/* ==================== 1. 设计系统 (CSS Variables) ==================== */
:root {
  /* 基础字号与字体 */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: 'JetBrains Mono', Fira Code, monospace;
  
  /* 页面最大宽度 */
  --max-width: 1000px;
  --border-radius-sm: 8px;
  --border-radius-md: 12px;
  --border-radius-lg: 16px;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);

  /* === 极简天亮（浅色）模式 === */
  --bg-base: hsl(220, 20%, 97%);
  --bg-surface: hsl(0, 0%, 100%);
  --bg-surface-hover: hsl(220, 20%, 94%);
  --border-color: hsl(220, 15%, 88%);
  --border-color-hover: hsl(220, 15%, 80%);
  
  --text-primary: hsl(220, 25%, 15%);
  --text-secondary: hsl(220, 15%, 40%);
  --text-muted: hsl(220, 10%, 60%);
  
  --primary: hsl(220, 80%, 50%);
  --primary-hover: hsl(220, 90%, 55%);
  --primary-glow: hsla(220, 80%, 50%, 0.08);
  
  --accent: hsl(160, 70%, 35%);
  --accent-glow: hsla(160, 70%, 35%, 0.08);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.12);

  --gradient-rainbow: linear-gradient(135deg, hsl(220, 70%, 55%), hsl(280, 60%, 55%), hsl(340, 65%, 55%));
}

/* ==================== 2. 全局基础样式 ==================== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-base);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s ease, color 0.3s ease;
  display: flex;
  flex-direction: column;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-smooth);
}

img {
  max-width: 100%;
  height: auto;
  border-radius: var(--border-radius-md);
}

/* 现代网格背景效果 (极简发光) */
.bg-grid {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  background-image: 
    radial-gradient(var(--border-color) 1px, transparent 1px);
  background-size: 24px 24px;
  mask-image: radial-gradient(circle at 50% 30%, black, transparent 80%);
  -webkit-mask-image: radial-gradient(circle at 50% 30%, black, transparent 80%);
  opacity: 0.7;
}

/* ==================== 3. 布局 & 导航 ==================== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* 导航栏 */
header.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  background-color: rgba(255, 255, 255, 0.7);
  transition: var(--transition-smooth);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 4rem;
}

.nav-logo {
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.5px;
  background: var(--gradient-rainbow);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* 暗色模式切换按钮 */
.theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
}

.theme-toggle:hover {
  background-color: var(--bg-surface-hover);
  border-color: var(--border-color-hover);
}

.theme-toggle svg {
  width: 1.1rem;
  height: 1.1rem;
  fill: currentColor;
}

/* 主内容区域弹性填充 */
main.main-content {
  flex: 1;
  padding: 3rem 0;
}

/* 页脚 */
footer.site-footer {
  border-top: 1px solid var(--border-color);
  padding: 2rem 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  text-align: center;
  background-color: rgba(0, 0, 0, 0.1);
}

/* ==================== 4. 公用 UI 组件 ==================== */

/* 渐变标题 */
.gradient-text {
  background: var(--gradient-rainbow);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* 按钮样式 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.6rem 1.2rem;
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  transition: var(--transition-smooth);
  border: 1px solid transparent;
}

.btn-primary {
  background-color: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  box-shadow: 0 0 20px var(--primary-glow);
}

.btn-secondary {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-surface-hover);
  border-color: var(--border-color-hover);
}

/* 精美卡片 (Glassmorphism & Border Gradient Glow) */
.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  padding: 1.5rem;
  transition: var(--transition-bounce);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.05);
  pointer-events: none;
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--border-color-hover);
  box-shadow: var(--shadow-md);
}

/* ==================== 5. 首页 (Hero & Grid) ==================== */
.hero-section {
  text-align: center;
  padding: 4rem 0 5rem 0;
  max-width: 700px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.25rem 0.75rem;
  background-color: var(--primary-glow);
  border: 1px solid var(--primary);
  color: var(--primary);
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  animation: pulse 2s infinite;
}

.hero-title {
  font-size: 3.5rem;
  line-height: 1.1;
  font-weight: 800;
  letter-spacing: -2px;
  margin-bottom: 1.5rem;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  white-space: pre-line;
  line-height: 1.85;
}

.hero-buttons {
  display: flex;
  justify-content: center;
  gap: 1rem;
}

/* 首页区块 */
.section-title-wrap {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 2rem;
  margin-top: 4rem;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.section-more {
  font-size: 0.9rem;
  color: var(--primary);
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.section-more:hover {
  color: var(--primary-hover);
}

