.g div:nth-child(1) {
  width: calc(99.99% * 1/4 - (30px - 30px * 1/4));
}

.g div:nth-child(2) {
  width: calc(99.99% * 1/2 - (30px - 30px * 1/2));
}

.g div:nth-child(3) {
  width: calc(99.99% * 1/4 - (30px - 30px * 1/4));
}