* {
  box-sizing: border-box;
}

body {
    display: flex;
    justify-content: space-evenly;
}

#menu {

}

#canva {
    display: flex;
    flex-wrap: wrap;
    width: calc(900px + 1px);
    border-top: 1px solid #d1d1d1;
    border-left: 1px solid #d1d1d1;
}

.square {
    border-bottom: 1px solid #d1d1d1;
    border-right: 1px solid #d1d1d1;
}