style.scss

@import url('https://fonts.googleapis.com/css?family=Cormorant+Garamond:300,400,600|Tulpen+One&display=swap');

:root {
  /* colors */
  --body-bg: #FAFAFA;
  --page-bg: #F5F5F5;
  --dark-text: #2A2935;
  
  /* spacing */
  /* this is what defines the global scale */
  --baseline: 12px;
  
  /* fonts */
  --book-title: 'Tulpen One', sans-serif;
  --title: 'Cormorant Garamond', serif;
  --body: 'Cormorant Garamond', serif;
  --base-size: var(--baseline) * 1.2;
}

* {
  box-sizing: border-box;
}

body {
  background-color: var(--body-bg);
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.cover {
  width: calc(var(--baseline) * 60);
  height: calc(var(--baseline) * 42.6);
  box-shadow: 0 0 100px rgba(0, 0, 0, .3);
}

.book {
  width: 100%;
  height: 100%;
  display: flex;
  perspective: 1200px;
  
  &__page {
    position: relative;
    width: 50%;
    height: 100%;
    display: grid;
    transform: rotateY(0deg);
    transition: transform 0.9s cubic-bezier(0.645, 0.045, 0.355, 1);
    transform-origin: 0% 0%;
    background-color: var(--page-bg);
    background-image: linear-gradient(90deg, rgba(227,227,227,1) 0%, rgba(247,247,247,0) 18%);
    
    &:nth-of-type(1) {
      background-image: linear-gradient(-90deg, rgba(227,227,227,1) 0%, rgba(247,247,247,0) 18%);
    }

    &--1 {
      cursor: pointer;
      overflow: hidden;
      
      img {
        width: 100%;
        max-width: 100%;
        height: auto;
      }
    }
    
    &--2 {
      position: absolute;
      right: 0;
      pointer-events: none;
      transform-style: preserve-3d;
      background-color: var(--page-bg);
      background-image: linear-gradient(90deg, rgba(227,227,227,1) 0%, rgba(247,247,247,0) 18%);
    }
    
    &--4 {
      cursor: pointer;
      padding: 0 calc(var(--baseline) * 3);
    }
    
    &-front {
      position: absolute;
      width: 100%;
      height: 100%;
      transform: rotateY(0deg) translateZ(1px);
    }
    
    &-back {
      position: absolute;
      width: 100%;
      height: 100%;
      padding: 0 calc(var(--baseline) * 1.8);
      transform: rotateY(180deg) translateZ(1px);
    }
    
    .page__content {
      padding: var(--baseline);
      height: 100%;
      position: relative;
      text-align: center;
      overflow: auto;
      
      &-book-title {
        font-family: var(--book-title);
        font-size: calc(var(--base-size) * 3);
        font-weight: bold;
        text-transform: uppercase;
        letter-spacing: 3px;
        color: var(--dark-text);
        margin-top: calc(var(--baseline) * 5);
        margin-bottom: calc(var(--baseline) * 2);
      }
      
      &-author {
        font-family: var(--title);
        font-size: calc(var(--base-size) * 1.2);
        font-weight: 100;
        text-transform: uppercase;
        color: var(--dark-text);
        border-top: 1px solid var(--dark-text);
        border-bottom: 1px solid var(--dark-text);
        display: inline-block;
        padding: calc(var(--baseline) / 2) calc(var(--baseline) / 5);
        margin-bottom: calc(var(--baseline) * 6);
      }
      
      &-credits {
        font-family: var(--title);
        text-transform: uppercase;
        font-size: calc(var(--base-size) * 0.8);
        margin-bottom: calc(var(--baseline) * 2);
        letter-spacing: 1px;
        
        span {
          display: block;
          font-size: calc(var(--base-size) * 1.2);
          letter-spacing: 0;
        }
      }
      
      &-copyright {
        position: absolute;
        width: calc(100% - (var(--baseline) * 2));
        bottom: calc(var(--baseline) * 2);
        font-family: var(--title);
        font-size: calc(var(--base-size) * 0.8);
        text-transform: uppercase;
      }
      
      &-title {
        font-family: var(--title);
        font-size: calc(var(--base-size) * 1);
        text-transform: uppercase;
        letter-spacing: 1px;
        margin-top: calc(var(--baseline) * 5);
        margin-bottom: calc(var(--baseline) * 3);
      }
      
      &-table {
        width: 100%;
        margin-top: calc(var(--baseline) * 2);
        
        td {
          font-family: var(--title);
          font-size: calc(var(--base-size) * 1);
          padding-bottom: calc(var(--baseline) * 1.5);
          text-transform: uppercase;
        }
      }
      
      &-blockquote {
        margin-bottom: calc(var(--baseline) * 2);
      }
      
      &-blockquote-text {
        font-family: var(--title);
        font-size: calc(var(--base-size) * 0.67);
        font-style: italic;
        text-align: justify;
      }
      
      &-blockquote-reference {
        font-family: var(--title);
        font-size: calc(var(--base-size) * 0.7);
        margin-top: calc(var(--baseline) * 0.3);
        float: right;
        text-transform: uppercase;
      }
      
      &-text {
        font-family: var(--title);
        font-size: calc(var(--base-size) * 0.67);
        text-align: justify;
        text-indent: var(--baseline);
      }
    }
    .page__number {
      position: absolute;
      bottom: var(--baseline);
      width: calc(100% - (var(--baseline) * 2));
      font-family: var(--title);
      font-size: calc(var(--base-size) * 0.67);
      text-align: center;
    }
  }
  
  input[type="radio"] {
    display: none;
    
    &:checked+.book__page {
      transition: transform 0.9s cubic-bezier(0.645, 0.045, 0.355, 1);
      transform: rotateY(-180deg);
    }
  }
}