/* ================================
   全局样式表
   ================================ */

:root {
  /* 颜色变量 */
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --text-primary: #1f2d3d;
  --text-secondary: #4b5563;
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

  /* 暗黑模式变量 */
  --dark-text-primary: #e2e8f0;
  --dark-text-secondary: #94a3b8;
  --dark-bg-primary: #0f172a;
  --dark-bg-secondary: #1e293b;
  --dark-bg-tertiary: #334155;
  --dark-border-color: #334155;
}

/* 深色模式 */
@media (prefers-color-scheme: dark) {
  :root {
    --text-primary: var(--dark-text-primary);
    --text-secondary: var(--dark-text-secondary);
    --bg-primary: var(--dark-bg-primary);
    --bg-secondary: var(--dark-bg-secondary);
    --bg-tertiary: var(--dark-bg-tertiary);
    --border-color: var(--dark-border-color);
  }
}

/* ================================
   重置和基础样式
   ================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* ================================
   容器和布局
   ================================ */

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-main {
  flex: 1;
  padding: 3rem 0;
}

/* ================================
   页眉样式
   ================================ */

.site-header {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
  color: white;
  padding: 2rem 0;
  box-shadow: var(--shadow-md);
  border-bottom: 4px solid var(--primary-color);
}

.header-content {
  text-align: center;
}

.site-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.5px;
}

.site-title a {
  color: white;
  text-decoration: none;
  transition: opacity 0.3s ease;
}

.site-title a:hover {
  opacity: 0.9;
}

.site-tagline {
  font-size: 1rem;
  opacity: 0.95;
  font-weight: 300;
}

/* ================================
   页脚样式
   ================================ */

.site-footer {
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 2rem 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
  margin-top: 3rem;
}

.site-footer p {
  margin: 0;
  font-size: 0.9rem;
}

/* ================================
   首页样式
   ================================ */

.index-content {
  padding: 2rem 0;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 600;
  margin-bottom: 2rem;
  color: var(--text-primary);
  position: relative;
  padding-bottom: 1rem;
  border-bottom: 3px solid var(--primary-color);
}

.posts-list {
  list-style: none;
}

.post-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  transition: all 0.3s ease;
  cursor: pointer;
}

.post-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-color);
}

.post-item-content {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.post-item .post-title {
  font-size: 1.25rem;
  margin: 0;
}

.post-item .post-title a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color 0.3s ease;
}

.post-item .post-title a:hover {
  color: var(--primary-hover);
  text-decoration: underline;
}

.post-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.post-date {
  display: flex;
  align-items: center;
}

.empty-state {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--text-secondary);
}

.empty-state p {
  font-size: 1.1rem;
}

/* ================================
   文章页面样式
   ================================ */

.post-article {
  padding: 2rem 0;
}

.breadcrumb {
  margin-bottom: 2rem;
}

.breadcrumb a {
  color: var(--primary-color);
  text-decoration: none;
  font-size: 0.95rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: color 0.3s ease;
}

.breadcrumb a:hover {
  color: var(--primary-hover);
}

.post-header {
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--border-color);
}

.post-article .post-title {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  line-height: 1.2;
  color: var(--text-primary);
}

.post-metadata {
  display: flex;
  align-items: center;
  gap: 2rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.post-footer {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border-color);
}

.post-navigation {
  display: flex;
  gap: 1rem;
}

.btn-back {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background-color: var(--primary-color);
  color: white;
  text-decoration: none;
  border-radius: 8px;
  transition: all 0.3s ease;
  font-weight: 500;
}

.btn-back:hover {
  background-color: var(--primary-hover);
  transform: translateX(-4px);
}

/* ================================
   响应式设计
   ================================ */

@media (max-width: 768px) {
  .site-header {
    padding: 1.5rem 0;
  }

  .site-title {
    font-size: 1.5rem;
  }

  .site-tagline {
    font-size: 0.9rem;
  }

  .site-main {
    padding: 2rem 0;
  }

  .section-title {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
  }

  .post-item {
    padding: 1rem;
    margin-bottom: 1rem;
  }

  .post-article .post-title {
    font-size: 1.75rem;
  }

  .post-meta {
    flex-direction: column;
    gap: 0.5rem;
    align-items: flex-start;
  }

  .container {
    padding: 0 1rem;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 15px;
  }

  .site-title {
    font-size: 1.25rem;
  }

  .post-article .post-title {
    font-size: 1.5rem;
  }

  .post-navigation {
    flex-direction: column;
  }

  .btn-back {
    width: 100%;
    justify-content: center;
  }
}

/* ================================
   辅助样式
   ================================ */

/* 平滑过渡 */
a, button {
  transition: all 0.3s ease;
}

/* 选中文本 */
::selection {
  background-color: var(--primary-color);
  color: white;
}

/* 滚动条样式 */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--primary-color);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--primary-hover);
}