:root {

  /* Text: */
  font-family: 'ヒラギノ角ゴ Pro W3', 'Hiragino Kaku Gothic Pro', Osaka, メイリオ, Meiryo, 'ＭＳ Ｐゴシック', 'MS PGothic', 'ＭＳ ゴシック' , 'MS Gothic', 'Noto Sans CJK JP', TakaoPGothic, sans-serif;
  font-size: 20px;
background-image: url("https://64.media.tumblr.com/d9573aea3bf4d7386b42ddd516ea1ce6/147bfebdf112f180-78/s250x400/6895a383d6d2b83a717218a904480bd772fcc875.gifv") ;

  /* Other Settings: */
  margin: 0px;
  padding: 50px;
  
}




.container {
  display: grid;
  grid-gap: 2.5px;
  grid-template:
    "sidebar main"
    / 200px 600px;
}

aside { grid-area: sidebar;
height: 400px;
width: 200px; 
border: 3px inset;
border-radius: 2.5px;
overflow-y: auto;
color: white;
background-color: grey;
text-align: center;

}

main { grid-area: main; 
height: 500px;
width: 590px;
border: 2px dotted grey;
border-radius: 2.5px;
overflow-y: auto;
text-align: center;
line-height: .9;
background-color: white;
}