It won't let me adjust the gallery caption font size, please help!

This is the code:

@font-face { font-family: 'Sig';
src: url('https://static1.squarespace.com/static/5f21c44a4c48ab1c1714aa45/t/6352d8c2f6d90b1fae6dc0bd/1666373826731/Latinotype+-+Arida+Regular+DEMO.otf');
}  

#site-title {font-family: 'Sig'; src:local('Sig'), url(http://static1.squarespace.com/static/5683f9f1cbced6d45d92de3d/t/56855928e0327c02e3702e57/1451579688037/Example.otf)}

h1 { 
font-family:Sig;
}  

//Gallery Caption CSS
.gallery-caption p:first-line {
  font-weight:bold;
}
.gallery-caption p {
  font-size: 0.2rem
}

.gallery-section .gallery-caption {
  background: ;
  padding: 1px 0px;
}

.gallery-caption p {white-space:pre}

.header-nav-folder-content {
  background: transparent !important;
}

// Button //
.header-actions-action .btn {
}

.header-actions-action .btn {
    padding: 0px 0px;
    background: Transparent !important;
    border-color: violet !important;
}

Try this code