调整大小的引导轮

我想调整引导传送带的宽度，使其适合整个页面，并且我想减小宽度并将其放置在中间。

<div id="carouselExampleControls" class="carousel slide" data-ride="carousel" data-interval="2500">
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img class="d-block w-100" src="./img/_L1A3780.jpg" alt="First slide">
    </div>
    <div class="carousel-item">
      <img class="d-block w-100" src="./img/CD2A0553.jpg" alt="Second slide">
    </div>
    <div class="carousel-item">
      <img class="d-block w-100" src="./img/CD2A2515.jpg" alt="Third slide">
    </div>
  </div>

CSS：

.carousel-item {
  height: 70vh;
  min-height: 350px;
  max-height: 700px;
  background: no-repeat center center scroll;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}


.carousel .carousel-item {
  transition-duration: 1.5s;
}