/* 全局样式增强 */
body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

/* 卡片网格布局 */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 20px;
}

.card {
  background: #f9f9f9;
  border-radius: 8px;
  padding: 20px;
  transition: transform 0.3s, box-shadow 0.3s;
  border: 1px solid #e0e0e0;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 5px 15px rgba(0,0,0,0.15);
}

.card h3 {
  color: #2c3e50;
  margin-bottom: 10px;
  font-size: 1.2em;
}

.card h3 a {
  color: #667eea;
  transition: color 0.3s;
}

.card h3 a:hover {
  color: #764ba2;
}

.card .meta {
  color: #999;
  font-size: 0.9em;
  margin-bottom: 10px;
}

.card .one-line {
  color: #666;
  line-height: 1.6;
  margin-bottom: 15px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card .btn {
  display: inline-block;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 8px 20px;
  border-radius: 20px;
  font-size: 0.9em;
  transition: transform 0.2s, box-shadow 0.2s;
}

.card .btn:hover {
  transform: scale(1.05);
  box-shadow: 0 3px 10px rgba(102,126,234,0.4);
}

/* 列表容器 */
.list-container {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.list-item {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 20px;
  background: #f9f9f9;
  border-radius: 8px;
  border-left: 4px solid #667eea;
  transition: background 0.3s;
}

.list-item:hover {
  background: #f0f0f0;
}

.list-item .rank {
  font-size: 2em;
  font-weight: bold;
  color: #667eea;
  min-width: 50px;
  text-align: center;
}

.list-item .list-content {
  flex: 1;
}

.list-item h3 {
  margin-bottom: 8px;
  font-size: 1.3em;
}

.list-item h3 a {
  color: #2c3e50;
  transition: color 0.3s;
}

.list-item h3 a:hover {
  color: #667eea;
}

.list-item .meta {
  color: #999;
  font-size: 0.9em;
  margin-bottom: 8px;
}

.list-item .summary {
  color: #666;
  line-height: 1.6;
  margin-bottom: 8px;
}

.list-item .tags {
  color: #764ba2;
  font-size: 0.85em;
}

.list-item .btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 10px 25px;
  border-radius: 20px;
  white-space: nowrap;
  transition: transform 0.2s;
}

.list-item .btn:hover {
  transform: scale(1.05);
}

/* 详情页信息网格 */
.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 15px;
  line-height: 1.8;
}

.info-item {
  color: #555;
}

.info-item strong {
  color: #2c3e50;
}

/* 响应式优化 */
@media (max-width: 768px) {
  header h1 {
    font-size: 1.8em;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .list-item {
    flex-direction: column;
    align-items: flex-start;
  }

  .list-item .rank {
    font-size: 1.5em;
    min-width: auto;
  }

  .info-grid {
    grid-template-columns: 1fr;
  }
}

/* UI风格变体（16种） */
.ui-style-0 { --primary: #667eea; --secondary: #764ba2; }
.ui-style-1 { --primary: #f093fb; --secondary: #f5576c; }
.ui-style-2 { --primary: #4facfe; --secondary: #00f2fe; }
.ui-style-3 { --primary: #43e97b; --secondary: #38f9d7; }
.ui-style-4 { --primary: #fa709a; --secondary: #fee140; }
.ui-style-5 { --primary: #30cfd0; --secondary: #330867; }
.ui-style-6 { --primary: #a8edea; --secondary: #fed6e3; }
.ui-style-7 { --primary: #ff9a56; --secondary: #ff6a88; }
.ui-style-8 { --primary: #fbc2eb; --secondary: #a6c1ee; }
.ui-style-9 { --primary: #fdcbf1; --secondary: #e6dee9; }
.ui-style-10 { --primary: #a1c4fd; --secondary: #c2e9fb; }
.ui-style-11 { --primary: #ffecd2; --secondary: #fcb69f; }
.ui-style-12 { --primary: #ff6e7f; --secondary: #bfe9ff; }
.ui-style-13 { --primary: #e0c3fc; --secondary: #8ec5fc; }
.ui-style-14 { --primary: #f8b500; --secondary: #fceabb; }
.ui-style-15 { --primary: #d299c2; --secondary: #fef9d7; }

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

.card, .list-item {
  animation: fadeIn 0.5s ease-out;
}

/* 返回顶部按钮 */
#back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.3s, transform 0.3s;
  box-shadow: 0 4px 10px rgba(0,0,0,0.2);
  z-index: 999;
}

#back-to-top.show {
  opacity: 1;
}

#back-to-top:hover {
  transform: translateY(-5px);
}

@media (max-width: 768px) {
  #back-to-top {
    width: 45px;
    height: 45px;
    bottom: 20px;
    right: 20px;
  }
}