如何使引导按钮全宽？

Question

我无法让表单中的按钮全宽。 此外，我希望按钮与表单底部对齐，因此它在宽度和底部占用 100% 的空白空间。

我想我在使用某些容器时遇到了一些问题，因此无法使用标准全宽选项正确缩放？

body {
  font-family: 'Open Sans', sans-serif;
  width: 100%;
  text-align: center;
  margin: 20px 0px 20px 0px;
}

.forma {
  margin: 0 auto 0 auto;
  max-width: 450px;
  width: 450px;
  height: 700px;
}

.fa-container {
  float: left;
  background-color: #0975BB;
  width: 10%;
  height: calc(1.5em + .75rem + 2px);
  position: relative;
}

i {
  color: white;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.form-control {
  border-radius: 0%;
  float: left;
  width: 90%;
  margin-bottom: 25px;
}

.btn {
  border-radius: 0%;
  width: 100%;
  background-color: #0975BB;
  border-style: hidden;
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" type="text/css " integrity="sha384-wvfXpqpZZVQGK6TAh5PVlGOfQNHSoD2xbE+QkPxCAFlNEevoEH3Sl0sibVcOQVnN" crossorigin="anonymous">
<link rel="stylesheet" href="styles.css" type="text/css">

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<script src="js/script.js"></script>
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>
<script src='https://kit.fontawesome.com/a076d05399.js'></script>

<div class="forma shadow p-3 mb-5 bg-white rounded">

  <img class="top-logo" src="images/csd.png">
  <form>
    <div class="form-group">

      <div class="fa-container">
        <i class="fas fa-key"></i>
      </div>
      <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp" placeholder="Šifra">

    </div>

    <div class="form-group">
      <div class="fa-container">
        <i class="fas fa-lock"></i>
      </div>
      <input type="password" class="form-control btn-block" id="exampleInputPassword1" placeholder="Lozinka">
    </div>

    <button type="button" class="btn btn-primary ">Sign In</button>
  </form>

</div>

Answer 1

CSS 应该写在<style> 标记或单独的文件中。

代码运行良好。如果按钮也是全宽的。

在这里查看现场直播：https://codepen.io/manaskhandelwal1/pen/rNVWEEX

编辑

为此，请从类为 .forma 的 div 中删除 p-3 和 mb-5 类。

并且不要给表格一个固定的高度。

请看这里：https://codepen.io/manaskhandelwal1/pen/zYGogBG

Answer 2

Bootstrap 4 有一个为此预定义的类，将“btn-block”添加到按钮类

btn-block 添加以下 CSS 样式

display: block;
width: 100%;

以下是如何使其接近您所链接的内容的示例

        body {
            font-family: 'Open Sans', sans-serif;
            width: 100%;
            text-align: center;
            margin: 20px 0px 20px 0px;
        }

        .forma {
            margin: 0 auto 0 auto;
            max-width: 450px;
            width: 450px;
            height: 300px;
        }

        .fa-container {

            float: left;
            background-color: #0975BB;
            width: 10%;
            height: calc(1.5em + .75rem + 2px);
            position: relative;

        }

        i {
            color: white;
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }

        .form-control {
            border-radius: 0%;
            float: left;
            width: 90%;
            margin-bottom: 25px;
        }


        .btn {
            border-radius: 0%;
            width: 100%;
            background-color: #0975BB;
            border-style: hidden;
        }

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<body style="margin-top: 200px;">
    <div class="forma shadow mb-5 bg-white rounded">

        <img class="top-logo" src="images/csd.png">
        <form>
            <div class="form-group p-3">

                <div class="fa-container">
                    <i class="fas fa-key"></i>
                </div>
                <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp"
                    placeholder="Šifra">

            </div>

            <div class="form-group p-3">
                <div class="fa-container">
                    <i class="fas fa-lock"></i>
                </div>
                <input type="password" class="form-control btn-block" id="exampleInputPassword1" placeholder="Lozinka">
            </div>

            <button type="button" class="btn btn-primary ">Sign In</button>
        </form>

    </div>