/*
Theme Name: SEO Lite Pro 
Theme URI: https://example.com/seo-lite-pro  
Author: Your Name 
Author URI: https://example.com  
Description: 轻量级双栏响应式SEO优化主题，专为内容创作者打造。支持结构化数据、极速加载、移动端完美适配。
Version: 1.0.0 
License: GNU General Public License v2 or later 
License URI: http://www.gnu.org/licenses/gpl-2.0.html  
Text Domain: seo-lite-pro 
*/
 
/* ========================================
   CSS Variables - 设计系统 
======================================== */
:root {
  --color-bg: #f8f9fa;
  --color-surface: #ffffff;
  --color-primary: #1a56db;
  --color-primary-hover: #1e40af;
  --color-text: #1f2937;
  --color-text-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-accent: #059669;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
  --radius: 8px;
  --max-width: 1200px;
  --content-width: 720px;
  --sidebar-width: 320px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Monaco, "Cascadia Code", monospace;
}
 
/* ========================================
   Reset & Base 
======================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
 
html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}
 
body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
 
a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}
 
a:hover {
  color: var(--color-primary-hover);
}
 
img {
  max-width: 100%;
  height: auto;
  display: block;
}
 
/* ========================================
   Typography 
======================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 0.75em;
  color: var(--color-text);
}
 
h1 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: clamp(1.25rem, 2.5vw, 1.5rem); }
h4 { font-size: 1.25rem; }
 
p { margin-bottom: 1.25em; }
 
.entry-content ul,
.entry-content ol {
  margin: 1em 0;
  padding-left: 1.5em;
}
 
.entry-content li {
  margin-bottom: 0.5em;
}
 
blockquote {
  border-left: 4px solid var(--color-primary);
  padding-left: 1.5em;
  margin: 1.5em 0;
  color: var(--color-text-muted);
  font-style: italic;
}
 
code {
  font-family: var(--font-mono);
  background: #f1f5f9;
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-size: 0.9em;
}
 
pre {
  background: #1e293b;
  color: #e2e8f0;
  padding: 1.25em;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 1.5em 0;
}
 
pre code {
  background: none;
  padding: 0;
  color: inherit;
}
 
/* ========================================
   Layout - 双栏结构 
======================================== */
.site-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
}
 
.site-main {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: 2rem;
  padding: 2rem 0;
}
 
.content-area {
  min-width: 0;
}
 
.sidebar-area {
  position: sticky;
  top: 2rem;
  height: fit-content;
}
 
/* ========================================
   Header 
======================================== */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
  background: rgba(255,255,255,0.95);
}
 
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
 
.site-branding {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
 
.site-logo {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: 1.25rem;
}
 
.site-title {
  font-size: 1.25rem;
  margin: 0;
}
 
.site-title a {
  color: var(--color-text);
}
 
.site-title a:hover {
  color: var(--color-primary);
}
 
/* Navigation */
.main-nav ul {
  display: flex;
  gap: 0.5rem;
  list-style: none;
}
 
.main-nav a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--color-text);
  border-radius: var(--radius);
  font-weight: 500;
  transition: all 0.2s ease;
}
 
.main-nav a:hover,
.main-nav .current-menu-item a {
  background: var(--color-bg);
  color: var(--color-primary);
}
 
/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  padding: 0.5rem;
  cursor: pointer;
  color: var(--color-text);
}
 
.menu-toggle svg {
  width: 24px;
  height: 24px;
}
 
/* ========================================
   Posts List 
======================================== */
.posts-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
 
.post-card {
  background: var(--color-surface);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all 0.3s ease;
  display: grid;
  grid-template-columns: 200px 1fr;
}
 
.post-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
 
.post-thumbnail {
  position: relative;
  overflow: hidden;
}
 
.post-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
 
.post-card:hover .post-thumbnail img {
  transform: scale(1.05);
}
 
.post-thumbnail-placeholder {
  width: 100%;
  height: 100%;
  min-height: 160px;
  background: linear-gradient(135deg, #e0e7ff 0%, #c7d2fe 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-weight: 600;
}
 
.post-content {
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
}
 
.post-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}
 
.post-meta-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}
 
.post-meta-item svg {
  width: 14px;
  height: 14px;
}
 
.entry-title {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
  line-height: 1.4;
}
 
.entry-title a {
  color: var(--color-text);
}
 
.entry-title a:hover {
  color: var(--color-primary);
}
 
.entry-excerpt {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 0;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
 
/* ========================================
   Single Post 
======================================== */
.single-post {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
 
.single-post .entry-header {
  padding: 2rem 2rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
}
 
