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

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: "微软雅黑", sans-serif;
  /* 动态渐变背景 */
  background: linear-gradient(-45deg, #ee7752, #e73c7e, #23a6d5, #23d5ab);
  background-size: 400% 400%;
  animation: gradientBG 12s ease infinite;
}

@keyframes gradientBG {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* 毛玻璃卡片 */
.card {
  background: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: 20px;
  padding: 50px 60px;
  text-align: center;
  color: #fff;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.25);
  animation: floatIn 1s ease;
}

@keyframes floatIn {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}

h1 {
  font-size: 2.2rem;
  margin-bottom: 15px;
  text-shadow: 0 0 20px rgba(255, 255, 255, 0.8);
}

p {
  margin-bottom: 25px;
  font-size: 1rem;
  opacity: 0.95;
}

button {
  padding: 12px 30px;
  font-size: 1rem;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  color: #fff;
  background: linear-gradient(45deg, #ff6b6b, #feca57);
  box-shadow: 0 4px 15px rgba(255, 107, 107, 0.5);
  transition: transform 0.2s, box-shadow 0.2s;
}

button:hover {
  transform: scale(1.08);
  box-shadow: 0 6px 25px rgba(255, 107, 107, 0.8);
}

#msg {
  margin-top: 20px;
  font-weight: bold;
  min-height: 1.2em;
}