/* Modern Sci-Fi Chemistry Design System */
@import url('https://fonts.googleapis.com/css2?family=Fira+Code:wght@400;600&family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
  --bg-dark: #090d16;
  --bg-card: rgba(18, 26, 44, 0.7);
  --bg-card-hover: rgba(28, 40, 68, 0.9);
  --border-color: rgba(255, 255, 255, 0.1);
  --text-main: #f0f4f8;
  --text-muted: #8a9bb0;
  --accent-cyan: #00f0ff;
  --accent-glow: rgba(0, 240, 255, 0.3);

  /* Element Category Palette */
  --cat-alkali-metal: #ff4757;
  --cat-alkaline-earth: #ffa502;
  --cat-transition-metal: #00d2d3;
  --cat-post-transition-metal: #54a0ff;
  --cat-metalloid: #9c88ff;
  --cat-reactive-nonmetal: #2ed573;
  --cat-noble-gas: #ff6b81;
  --cat-lanthanide: #eccc68;
  --cat-actinide: #ff7f50;
  --cat-unknown: #747d8c;

  --shadow-glow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-dark);
  background-image: 
    radial-gradient(circle at 15% 15%, rgba(0, 240, 255, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 85% 85%, rgba(156, 136, 255, 0.05) 0%, transparent 40%);
  background-attachment: fixed;
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.5;
}

/* Header & Navigation */
header {
  background: rgba(13, 19, 33, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 1rem 2rem;
}

.header-container {
  max-width: 1600px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: #fff;
  text-decoration: none;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--accent-cyan), #7209b7);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: #fff;
  box-shadow: 0 0 15px var(--accent-glow);
}

.search-box {
  position: relative;
  flex: 1;
  max-width: 400px;
}

.search-box input {
  width: 100%;
  padding: 0.75rem 1rem 0.75rem 2.75rem;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-color);
  border-radius: 30px;
  color: #fff;
  font-size: 0.95rem;
  outline: none;
  transition: all 0.3s ease;
}

.search-box input:focus {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--accent-cyan);
  box-shadow: 0 0 15px var(--accent-glow);
}

.search-icon {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

.nav-tools {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.btn-toggle {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 0.6rem 1.2rem;
  border-radius: 30px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
}

.btn-toggle:hover, .btn-toggle.active {
  background: rgba(0, 240, 255, 0.15);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  box-shadow: 0 0 12px var(--accent-glow);
}

/* Main Content Area */
main {
  max-width: 1600px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
  flex: 1;
}

/* Filters & Category Pills Bar */
.controls-bar {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 1.25rem;
  border-radius: var(--radius-md);
  backdrop-filter: blur(10px);
}

.filter-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.category-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.pill {
  padding: 0.4rem 0.85rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
  transition: all 0.2s ease;
  user-select: none;
}

.pill:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
}

.pill.active {
  color: #fff;
  border-color: currentColor;
  box-shadow: 0 0 10px currentColor;
}

/* Category colors for active pills */
.pill[data-cat="alkali-metal"].active { color: var(--cat-alkali-metal); background: rgba(255, 71, 87, 0.15); }
.pill[data-cat="alkaline-earth"].active { color: var(--cat-alkaline-earth); background: rgba(255, 165, 2, 0.15); }
.pill[data-cat="transition-metal"].active { color: var(--cat-transition-metal); background: rgba(0, 210, 211, 0.15); }
.pill[data-cat="post-transition-metal"].active { color: var(--cat-post-transition-metal); background: rgba(84, 160, 255, 0.15); }
.pill[data-cat="metalloid"].active { color: var(--cat-metalloid); background: rgba(156, 136, 255, 0.15); }
.pill[data-cat="reactive-nonmetal"].active { color: var(--cat-reactive-nonmetal); background: rgba(46, 213, 115, 0.15); }
.pill[data-cat="noble-gas"].active { color: var(--cat-noble-gas); background: rgba(255, 107, 129, 0.15); }
.pill[data-cat="lanthanide"].active { color: var(--cat-lanthanide); background: rgba(236, 204, 104, 0.15); }
.pill[data-cat="actinide"].active { color: var(--cat-actinide); background: rgba(255, 127, 80, 0.15); }

