/* =========================================================
   蟹老板笔记 - 全局样式
   ========================================================= */

:root {
  --color-primary: #E94F37;
  --color-primary-dark: #C73E2A;
  --color-accent: #F5A623;
  --color-bg: #FFFFFF;
  --color-bg-soft: #FAFAFA;
  --color-bg-code: #F6F8FA;
  --color-text: #1F2328;
  --color-text-soft: #57606A;
  --color-text-mute: #8B949E;
  --color-border: #E5E7EB;
  --color-border-soft: #EFF1F3;

  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC",
               "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08);

  --header-h: 64px;
  --container-w: 1200px;
}

/* Reset */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img, svg { display: block; max-width: 100%; }
a {
  color: var(--color-text);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover { color: var(--color-primary); }
ul, ol { padding-left: 1.4em; }

/* Container */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* =========================================================
   顶栏
   ========================================================= */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid transparent;
  z-index: 100;
  transition: box-shadow 0.2s ease, border-color 0.2s ease;
}
.site-header.is-scrolled {
  box-shadow: var(--shadow-sm);
  border-bottom-color: var(--color-border-soft);
}
.site-header .container {
  height: 100%;
  display: flex;
  align-items: center;
  gap: 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 17px;
  color: var(--color-text);
  flex-shrink: 0;
}
.brand:hover { color: var(--color-text); }
.brand .crab-logo { width: 32px; height: 32px; }

.nav {
  display: flex;
  align-items: center;
  gap: 28px;
  flex: 1;
}
.nav a {
  font-size: 15px;
  color: var(--color-text-soft);
  font-weight: 500;
  position: relative;
}
.nav a:hover { color: var(--color-primary); }
.nav a.is-active { color: var(--color-text); }
.nav a.is-active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -22px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 2px;
}

.search-box {
  display: flex;
  align-items: center;
  gap: 6px;
  height: 36px;
  padding: 0 12px;
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text-mute);
  font-size: 13px;
  cursor: pointer;
  min-width: 220px;
  transition: border-color 0.15s ease;
}
.search-box:hover { border-color: var(--color-primary); }
.search-box .search-icon { width: 14px; height: 14px; }
.search-box .kbd {
  margin-left: auto;
  padding: 1px 6px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-text-mute);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  width: 36px; height: 36px;
  padding: 0;
  cursor: pointer;
  color: var(--color-text);
}
.nav-toggle svg { width: 22px; height: 22px; margin: auto; }

/* =========================================================
   主体留出顶栏高度
   ========================================================= */
main { padding-top: var(--header-h); }

/* =========================================================
   通用按钮
   ========================================================= */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 44px;
  padding: 0 24px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s ease;
}
.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover {
  background: var(--color-primary-dark);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}
.btn-ghost {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn-ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* =========================================================
   通用卡片
   ========================================================= */
.card {
  display: block;
  padding: 22px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all 0.2s ease;
}
.card:hover {
  border-color: var(--color-primary);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  color: var(--color-text);
}
.card h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
}
.card p {
  margin: 0;
  font-size: 14px;
  color: var(--color-text-soft);
  line-height: 1.6;
}
.card .card-meta {
  margin-top: 12px;
  font-size: 12px;
  color: var(--color-text-mute);
}
.card .card-emoji {
  font-size: 28px;
  margin-bottom: 10px;
  display: block;
}

/* =========================================================
   Hero
   ========================================================= */
.hero {
  padding: 80px 0 60px;
}
.hero .container {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 60px;
  align-items: center;
}
.hero-title {
  font-size: 44px;
  line-height: 1.25;
  font-weight: 800;
  margin: 0 0 18px;
  letter-spacing: -0.5px;
}
.hero-title .hl {
  color: var(--color-primary);
}
.hero-sub {
  font-size: 17px;
  color: var(--color-text-soft);
  margin: 0 0 28px;
  line-height: 1.7;
}
.hero-cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.hero-art {
  display: flex;
  align-items: center;
  justify-content: center;
}
.hero-art .crab-big {
  width: 240px;
  height: 240px;
  filter: drop-shadow(0 12px 24px rgba(233, 79, 55, 0.25));
}

