/* ===== 通用设置 ===== */
body {
  margin: 0;
  padding: 0;
  font-family: 'Orbitron', sans-serif;
  color: white;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: url('background.jpg') center/cover no-repeat fixed;
  overflow: hidden;
  animation: fadeIn 1.5s ease;
}

/* 柔光遮罩 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(8px);
  z-index: -1;
}

/* ===== Logo 样式 ===== */
header {
  position: absolute;
  top: 25px;
  right: 40px;
}

.logo {
  width: 85px;
  height: 85px;
  border-radius: 50%;
  border: 2px solid rgba(255,255,255,0.6);
  box-shadow: 0 0 20px rgba(51, 209, 255, 0.5);
  object-fit: cover;
  transition: all 0.4s ease;
}

.logo:hover {
  box-shadow: 0 0 35px rgba(51, 209, 255, 0.8);
  transform: scale(1.05);
}

/* ===== 欢迎文本 ===== */
.welcome-text {
  text-align: center;
  text-shadow: 0 0 15px rgba(51,209,255,0.5);
  letter-spacing: 2px;
  animation: glowText 3s ease-in-out infinite alternate;
}

.welcome-text h1 {
  font-size: 3.5rem;
  font-weight: 800;
  margin: 0;
  background: linear-gradient(90deg, #33d1ff, #a855f7, #33d1ff);
  background-size: 200%;
  -webkit-background-clip: text;
  background-clip: text;            /* ✅ 标准写法补上 */
  -webkit-text-fill-color: transparent;
  animation: colorFlow 5s linear infinite;
  text-shadow: 0 0 20px rgba(51, 209, 255, 0.4);
}

/* ===== 按钮样式 ===== */
#enterBtn {
  margin-top: 50px;
  padding: 14px 40px;
  font-size: 1.2rem;
  color: white;
  background: transparent;
  border: 2px solid rgba(255,255,255,0.7);
  border-radius: 10px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  box-shadow: 0 0 15px rgba(255,255,255,0.2);
  transition: all 0.3s ease;
}

#enterBtn:hover {
  background: rgba(51, 209, 255, 0.15);
  box-shadow: 0 0 25px rgba(51, 209, 255, 0.6);
  border-color: #33d1ff;
  transform: scale(1.05);
}

/* ===== 动画效果 ===== */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

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

@keyframes glowText {
  from { text-shadow: 0 0 10px rgba(51,209,255,0.3); }
  to { text-shadow: 0 0 30px rgba(168,85,247,0.7); }
}

.fade-out {
  animation: fadeOut 0.8s forwards;
}

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}

/* ===== 手机端优化 ===== */
@media (max-width: 768px) {
  .welcome-text h1 {
    font-size: 2.2rem;
  }
  #enterBtn {
    padding: 12px 30px;
    font-size: 1rem;
  }
  .logo {
    width: 65px;
    height: 65px;
  }
}