如何在带阴影的表单上制作三角形？

Question

如您所见，表单左侧和右侧有三角形。并且双阴影0 0 0 2px，0 0 0 6px。我已经实现了这个功能：after和：before，但它打破了布局。如果你能帮助我，请帮忙。我会很高兴任何可以解决这个问题的链接或文章

https://jsfiddle.net/BeriaFantom/sLkdy0fx/1/

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#middle {
  position: relative;
}
#middle-form {
  position: absolute;
  bottom: 0;
  right: 0;
  left: 0;
}
#middle-form:after,
#middle-form:before {
  position: absolute;
  top: 0;
  display: block;
  content: '';
  width: 0;
  height: 0;
}
#middle-form::after {
  right: -24px;
  border-bottom: 75px solid transparent;
  border-top: 75px solid transparent;
  border-left: 24px solid #1e9baf;
}
#middle-form::before {
  left: -24px;
  border-bottom: 75px solid transparent;
  border-top: 75px solid transparent;
  border-right: 24px solid #1e9baf;
}

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<div id="middle">

  <div id="middle-form" class='container'>
    <h2>заказать мастера</h2>
    <form action="" class='clear'>
      <input type="text" class='name'>
      <input type="tel" class='tel'>
      <button class="btn-sen">отправить</button>
    </form>
  </div>
</div>

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Answer 1

我已经改变了你的小提琴，现在检查。

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body {background: black;}
#middle {position: relative; width: 300px; margin-left: 100px; box-shadow: 0 0 10px 2px #ccc;}
#middle-form {background: #1e9baf none repeat scroll 0 0; height: 128px; position: relative; z-index: 100; border:2px solid #fff; border-width:2px 0;}
#middle:after, #middle:before {background: #1e9baf none repeat scroll 0 0; box-shadow: 0 0 10px 2px #ccc; content: ""; display: block; height: 90px; position: absolute; top: 19px; transform: rotate(45deg); width: 90px; z-index: 10; border:2px solid #fff;}
#middle::after {right: -48px;}
#middle::before {left: -48px;}

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<div id="middle">
    <div id="middle-form" class='container'>
        <h2>заказать мастера</h2>
        <form action="" class='clear'>
            <input type="text" class='name'>
            <input type="tel" class='tel'>
            <button class="btn-sen">отправить</button>
        </form>
    </div>
</div>

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Answer 2

我会再次使用渐变的东西

#middle {
  font-size: 14px;
  display: table;
  margin: 2em auto;
  padding: 0 3em 1.5em;
  text-align: center;
  background: linear-gradient(to bottom, gray 4px, white 4px, white 6px, #1e9baf 6px, #1e9baf calc(100% - 6px), white calc(100% - 6px), white calc(100% - 4px), gray calc(100% - 4px)) center no-repeat, linear-gradient(70deg, transparent 1.5em, gray 1.5em, gray calc(1.5em + 3px), white calc(1.5em + 3px), white calc(1.5em + 4px), #1e9baf calc(1.5em + 6px)) bottom left no-repeat, linear-gradient(-70deg, transparent 1.5em, gray 1.5em, gray calc(1.5em + 3px), white calc(1.5em + 3px), white calc(1.5em + 4px), #1e9baf calc(1.5em + 6px)) bottom right no-repeat, linear-gradient(-250deg, transparent 1.5em, gray 1.5em, gray calc(1.5em + 3px), white calc(1.5em + 3px), white calc(1.5em + 4px), #1e9baf calc(1.5em + 6px)) top left no-repeat, linear-gradient(250deg, transparent 1.5em, gray 1.5em, gray calc(1.5em + 3px), white calc(1.5em + 3px), white calc(1.5em + 4px), #1e9baf calc(1.5em + 6px)) top right no-repeat;
  background-size: calc(100% - 3em - 8px) 100%, 50.05% 50.05%, 50.05% 50.05%, 50.05% 50.05%, 50.05% 50.05%;
  box-shadow: 0 2.25em 15px -2em white, 0 -2.25em 15px -2em white
}
h2 {
  color: white;
  text-shadow: 1px 1px 1px #333;
}
input,
button {
  box-shadow: inset 0 3px 8px -1px #555, inset 0 0 0 2em white;
  background: none;
  border: none;
  border-radius: 3px;
  font-size: 1em;
  padding: 0.25em 0.5em;
  font-variant: small-caps;
  margin: 0.5em 0.1em;
  width: 11em;
}
button {
  background: linear-gradient(to top, #ffab00 30%, #fff800);
  padding: 0.2em 3em;
  width: 9.5em;
  font-weight: bold;
  box-shadow: 2px 2px 1px #A46D02;
  text-shadow: 0px 1px 1px white
}
/* demo purpose, show transparency */

html {
  min-height: 100%;
  background: linear-gradient(45deg, gray, white, #333, gold, tomato, gray, turquoise, tomato);
}

<div id="middle">
  <div id="middle-form" class='container'>
    <h2>заказать мастера</h2>
    <form action="" class='clear'>
      <input placeholder=" Name" type="text" class='name' />
      <input placeholder="☎ Phone" type="tel" class='tel' />
      <button class="btn-sen">отправить</button>
    </form>
  </div>
</div>

Answer 3

对于具有对角线的div，您可以使用trasform 2d skew

这是一个样本

#id_div_diag {
  -ms-transform: skew(20deg); 
  -webkit-transform: skew(20deg);
   transform: skew(20deg);
}

解决方案是组合更多不同的div与不同的变换