@media (prefers-color-scheme: dark)
{

    /* h1 タグのスタイル */
    h1 {
        position: relative;
        display: inline-block;
        padding: 0 55px;
      }
      
    h1:before, h1:after {
        content: '';
        position: absolute;
        top: 50%;
        display: inline-block;
        width: 45px;
        height: 1px;
        background-color: rgb(16, 45, 214);
      }
      
    h1:before {
        left:0;
      }
    h1:after {
        right: 0;
      }

    h2 {
        border-bottom: solid 3px #cce4ff;
        position: relative;
      }
      
    h2:after {
        position: absolute;
        content: " ";
        display: block;
        border-bottom: solid 3px #5472cd;
        bottom: -3px;
        width: 20%;
      }
}