html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, font, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td {
margin: 0;
padding: 0;
border: 0;
outline: 0;
font-weight: inherit;
font-style: inherit;
font-size: 100%;
font-family: inherit;
vertical-align: baseline;
background: transparent;
}
/* remember to define focus styles! */
:focus {
outline: 0;
}
body {
line-height: 1;
color: black;
background: white;
}
ol, ul {
list-style: none;
}
/* tables still need 'cellspacing="0"' in the markup */
table {
border-collapse: collapse;
border-spacing: 0;
}
caption, th, td {
text-align: left;
font-weight: normal;
}
blockquote:before, blockquote:after,
q:before, q:after {
content: "";
}
blockquote, q {
quotes: "" "";
}
.all {
   width: 685px;
   height: 300px;
   margin: auto;
   position: absolute;
   top:0; bottom:0; 
   left:0; right:0; 
   max-width: 100%;
   max-height: 100%;
      }
      
    .top{position:absolute;top:0;left:0;opacity:0;
      -webkit-transition: opacity 0.5s ease-in-out;
      -moz-transition: opacity 0.5s ease-in-out;
      -ms-transition: opacity 0.5s ease-in-out;
      -transition: opacity 0.5s ease-in-out;
    }
    .bottom{opacity:1;
      -webkit-transition: opacity 0.5s ease-in-out;
      -moz-transition: opacity 0.5s ease-in-out;
      -ms-transition: opacity 0.5s ease-in-out;
      -transition: opacity 0.5s ease-in-out;
     }
    .top:hover{opacity:1;}
    .bottom:hover{opacity:0;}