/* ==============================
   全局重置与基础
============================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --color-bg: #ffffff;
  --color-surface: #f8f8f6;
  --color-border: #e8e8e8;
  --color-text: #1a1a1a;
  --color-text-muted: #888;
  --color-accent: #1a1a1a;
  --color-accent-soft: #f0f0f0;
  --color-tag: #efefef;
  --font-sans: 'Inter', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-serif: 'Georgia', 'Noto Serif SC', serif;
  --max-width: 720px;
  --radius: 6px;
  --transition: 0.2s ease;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
  display: block;
}

/* ==============================
   布局容器
============================== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ==============================
   导航栏
============================== */
header {
  border-bottom: 1px solid var(--color-border);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 100;
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.nav-logo {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
}

/* 搜索图标 */
.nav-search-btn {
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  color: var(--color-text-muted);
  transition: color var(--transition);
  display: flex;
  align-items: center;
}

.nav-search-btn:hover {
  color: var(--color-text);
}

/* ==============================
   搜索覆盖层
============================== */
.search-overlay {
  position: fixed;
  inset: 0;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(12px);
  z-index: 200;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-top: 120px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.search-overlay.open {
  opacity: 1;
  pointer-events: all;
}

.search-box {
  width: 100%;
  max-width: 560px;
  position: relative;
}

.search-input {
  width: 100%;
  padding: 16px 20px;
  font-size: 1.25rem;
  border: none;
  border-bottom: 2px solid var(--color-text);
  background: transparent;
  outline: none;
  font-family: var(--font-sans);
}

.search-results {
  margin-top: 24px;
  width: 100%;
  max-width: 560px;
}

.search-result-item {
  padding: 14px 0;
  border-bottom: 1px solid var(--color-border);
  cursor: pointer;
  transition: opacity var(--transition);
}

.search-result-item:hover {
  opacity: 0.6;
}

.search-result-item h3 {
  font-size: 1rem;
  font-weight: 600;
}

.search-result-item p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 2px;
}

.search-close {
  position: absolute;
  top: 20px;
  right: 24px;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
  color: var(--color-text-muted);
}

.search-hint {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* ==============================
   主内容区
============================== */
main {
  padding: 48px 0 80px;
}

/* ==============================
   页面标题区
============================== */
.page-header {
  margin-bottom: 40px;
}

.page-header h1 {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.page-header p {
  color: var(--color-text-muted);
  margin-top: 8px;
  font-size: 0.95rem;
}

/* ==============================
   首页 Hero
============================== */
.hero {
  padding: 72px 0 56px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 56px;
}

.hero-intro {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 16px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 20px;
}

.hero p {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 480px;
  line-height: 1.8;
}

/* ==============================
   文章列表
============================== */
.section-title {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-text-muted);
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-border);
}

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

.post-item {
  padding: 24px 0;
  border-bottom: 1px solid var(--color-border);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 16px;
  align-start: start;
  cursor: pointer;
  transition: opacity var(--transition);
}

.post-item:hover {
  opacity: 0.65;
}

.post-item:last-child {
  border-bottom: none;
}

.post-item-left {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.post-category {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.post-title {
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.4;
}

.post-excerpt {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  margin-top: 4px;
}

.post-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.tag {
  display: inline-block;
  padding: 2px 8px;
  background: var(--color-tag);
  border-radius: 20px;
  font-size: 0.72rem;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: background var(--transition);
}

.tag:hover, .tag.active {
  background: var(--color-text);
  color: #fff;
}

.post-date {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  white-space: nowrap;
  margin-top: 4px;
}

/* ==============================
   文章详情页
============================== */
.article-header {
  padding: 48px 0 32px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 40px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

.article-meta span::after {
  content: '·';
  margin-left: 12px;
}

.article-meta span:last-child::after {
  content: '';
}

.article-title {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.2;
  margin-bottom: 16px;
}

.article-subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.article-content {
  font-size: 1rem;
  line-height: 1.9;
}

.article-content h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 40px 0 16px;
  letter-spacing: -0.02em;
}

.article-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 32px 0 12px;
}

.article-content p {
  margin-bottom: 20px;
}

.article-content blockquote {
  border-left: 3px solid var(--color-text);
  padding-left: 20px;
  margin: 28px 0;
  color: var(--color-text-muted);
  font-style: italic;
}

.article-content img {
  border-radius: var(--radius);
  margin: 28px 0;
}

.article-footer {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.back-btn {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  transition: color var(--transition);
}

.back-btn:hover {
  color: var(--color-text);
}

/* ==============================
   分类 / 标签页
============================== */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 48px;
}

.category-card {
  padding: 20px;
  background: var(--color-surface);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
}

.category-card:hover,
.category-card.active {
  border-color: var(--color-text);
  background: var(--color-accent-soft);
}

.category-card .cat-name {
  font-size: 0.95rem;
  font-weight: 600;
}

.category-card .cat-count {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  margin-top: 4px;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 48px;
}

.tag-cloud .tag {
  padding: 4px 12px;
  font-size: 0.82rem;
}

/* ==============================
   关于我页面
============================== */
.about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 48px;
}

.about-avatar {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  object-fit: cover;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  overflow: hidden;
}

.about-avatar-placeholder {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
}

.about-name {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 16px;
  letter-spacing: -0.02em;
}

.about-bio {
  color: var(--color-text-muted);
  margin-top: 8px;
  font-size: 0.95rem;
  line-height: 1.7;
}

.about-body h2 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 32px 0 12px;
  letter-spacing: -0.01em;
}

.about-body p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.8;
  margin-bottom: 14px;
}

.social-links {
  display: flex;
  gap: 16px;
  margin-top: 20px;
  flex-wrap: wrap;
}

.social-link {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  padding: 6px 14px;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  transition: border-color var(--transition), color var(--transition);
}

.social-link:hover {
  border-color: var(--color-text);
  color: var(--color-text);
}

/* ==============================
   页脚
============================== */
footer {
  border-top: 1px solid var(--color-border);
  padding: 28px 0;
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* ==============================
   工具类
============================== */
.hidden { display: none !important; }

.fade-in {
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ==============================
   响应式
============================== */
@media (max-width: 600px) {
  .post-item {
    grid-template-columns: 1fr;
  }
  .post-date {
    margin-top: 0;
  }
  .nav-links {
    gap: 20px;
  }
}