I made this responsive grid that does what you need using CSS. It uses media queries and nth-child().
The horizontal and vertical margins are equal.
It shows you can use calculation to position grid elements with equal margins between each other. The margin between elements and window is also the same.
Code for screens wider than 751px isn't written yet though but you get the idea. Here is the code :
HTML :
<div id="container">
<div class="wrap">
<div class="foto">1</div>
</div>
<div class="wrap">
<div class="foto">2</div>
</div>
<div class="wrap">
<div class="foto">3</div>
</div>
... And so on ...
</div>
CSS :
html, body {
margin:0;
padding:0;
min-width:150px;
}
.wrap {
float:left;
position:relative;
}
.foto {
width: 150px;
height: 150px;
background: gold;
position:absolute;
}
#warning{display:none;}
@media screen and (min-width: 631px) {
.wrap {
width:20%;
padding-bottom:25%;
}
.wrap:nth-child(4n+2), .wrap:nth-child(4n+3){
}
.wrap .foto {
top:-75px;
margin-top:100%;
right:-30px;
}
.wrap:nth-child(4n+2){
margin:0 5% 0 7.5%;
}
.wrap:nth-child(4n+3){
margin-right:7.5%;
}
.wrap:nth-child(4n+2) .foto{
left:50%;
margin-left:-75px;
}
.wrap:nth-child(4n+3) .foto{
right:50%;
margin-right:-75px;
}
.wrap:nth-child(4n) .foto{
left:-30px;
}
#container{
margin-top:-45px;
}
}
@media screen and (min-width: 481px) and (max-width: 631px) {
.wrap {
width:25%;
padding-bottom:33.3%;
}
.wrap:nth-child(3n+2){
margin:0 12.5%;
}
.wrap .foto {
top:-75px;
margin-top:100%;
right:-37px;
}
.wrap:nth-child(3n+2) .foto{
left:50%;
margin-left:-75px;
}
.wrap:nth-child(3n) .foto{
left:-37px;
}
#container{
margin-top:-37px;
}
}
@media screen and (min-width: 331px) and (max-width: 480px) {
.wrap {
width:33.3%;
padding-bottom:50%;
clear:left;
}
.wrap:nth-child(even) {
float:right;
clear:right;
}
.wrap .foto {
top:-75px;
margin-top:100%;
right:-50px;
}
.wrap:nth-child(even) .foto {
left:-50px;
}
.wrap:nth-child(4n+3) .foto, .wrap:nth-child(4n+4) .foto {
bottom:-75px;
margin-bottom:100%;
}
#container{
margin-top:-25px;
}
}
@media screen and (max-width: 330px) {
.wrap {
width:50%;
padding-bottom:100%;
clear:left;
}
.wrap:nth-child(odd) .foto {
right:-75px;
bottom:0;
bottom:-75px;
margin-bottom:100%;
}
.wrap:nth-child(even) .foto {
top:0px;
right:-75px;
top:-75px;
margin-top:100%;
}
}
@media screen and (min-width: 751px) {
#warning{
color:#fff;
display:block;
position:fixed;
width:100%;
height:50%;
top:25%;
left:0;
background:#000;
text-align:center;
font-size:30px;
}