JSFiddle - React, Tailwind, and code Playground

HTML

<div class="panel panel-default1">

            <div class="panel-body">

                <div class='amg-corner-button_wrap'>

                    <div class="overlay"></div>

                        <div class="overlay-content">
                            <h2>Image Ink Logo</h2>
                            <p>Logo for a screen printing company. They wanted a detachable/recognizable brand that didn't need the name of the company.</p>
                        </div>

                </div> <!-- wrap -->

            </div> <!-- panel body -->

          </div> <!-- panel default -->

CSS

.panel-default1 {
  padding-top: 10px;
  border-radius: 20px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.10);
  height: 400px;
  width: 400px;
  overflow: hidden;
  margin: 0 auto;
  position: relative;
}

.amg-corner-button_wrap {
  display: block;
  position: absolute;
  bottom: 0;
  right: 0;
  width: 40px;
  height: 40px;
}

.amg-corner-button_wrap .overlay {
  border-bottom: 40px solid #e8c63d;
  border-left: 40px solid transparent;
  bottom: 0;
  height: 0;
  opacity: .95;
  position: absolute;
  right: 0;
  text-indent: -9999px;
  -moz-transition: all 0.5s ease-out;
  -o-transition: all 0.5s ease-out;
  -webkit-transition: all 0.5s ease-out;
  transition: all 0.5s ease-out;
  width: 0;
}

.amg-corner-button_wrap:hover .overlay {
  border-bottom: 800px solid #e8c63d;
  border-left: 800px solid transparent;
  -moz-transition: all 0.5s ease-out;
  -o-transition: all 0.5s ease-out;
  -webkit-transition: all 0.5s ease-out;
  transition: all 0.5s ease-out;
}

.amg-corner-button_wrap .overlay-content {
  bottom: 0;
  color: #333;
  left: 0;
  opacity: 0;
  padding: 30px;
  position: absolute;
  right: 0;
  top: 0;
  -moz-transition: all 0.3s ease-out;
  -o-transition: all 0.3s ease-out;
  -webkit-transition: all 0.3s ease-out;
  transition: all 0.3s ease-out;
}
.amg-corner-button_wrap .overlay-content h2 {
  border-bottom: 1px solid #333;
  padding: 0 0 12px;
}
.amg-corner-button_wrap:hover .overlay-content {
  opacity: 1;
  -moz-transition: all 0.3s ease-out;
  -o-transition: all 0.3s ease-out;
  -webkit-transition: all 0.3s ease-out;
  transition: all 0.3s ease-out;
  -moz-transition-delay: 0.3s;
  -o-transition-delay: 0.3s;
  -webkit-transition-delay: 0.3s;
  transition-delay: 0.3s;
}