/* =========================================================
   首页分区
   ========================================================= */
.section {
  padding: 60px 0;
}
.section.alt { background: var(--color-bg-soft); }
.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 28px;
  gap: 16px;
  flex-wrap: wrap;
}
.section-header h2 {
  margin: 0;
  font-size: 26px;
  font-weight: 700;
  letter-spacing: -0.3px;
}
.section-header .sub {
  font-size: 14px;
  color: var(--color-text-mute);
}
.grid {
  display: grid;
  gap: 20px;
}
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.grid.cols-5 { grid-template-columns: repeat(5, 1fr); }

/* =========================================================
   关于
   ========================================================= */
.about {
  display: grid;
  grid-template-columns: 1fr 1.8fr;
  gap: 48px;
  align-items: center;
}
.about-art {
  text-align: center;
}
.about-art .crab-medium { width: 160px; height: 160px; margin: 0 auto; }
.about p {
  font-size: 15px;
  color: var(--color-text-soft);
  line-height: 1.8;
  margin: 0 0 12px;
}
.about h2 {
  margin: 0 0 18px;
  font-size: 26px;
}

/* =========================================================
   Footer
   ========================================================= */
.site-footer {
  padding: 32px 0;
  border-top: 1px solid var(--color-border-soft);
  color: var(--color-text-mute);
  font-size: 13px;
  text-align: center;
  background: var(--color-bg-soft);
}
.site-footer a { color: var(--color-text-soft); }
.site-footer .footer-links {
  display: flex;
  justify-content: center;
  gap: 18px;
  margin-bottom: 8px;
}

/* =========================================================
   面包屑
   ========================================================= */
.breadcrumb {
  padding: 24px 0 8px;
  font-size: 13px;
  color: var(--color-text-mute);
}
.breadcrumb a { color: var(--color-text-soft); }
.breadcrumb .sep { margin: 0 8px; color: var(--color-border); }

/* =========================================================
   分类页 / 文章页 布局
   ========================================================= */
.page-layout {
  display: grid;
  gap: 36px;
  padding: 8px 0 60px;
}
.page-layout.two-col { grid-template-columns: 240px 1fr; }
.page-layout.three-col { grid-template-columns: 220px 1fr 200px; }

.side-toc {
  position: sticky;
  top: calc(var(--header-h) + 20px);
  align-self: start;
  max-height: calc(100vh - var(--header-h) - 40px);
  overflow-y: auto;
}
.side-toc h4 {
  margin: 0 0 10px;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-text-mute);
}
.side-toc ul { list-style: none; padding: 0; margin: 0; }
.side-toc li { margin: 0; }
.side-toc a {
  display: block;
  padding: 7px 12px;
  font-size: 14px;
  color: var(--color-text-soft);
  border-left: 2px solid transparent;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.side-toc a:hover {
  background: var(--color-bg-soft);
  color: var(--color-primary);
}
.side-toc a.is-active {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  background: var(--color-bg-soft);
  font-weight: 600;
}

/* =========================================================
   文章列表
   ========================================================= */
.article-list {
  display: grid;
  gap: 16px;
}
.article-item {
  padding: 20px 22px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all 0.2s ease;
}
.article-item:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}
.article-item h3 {
  margin: 0 0 6px;
  font-size: 18px;
  font-weight: 600;
}
.article-item h3 a { color: var(--color-text); }
.article-item h3 a:hover { color: var(--color-primary); }
.article-item .excerpt {
  margin: 0 0 10px;
  font-size: 14px;
  color: var(--color-text-soft);
  line-height: 1.65;
}
.article-item .meta {
  font-size: 12px;
  color: var(--color-text-mute);
  display: flex;
  gap: 12px;
}
.article-item .meta .tag {
  background: rgba(245, 166, 35, 0.12);
  color: #B97C0A;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 500;
}

/* =========================================================
   文章正文
   ========================================================= */
.article-main { min-width: 0; }
.article-title {
  font-size: 34px;
  font-weight: 800;
  line-height: 1.3;
  margin: 0 0 12px;
  letter-spacing: -0.5px;
}
.article-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--color-text-mute);
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--color-border-soft);
}

