即使设置位置元素和 z-index，Z-index 也无法正常工作？

Question

我在 css 中的元素中添加了相对和绝对位置，但它不能正常工作。

这是我的 HTML 网站标题和功能部分的代码。我想让狗的图像出现在功能部分的后面。我已经为功能部分添加了 z-index 作为 1，但它没有出现在图像前面。

        <!-- Title -->
    <div class="row">
      <div class="col-lg-6">
        <h1>Meet new and interesting dogs nearby.</h1>

        <button type="button" class="btn btn-dark btn-lg download-button">
          <i class="fab fa-apple"></i> Download
        </button>

        <button
          type="button"
          class="btn btn-outline-light btn-lg download-button"
        >
          <i class="fab fa-google-play"></i> Download
        </button>
      </div>

      <div class="iphone-container col-lg-6">
        <img class="iphone" src="images/iphone6.png" alt="iphone-mockup" />
      </div>
    </div>
  </div>
</section>

<!-- Features -->

<section id="features">
  <div class="container-fluid">
    <div class="row">
      <div class="col-lg-4">
        <i class="far fa-check-circle fa-4x feature-img"></i>
        <h3>Easy to use.</h3>
        <p class="sub-text">So easy to use, even your dog could do it.</p>
      </div>

      <div class="col-lg-4">
        <i class="fas fa-bullseye fa-4x feature-img"></i>
        <h3>Elite Clientele</h3>
        <p class="sub-text">We have all the dogs, the greatest dogs.</p>
      </div>

      <div class="col-lg-4">
        <i class="fas fa-heart fa-4x feature-img"></i>
        <h3>Guaranteed to work.</h3>
        <p class="sub-text">
          Find the love of your dog's life or your money back.
        </p>
      </div>
    </div>
  </div>
</section>

这是我的CSS代码

.iphone{
  width: 60%;
  transform: rotate(25deg);
  position: absolute;
  right: 30%;
 }

.iphone-container {
 position: relative;
 }

/* Features */

#features {
 padding: 10% 15%;
 position: relative;
 text-align: center;
 z-index: 1;
 }

我网站问题的图片

我想要的结果的图片

Answer 1

请查看我在底部 /* additions */ 下所做的 CSS 更改。对于 #features 部分，它默认为白色背景，实际上您必须声明 background-color: white; 以便 CSS 知道将白色背景放在 section#title[= 的前面16=]

body {
  font-family: "Montserrat";
}

#title {
  background-color: #000b49;
  color: white;
}

h1 {
  font-family: "Montserrat";
  font-size: 3.5rem;
  line-height: 1.5;
  font-weight: 900;
}

h2 {
  font-family: "Montserrat";
  font-size: 2.5rem;
  font-weight: 500;
}

h3 {
  font-size: 1.5rem;
}

.container-fluid {
  padding: 3% 15%;
}

/* Navigation_bar */

.navbar-brand {
  font-family: "Ubuntu";
  font-size: 2.5rem;
  font-weight: bold;
}

.navbar {
  padding: 0 0 4.5rem;
}

.nav-item {
  padding: 0 18px;
}

.nav-link {
  font-family: "Montserrat-Light";
  font-size: 1.2rem;
}

.download-button {
  margin: 5% 3% 5% 0;
}

/* Title */

.iphone {
  width: 60%;
  transform: rotate(25deg);
  position: absolute;
  right: 30%;
}

.iphone-container {
  position: relative;
}

/* Features */

#features {
  padding: 10% 15%;
  position: relative;
  text-align: center;
  z-index: 1;
}

.feature-img {
  color: #35589a;
  padding-bottom: 15%;
}

.feature-img:hover {
  color: #c84b31;
}

.sub-text {
  color: #8f8f8f;
}

/* Testimonials */

#testimonials {
  text-align: center;
  background-color: #0f4d92;
  color: white;
}

