设置input placeholder属性的字体颜色样式等

        input::-webkit-input-placeholder, textarea::-webkit-input-placeholder {
          /* WebKit browsers */
          color: #ced0d6;
        }
        input:-moz-placeholder, textarea:-moz-placeholder {
          /* Mozilla Firefox 4 to 18 */
          color: #ced0d6;
        }
        input::-moz-placeholder, textarea::-moz-placeholder {
          /* Mozilla Firefox 19+ */
          color: #ced0d6;
        }
        input:-ms-input-placeholder, textarea:-ms-input-placeholder {
          /* Internet Explorer 10+ */
          color: #ced0d6;
        }