/* Temperature Slider Box */
.temp-control {
  display: flex;
  align-items: center;
  gap: 1rem;
  background: rgba(0, 0, 0, 0.3);
  padding: 0.6rem 1.2rem;
  border-radius: 30px;
  border: 1px solid var(--border-color);
  min-width: 320px;
}

.temp-control label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
}

.temp-control input[type="range"] {
  flex: 1;
  accent-color: var(--accent-cyan);
  cursor: pointer;
}

.temp-display {
  font-family: 'Fira Code', monospace;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-cyan);
  min-width: 85px;
  text-align: right;
}

/* Heatmap Selector */
.select-box {
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--border-color);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-size: 0.85rem;
  outline: none;
  cursor: pointer;
}

/* Periodic Table Grid Container */
.periodic-table-wrapper {
  overflow-x: auto;
  padding-bottom: 1rem;
}

.periodic-table {
  display: grid;
  grid-template-columns: repeat(18, minmax(64px, 1fr));
  gap: 6px;
  min-width: 1200px;
}

/* Element Cell Component */
.element-cell {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.4rem 0.3rem;
  aspect-ratio: 1 / 1.15;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
  position: relative;
  transition: transform 0.2s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.2s ease, border-color 0.2s ease, opacity 0.3s ease;
  user-select: none;
}

.element-cell:hover {
  transform: translateY(-4px) scale(1.08);
  z-index: 10;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.6);
  border-color: #fff;
}

.element-cell.dimmed {
  opacity: 0.15;
  transform: scale(0.95);
  pointer-events: none;
}

/* Category Banners / Color Coding */
.element-cell::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

.element-cell[data-category="alkali-metal"]::before { background: var(--cat-alkali-metal); }
.element-cell[data-category="alkaline-earth"]::before { background: var(--cat-alkaline-earth); }
.element-cell[data-category="transition-metal"]::before { background: var(--cat-transition-metal); }
.element-cell[data-category="post-transition-metal"]::before { background: var(--cat-post-transition-metal); }
.element-cell[data-category="metalloid"]::before { background: var(--cat-metalloid); }
.element-cell[data-category="reactive-nonmetal"]::before { background: var(--cat-reactive-nonmetal); }
.element-cell[data-category="noble-gas"]::before { background: var(--cat-noble-gas); }
.element-cell[data-category="lanthanide"]::before { background: var(--cat-lanthanide); }
.element-cell[data-category="actinide"]::before { background: var(--cat-actinide); }
.element-cell[data-category="unknown"]::before { background: var(--cat-unknown); }

.cell-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.65rem;
  color: var(--text-muted);
}

.cell-number {
  font-family: 'Fira Code', monospace;
  font-weight: 600;
}

.cell-state-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
}
.cell-state-dot.Solid { background: #40c057; }
.cell-state-dot.Liquid { background: #4895ef; box-shadow: 0 0 6px #4895ef; }
.cell-state-dot.Gas { background: #ff6b81; box-shadow: 0 0 6px #ff6b81; }
.cell-state-dot.Unknown { background: #8a9bb0; }

.cell-symbol {
  font-size: 1.25rem;
  font-weight: 800;
  text-align: center;
  color: #fff;
  letter-spacing: -0.5px;
  line-height: 1;
  margin: 0.15rem 0;
}

.cell-name {
  font-size: 0.65rem;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--text-muted);
  font-weight: 500;
}

.cell-mass {
  font-family: 'Fira Code', monospace;
  font-size: 0.6rem;
  text-align: center;
  color: var(--text-muted);
  opacity: 0.8;
}

/* Separate Lanthanide & Actinide Block Spacer */
.f-block-spacer {
  grid-column: 1 / -1;
  height: 24px;
}

.f-block-label {
  grid-column: 1 / span 2;
  display: flex;
  align-items: center;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-cyan);
  letter-spacing: 0.5px;
}

/* List / Table View Styling */
.list-view-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  display: none;
}

.list-view-table th, .list-view-table td {
  padding: 0.85rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.9rem;
}

.list-view-table th {
  background: rgba(0, 0, 0, 0.4);
  color: var(--accent-cyan);
  font-weight: 700;
  cursor: pointer;
}

