/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --cat-alkali: #C5A059;
  --cat-alkaline: #9a7d38;
  --cat-transition: #003366;
  --cat-post: #1a5a8a;
  --cat-metalloid: #2d7d4a;
  --cat-nonmetal: #1a7a6e;
  --cat-halogen: #6b3fa0;
  --cat-noble: #8b1a4a;
  --cat-lanthanide: #7a3a00;
  --cat-actinide: #5a0000;
  --cat-unknown: #4a4a55;

  --bg: #FAFAFA;
  --surface: #FFFFFF;
  --border: rgba(0,0,0,0.10);
  --border-strong: rgba(0,0,0,0.18);
  --text-primary: #0f172a;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  --accent: #003366;
  --gold: #C5A059;

  --radius: 6px;
  --radius-lg: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.05);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.12), 0 2px 6px rgba(0,0,0,0.07);
}

html { font-size: 16px; }

body {
  font-family: 'DM Sans', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
}

/* ===== Layout ===== */
#app {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
}

/* ===== Header ===== */
header {
  margin-bottom: 1.5rem;
}

header h1 {
  font-family: 'DM Mono', monospace;
  font-size: 1.75rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: -0.02em;
}

.subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 2px;
  font-family: 'DM Mono', monospace;
}

/* ===== Toolbar ===== */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-bottom: 1rem;
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  flex: 1;
}

.filter-btn {
  font-family: 'DM Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.04em;
  padding: 4px 10px;
  border-radius: 20px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.13s ease;
  white-space: nowrap;
}

.filter-btn:hover {
  background: #f1f5f9;
  color: var(--text-primary);
}

.filter-btn.active { color: #fff; border-color: transparent; }
.filter-btn[data-cat="all"].active { background: var(--accent); }
.filter-btn[data-cat="alkali-metal"].active { background: var(--cat-alkali); }
.filter-btn[data-cat="alkaline-earth-metal"].active { background: var(--cat-alkaline); }
.filter-btn[data-cat="transition-metal"].active { background: var(--cat-transition); }
.filter-btn[data-cat="post-transition-metal"].active { background: var(--cat-post); }
.filter-btn[data-cat="metalloid"].active { background: var(--cat-metalloid); }
.filter-btn[data-cat="nonmetal"].active { background: var(--cat-nonmetal); }
.filter-btn[data-cat="halogen"].active { background: var(--cat-halogen); }
.filter-btn[data-cat="noble-gas"].active { background: var(--cat-noble); }
.filter-btn[data-cat="lanthanide"].active { background: var(--cat-lanthanide); }
.filter-btn[data-cat="actinide"].active { background: var(--cat-actinide); }

/* ===== Search ===== */
.search-wrap {
  position: relative;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 9px;
  width: 14px;
  height: 14px;
  color: var(--text-muted);
  pointer-events: none;
}

#search-input {
  font-family: 'DM Mono', monospace;
  font-size: 11px;
  padding: 5px 10px 5px 28px;
  border-radius: 20px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text-primary);
  width: 160px;
  outline: none;
  transition: border-color 0.15s;
}

#search-input::placeholder { color: var(--text-muted); }
#search-input:focus { border-color: var(--accent); }

/* ===== Grid ===== */
.grid-scroll {
  overflow: visible;
  padding-bottom: 4px;
  container-type: inline-size;
}

.pt-grid {
  display: grid;
  grid-template-columns: repeat(18, 1fr);
  gap: 2px;
  width: 100%;
}

/* ===== Element cells ===== */
.el {
  width: 100%;
  height: auto;
  aspect-ratio: 1;
  border-radius: var(--radius);
  border: 1px solid rgba(255,255,255,0.15);
  cursor: pointer;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  transition: transform 0.12s ease, box-shadow 0.12s ease, opacity 0.15s ease;
  outline: none;
  user-select: none;
}

.el:hover, .el:focus-visible {
  transform: scale(1.18);
  z-index: 20;
  box-shadow: var(--shadow-lg);
}

.el:focus-visible {
  box-shadow: 0 0 0 2px var(--gold), var(--shadow-lg);
}

.el.dimmed { opacity: 0.12; transform: none !important; pointer-events: none; }
.el.highlighted { opacity: 1; }

/* Category colors */
.el[data-cat="alkali-metal"]          { background: var(--cat-alkali); }
.el[data-cat="alkaline-earth-metal"]  { background: var(--cat-alkaline); }
.el[data-cat="transition-metal"]      { background: var(--cat-transition); }
.el[data-cat="post-transition-metal"] { background: var(--cat-post); }
.el[data-cat="metalloid"]             { background: var(--cat-metalloid); }
.el[data-cat="nonmetal"]              { background: var(--cat-nonmetal); }
.el[data-cat="halogen"]               { background: var(--cat-halogen); }
.el[data-cat="noble-gas"]             { background: var(--cat-noble); }
.el[data-cat="lanthanide"]            { background: var(--cat-lanthanide); }
.el[data-cat="actinide"]              { background: var(--cat-actinide); }
.el[data-cat="unknown"]               { background: var(--cat-unknown); }

