* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: '微软雅黑', sans-serif;
}

body {
  background: url("../background.png") no-repeat center center fixed;
  background-size: cover;
  min-height: 100vh;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 50px;
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(5px);
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  position: relative;
}

.logo img {
  height: 40px;
  max-width: 180px;
  transition: transform 0.3s;
}

.logo:hover img {
  transform: scale(1.05);
}

.nav-links {
  display: flex;
  gap: 30px;
}

.nav-links li {
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: #2c3e50;
  font-weight: 500;
  padding: 10px 15px;
  border-radius: 5px;
  transition: all 0.3s;
  position: relative;
}

.nav-links a::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: #3498db;
  transition: width 0.3s;
}

.nav-links a:hover::before {
  width: 100%;
}

.nav-links a:hover {
  color: #3498db;
}

.back-button {
  position: absolute;
  left: 50px;
  top: 90px;
  display: flex;
  align-items: center;
  color: #3498db;
  text-decoration: none;
  font-weight: 500;
  padding: 8px 15px;
  border-radius: 20px;
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(2px);
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: all 0.3s ease;
  z-index: 100;
}

.back-button::before {
  content: '';
  display: block;
  width: 12px;
  height: 12px;
  border-left: 2px solid #3498db;
  border-bottom: 2px solid #3498db;
  transform: rotate(45deg);
  margin-right: 8px;
  transition: all 0.3s;
}

.back-button:hover {
    transform: translateX(-5px);
    background: rgba(255,255,255,1);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.back-button:hover::before {
    border-color: #2980b9;
}

.container {
  width: 85%;
  max-width: 800px;
  margin: 100px auto;
  padding: 40px;
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(3px);
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.1);
  text-align: center;
}

h1 {
  color: #2c3e50;
  margin-bottom: 30px;
  font-size: 2.4em;
}

h1 a {
  color: #2c3e50;
  text-decoration: none;
  transition: color 0.3s;
}

h1 a:hover {
  color: #3498db;
}

.friend-link {
  display: inline-block;
  width: 500px;
  padding: 15px 30px;
  margin: 15px 0;
  background: #3498db;
  color: white !important;
  border-radius: 25px;
  text-decoration: none;
  transition: all 0.3s;
  box-shadow: 0 4px 15px rgba(52,152,219,0.3);
  border: 1px solid #2980b9;
  font-size: 1.1em;
}

.friend-link:hover {
  background: #2980b9;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(52,152,219,0.4);
}

@media (max-width: 768px) {
  .navbar {
      padding: 10px 20px;
  }

  .container {
      width: 95%;
      padding: 25px;
  }

  h1 {
      font-size: 1.8em;
  }

  .friend-link {
      width: 100%;
      padding: 12px 25px;
  }

  .back-button {
      left: 20px;
      top: 70px;
  }
}