:root {
  color-scheme: light;
  --ink: #eee7dd;
  --muted: #b2a89a;
  --paper: #181412;
  --accent: #ff8a5b;
  --accent-dark: #d96135;
  --panel: #241d1a;
  --shadow: 0 24px 60px rgba(10, 6, 4, 0.5);
  --stroke: rgba(240, 220, 200, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Source Sans 3", "Segoe UI", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 20% 20%, rgba(96, 70, 50, 0.5), transparent 55%),
    radial-gradient(circle at 85% 10%, rgba(50, 40, 35, 0.6), transparent 45%),
    linear-gradient(135deg, #171311, #201917);
  min-height: 100vh;
}

.page {
  max-width: 1200px;
  margin: 0 auto;
  padding: 48px 24px 40px;
}

.hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  align-items: center;
  margin-bottom: 36px;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-size: 0.75rem;
  margin: 0 0 12px;
  color: var(--muted);
}

h1 {
  font-family: "Playfair Display", "Times New Roman", serif;
  font-size: clamp(2.2rem, 4vw, 3.4rem);
  margin: 0 0 12px;
  letter-spacing: 0.01em;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
  letter-spacing: 0.01em;
}

.hero-card {
  background: var(--panel);
  padding: 24px;
  border-radius: 24px;
  box-shadow: var(--shadow);
  border: 1px solid var(--stroke);
  display: grid;
  gap: 16px;
}

.hero-stat {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
}

.hero-stat span {
  color: var(--muted);
  font-size: 0.9rem;
}

.hero-stat strong {
  font-size: 1.2rem;
}

.primary {
  background: var(--accent);
  color: white;
  border: none;
  padding: 12px 16px;
  border-radius: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 24px rgba(255, 106, 61, 0.28);
}

.layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.panel {
  background: var(--panel);
  border-radius: 22px;
  padding: 22px;
  border: 1px solid var(--stroke);
  box-shadow: var(--shadow);
  min-height: auto;
}

.panel-header h2,
.panel-header h3 {
  margin: 0 0 6px;
}

.panel-header p {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 0.95rem;
  letter-spacing: 0.01em;
}

.table-wrap {
  overflow: visible;
  padding-bottom: 0;
}

.table {
  display: grid;
  grid-template-columns: repeat(18, minmax(28px, 1fr));
  gap: 5px;
  min-width: 0;
}

.element {
  background: #2b2320;
  border-radius: 12px;
  padding: 4px;
  border: 1px solid rgba(255, 138, 91, 0.25);
  text-align: center;
  cursor: grab;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  font-size: 0.68rem;
  user-select: none;
}

.element.metal {
  background: #2a1f18;
  border-color: rgba(255, 155, 80, 0.45);
}

.element.nonmetal {
  background: #1b2530;
  border-color: rgba(110, 170, 255, 0.4);
}

.element.metalloid {
  background: #222132;
  border-color: rgba(170, 150, 255, 0.45);
}

.element:active {
  cursor: grabbing;
}

.element:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 18px rgba(255, 106, 61, 0.2);
}

.element .symbol {
  display: block;
  font-weight: 700;
  font-size: 0.85rem;
}

.element .number {
  color: var(--muted);
  font-size: 0.58rem;
}

.bond-section {
  display: grid;
  grid-template-columns: minmax(260px, 1.2fr) minmax(220px, 0.8fr);
  gap: 18px;
  align-items: start;
}

.bond-area {
  position: relative;
  min-height: 180px;
  border-radius: 22px;
  border: 2px dashed rgba(255, 138, 91, 0.45);
  background: linear-gradient(135deg, rgba(52, 38, 32, 0.9), rgba(34, 28, 26, 0.9));
  margin-bottom: 10px;
  overflow: hidden;
}

.bond-area.drag-over {
  background: rgba(255, 138, 91, 0.12);
}

.bond-node {
  position: absolute;
  display: grid;
  place-items: center;
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: #2d231d;
  border: 1px solid rgba(255, 138, 91, 0.35);
  cursor: grab;
  user-select: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.bond-node:active {
  cursor: grabbing;
}

.bond-node:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 22px rgba(255, 138, 91, 0.22);
}

.bond-node .symbol {
  font-size: 1.5rem;
  font-weight: 700;
}

.bond-node .number {
  font-size: 0.7rem;
  color: var(--muted);
}

.hint {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 0.9rem;
}

.bond-lines {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.details {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.detail-card {
  background: #2a211e;
  border-radius: 16px;
  padding: 12px;
  border: 1px solid rgba(255, 138, 91, 0.2);
  min-height: 110px;
}

.bond-canvas {
  position: relative;
}

.trash {
  position: absolute;
  right: 14px;
  bottom: 14px;
  background: rgba(20, 16, 14, 0.75);
  border: 1px solid rgba(255, 138, 91, 0.35);
  border-radius: 14px;
  padding: 8px 10px;
  display: inline-flex;
  gap: 6px;
  align-items: center;
  color: var(--muted);
  font-size: 0.85rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.trash.active {
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(255, 138, 91, 0.2);
  color: var(--ink);
}

.detail-card h4 {
  margin: 0 0 8px;
}

.detail-card ul {
  margin: 0;
  padding-left: 16px;
  color: var(--muted);
  line-height: 1.55;
}

.footer {
  text-align: center;
  margin-top: 32px;
  color: var(--muted);
  font-size: 0.85rem;
}

@media (max-width: 720px) {
  .table {
    grid-template-columns: repeat(9, minmax(32px, 1fr));
    gap: 6px;
  }

  .panel {
    min-height: auto;
  }
  .table-wrap {
    overflow-x: auto;
    padding-bottom: 6px;
  }

  .bond-section {
    grid-template-columns: 1fr;
  }
}
.bond-side .hero-card {
  margin-bottom: 18px;
}