Stylish Chrome plugin style based on https://userstyles.org/styles/62699/memrise-japanese

memrise_japanese.js

/* Clear background image */
body.memrise.fullscreen.garden {
  background-size:100%;
  background-repeat:no-repeat;
}
 
/* Put a huge gap between the questions and answers to avoid contamination */
.typing-wrapper, ol.choices { margin-top: 34em !important; }
 
/* Use Japanese fonts. Sorry Chinese learners. */
.val, .things, .qquestion, table.pool-things tr.thing, table.level-things tr.thing, body.level-view .things, .layout.level-view .things, .thing-show .row .row-value, .question-row .extra-info, .garden-box .typing-wrapper .typing-type-here, .mem .mem-middle, .forum-thread .detail p, .forum-thread ul.comments > li .comment-body p, .mem.garden .mem-text p {
 
     font-family: Times, "Times New Roman", Helvetica, "Helvetica Neue",Arial, "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", "小塚明朝 Pro L", sans-serif !important;
 
}
 
/* Make the questions really big */
.qquestion {
     font-size: 800% !important;
     line-height: 100% !important;
}
 
/* Make some things non-bold */
body.level-view .thing .col_a, .layout.level-view .thing .col_a, .row .row-value {
     font-weight: normal !important;
}