$dog-width: 100px;
$interval: 200ms;
$color-gray: #F8EFE2;
$easing: ease-in-out;

body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

html, body {  //배경
  background: #D6AA6A;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}

*, *:before, *:after {
  box-sizing: border-box;
  position: relative;
}

// dog
.dog {
  width: $dog-width;
  height: $dog-width;
  z-index: 1;
  
  &:before { //그림자
    content: '';
    display: block;
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background: rgba(black, 0.03);
    transform: translatey(-30%) scale(1.5);
  }
  
  * {
    position: absolute;
  }
}

.dog-body, .dog-head, .dog-torso {
  border-radius: 50%;
  background: white;
  position: absolute;
  width: 100%;
  height: 100%;
}

// dog-body
.dog-body {
  top: -50%;
  box-shadow: inset 0 -15px 0 0 $color-gray;
  animation: dog-body $interval $easing infinite alternate;
  
  &:before { //꼬리 잔상
    content:'';
    position: absolute;
    bottom: 90%;
    right: 50%;
    width: 60%;
    height: 60%;
    background: rgba(white, 0.4);
    border-top-left-radius: 100%;
    border-bottom-left-radius: 10%;
    border-top-right-radius: 10%;
    transform-origin: right bottom;
    animation: dog-tail-blur $interval $interval / 6 $easing infinite alternate both; //숫자를 두번 적으면 딜레이
    
    @keyframes dog-tail-blur {
      0% {
        transform: rotate(0);
        opacity: 0;
      }
      50% {
        opacity: 1;
      }
      100% {
        opacity: 0;
        transform: rotate(90deg);
      }
    }
  }
  
  @keyframes dog-body {
    from {transform: translatex(-10%);} // 0%와 똑같이 시작을 의미한다.
    to {transform: translatex(10%);}  //100%와 똑같이 마지막을 의미한다.
  }
}

// dog-head
.dog-head {
  animation: dog-head $interval * 9 cubic-bezier(0.11, 0.79, 0, 0.99) infinite;
  
  @keyframes dog-head {
    0% {transform: rotate(45deg);}
    33% {transform: rotate(-45deg);}
    66% {transform: rotate(0deg);}
    100% {transform: rotate(45deg);}
  }
}

// dog-torso
.dog-torso {
  top: -20%;
  background: white;
  box-shadow: inset 0 -15px 0 0 $color-gray;
  animation: dog-torso $interval $easing infinite alternate-reverse;
  
  @keyframes dog-torso {
    0% {transform: translatex(-5%);}
    100% {transform: translatex(5%);}
  }
}

// dog-eyes
.dog-eyes {
  width: 60%;
  top: 55%;
  left: 20%;
  z-index: 1;
  
  &:before { //점박이
    content: '';
    display: block;
    width: 40px;
    height: 40px;
    border-radius: 40px;
    background: #E5D0B1;
    position: absolute;
    top: -10px;
    left: -10px;
    z-index: 0;
    border: 4px solid white;
    border-left-width: 0;
    border-bottom-width: 0;
    border-top-width: 0;
    transform: rotate(-45deg);
  }
}
.dog-eye {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #513318;
  z-index: 1;
  
  &:first-child {
    left: 0;
  }
  &:last-child {
    right: 0;
  }
}

// dog-muzzle
.dog-muzzle {
  width: 60%;
  left: 20%;
  height: 50%;
  border-bottom-left-radius: 100%;
  border-bottom-right-radius: 100%;
  bottom: -15%;
  background: white;
  
  &:before, &:after {
    content:'';
    display: block;
    position: absolute
  }
  
  &:before { //인중
    width: 6px;
    height: 20px;
    bottom: 0;
    background: $color-gray;
    left: calc(50% - 3px);
  }
  
  &:after { //코
    background: #513318;
    width: 20px;
    height: 15px;
    bottom: 12px;
    left: calc(50% - 10px);
    border-bottom-left-radius: 60% 60%;
    border-bottom-right-radius: 60% 60%;
    border-top-left-radius: 50% 40%;
    border-top-right-radius: 50% 40%;
  }
}

// dog-ears
.dog-ears {
  width: 40%;
  top: 25%;
  left: 30%;
  
}
.dog-ear {
  bottom: -2px;
  height: 30px;
  width: 30px;
  background: pink;
  
  &:first-child { //왼쪽 귀
    right: 130%;
    border-bottom-left-radius: 80%;
    border-top-right-radius: 80%;
    box-shadow: inset -5px 15px 0 -3px white;
    transform: rotate(5deg);
  }
  &:last-child { //오른쪽 귀
    left: 130%;
    border-bottom-right-radius: 80%;
    border-top-left-radius: 80%;
    box-shadow: inset 5px 15px 0 -3px white;
    transform: rotate(-5deg);
  }
}

// dogtongue
.dogtongue {
  width: 40%;
  height: 100%;
  left: calc(50% - 20px);
  z-index: -1;
  transform-origin: center top;
  
  &:before {
    content: '';
    position: absolute;
    left: 8px;
    display: block;
    width: 100%;
    height: 100%;
    border-radius: 40px;
    background: #fd3163;
    animation: dog-tongue-inner $interval / 2 $easing infinite alternate;
    
    @keyframes dog-tongue-inner {
      from {transform: translatey(5%);}
      to {transform: translatey(22%);}
    }
  }
}

// dog-tail
.dog-tail {
  $tail-width: 22px;
  width: $tail-width;
  height: $tail-width * 1.1;
  background: white;
  bottom: 35%;
  border-radius: $tail-width / 2; //bdrs
  left: calc(50% - #{$tail-width / 2});
  transform-origin: center bottom;
  
    .dog-tail {
      animation: dog-tail-segment $interval $easing infinite alternate;

      @keyframes dog-tail-segment {
        0% {transform: rotate(-10deg);}
        100% {transform: rotate(10deg);}
      }
    }
}

.dog-body > .dog-tail {
  bottom: 60%;
}