为什么按钮文本在8浏览器中始终显示白色？

Question

我使用的是以下按钮样式。

.button{
 border:1px solid #8dbdd8;
 color:#000000;
 font-size:10px;
 font-family:arial, helvetica, sans-serif;
 width:50px;
 vertical-align:top;
 margin-top: 0px;
 background-image: -webkit-gradient(linear, left top, left bottom, from(#92cfde), to(#76bdd1));
 background-image: -webkit-linear-gradient(top, #92cfde, #76bdd1);
 background-image: -moz-linear-gradient(top, #92cfde, #76bdd1);
 background-image: -ms-linear-gradient(top, #92cfde, #76bdd1);
 background-image: -o-linear-gradient(top, #92cfde, #76bdd1);
 background-image: linear-gradient(to bottom, #92cfde, #76bdd1);
 filter:progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr=#92cfde, endColorstr=#76bdd1);
}
.button{
 border:1px solid #44adc6;
 background-color: #8dbdd8; 
 background-image: -webkit-gradient(linear, left top, left bottom, from(#6bbed2), to(#50abc4));
 background-image: -webkit-linear-gradient(top, #6bbed2, #50abc4);
 background-image: -moz-linear-gradient(top, #6bbed2, #50abc4);
 background-image: -ms-linear-gradient(top, #6bbed2, #50abc4);
 background-image: -o-linear-gradient(top, #6bbed2, #50abc4);
 background-image: linear-gradient(to bottom, #6bbed2, #50abc4);
 filter:progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr=#6bbed2, endColorstr=#50abc4);
}

问题是我给了文字颜色为黑色。但是总是只显示白色。这个问题只有用户拥有ie8浏览器是最新的如果用户有ie9它不会影响。请告诉我如何解决这个问题ie8浏览器？