bootstrap4.css
.container-fluid {
  width: 100%;
  padding-right: 15px;
  padding-left: 15px;
  margin-right: auto;
  margin-left: auto;
}
bootstrap4.css
.navbar > .container,
.navbar > .container-fluid {
  display: -ms-flexbox;
  display: flex;
  -ms-flex-wrap: wrap;
  flex-wrap: wrap;
  -ms-flex-align: center;
  align-items: center;
  -ms-flex-pack: justify;
  justify-content: space-between;
}
bootstrap4.css
@media (max-width: 575.98px) {
  .navbar-expand-sm > .container,
  .navbar-expand-sm > .container-fluid {
    padding-right: 0;
    padding-left: 0;
  }
}
bootstrap4.css
@media (min-width: 576px) {
  .navbar-expand-sm {
    -ms-flex-flow: row nowrap;
    flex-flow: row nowrap;
    -ms-flex-pack: start;
    justify-content: flex-start;
  }
  .navbar-expand-sm .navbar-nav {
    -ms-flex-direction: row;
    flex-direction: row;
  }
  .navbar-expand-sm .navbar-nav .dropdown-menu {
    position: absolute;
  }
  .navbar-expand-sm .navbar-nav .nav-link {
    padding-right: 0.5rem;
    padding-left: 0.5rem;
  }
  .navbar-expand-sm > .container,
  .navbar-expand-sm > .container-fluid {
    -ms-flex-wrap: nowrap;
    flex-wrap: nowrap;
  }
  .navbar-expand-sm .navbar-collapse {
    display: -ms-flexbox !important;
    display: flex !important;
    -ms-flex-preferred-size: auto;
    flex-basis: auto;
  }
  .navbar-expand-sm .navbar-toggler {
    display: none;
  }
}
bootstrap4.css
@media (max-width: 767.98px) {
  .navbar-expand-md > .container,
  .navbar-expand-md > .container-fluid {
    padding-right: 0;
    padding-left: 0;
  }
}
bootstrap4.css
@media (min-width: 768px) {
  .navbar-expand-md {
    -ms-flex-flow: row nowrap;
    flex-flow: row nowrap;
    -ms-flex-pack: start;
    justify-content: flex-start;
  }
  .navbar-expand-md .navbar-nav {
    -ms-flex-direction: row;
    flex-direction: row;
  }
  .navbar-expand-md .navbar-nav .dropdown-menu {
    position: absolute;
  }
  .navbar-expand-md .navbar-nav .nav-link {
    padding-right: 0.5rem;
    padding-left: 0.5rem;
  }
  .navbar-expand-md > .container,
  .navbar-expand-md > .container-fluid {
    -ms-flex-wrap: nowrap;
    flex-wrap: nowrap;
  }
  .navbar-expand-md .navbar-collapse {
    display: -ms-flexbox !important;
    display: flex !important;
    -ms-flex-preferred-size: auto;
    flex-basis: auto;
  }
  .navbar-expand-md .navbar-toggler {
    display: none;
  }
}
bootstrap4.css
@media (max-width: 991.98px) {
  .navbar-expand-lg > .container,
  .navbar-expand-lg > .container-fluid {
    padding-right: 0;
    padding-left: 0;
  }
}
bootstrap4.css
@media (min-width: 992px) {
  .navbar-expand-lg {
    -ms-flex-flow: row nowrap;
    flex-flow: row nowrap;
    -ms-flex-pack: start;
    justify-content: flex-start;
  }
  .navbar-expand-lg .navbar-nav {
    -ms-flex-direction: row;
    flex-direction: row;
  }
  .navbar-expand-lg .navbar-nav .dropdown-menu {
    position: absolute;
  }
  .navbar-expand-lg .navbar-nav .nav-link {
    padding-right: 0.5rem;
    padding-left: 0.5rem;
  }
  .navbar-expand-lg > .container,
  .navbar-expand-lg > .container-fluid {
    -ms-flex-wrap: nowrap;
    flex-wrap: nowrap;
  }
  .navbar-expand-lg .navbar-collapse {
    display: -ms-flexbox !important;
    display: flex !important;
    -ms-flex-preferred-size: auto;
    flex-basis: auto;
  }
  .navbar-expand-lg .navbar-toggler {
    display: none;
  }
}
bootstrap4.css
@media (max-width: 1199.98px) {
  .navbar-expand-xl > .container,
  .navbar-expand-xl > .container-fluid {
    padding-right: 0;
    padding-left: 0;
  }
}
bootstrap4.css
@media (min-width: 1200px) {
  .navbar-expand-xl {
    -ms-flex-flow: row nowrap;
    flex-flow: row nowrap;
    -ms-flex-pack: start;
    justify-content: flex-start;
  }
  .navbar-expand-xl .navbar-nav {
    -ms-flex-direction: row;
    flex-direction: row;
  }
  .navbar-expand-xl .navbar-nav .dropdown-menu {
    position: absolute;
  }
  .navbar-expand-xl .navbar-nav .nav-link {
    padding-right: 0.5rem;
    padding-left: 0.5rem;
  }
  .navbar-expand-xl > .container,
  .navbar-expand-xl > .container-fluid {
    -ms-flex-wrap: nowrap;
    flex-wrap: nowrap;
  }
  .navbar-expand-xl .navbar-collapse {
    display: -ms-flexbox !important;
    display: flex !important;
    -ms-flex-preferred-size: auto;
    flex-basis: auto;
  }
  .navbar-expand-xl .navbar-toggler {
    display: none;
  }
}
bootstrap4.css
.navbar-expand > .container,
.navbar-expand > .container-fluid {
  padding-right: 0;
  padding-left: 0;
}
bootstrap4.css
.navbar-expand > .container,
.navbar-expand > .container-fluid {
  -ms-flex-wrap: nowrap;
  flex-wrap: nowrap;
}
■モーダル:modal:グリッドレイアウトを使用したモーダル

<div class="container"> 
  <button type="button" class="btn btn-secondary" data-toggle="modal" data-target="#exampleModal">モーダルボタン</button>
  <div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true"> 
    <div class="modal-dialog modal-dialog-centered" role="document"> 
      <div class="modal-content"> 
        <div class="modal-header"> 
          <h5 class="modal-title" id="exampleModalLabel">モーダルのタイトル</h5>
          <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
        </div>
        <div class="modal-body">
          <div class="container-fluid"> 
            <div class="row">
              <div class="col-md-4">col-md-4</div>
              <div class="col-md-4 ml-auto">col-md-4、ml-auto</div>
            </div>
            <div class="row">
              <div class="col-md-3 ml-auto">col-md-3、ml-auto</div>
              <div class="col-md-2 ml-auto">col-md-2、ml-auto</div>
            </div>
          </div>
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-secondary" data-dismiss="modal">閉じる</button>
        </div>
      </div>
      
    </div>
  </div>
</div>