.single-post .entry-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
 
.single-post .entry-meta a {
  color: var(--color-text-muted);
}
 
.single-post .entry-meta a:hover {
  color: var(--color-primary);
}
 
.single-post .entry-content {
  padding: 2rem;
}
 
.single-post .entry-content p {
  max-width: var(--content-width);
}
 
.single-post .entry-footer {
  padding: 1.5rem 2rem;
  border-top: 1px solid var(--color-border);
  background: var(--color-bg);
  border-radius: 0 0 var(--radius) var(--radius);
}
 
.tags-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
 
.tags-links a {
  display: inline-block;
  padding: 0.35rem 0.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  transition: all 0.2s ease;
}
 
.tags-links a:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}
 
/* Post Navigation */
.post-navigation {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
}
 
.nav-link {
  background: var(--color-surface);
  padding: 1.25rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: all 0.2s ease;
}
 
.nav-link:hover {
  box-shadow: var(--shadow-md);
}
 
.nav-link.next {
  text-align: right;
}
 
.nav-label {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.35rem;
}
 
.nav-title {
  font-weight: 600;
  color: var(--color-text);
}
 
/* ========================================
   Sidebar 
======================================== */
.widget {
  background: var(--color-surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
}
 
.widget-title {
  font-size: 1rem;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}
 
.widget ul {
  list-style: none;
}
 
.widget li {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--color-border);
}
 
.widget li:last-child {
  border-bottom: none;
}
 
.widget a {
  color: var(--color-text);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
 
.widget a:hover {
  color: var(--color-primary);
}
 
.widget .count {
  background: var(--color-bg);
  padding: 0.15rem 0.5rem;
  border-radius: 12px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}
 
/* Search Widget */
.widget_search .search-form {
  display: flex;
  gap: 0.5rem;
}
 
.widget_search input[type="search"] {
  flex: 1;
  padding: 0.65rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  transition: border-color 0.2s ease;
}
 
.widget_search input[type="search"]:focus {
  outline: none;
  border-color: var(--color-primary);
}
 
.widget_search button {
  padding: 0.65rem 1rem;
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 500;
  transition: background 0.2s ease;
}
 
.widget_search button:hover {
  background: var(--color-primary-hover);
}
 
/* ========================================
   Pagination 
======================================== */
.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 2rem;
}
 
.pagination .page-numbers {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 40px;
  height: 40px;
  padding: 0 0.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  font-weight: 500;
  transition: all 0.2s ease;
}
 
.pagination .page-numbers:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}
 
.pagination .page-numbers.current {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}
 
/* ========================================
   Footer 
======================================== */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  margin-top: 3rem;
}
 
.footer-widgets {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  padding: 2.5rem 0;
}
 
.footer-bottom {
  padding: 1.5rem 0;
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
 
.footer-links {
  display: flex;
  gap: 1.5rem;
}
 
.footer-links a {
  color: var(--color-text-muted);
}
 
.footer-links a:hover {
  color: var(--color-primary);
}
 
/* ========================================
   Responsive Design 
======================================== */
@media (max-width: 1024px) {
  .site-main {
    grid-template-columns: 1fr;
  }
  
  .sidebar-area {
    position: static;
  }
  
  .footer-widgets {
    grid-template-columns: repeat(2, 1fr);
  }
}
 
@media (max-width: 768px) {
  .main-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: 1rem;
    box-shadow: var(--shadow-md);
  }
  
  .main-nav.active {
    display: block;
  }
  
  .main-nav ul {
    flex-direction: column;
    gap: 0;
  }
  
  .main-nav a {
    padding: 0.75rem 1rem;
  }
  
  .menu-toggle {
    display: block;
  }
  
  .post-card {
    grid-template-columns: 1fr;
  }
  
  .post-thumbnail {
    height: 180px;
  }
  
  .single-post .entry-header,
  .single-post .entry-content,
  .single-post .entry-footer {
    padding: 1.5rem;
  }
  
  .post-navigation {
    grid-template-columns: 1fr;
  }
  
  .footer-widgets {
    grid-template-columns: 1fr;
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}
 
@media (max-width: 480px) {
  .site-container {
    padding: 0 1rem;
  }
  
  .site-main {
    padding: 1.5rem 0;
  }
  
  .post-content {
    padding: 1rem;
  }
  
  .widget {
    padding: 1.25rem;
  }
}
 
/* ========================================
   Accessibility 
======================================== */
.screen-reader-text {
  clip: rect(1px, 1px, 1px, 1px);
  position: absolute !important;
  height: 1px;
  width: 1px;
  overflow: hidden;
}
 
.screen-reader-text:focus {
  background-color: var(--color-surface);
  clip: auto !important;
  display: block;
  font-size: 1rem;
  font-weight: bold;
  height: auto;
  left: 5px;
  line-height: normal;
  padding: 15px 23px 14px;
  text-decoration: none;
  top: 5px;
  width: auto;
  z-index: 100000;
}
 
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
 
/* Skip Link */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  z-index: 1000;
  transition: top 0.2s ease;
}
 
.skip-link:focus {
  top: 1rem;
}