/** base */
*,
*::before,
*::after {
  box-sizing: border-box;
}

/** slider */
.slider {
  position: relative;
  max-width: 100%;
  max-height: 100%;
  margin: 0 auto;
}
.slider:hover .slider__radiobox-label--prev,
.slider:hover .slider__radiobox-label--next {
  opacity: 1;
}
.slider:hover .slider__radiobox-label--prev {
  left: 6%;
}
.slider:hover .slider__radiobox-label--next {
  right: 6%;
}
.slider--full {
  width: 100vw;
  height: 100vh;
}
.slider--fixed {
  width: 600px;
  height: 400px;
}
.slider--proportional {
  width: 100%;
  height: auto;
}

.slider__inner {
  position: relative;
  margin: 0 auto;
  overflow: hidden;
  background: #fff;
}
.slider--full .slider__inner {
  width: 100%;
  height: 100%;
}
.slider--fixed .slider__inner {
  width: 100%;
  height: 100%;
}
.slider--proportional .slider__inner {
  width: 100%;
  height: 0;
}
.slider--proportional-4x3 .slider__inner {
  padding-top: 75%;
}
.slider--proportional-5x4 .slider__inner {
  padding-top: 80%;
}
.slider--proportional-16x9 .slider__inner {
  padding-top: 20%;/*56.25%;*/
}

.slider__slides {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 1;
  width: 400%;
  height: 100%;
  overflow-y: hidden;
  transition: margin-left 0.4s;
}

.slider__slide {
  display: block;
  float: left;
  position: relative;
  width: 25%;
  height: 100%;
}
.slider__slide img {
  width: 100%;
  height: 100%;
  -o-object-fit: cover;
     object-fit: cover;
}

.slider__radiobox-label {
  display: block;
  position: absolute;
  z-index: 2;
  cursor: pointer;
}
.slider__radiobox-label--item {
  bottom: 6%;
  left: 50%;
  transform: translateX(-50%);
  padding: 6px;
  border-radius: 50%;
  background: #4caee2;
  opacity: 0.3;
  transition: opacity 0.2s;
}
.slider__radiobox-label--item:hover {
  opacity: 0.5;
}
.slider__radiobox-label--item-1 {
  margin-left: -36px;
}
.slider__radiobox-label--item-2 {
  margin-left: -12px;
}
.slider__radiobox-label--item-3 {
  margin-left: 12px;
}
.slider__radiobox-label--item-4 {
  margin-left: 36px;
}
.slider__radiobox-label--prev, .slider__radiobox-label--next {
  display: none;
  top: 50%;
  transform: translateY(-50%);
  height: 0;
  border: 10px solid #4caee2;
  border-top-color: transparent;
  border-bottom-color: transparent;
  opacity: 0;
  transition: left 0.2s, right 0.2s, opacity 0.2s;
}
.slider__radiobox-label--prev {
  left: -6%;
  border-left: 0;
  border-right-width: 17px;
}
.slider__radiobox-label--next {
  right: -6%;
  border-right: 0;
  border-left-width: 17px;
}

.slider__radiobox {
  display: none;
}
.slider__radiobox--1:checked ~ .slider__slides {
  margin-left: 0;
}
.slider__radiobox--2:checked ~ .slider__slides {
  margin-left: -100%;
}
.slider__radiobox--3:checked ~ .slider__slides {
  margin-left: -200%;
}
.slider__radiobox--4:checked ~ .slider__slides {
  margin-left: -300%;
}
.slider__radiobox--1:checked + .slider__radiobox-label--item-1, .slider__radiobox--2:checked + .slider__radiobox-label--item-2, .slider__radiobox--3:checked + .slider__radiobox-label--item-3, .slider__radiobox--4:checked + .slider__radiobox-label--item-4 {
  opacity: 1;
}
.slider__radiobox--1:checked ~ .slider__radiobox-label--prev-4, .slider__radiobox--1:checked ~ .slider__radiobox-label--next-2, .slider__radiobox--2:checked ~ .slider__radiobox-label--prev-1, .slider__radiobox--2:checked ~ .slider__radiobox-label--next-3, .slider__radiobox--3:checked ~ .slider__radiobox-label--prev-2, .slider__radiobox--3:checked ~ .slider__radiobox-label--next-4, .slider__radiobox--4:checked ~ .slider__radiobox-label--prev-3, .slider__radiobox--4:checked ~ .slider__radiobox-label--next-1 {
  display: block;
}