* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background: linear-gradient(135deg, #1a2a6c, #25214d);
  color: #f5f5f5;
  min-height: 100vh;
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1.6;
}

:root {
  --nav-height: 60px;
}
.container::before {
  display: none;
  content: "";
  position: absolute;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0) 70%);
  z-index: -1;
}
.container {
  max-width: 1200px;
  width: 100%;
  background: rgba(25, 25, 35, 0.9);
  border-radius: 20px;
  padding: 30px 30px; 
  margin: 20px 0;
  position: relative;
  overflow: hidden;
  margin-top: 80px; 
  flex: 1;
}

.top-nav-menu {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(135deg, #1a2a6c, #1f1e52);
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 0;
  z-index: 1000;
  backdrop-filter: blur(10px);
  height: var(--nav-height); /* 明确导航栏高度，方便内容定位 */
}

.nav-links {
  display: flex;
  justify-content: left;
  text-decoration: none;
}

.site-brand {
  font-size: 1.5rem;
  font-weight: bold;
  color: white;
  padding: 0 30px;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
  background: linear-gradient(45deg, #b09aff, #c4d1fa, #a1c4fd);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-right: 20px;
  animation: pulse 3s infinite;
}

@keyframes pulse {
  0% { opacity: 0.8; }
  50% { opacity: 1; }
  100% { opacity: 0.8; }
}

.top-nav-menu .nav-item {
  border-radius: 10px;
  color: #ffffff;
  padding: 20px 30px;
  margin: 10px 10px; 
  text-decoration: none;
}


.top-nav-menu .nav-item:hover,
.top-nav-menu .nav-item.active {
  background: rgba(106, 123, 212, 0.8);
  font-weight: bold;
}

button, .test-btn {
  background: linear-gradient(45deg, #4e54c8, #8f94fb);
  color: white;
  border: none;
  padding: 14px 30px;
  font-size: 1.1rem;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  text-decoration: none;
}

button:hover, .test-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

button:disabled {
  background: #444;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

footer {
  text-align: center;
  margin-top: 60px;
  padding-top: 30px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #aaa;
  width: 100%;
  position: relative;
  z-index: 10;
}

.footer-links {
  display: flex;
  justify-content: center;
  margin: 20px 0;
  flex-wrap: wrap;
}

.footer-link {
  margin: 0 15px;
  color: #8f94fb;
  text-decoration: none;
}

.footer-link:hover {
  text-decoration: underline;
}

.copyright {
  margin-top: 20px;
  font-size: 0.9rem;
}

.content-section {
  display: none;
  animation: fadeIn 0.5s ease forwards;
}

.content-section.active {
  display: block;
}

.nav-spacer {
  height: var(--nav-height);
  width: 100%;
}

.navigation {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 15px;
}

 .options-container {
  display: grid;
  grid-template-columns: 1fr; 
  gap: 15px;
  margin: 20px 0;
}
    
.options-container::before {
  display: none;
}
    
 .option {
  background: rgba(70, 70, 90, 0.5);
  border-radius: 12px;
  padding: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 2px;
  position: relative; 
}

.option::before {
  display: none;
}

.option.selected {
  background: rgba(78, 84, 200, 0.4);
  border: 2px solid #6a7bd4;
}

.option:hover {
  background: rgba(90, 90, 120, 0.6);
  transform: translateY(-3px);
}
    
.option-text {
  height: auto;
  display: block;
  text-align: left;
  font-size: 1.1rem;
  line-height: 1.5;
  flex: 1;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 响应式设计 */
@media (max-width: 768px) {
  :root {
    --nav-height: 48px;
  }
  .site-brand {
    font-size: 1.2rem;
    padding: 0 10px;
    margin-right: 10px;
  }
  
  .top-nav-menu .nav-item {
    padding: 10px 10px;
    font-size: 0.9rem;
  }

  .top-nav-menu
  {
    height: min-content;
  }

  .navigation {
    flex-direction: row !important;
    justify-content: space-between;
    align-items: center;
    gap: 15px;
   }
}
  @media (max-width: 480px) {
  .container {
    padding: 20px;
    width: 100%;
    }
  .site-title {
      font-size: 2.2rem;
    }

    .top-nav-menu .nav-item {
    padding: 8px 8px;
    font-size: 0.7rem;
  }
    
    .site-subtitle {
      font-size: 1.3rem;
    }
    
    .test-card {
      padding: 20px;
    }
    
    .test-title {
      font-size: 1.5rem;
    }
    
    .test-description {
      font-size: 1rem;
    }

    .option {
      padding: 10px;
    }
      
    .option-label {
      font-size: 1rem;
    }    
  }