.custom-selector {
  position: relative;
  width: 270px;
  font-family: 'Segoe UI', Arial, sans-serif;
  font-size: 16px;
  margin-bottom: 8px;
}

.custom-selector .selected {
  background: #f9fafb;
  padding: 14px 18px;
  border: 1.5px solid #bfc7d1;
  cursor: pointer;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(60, 60, 60, 0.04);
  transition: all 0.25s ease;
  color: #222;
  font-weight: 500;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.custom-selector .selected::after {
  content: '▼';
  font-size: 12px;
  color: #4f8cff;
  margin-left: 10px;
  transition: transform 0.2s ease;
}

.custom-selector.open .selected::after {
  transform: rotate(180deg);
}

.custom-selector .selected:hover,
.custom-selector.open .selected {
  border-color: #4f8cff;
  box-shadow: 0 4px 16px rgba(79, 140, 255, 0.12);
  background: #f0f7ff;
}

.custom-selector .options {
  display: none;
  position: absolute;
  width: 100%;
  background: #fff;
  border: 1.5px solid #bfc7d1;
  border-top: none;
  max-height: 280px;
  overflow-y: auto;
  z-index: 10;
  border-radius: 0 0 8px 8px;
  margin: 0;
  padding: 6px 0;
  list-style: none;
  box-shadow: 0 8px 24px rgba(60, 60, 60, 0.12);
  animation: fadeIn 0.2s;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-10px);}
  to { opacity: 1; transform: translateY(0);}
}

.custom-selector.open .options {
  display: block;
}

.custom-selector .options li {
  padding: 12px 18px;
  cursor: pointer;
  transition: all 0.15s;
  color: #333;
}

.custom-selector .options li:hover,
.custom-selector .options li:focus {
  background: #eaf2ff;
  color: #2563eb;
  padding-left: 24px;
}

.custom-selector .options li:not(:last-child) {
  border-bottom: 1px solid #f0f0f0;
}

.custom-selector .selected[data-has-value="true"] {
  color: #1746a2;
  font-weight: 600;
  background: #f0f7ff;
}

.selector-row {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-bottom: 32px;
  padding: 20px;
  background: #ffffff;
  border-radius: 12px;
}

#calc-btn {
  padding: 14px 24px;
  font-size: 16px;
  background: linear-gradient(135deg, #2563eb, #1746a2);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  margin-left: 10px;
  transition: all 0.25s;
  font-weight: 600;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

#calc-btn:hover {
  background: linear-gradient(135deg, #1746a2, #0d3179);
  transform: translateY(-2px);
  box-shadow: 0 6px 15px rgba(37, 99, 235, 0.25);
}

#calc-btn:active {
  transform: translateY(1px);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.2);
}

/* Custom scrollbar for options dropdown */
.custom-selector .options::-webkit-scrollbar {
  width: 8px;
}

.custom-selector .options::-webkit-scrollbar-track {
  background: #f1f1f1;
  border-radius: 8px;
}

.custom-selector .options::-webkit-scrollbar-thumb {
  background: #c5d5f2;
  border-radius: 8px;
}

.custom-selector .options::-webkit-scrollbar-thumb:hover {
  background: #a3bae9;
}