/* 卡片网格 */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

/* ==================== 6. 博客卡片 & 文章页 ==================== */
.blog-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.blog-meta {
  display: flex;
  gap: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.blog-card-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.blog-card-summary {
  font-size: 0.95rem;
  color: var(--text-secondary);
  flex-grow: 1;
  margin-bottom: 1.5rem;
}

.blog-tag {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  background-color: var(--border-color);
  color: var(--text-secondary);
  border-radius: var(--border-radius-sm);
  font-size: 0.75rem;
  font-weight: 500;
}

/* 博客正文页样式 */
.blog-header {
  margin-bottom: 3rem;
  text-align: center;
}

.blog-header h1 {
  font-size: 2.75rem;
  font-weight: 800;
  letter-spacing: -1px;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.blog-header-meta {
  color: var(--text-secondary);
  font-size: 0.95rem;
  display: flex;
  justify-content: center;
  gap: 1rem;
}

.blog-content {
  font-size: 1.1rem;
  line-height: 1.8;
  color: var(--text-primary);
  max-width: 720px;
  margin: 0 auto;
}

.blog-content p {
  margin-bottom: 1.5rem;
}

.blog-content h2, .blog-content h3 {
  margin: 2.5rem 0 1rem 0;
  letter-spacing: -0.5px;
}

.blog-content h2 { font-size: 1.75rem; }
.blog-content h3 { font-size: 1.4rem; }

.blog-content pre {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 1.25rem;
  border-radius: var(--border-radius-md);
  overflow-x: auto;
  margin: 2rem 0;
}

.blog-content code {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  padding: 0.2rem 0.4rem;
  background-color: var(--bg-surface);
  border-radius: 4px;
}

.blog-content pre code {
  padding: 0;
  background: none;
}

.blog-content ul, .blog-content ol {
  margin: 1.25rem 0 1.25rem 1.5rem;
}

.blog-content li {
  margin-bottom: 0.5rem;
}

.blog-content blockquote {
  border-left: 4px solid var(--accent);
  padding: 0.75rem 1.25rem;
  margin: 1.5rem 0;
  background-color: var(--bg-surface);
  border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
  color: var(--text-secondary);
}

/* Markdown 表格样式 */
.blog-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  font-size: 0.95rem;
  border-radius: var(--border-radius-md);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.blog-content th,
.blog-content td {
  padding: 0.85rem 1.25rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
}

.blog-content th:last-child,
.blog-content td:last-child {
  border-right: none;
}

.blog-content tr:last-child td {
  border-bottom: none;
}

.blog-content th {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.blog-content tr:nth-child(even) {
  background-color: rgba(255, 255, 255, 0.015);
}

.blog-content tr:hover td {
  background-color: rgba(255, 255, 255, 0.03);
}

/* Mermaid 架构图/流程图容器 */
.blog-content .mermaid-container {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 2rem 0;
  padding: 1.5rem;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  overflow-x: auto;
}

.blog-content .mermaid-container .mermaid {
  width: 100%;
  display: flex;
  justify-content: center;
}

/* ==================== 7. 项目卡片样式 ==================== */
.project-card {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
  height: 100%;
}

.project-icon {
  font-size: 2rem;
  width: 3.5rem;
  height: 3.5rem;
  background-color: var(--border-color);
  border-radius: var(--border-radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.project-info {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.project-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.project-title svg {
  width: 0.9rem;
  height: 0.9rem;
  color: var(--text-muted);
  transition: var(--transition-smooth);
}

.project-card:hover .project-title svg {
  transform: translate(2px, -2px);
  color: var(--primary);
}

.project-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  flex-grow: 1;
}

.project-category {
  font-size: 0.75rem;
  color: var(--primary);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ==================== 8. 404 & 动画 ==================== */
.error-container {
  text-align: center;
  padding: 5rem 0;
}

.error-code {
  font-size: 6rem;
  font-weight: 900;
  letter-spacing: -2px;
  line-height: 1;
  background: var(--gradient-rainbow);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 1rem;
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
    box-shadow: 0 0 10px var(--primary-glow);
  }
  50% {
    opacity: 0.8;
    box-shadow: 0 0 4px var(--primary-glow);
  }
}

/* 响应式适配 */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.5rem;
  }
  .nav-links {
    gap: 1rem;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
}