html, body, div, a {
    padding: 0;
    margin: 0;
}

.wrap {
    margin: 0 auto;
    overflow: hidden;
}

.btn {
    display: block;
    text-decoration: none;
    text-indent: -1000px;
    overflow: hidden;
}


.wrap.bv {
    background: url(../img/b/240x400.png) no-repeat 0 0;
    width: 240px;
    height: 400px;
}

.bv .btn {
    margin: 340px auto;
    background: url(../img/b/btn.png) no-repeat 0 0;
    width: 173px;
    height: 38px;
}
.bv .btn:hover {
    background-position: 0 -38px;
}


.wrap.bh {
    background: url(../img/b/980x500.jpg) no-repeat 0 0;
    width: 980px;
    height: 500px;
}

.bh .btn {
    margin: 410px auto;
    background: url(../img/b/btnh.png) no-repeat 0 0;
    width: 296px;
    height: 65px;
}
.bh .btn:hover {
    background-position: 0 -65px;
}