assets/style_v2.css

input:disabled {
    color: transparent !important;
}

/* Hide dropdown selected text */
.Select.is-disabled .Select-value-label {
    color: transparent !important;
}

/* Hide selected value AND placeholder when the dropdown is disabled */
.Select.is-disabled .Select-value,
.Select.is-disabled .Select-value-label,
.Select.is-disabled .Select-placeholder {
  color: transparent !important;
}

/* Some versions keep layout space; this fully removes the text nodes */
.Select.is-disabled .Select-value,
.Select.is-disabled .Select-placeholder {
  display: none !important;
}

.Select__control--is-disabled .Select__single-value,
.Select__control--is-disabled .Select__placeholder {
  color: transparent !important;
  display: none !important;
}

.Select.is-disabled .Select-control {
  background-color: #f5f5f5 !important;
}