.testimonial-image {
  width: 10%;
  border-radius: 100%;
  margin: 20px;
}

#press {
  background-color: #0f4d92;
  text-align: center;
  padding: 3%;
}

.press-logo {
  width: 15%;
  margin: 20px 20px 15px;
}

.carousel-item {
  padding: 7% 15%;
}

/* Pricing section */

#pricing {
  padding: 100px;
}

.pricing-col {
  padding: 3% 2%;
  text-align: center;
}

/* additions */

section#features {
  position: relative;
  background-color: white;
  z-index: 1;
}

section#title {
  position: relative;
  z-index: 0;
}


img.iphone {
  height: 400px;
  width: 200px;
}

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Vietalk</title>

    <!-- Bootstrap  -->
    <link
      rel="stylesheet"
      href="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/css/bootstrap.min.css"
      integrity="sha384-TX8t27EcRE3e/ihU7zmQxVncDAy5uIKz4rEkgIXeMed4M0jlfIDPvg6uqKI2xXr2"
      crossorigin="anonymous"
    />

    <script
      src="https://code.jquery.com/jquery-3.5.1.slim.min.js"
      integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj"
      crossorigin="anonymous"
    ></script>
    <script
      src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js"
      integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN"
      crossorigin="anonymous"
    ></script>
    <script
      src="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/js/bootstrap.min.js"
      integrity="sha384-w1Q4orYjBQndcko6MimVbzY0tgp4pWB4lZ7lr30WKz0vr/aWKhXdBNmNb5D92v7s"
      crossorigin="anonymous"
    ></script>

    <!-- CSS Style Sheets -->
    <link rel="stylesheet" href="css/styles.css" />
    <!-- Google fonts -->
    <link rel="preconnect" href="https://fonts.googleapis.com" />
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
    <link
      href="https://fonts.googleapis.com/css2?family=Montserrat:ital,wght@0,700;0,900;1,400;1,500&family=Ubuntu:ital,wght@0,400;0,700;1,300&display=swap"
      rel="stylesheet"
    />

    <!-- Font Awesome -->
    <link
      rel="stylesheet"
      href="https://pro.fontawesome.com/releases/v5.10.0/css/all.css"
      integrity="sha384-AYmEC3Yw5cVb3ZcuHtOA93w35dYTsvhLPVnYs9eStHfGJvOvKxVfELGroGkvsg+p"
      crossorigin="anonymous"
    />
  </head>

  <body>
    <section id="title">
      <div class="container-fluid">
        <!-- Nav Bar -->
        <nav class="navbar navbar-expand-lg navbar-dark">
          <a class="navbar-brand" href="">tindog</a>
          <button
            class="navbar-toggler"
            type="button"
            data-toggle="collapse"
            data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent"
            aria-expanded="false"
            aria-label="Toggle navigation"
          >
            <span class="navbar-toggler-icon"></span>
          </button>
          <div class="collapse navbar-collapse" id="navbarSupportedContent">
            <ul class="navbar-nav ml-auto">
              <li class="nav-item">
                <a class="nav-link" href="">Contact</a>
              </li>
              <li class="nav-item">
                <a class="nav-link" href="">Pricing</a>
              </li>
              <li class="nav-item">
                <a class="nav-link" href="">Download</a>
              </li>
            </ul>
          </div>
        </nav>

        <!-- Title -->
        <div class="row">
          <div class="col-lg-6">
            <h1>Meet new and interesting dogs nearby.</h1>

            <button type="button" class="btn btn-dark btn-lg download-button">
              <i class="fab fa-apple"></i> Download
            </button>

            <button
              type="button"
              class="btn btn-outline-light btn-lg download-button"
            >
              <i class="fab fa-google-play"></i> Download
            </button>
          </div>

          <div class="iphone-container col-lg-6">
            <img class="iphone" src="https://raw.githubusercontent.com/BrianTruong23/tindog/main/TinDog%20Start%20Here/images/iphone6.png" alt="iphone-mockup" />
          </div>
        </div>
      </div>
    </section>

    <!-- Features -->

    <section id="features">
      <div class="container">
        <div class="row">
          <div class="col-lg-4">
            <i class="far fa-check-circle fa-4x feature-img"></i>
            <h3>Easy to use.</h3>
            <p class="sub-text">So easy to use, even your dog could do it.</p>
          </div>

          <div class="col-lg-4">
            <i class="fas fa-bullseye fa-4x feature-img"></i>
            <h3>Elite Clientele</h3>
            <p class="sub-text">We have all the dogs, the greatest dogs.</p>
          </div>

          <div class="col-lg-4">
            <i class="fas fa-heart fa-4x feature-img"></i>
            <h3>Guaranteed to work.</h3>
            <p class="sub-text">
              Find the love of your dog's life or your money back.
            </p>
          </div>
        </div>
      </div>
    </section>