.list-view-table tr:hover {
  background: var(--bg-card-hover);
  cursor: pointer;
}

/* Chemistry Tools Section */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
  gap: 1.5rem;
  margin-top: 2.5rem;
}

.tool-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  backdrop-filter: blur(10px);
}

.tool-card h3 {
  font-size: 1.15rem;
  margin-bottom: 1rem;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.tool-input-group {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.tool-input-group input {
  flex: 1;
  padding: 0.75rem 1rem;
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: #fff;
  font-family: 'Fira Code', monospace;
  font-size: 1rem;
}

.btn-action {
  background: linear-gradient(135deg, var(--accent-cyan), #4895ef);
  border: none;
  color: #000;
  font-weight: 700;
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  cursor: pointer;
  transition: opacity 0.2s ease;
}

.btn-action:hover {
  opacity: 0.9;
}

.tool-result {
  background: rgba(0, 0, 0, 0.3);
  padding: 1rem;
  border-radius: 8px;
  font-family: 'Fira Code', monospace;
  font-size: 0.9rem;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

/* Quiz Option Buttons */
.quiz-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 1rem;
}

.btn-quiz-opt {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-color);
  color: #fff;
  padding: 0.75rem;
  border-radius: 8px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: center;
}

.btn-quiz-opt:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: var(--accent-cyan);
}

/* Element Inspector Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(5, 8, 15, 0.85);
  backdrop-filter: blur(12px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  padding: 1.5rem;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-container {
  background: #111827;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-lg);
  max-width: 850px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.8);
  display: flex;
  flex-direction: column;
}

.modal-close {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  background: rgba(255, 255, 255, 0.1);
  border: none;
  color: #fff;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  font-size: 1.2rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s ease;
  z-index: 10;
}

.modal-close:hover {
  background: rgba(255, 71, 87, 0.4);
}

.modal-body {
  padding: 2rem;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 2rem;
}

.modal-element-hero {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  position: relative;
}

.hero-number {
  position: absolute;
  top: 1rem;
  left: 1rem;
  font-family: 'Fira Code', monospace;
  font-size: 1.1rem;
  color: var(--text-muted);
}

.hero-symbol {
  font-size: 4.5rem;
  font-weight: 800;
  margin: 0.5rem 0;
  color: #fff;
  line-height: 1;
}

.hero-name {
  font-size: 1.5rem;
  font-weight: 700;
  color: #fff;
}

.hero-category {
  display: inline-block;
  margin-top: 0.5rem;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.bohr-canvas-container {
  margin-top: 1.25rem;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.bohr-canvas-container canvas {
  width: 200px;
  height: 200px;
}

.modal-details {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.detail-section h4 {
  font-size: 0.95rem;
  color: var(--accent-cyan);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.summary-text {
  color: #d1d5db;
  font-size: 0.95rem;
  line-height: 1.6;
}

.properties-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.prop-item {
  background: rgba(255, 255, 255, 0.04);
  padding: 0.75rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.prop-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  display: block;
}

.prop-val {
  font-family: 'Fira Code', monospace;
  font-size: 0.95rem;
  font-weight: 600;
  color: #fff;
}

/* Minimal Clean Social Footer (Matching Screenshot) */
.site-footer-minimal {
  margin-top: 4rem;
  padding: 4.5rem 1.5rem 3.5rem 1.5rem;
  background: radial-gradient(circle at center bottom, rgba(40, 10, 20, 0.7) 0%, #05070e 75%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  text-align: center;
}

.footer-social-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.social-btn {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: #ffffff;
  color: #000000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.25s ease, background 0.25s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.5);
}

.social-btn:hover {
  transform: translateY(-5px) scale(1.1);
  box-shadow: 0 10px 25px rgba(255, 255, 255, 0.35);
  background: #f8f9fa;
  color: #000000;
}

.site-footer-minimal .copyright-text {
  font-size: 0.95rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.65);
  letter-spacing: 0.2px;
}

.site-footer-minimal .author-link {
  color: rgba(255, 255, 255, 0.95);
  font-weight: 700;
  text-decoration: none;
  transition: color 0.2s ease;
}

.site-footer-minimal .author-link:hover {
  color: var(--accent-cyan);
  text-decoration: underline;
}