom: 1.5rem;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-marker {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
}

.timeline-dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-color), var(--accent-color));
  border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 2px var(--brand-color);
  z-index: 2;
  flex-shrink: 0;
}

.timeline-line {
  width: 2px;
  flex-grow: 1;
  background: linear-gradient(180deg, var(--brand-color), var(--border-color));
  margin-top: 0.25rem;
}

.timeline-content {
  flex-grow: 1;
  padding: 0.5rem 1rem;
  background: var(--bg-secondary);
  border-radius: 8px;
  border-left: 3px solid var(--brand-color);
  transition: all 0.3s ease;
}

.timeline-content:hover {
  background: var(--bg-tertiary);
  border-left-color: var(--accent-color);
  transform: translateX(4px);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.timeline-year {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--brand-color);
  margin-bottom: 0.25rem;
  font-family: 'Courier New', monospace;
}

.timeline-event {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.timeline-details {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--text-secondary);
}


/* ===== Spectral Display ===== */
.spectral-display {
  margin: 1rem 0;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

#spectrumCanvas {
  width: 100%;
  height: auto;
  max-width: 600px;
  display: block;
  margin: 0 auto;
  border-radius: 4px;
  box-shadow: 0 2px 8px var(--shadow);
}

.spectral-legend {
  text-align: center;
  margin-top: 0.5rem;
}

.spectral-dot {
  display: inline-block;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  vertical-align: middle;
  box-shadow: 0 1px 3px var(--shadow);
}

/* ===== Buttons ===== */
.btn {
  transition: all var(--transition-speed) var(--transition-function);
}



/* ===== Footer ===== */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}

.footer a {
  color: var(--brand-color);
  text-decoration: none;
  transition: color var(--transition-speed) var(--transition-function);
}

.footer a:hover {
  color: var(--text-primary);
  text-decoration: underline;
}

/* ===== Responsive Design ===== */
@media (max-width: 1400px) {
  .periodic-table-grid {
    grid-template-columns: repeat(18, 60px);
    grid-template-rows: repeat(7, 60px);
  }
  
  .element-card {
    min-height: 60px;
  }
  
  .element-symbol {
    font-size: 1.2rem;
  }
  
  .element-name {
    font-size: 0.6rem;
  }
}

@media (max-width: 992px) {
  .brand-text {
    display: none;
  }
  
  .status-info {
    font-size: 0.8rem;
  }
  
  .periodic-table-grid {
    grid-template-columns: repeat(18, 50px);
    grid-template-rows: repeat(7, 50px);
    gap: 3px;
  }
  
  .element-card {
    min-height: 50px;
    padding: 0.25rem;
  }
  
  .element-symbol {
    font-size: 1rem;
  }
  
  .element-name {
    font-size: 0.55rem;
  }
  
  .element-weight {
    display: none;
  }
  
  .f-block-elements .element-card {
    width: 50px;
    min-height: 60px;
  }
}

@media (max-width: 768px) {
  .periodic-table-container {
    padding: 0.5rem;
  }
  
  .periodic-table-grid {
    grid-template-columns: repeat(18, 42px);
    grid-template-rows: repeat(7, 42px);
    gap: 2px;
    min-width: 800px;
  }
  
  .element-card {
    min-height: 42px;
    border-radius: 4px;
  }
  
  .element-number {
    font-size: 0.6rem;
    top: 2px;
    left: 3px;
  }
  
  .element-symbol {
    font-size: 0.9rem;
  }
  
  .element-name {
    font-size: 0.5rem;
  }
  
  .f-block-label {
    font-size: 0.8rem;
    min-width: 80px;
  }
  
  .f-block-elements .element-card {
    width: 42px;
    min-height: 52px;
  }
  
  .modal-dialog {
    margin: 0.5rem;
  }
  
  .element-symbol-large {
    font-size: 2rem;
  }
}

@media (max-width: 576px) {
  #statusBar .row {
    font-size: 0.85rem;
  }
  
  .brand {
    font-size: 1.2rem;
  }
  
  .brand-icon {
    font-size: 1.4rem;
  }
  
  .status-info span {
    font-size: 0.75rem;
  }
  
  .card-body {
    padding: 1rem;
  }
  
  .form-label {
    font-size: 0.85rem;
  }
}

/* ===== Animations ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.element-card {
  animation: fadeIn 0.3s var(--transition-function) backwards;
}

.element-card:nth-child(n) {
  animation-delay: calc(0.01s * var(--i, 0));
}

/* ===== Scrollbar Styling ===== */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* Firefox */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--border-color) var(--bg-secondary);
}

/* ===== Print Styles ===== */
@media print {
  #statusBar,
  .footer,
  .card-body > .row:first-child,
  .modal {
    display: none !important;
  }
  
  body {
    background: white;
  }
  
  .periodic-table-grid {
    page-break-inside: avoid;
  }
}