JSFiddle - React, Tailwind, and code Playground

HTML

<div class="admonition">
    <div class="admonition-title">Tip</div>
    <p>default</p>
</div>
<div class="admonition">
    <div class="admonition-tip">Tip</div>
    <p>tip</p>
</div>
<div class="admonition">
    <div class="admonition-note">Note</div>
    <p>note</p>
</div>
<div class="admonition">
    <div class="admonition-caution">Caution</div>
    <p>caution</p>
</div>
<div class="admonition">
    <div class="admonition-warning">Warning</div>
    <p>warning</p>
</div>

CSS

.admonition {
    position: relative;
    padding: 23px 10px 22px;
    margin: 20px;
    background: #FEFEFE;
    border: 1px solid black;
    font-family: Helvetica, Arial;
}
.admonition-title {
    position: absolute;
    top: -10px;
    left: -10px;
    padding: 4px 8px;
    background: #343332;
    color: #fff;
    -webkit-box-shadow: 100px 100px 20px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}
.admonition-tip {
    position: absolute;
    top: -10px;
    left: -10px;
    padding: 4px 8px;
    background: blue;
    color: #fff;
    -webkit-box-shadow: 1px 1px 2px rgba(1, 1, 1, 0.3);
    -moz-box-shadow: 1px 1px 2px rgba(1, 1, 1, 0.3);
    box-shadow: 1px 1px 2px rgba(1, 1, 1, 0.3);
}
.admonition-note {
    position: absolute;
    top: -10px;
    left: -10px;
    padding: 4px 8px;
    background: green;
    color: #fff;
    -webkit-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}
.admonition-caution {
    position: absolute;
    top: -10px;
    left: -10px;
    padding: 4px 8px;
    background: orange;
    color: #fff;
    -webkit-box-shadow: 50px 50px 50px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}
.admonition-warning {
    position: absolute;
    top: -10px;
    left: -10px;
    padding: 4px 8px;
    background: red;
    color: #fff;
    -webkit-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}
.admonition-tip:after {
    content:'';
    display: block;
    height: 20px;
    width: 8px;
    position: absolute;
    top: 24px;
    left: 0px;
    background: transparent;
    z-index: -1;
    border-top: 45px solid blue;
    border-left: 45px solid transparent;
}