@import url("https://fonts.googleapis.com/css2?family=Montserrat:wght@500;600;700;800&display=swap");
:root {
  --card-width: 200px;
  --card-height: 300px;
  --card-transition-duration: 800ms;
  --card-transition-easing: ease;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  width: 100%;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  /*background: rgba(0, 0, 0, 0.787);*/
  overflow: hidden;
}

button {
  border: none;
  background: none;
  cursor: pointer;
}
button:focus {
  outline: none;
  border: none;
}

.app {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}
.app__bg {
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: -5;
  filter: blur(3px);
  /*pointer-events: none;*/
  /*user-select: none;*/
  overflow: hidden;
}
.app__bg::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: #000;
  z-index: 1;
  opacity: 0.8;
}
.app__bg__image {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%) translateX(var(--image-translate-offset, 0));
  width: 180%;
  height: 180%;
  transition: transform 1000ms ease, opacity 1000ms ease;
  overflow: hidden;
}
.app__bg__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 1;
  transition: opacity 600ms ease;
}
  height: 100%;
  object-fit: cover;
}
.app__bg__image.current--image {
  opacity: 1;
  --image-translate-offset: 0;
}
.app__bg__image.previous--image, .app__bg__image.next--image {
  opacity: 0;
}
.app__bg__image.previous--image {
  --image-translate-offset: -25%;
}
.app__bg__image.next--image {
  --image-translate-offset: 25%;
}

.cardList {
  position: absolute;
  width: calc(3 * var(--card-width));
  height: auto;
}
.cardList__btn {
  --btn-size: 35px;
  width: var(--btn-size);
  height: var(--btn-size);
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 100;
}
.cardList__btn.btn--left {
  left: -5%;
}
.cardList__btn.btn--right {
  right: -5%;
}
.cardList__btn .icon {
  width: 100%;
  height: 100%;
}
.cardList__btn .icon svg {
  width: 100%;
  height: 100%;
}
.cardList .cards__wrapper {
  position: relative;
  width: 100%;
  height: 100%;
  perspective: 1000px;
}

.card {
  --card-translateY-offset: 100vh;
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%) translateX(var(--card-translateX-offset)) translateY(var(--card-translateY-offset)) rotateY(var(--card-rotation-offset)) scale(var(--card-scale-offset));
  display: inline-block;
  width: var(--card-width);
  height: var(--card-height);
  transition: transform var(--card-transition-duration) var(--card-transition-easing);
  /*user-select: none;*/
}
.card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: #000;
  z-index: 1;
  transition: opacity var(--card-transition-duration) var(--card-transition-easing);
  opacity: calc(1 - var(--opacity));
}
.card__image {
  position: relative;
  width: 100%;
  height: 100%;
}
.card__image img {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.card.current--card {
  --current-card-rotation-offset: 0;
  --card-translateX-offset: 0;
  --card-rotation-offset: var(--current-card-rotation-offset);
  --card-scale-offset: 1.2;
  --opacity: 0.8;
  z-index: 50;
}
/* 通用堆叠：--distance 为相对当前卡片的循环偏移（-1=上一个, 1=下一个, 2=下下个...），
   由 JS 动态设置，因此支持任意数量的卡片 */
.card {
  --card-translateX-offset: calc(var(--card-width) * 1.1 * var(--distance, 0));
  --card-rotation-offset: calc(-25deg * var(--distance, 0));
  --card-scale-offset: 1;
  --opacity: 0.4;
  z-index: calc(50 - var(--abs-distance, 0) * 10);
  transform: translate(-50%, -50%)
    translateX(var(--card-translateX-offset))
    translateY(var(--card-translateY-offset))
    rotateY(var(--card-rotation-offset))
    scale(var(--card-scale-offset));
}
.card.current--card {
  --opacity: 0.8;
}
/* 距离过远（环绕到对侧）的卡片直接隐藏，避免重叠干扰 */
.card.hidden--card {
  opacity: 0;
  pointer-events: none;
}

.loading__wrapper {
  position: fixed;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: #000;
  z-index: 200;
}
.loading__wrapper .loader--text {
  color: #fff;
  font-family: "Montserrat";
  font-weight: 500;
  margin-bottom: 1.4rem;
}
.loading__wrapper .loader {
  position: relative;
  width: 200px;
  height: 2px;
  background: rgba(255, 255, 255, 0.25);
}
.loading__wrapper .loader span {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: red;
  transform: scaleX(0);
  transform-origin: left;
}

@media only screen and (min-width: 800px) {
  :root {
    --card-width: 250px;
    --card-height: 400px;
  }
}

/* 手机端布局：屏幕较窄，仅中心卡完整展示，左右各露约 10% */
@media only screen and (max-width: 768px) {
  :root {
    --card-width: 70vw;
    --card-height: calc(70vw * 1.5);
  }
  /* 卡片定位（位移/缩放/透明度/层级）改由 script.js 在手机端统一内联设置，
     此处不再写公式，避免与桌面端逻辑冲突或被动画覆盖 */
  /* 箭头默认半透明，触摸/点击时高亮 */
  .cardList__btn {
    opacity: 0.4;
    transition: opacity 200ms ease;
  }
  .cardList__btn:active,
  .cardList__btn.active {
    opacity: 1;
  }
  /* 背景图在手机端强制撑满视口，防止滑动后缩放错位留白 */
  .app__bg,
  .app__bg__image {
    width: 100vw;
    height: 100vh;
  }
  .app__bg__image {
    transform: translate(-50%, -50%) translateX(var(--image-translate-offset, 0));
  }
}
.support {
  position: absolute;
  right: 10px;
  bottom: 10px;
  padding: 10px;
  display: flex;
}
.support a {
  margin: 0 10px;
  color: #fff;
  font-size: 1.8rem;
  backface-visibility: hidden;
  transition: all 150ms ease;
}
.support a:hover {
  transform: scale(1.1);
}