:root {
  --bg-main: #121212;
  --bg-container: #1e1e2f;
  --text-primary: #e0e0f0;
  --text-secondary: #a0a0b8;
  --violet-primary: #8c7ae6;
  --violet-hover: #a899f9;
  --border-color: #2a2a45;
  --btn-bg: var(--violet-primary);
  --btn-bg-hover: var(--violet-hover);
  --accent-bg: #29294b;
  --success-color: #4caf50;
  --warning-color: #ff9800;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}

body {
  background: linear-gradient(135deg, var(--bg-main) 0%, #1a1a2e 100%);
  color: var(--text-primary);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  line-height: 1.6;
  padding: 20px;
}

.container {
  max-width: 580px;
  width: 100%;
  background: var(--bg-container);
  padding: 38px;
  border-radius: 20px;
  box-shadow: 
    0 20px 40px rgba(0, 0, 0, 0.4),
    0 0 0 1px var(--border-color);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(10px);
  position: relative;
  overflow: hidden;
}

.container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--violet-primary), var(--violet-hover));
  opacity: 0.8;
}

header {
  text-align: center;
  margin-bottom: 30px;
  position: relative;
}

.back-button {
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  color: var(--violet-primary);
  text-decoration: none;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  transition: all 0.3s ease;
  padding: 8px 12px;
  border-radius: 8px;
}

.back-button:hover {
  color: var(--violet-hover);
  background: rgba(140, 122, 230, 0.1);
}

.back-button i {
  margin-right: 8px;
  font-size: 0.9rem;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--text-primary), var(--violet-hover));
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 400;
  margin-bottom: 8px;
}

.stats-info {
  background: linear-gradient(135deg, var(--violet-primary), var(--violet-hover));
  color: white;
  padding: 7px 14px;
  border-radius: 18px;
  font-size: 0.85rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 8px;
}

.stats-info i {
  font-size: 0.8rem;
}

.file-info {
  display: flex;
  align-items: center;
  background: var(--accent-bg);
  padding: 22px;
  border-radius: 14px;
  margin: 28px 0;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

.file-info:hover {
  box-shadow: 0 8px 25px rgba(140, 122, 230, 0.2);
  transform: translateY(-2px);
}

.file-icon {
  width: 50px;
  height: 50px;
  margin-right: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(140, 122, 230, 0.1);
  border-radius: 10px;
  border: 2px solid rgba(140, 122, 230, 0.3);
}

.file-icon img {
  width: 36px;
  height: 36px;
  object-fit: contain;
  filter: drop-shadow(0 0 8px var(--violet-primary));
}

.file-details {
  flex: 1;
}

.file-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.file-meta {
  font-size: 0.9rem;
  color: var(--text-secondary);
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

.file-meta span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.download-options {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 30px;
}

.download-button {
  background: linear-gradient(135deg, var(--btn-bg), var(--btn-bg-hover));
  color: white;
  padding: 16px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 1rem;
  text-align: center;
  text-decoration: none;
  transition: all 0.3s ease;
  border: none;
  box-shadow: 0 8px 20px rgba(140, 122, 230, 0.3);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  position: relative;
  overflow: hidden;
}

.download-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  transition: left 0.5s;
}

.download-button:hover::before {
  left: 100%;
}

.download-button:hover {
  background: linear-gradient(135deg, var(--btn-bg-hover), #b8a9ff);
  transform: translateY(-3px);
  box-shadow: 0 12px 30px rgba(168, 153, 249, 0.4);
}

.download-button.downloading {
  background: linear-gradient(135deg, var(--warning-color), #ffb74d);
  pointer-events: none;
}

.download-button.completed {
  background: linear-gradient(135deg, var(--success-color), #66bb6a);
}

.mirror-button {
  background: transparent;
  border: 2px solid var(--btn-bg);
  color: var(--btn-bg);
  font-weight: 600;
  box-shadow: 0 4px 15px rgba(140, 122, 230, 0.2);
}

.mirror-button:hover {
  background: linear-gradient(135deg, var(--btn-bg), var(--btn-bg-hover));
  color: white;
  border-color: var(--btn-bg-hover);
  box-shadow: 0 8px 25px rgba(168, 153, 249, 0.4);
}

.download-icon {
  font-size: 1.2rem;
}

.old-versions {
  border-top: 1px solid var(--border-color);
  padding-top: 22px;
  text-align: center;
}

.old-versions h2 {
  font-weight: 600;
  font-size: 1.2rem;
  color: var(--text-primary);
  margin-bottom: 18px;
}

.old-versions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
  margin-top: 18px;
}

.old-download-button {
  background: transparent;
  border: 2px solid var(--border-color);
  color: var(--text-secondary);
  padding: 10px 16px;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  transition: all 0.3s ease;
  cursor: pointer;
}

.old-download-button:hover {
  background: var(--btn-bg);
  color: white;
  border-color: var(--btn-bg);
  box-shadow: 0 6px 20px rgba(140, 122, 230, 0.3);
  transform: translateY(-2px);
}

footer {
  color: var(--text-secondary);
  font-size: 0.85rem;
  text-align: center;
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid var(--border-color);
}

.loading-spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2px solid #ffffff40;
  border-radius: 50%;
  border-top-color: #ffffff;
  animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@media (max-width: 768px) {
  .container {
    padding: 30px 22px;
    margin: 10px;
  }
  
  .back-button {
    position: static;
    transform: none;
    margin-bottom: 18px;
    display: inline-flex;
    justify-content: center;
  }
  
  h1 {
    font-size: 1.7rem;
  }
  
  .file-info {
    flex-direction: column;
    text-align: center;
    padding: 18px;
  }
  
  .file-icon {
    margin-right: 0;
    margin-bottom: 12px;
  }
  
  .file-meta {
    justify-content: center;
  }
  
  .download-button {
    padding: 14px 20px;
    font-size: 0.95rem;
  }
  
  .old-versions-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 22px 18px;
  }
  
  h1 {
    font-size: 1.5rem;
  }
  
  .file-meta {
    flex-direction: column;
    gap: 6px;
  }
  
  .download-button {
    padding: 12px 18px;
    font-size: 0.9rem;
  }
  
  .old-download-button {
    padding: 8px 14px;
    font-size: 0.8rem;
  }
}