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

:root {
  --slide-duration: 2000ms;
  --bg-color: #000;   /* 图片底部空白的背景色，按需修改 */
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg-color);
}

/* =====================
   主容器
===================== */
#app {
  position: relative;
  width: 100%;
  max-width: 480px;    /* 手机最大宽度，PC端居中 */
  height: 100vh;
  margin: 0 auto;
  overflow: hidden;
  background: var(--bg-color);
}

/* =====================
   轮播容器
===================== */
.carousel-wrapper {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  overflow: hidden;
}

.carousel-track {
  display: flex;
  width: 400%;        /* 4张图 × 100% */
  transition: transform 0.6s cubic-bezier(0.77, 0, 0.175, 1);
  will-change: transform;
}

/* =====================
   每张幻灯片
   宽度适配模式：图片宽=屏幕宽，高度auto保持比例
===================== */
.slide {
  width: 25%;          /* 400% ÷ 4 = 每张占屏幕100% */
  flex-shrink: 0;
}

.slide img {
  width: 100%;
  height: auto;        /* 高度自适应，保持图片原始比例 */
  display: block;
}

/* =====================
   指示点
===================== */
.carousel-dots {
  position: absolute;
  bottom: 110px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 7px;
  z-index: 10;
}

.dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: rgba(255,255,255,0.35);
  transition: all 0.35s ease;
  cursor: pointer;
}

.dot.active {
  background: #fff;
  width: 22px;
  border-radius: 4px;
}

/* =====================
   下载按钮（固定在底部）
===================== */
.download-bar {
  position: fixed;     /* fixed确保始终在屏幕底部可见 */
  bottom: 36px;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: 480px;
  padding: 0 40px;
  z-index: 30;
  background: transparent;
}

.download-btn-wrap {
  width: 100%;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  position: relative;
}

.download-btn-wrap:active { opacity: 0.88; }

.download-btn-wrap > img {
  width: 100%;
  height: auto;
  display: block;
}

.download-btn-fallback {
  width: 100%;
  padding: 15px 0;
  border-radius: 50px;
  text-align: center;
  font-size: 16px;
  font-weight: 800;
  color: #fff;
  letter-spacing: 3px;
  font-family: sans-serif;
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #ff6eb4 0%, #ff3fa0 40%, #d4006e 100%);
  box-shadow: 0 6px 24px rgba(255,62,160,0.55), 0 2px 8px rgba(0,0,0,0.25);
  animation: btn-shake 0.7s ease-in-out infinite,
             btn-glow-pulse 1.4s ease-in-out infinite;
}

.download-btn-fallback::before {
  content: "";
  position: absolute;
  top: 0; left: -75%;
  width: 50%; height: 100%;
  background: linear-gradient(120deg, transparent 0%, rgba(255,255,255,0.35) 50%, transparent 100%);
  animation: sheen 2.4s ease-in-out infinite;
}

@keyframes sheen {
  0%   { left: -75%; }
  60%  { left: 130%; }
  100% { left: 130%; }
}

.download-btn-fallback span {
  position: relative;
  z-index: 1;
  text-shadow: 0 1px 6px rgba(0,0,0,0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

@keyframes btn-shake {
  0%, 100% { transform: translateX(0) rotate(0deg); }
  15%       { transform: translateX(-4px) rotate(-1.2deg); }
  30%       { transform: translateX(4px) rotate(1.2deg); }
  45%       { transform: translateX(-3px) rotate(-0.8deg); }
  60%       { transform: translateX(3px) rotate(0.8deg); }
  75%       { transform: translateX(-2px) rotate(-0.4deg); }
  88%       { transform: translateX(2px) rotate(0.4deg); }
}

@keyframes btn-glow-pulse {
  0%, 100% { box-shadow: 0 6px 24px rgba(255,62,160,0.55), 0 0 0 0 rgba(255,62,160,0.6); }
  50%       { box-shadow: 0 8px 32px rgba(255,62,160,0.8), 0 0 0 10px rgba(255,62,160,0); }
}

.download-btn-wrap:active .download-btn-fallback {
  animation: none;
  transform: scale(0.96);
}

#loading-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.01);
  z-index: 9999;
  pointer-events: none;
}