.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 200ms ease-out;
}

.modal-backdrop[hidden] {
  display: none;
}

.modal-backdrop.is-open {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.75);
  border-radius: 16px;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.18), 0 4px 16px rgba(0, 0, 0, 0.08);
  display: grid;
  grid-template-columns: 220px 1fr;
  max-width: 760px;
  width: 100%;
  max-height: 90vh;
  overflow: hidden;
  position: relative;
  transform: scale(0.95);
  transition: transform 300ms ease-out;
}

.modal-backdrop.is-open .modal-card {
  transform: scale(1);
}

.modal-close {
  position: absolute;
  top: 12px;
  right: 14px;
  background: rgba(0, 0, 0, 0.07);
  border: none;
  border-radius: 50%;
  width: 28px;
  height: 28px;
  font-size: 1.1rem;
  cursor: pointer;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
  z-index: 10;
}

.modal-close:hover {
  background: rgba(0, 0, 0, 0.14);
}

.modal-left {
  background: linear-gradient(160deg, #f5f7ff, #eef0f8);
  border-right: 1px solid rgba(0, 0, 0, 0.06);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 32px 16px 24px;
}

.atom-container {
  width: 200px;
  height: 200px;
  position: relative;
}

.modal-symbol {
  font-size: 3rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.modal-right {
  overflow-y: auto;
  padding: 28px 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.modal-header-info h2 {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.modal-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 2px;
  text-transform: capitalize;
}

.modal-props-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px 16px;
}

.prop-item {
  display: flex;
  flex-direction: column;
  gap: 1px;
}

.prop-label {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.prop-value {
  font-size: 0.82rem;
  color: var(--text-primary);
  font-weight: 500;
}

.modal-description {
  font-size: 0.83rem;
  line-height: 1.6;
  color: var(--text-secondary);
}

.modal-section h3 {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.modal-section ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.modal-section ul li {
  font-size: 0.82rem;
  color: var(--text-secondary);
  padding-left: 12px;
  position: relative;
}

.modal-section ul li::before {
  content: '\2014';
  position: absolute;
  left: 0;
  color: var(--text-muted);
}

@media (max-width: 600px) {
  .modal-card {
    grid-template-columns: 1fr;
  }
  .modal-left {
    border-right: none;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    padding: 24px 16px 16px;
  }
  .atom-container {
    width: 140px;
    height: 140px;
  }
}