.download { float: left; width: 720px; height: 112px; }
.btn_1 { width: 280px; height: 100px; text-align: center; font-size: 13px; color: rgb(0, 0, 0); margin-right: 20px; background: url("../images/btn1.png") left top no-repeat; display: block; transition: letter-spacing 0.3s ease-in 0s; }
.btn_1:hover { background: url("../images/btn1-h.png") left top no-repeat; letter-spacing: 4px; }
.btn_2 { width: 280px; height: 100px; text-align: center; font-size: 13px; color: rgb(0, 0, 0); margin-top: -102px; margin-left: 356px; background: url("../images/btn2.png") right top no-repeat; display: block; transition: letter-spacing 0.3s ease-in 0s; }
.btn_2:hover { background: url("../images/btn2-h.png") left top no-repeat; letter-spacing: 4px; }