Bedford Theme: Hero/Banner area with the box around the text

Hi,

Please help

I need to create a border around the text in Hero/Banner area as below

Added this code to the Custom CSS area for the text and to minimize banner area: 

#yui_3_17_2_1_1680460552639_568 {
  background: #D9D9D9;
  border: 1px solid #000;
  outline: 15px solid #eee;
  text-align: center;
  padding: 15px 10px;
  margin: 30px;
  box-sizing: border-box;
  width: 35%;
  float: right;
  box-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

@media only screen and (max-width: 768px) {
#yui_3_17_2_1_1680460552639_568 {
    width: 60%;
  }
}

@media only screen and (max-width: 480px) {
#yui_3_17_2_1_1680460552639_568 {
    width: 80%;
    margin: 25px;
    padding: 10px;
  }
}

.desc-wrapper {
  display: block;
  margin: 0 auto;
  padding: 0;
}

.6420b6bb62ab5e0e8ee566c5 {
  background: cover;
  max-height: 50%;
}

As soon  as I refresh the page, the box around of text resets to none

Link to the site: https://grey-herring-nf8k.squarespace.com/

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