.prose h2 {
  font-size: 24px;
  margin: 40px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border-soft);
  scroll-margin-top: calc(var(--header-h) + 16px);
}
.prose h3 {
  font-size: 19px;
  margin: 28px 0 10px;
  scroll-margin-top: calc(var(--header-h) + 16px);
}
.prose p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.85;
  color: #2C333B;
}
.prose ul, .prose ol {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.85;
  color: #2C333B;
}
.prose li { margin: 4px 0; }
.prose strong { color: var(--color-text); }
.prose code {
  font-family: var(--font-mono);
  background: var(--color-bg-code);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.9em;
  color: #BF2C20;
}
.prose pre {
  background: var(--color-bg-code);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.6;
  margin: 0 0 18px;
}
.prose pre code {
  background: none;
  padding: 0;
  color: #2C333B;
}
.prose blockquote {
  margin: 0 0 14px;
  padding: 10px 18px;
  border-left: 4px solid var(--color-accent);
  background: rgba(245, 166, 35, 0.08);
  color: var(--color-text-soft);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.prose .ascii-diagram {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.5;
  white-space: pre;
}

.article-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border-soft);
}
.article-nav a {
  display: block;
  padding: 14px 18px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 14px;
}
.article-nav a:hover { border-color: var(--color-primary); }
.article-nav .label {
  font-size: 12px;
  color: var(--color-text-mute);
  margin-bottom: 4px;
}
.article-nav .next { text-align: right; }

/* =========================================================
   文章内 TOC
   ========================================================= */
.article-toc {
  position: sticky;
  top: calc(var(--header-h) + 20px);
  align-self: start;
  font-size: 13px;
}
.article-toc h4 {
  margin: 0 0 10px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-text-mute);
}
.article-toc ul { list-style: none; padding: 0; margin: 0; }
.article-toc a {
  display: block;
  padding: 5px 0 5px 10px;
  border-left: 2px solid var(--color-border-soft);
  color: var(--color-text-soft);
}
.article-toc a.is-h3 { padding-left: 22px; font-size: 12.5px; }
.article-toc a:hover {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
}

/* =========================================================
   搜索弹窗
   ========================================================= */
.search-modal {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  display: none;
  align-items: flex-start;
  justify-content: center;
  z-index: 200;
  padding-top: 18vh;
}
.search-modal.is-open { display: flex; }
.search-modal .box {
  width: min(560px, calc(100% - 32px));
  background: #fff;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 24px;
  text-align: center;
}
.search-modal h3 {
  margin: 0 0 6px;
  font-size: 18px;
}
.search-modal p {
  margin: 0 0 18px;
  color: var(--color-text-soft);
  font-size: 14px;
}
.search-modal .btn { width: 100%; }

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 1024px) {
  .grid.cols-5 { grid-template-columns: repeat(3, 1fr); }
  .grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .page-layout.three-col {
    grid-template-columns: 220px 1fr;
  }
  .article-toc { display: none; }
  .hero-title { font-size: 36px; }
  .hero-art .crab-big { width: 200px; height: 200px; }
}

@media (max-width: 768px) {
  .container { padding: 0 18px; }
  .nav, .search-box { display: none; }
  .nav-toggle { display: inline-flex; align-items: center; justify-content: center; margin-left: auto; }

  .site-header.nav-open .nav,
  .site-header.nav-open .search-box {
    display: flex;
  }
  .site-header.nav-open {
    height: auto;
    padding-bottom: 16px;
    background: #fff;
  }
  .site-header.nav-open .container {
    flex-wrap: wrap;
    height: auto;
    padding-top: 12px;
    padding-bottom: 12px;
  }
  .site-header.nav-open .nav {
    flex-direction: column;
    align-items: flex-start;
    width: 100%;
    gap: 12px;
    margin-top: 8px;
  }
  .site-header.nav-open .nav a.is-active::after { display: none; }
  .site-header.nav-open .search-box {
    width: 100%;
    margin-top: 8px;
  }

  .hero { padding: 40px 0 30px; }
  .hero .container {
    grid-template-columns: 1fr;
    gap: 24px;
    text-align: center;
  }
  .hero-cta { justify-content: center; }
  .hero-title { font-size: 30px; }
  .hero-art .crab-big { width: 160px; height: 160px; }

  .section { padding: 40px 0; }
  .section-header h2 { font-size: 22px; }
  .grid.cols-5, .grid.cols-4, .grid.cols-3, .grid.cols-2 {
    grid-template-columns: 1fr;
  }

  .about {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 20px;
  }

  .page-layout.two-col,
  .page-layout.three-col {
    grid-template-columns: 1fr;
  }
  .side-toc {
    position: static;
    max-height: none;
    padding: 16px;
    background: var(--color-bg-soft);
    border-radius: var(--radius-md);
  }

  .article-title { font-size: 26px; }
  .article-nav { grid-template-columns: 1fr; }
  .article-nav .next { text-align: left; }
}