    <!-- Testimonials -->

    <section id="testimonials">
      <div
        id="testimonials-carousel"
        class="carousel slide"
        data-ride="carousel"
      >
        <ol class="carousel-indicators">
          <li
            data-target="#carouselExampleIndicators"
            data-slide-to="0"
            class="active"
          ></li>
          <li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
        </ol>

        <div class="carousel-inner">
          <div class="carousel-item active">
            <h2>
              I no longer have to sniff other dogs for love. I've found the
              hottest Corgi on TinDog. Woof.
            </h2>
            <img
              class="testimonial-image"
              src="images/dog-img.jpg"
              alt="dog-profile"
            />
            <em>Pebbles, New York</em>
          </div>
          <div class="carousel-item">
            <h2 class="testimonial-text">
              My dog used to be so lonely, but with TinDog's help, they've found
              the love of their life. I think.
            </h2>
            <img
              class="testimonial-image"
              src="images/lady-img.jpg"
              alt="lady-profile"
            />
            <em>Beverly, Illinois</em>
          </div>
        </div>
        <a
          class="carousel-control-prev"
          href="#testimonials-carousel"
          role="button"
          data-slide="prev"
        >
          <span class="carousel-control-prev-icon" aria-hidden="true"></span>
          <span class="sr-only">Previous</span>
        </a>
        <a
          class="carousel-control-next"
          href="#testimonials-carousel"
          role="button"
          data-slide="next"
        >
          <span class="carousel-control-next-icon" aria-hidden="true"></span>
          <span class="sr-only">Next</span>
        </a>
      </div>
    </section>

    <!-- Press -->

    <section id="press">
      <img class="press-logo" src="images/techcrunch.png" alt="tc-logo" />
      <img class="press-logo" src="images/tnw.png" alt="tnw-logo" />
      <img class="press-logo" src="images/vn-logo.png" alt="biz-insider-logo" />
      <img class="press-logo" src="images/mashable.png" alt="mashable-logo" />
    </section>

    <!-- Pricing -->

    <section id="pricing">
      <h2>A Plan for Every Dog's Needs</h2>
      <p>Simple and affordable price plans for your and your dog.</p>

      <div class="row">
        <div class="pricing-col col-lg-4 col-md-6">
          <div class="card">
            <div class="card-header">
              <h3>Chihuahua</h3>
            </div>
            <div class="card-body">
              <h2>Free</h2>
              <p>5 Matches Per Day</p>
              <p>10 Messages Per Day</p>
              <p>Unlimited App Usage</p>
              <button type="button" class="btn btn-dark btn-lg">Sign Up</button>
            </div>
          </div>
        </div>

        <div class="pricing-col col-lg-4 col-md-6">
          <div class="card">
            <div class="card-header">
              <h3>Labrador</h3>
            </div>
            <div class="card-body">
              <h2> / mo</h2>
              <p>Unlimited Matches</p>
              <p>Unlimited Messages</p>
              <p>Unlimited App Usage</p>
              <button type="button" class="btn btn-dark btn-lg">Sign Up</button>
            </div>
          </div>
        </div>

        <div class="pricing-col col-lg-4 col-md-12">
          <div class="card">
            <div class="card-header">
              <h3>Mastiff</h3>
            </div>
            <div class="card-body">
              <h2> / mo</h2>
              <p>Pirority Listing</p>
              <p>Unlimited Matches</p>
              <p>Unlimited Messages</p>
              <p>Unlimited App Usage</p>
              <button type="button" class="btn btn-outline-dark btn-lg">
                Sign Up
              </button>
            </div>
          </div>
        </div>
      </div>
    </section>

    <!-- Call to Action -->

    <section id="cta">
      <h3>Find the True Love of Your Dog's Life Today.</h3>
      <button type="button">Download</button>
      <button type="button">Download</button>
    </section>

    <!-- Footer -->

    <footer id="footer">
      <p>© Copyright 2021 TinDog</p>
    </footer>
  </body>
</html>

即使设置位置元素和 z-index，Z-index 也无法正常工作？

Z-index does not work properly even when setting position elements and z-index?

html

css

visual-web-developer

positioning

z-index