/* Text inside cells */
.el-num {
  font-family: 'DM Mono', monospace;
  font-size: 1cqw;
  color: rgba(255,255,255,0.65);
  position: absolute;
  top: 2px;
  left: 3px;
  line-height: 1;
}

.el-sym {
  font-family: 'DM Mono', monospace;
  font-size: 2cqw;
  font-weight: 500;
  color: #fff;
  line-height: 1;
}

.el-name {
  font-family: 'DM Mono', monospace;
  font-size: 0.8cqw;
  color: rgba(255,255,255,0.75);
  margin-top: 1px;
  line-height: 1;
}


.blank { visibility: hidden; pointer-events: none; }

/* ===== Detail Panel ===== */
.panel {
  display: none;
  margin-top: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem 1.25rem;
  box-shadow: var(--shadow-lg);
  position: relative;
  animation: slide-in 0.18s ease;
}

.panel.visible { display: block; }

@keyframes slide-in {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.panel-close {
  position: absolute;
  top: 12px;
  right: 14px;
  background: none;
  border: none;
  font-size: 20px;
  color: var(--text-muted);
  cursor: pointer;
  line-height: 1;
  padding: 2px 5px;
  border-radius: 4px;
  transition: color 0.12s, background 0.12s;
}

.panel-close:hover { color: var(--text-primary); background: #f1f5f9; }

.panel-header {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.panel-sym-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 72px;
  min-width: 72px;
  height: 72px;
  border-radius: 10px;
  gap: 1px;
  flex-shrink: 0;
}

/* Reuse category bg colors on the panel block */
.panel-sym-block[data-cat="alkali-metal"]          { background: var(--cat-alkali); }
.panel-sym-block[data-cat="alkaline-earth-metal"]  { background: var(--cat-alkaline); }
.panel-sym-block[data-cat="transition-metal"]      { background: var(--cat-transition); }
.panel-sym-block[data-cat="post-transition-metal"] { background: var(--cat-post); }
.panel-sym-block[data-cat="metalloid"]             { background: var(--cat-metalloid); }
.panel-sym-block[data-cat="nonmetal"]              { background: var(--cat-nonmetal); }
.panel-sym-block[data-cat="halogen"]               { background: var(--cat-halogen); }
.panel-sym-block[data-cat="noble-gas"]             { background: var(--cat-noble); }
.panel-sym-block[data-cat="lanthanide"]            { background: var(--cat-lanthanide); }
.panel-sym-block[data-cat="actinide"]              { background: var(--cat-actinide); }
.panel-sym-block[data-cat="unknown"]               { background: var(--cat-unknown); }

.panel-big-num {
  font-family: 'DM Mono', monospace;
  font-size: 9px;
  color: rgba(255,255,255,0.65);
  line-height: 1;
}

.panel-big-sym {
  font-family: 'DM Mono', monospace;
  font-size: 28px;
  font-weight: 500;
  color: #fff;
  line-height: 1;
}

.panel-big-mass {
  font-family: 'DM Mono', monospace;
  font-size: 9px;
  color: rgba(255,255,255,0.75);
  line-height: 1;
}

.panel-title {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-right: 2rem;
}

.panel-title h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.01em;
  line-height: 1.2;
}

.panel-meta {
  font-family: 'DM Mono', monospace;
  font-size: 10px;
  color: var(--text-muted);
  margin-top: 4px;
  letter-spacing: 0.03em;
}

.panel-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1rem;
  border-left: 2px solid var(--gold);
  padding-left: 12px;
}

.panel-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: 8px;
  margin-bottom: 1rem;
}

.stat {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px 10px;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.stat.wide { grid-column: 1 / -1; }

.stat-label {
  font-family: 'DM Mono', monospace;
  font-size: 9px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.stat-val {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-primary);
}

.stat-val.mono {
  font-family: 'DM Mono', monospace;
  font-size: 12px;
}

/* Panel navigation */
.panel-nav {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  border-top: 1px solid var(--border);
  padding-top: 10px;
}

.nav-btn {
  font-family: 'DM Mono', monospace;
  font-size: 11px;
  padding: 5px 12px;
  border-radius: 20px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.13s;
}

.nav-btn:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ===== Footer ===== */
footer {
  margin-top: 2.5rem;
  text-align: center;
  font-family: 'DM Mono', monospace;
  font-size: 10px;
  color: var(--text-muted);
  letter-spacing: 0.03em;
}

/* ===== Responsive ===== */
@media (max-width: 650px) {
  #app { padding: 1rem 0.75rem 2rem; }

  .el-name { display: none; }

  .panel-title h2 { font-size: 1.1rem; }
  .panel-stats { grid-template-columns: 1fr 1fr; }
}