/* ===================
   页面基础设置
=================== */
html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  width: 100%;
  overflow: hidden;
  font-family: "Segoe UI", "PingFang SC", "Helvetica Neue", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ===================
   动态渐变背景（优化版：更柔和、高级）
=================== */
body {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  height: 100vh;
  width: 100vw;
  background: linear-gradient(135deg, #e0eafc 0%, #cfdef3 25%, #e8f0fe 50%, #f5f7fc 75%, #eef2f8 100%);
  background-size: 400% 400%;
  animation: gradientShift 14s ease infinite;
  position: relative;
}

/* 背景渐变动画：优雅循环 */
@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* ===================
   粒子效果（增强光感与动态）
=================== */
.particle {
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.5);
  animation: floatParticle linear infinite;
  filter: blur(3px);
  pointer-events: none;  /* 让粒子不干扰点击 */
  will-change: transform, opacity;
}

/* 不同粒子的差异化配置 */
.particle:nth-child(1) {
  width: 10px;
  height: 10px;
  left: 15%;
  top: 85%;
  animation-duration: 16s;
  background: rgba(255, 255, 255, 0.6);
}

.particle:nth-child(2) {
  width: 6px;
  height: 6px;
  left: 65%;
  top: 90%;
  animation-duration: 20s;
  background: rgba(200, 220, 255, 0.7);
}

.particle:nth-child(3) {
  width: 12px;
  height: 12px;
  left: 85%;
  top: 70%;
  animation-duration: 24s;
  background: rgba(255, 245, 220, 0.55);
}

.particle:nth-child(4) {
  width: 7px;
  height: 7px;
  left: 35%;
  top: 80%;
  animation-duration: 18s;
  background: rgba(210, 230, 255, 0.65);
}

/* 粒子上升飘散动画 */
@keyframes floatParticle {
  0% {
    transform: translateY(0) translateX(0);
    opacity: 0.8;
  }
  100% {
    transform: translateY(-120vh) translateX(25px);
    opacity: 0;
  }
}

/* ===================
   卡片样式（玻璃质感强化）
=================== */
.card {
  position: relative;
  z-index: 2;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: 32px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1), 0 4px 12px rgba(0, 0, 0, 0.05);
  padding: 28px 24px 32px 24px;
  text-align: center;
  max-width: 280px;
  width: 85%;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  animation: cardFadeIn 0.8s cubic-bezier(0.2, 0.9, 0.4, 1.1);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.15);
}

/* 卡片淡入 + 轻微上浮动画 */
@keyframes cardFadeIn {
  0% {
    transform: scale(0.94) translateY(12px);
    opacity: 0;
  }
  100% {
    transform: scale(1) translateY(0);
    opacity: 1;
  }
}

/* ===================
   卡片内容样式（精致细节）
=================== */
.qr-img {
  width: 200px;
  height: 200px;
  margin-bottom: 20px;
  border-radius: 20px;
  border: 3px solid white;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
  transition: transform 0.2s ease;
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.qr-img:hover {
  transform: scale(1.02);
}

.logo {
  width: 38px;
  height: auto;
  vertical-align: middle;
  margin-right: 8px;
  border-radius: 12px;
}

.title {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 10px;
  color: #1a2c3e;
  letter-spacing: 1px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.desc {
  font-size: 15px;
  color: #4a627a;
  margin-top: 6px;
  font-weight: 500;
  letter-spacing: 0.3px;
  background: rgba(255,255,240,0.3);
  display: inline-block;
  padding: 6px 14px;
  border-radius: 40px;
  backdrop-filter: blur(2px);
}

/* ===================
   底部版权（优雅不干扰）
=================== */
.copyright {
  font-size: 12px;
  color: rgba(30, 40, 55, 0.6);
  text-align: center;
  position: fixed;
  bottom: 14px;
  left: 0;
  right: 0;
  width: 100%;
  z-index: 99;
  background: transparent;
  font-weight: 400;
  backdrop-filter: blur(4px);
  padding: 6px 0;
  pointer-events: auto;
}

.copyright a {
  text-decoration: none;
  color: #2c5a7a;
  transition: color 0.2s;
  font-weight: 500;
}

.copyright a:hover {
  color: #1e3a5f;
  text-decoration: underline;
}

/* ===================
   响应式微调（小屏幕适配）
=================== */
@media (max-width: 480px) {
  .card {
    max-width: 260px;
    padding: 22px 18px 26px;
  }
  
  .qr-img {
    width: 180px;
    height: 180px;
  }
  
  .title {
    font-size: 20px;
  }
  
  .logo {
    width: 32px;
    margin-right: 6px;
  }
  
  .desc {
    font-size: 13px;
    padding: 4px 12px;
  }
  
  .copyright {
    font-size: 10px;
    bottom: 10px;
  }
}

/* 针对大屏幕保持居中舒适 */
@media (min-width: 1200px) {
  .card {
    max-width: 300px;
  }
  .qr-img {
    width: 220px;
    height: 220px;
  }
}