elementui modify the font color of the prompt text (placeholder) el-input/el-input-number/el-select/el-cascader/el-time-select applicable

elementui modify the font color of the prompt text (placeholder)
el-input/el-input-number/el-select/el-cascader/el-time-select/el-date-picker are applicable

achieve effect

Implementation code

		.el-input__inner::placeholder {
			color: #4cc;
		}