/* ==========================================================================
   xueshiqing.github.io — 纯静态技术博客模板
   零依赖 · 零构建 · 明暗双主题
   修改配色只需改下面的变量
   ========================================================================== */

/* ---------- 1. 设计变量 ---------- */
:root {
  color-scheme: light;

  --bg:            #ffffff;
  --bg-soft:       #f6f7f9;
  --surface:       #ffffff;
  --surface-2:     #fbfcfe;
  --border:        #e7e9ee;
  --border-strong: #d5dae3;

  --text:          #14181f;
  --text-soft:     #4b5565;
  --text-mute:     #5d6879;   /* 对比度 5.2:1，满足 WCAG AA */

  --accent:        #2563eb;
  --accent-ink:    #1e4fd8;
  --accent-soft:   #eef4ff;
  --accent-line:   #c7dbff;

  --code-bg:       #f7f9fc;
  --code-bar:      #eef2f8;
  --code-text:     #1f2937;

  --hl-comment:    #7c8798;
  --hl-string:     #0a7d4f;
  --hl-number:     #b4551b;
  --hl-keyword:    #a01a58;
  --hl-func:       #1e4fd8;
  --hl-punct:      #64748b;

  --shadow-sm: 0 1px 2px rgba(16, 24, 40, .05);
  --shadow-md: 0 4px 6px -2px rgba(16, 24, 40, .04), 0 14px 32px -14px rgba(16, 24, 40, .16);

  --radius:    16px;
  --radius-sm: 10px;
  --maxw:      1080px;
  --readw:     728px;
  --header-h:  62px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
               "Liberation Mono", monospace;

  --t: 200ms cubic-bezier(.4, 0, .2, 1);
}

html[data-theme="dark"] {
  color-scheme: dark;

  --bg:            #0a0d13;
  --bg-soft:       #0e121a;
  --surface:       #11161f;
  --surface-2:     #141a25;
  --border:        #222a37;
  --border-strong: #313b4c;

  --text:          #e7ebf2;
  --text-soft:     #a5b0c2;
  --text-mute:     #8b96a8;   /* 对比度 6.5:1 */

  --accent:        #6ea8fe;
  --accent-ink:    #9cc2ff;
  --accent-soft:   #142036;
  --accent-line:   #24405f;

  --code-bg:       #0d1219;
  --code-bar:      #131a24;
  --code-text:     #dbe3ee;

  --hl-comment:    #6b7a8d;
  --hl-string:     #7ee0a8;
  --hl-number:     #f0a868;
  --hl-keyword:    #f278a8;
  --hl-func:       #6ea8fe;
  --hl-punct:      #8794a8;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-md: 0 4px 6px -2px rgba(0, 0, 0, .3), 0 18px 40px -18px rgba(0, 0, 0, .7);
}

/* ---------- 2. 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 20px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  display: flex;
  flex-direction: column;
  transition: background var(--t), color var(--t);
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }

img { max-width: 100%; height: auto; }

::selection { background: var(--accent); color: #fff; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
.wrap--read { max-width: var(--readw); }

.skip-link {
  position: absolute; left: -9999px; top: 8px; z-index: 100;
  padding: 10px 16px; border-radius: var(--radius-sm);
  background: var(--accent); color: #fff; font-weight: 600;
}
.skip-link:focus { left: 12px; text-decoration: none; }

/* ---------- 3. 顶栏 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  height: var(--header-h);
  display: flex; align-items: center;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  border-bottom: 1px solid var(--border);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
}
.site-header .wrap { display: flex; align-items: center; gap: 20px; }

.brand {
  font-weight: 700; font-size: 15.5px; letter-spacing: .01em;
  color: var(--text); display: flex; align-items: center; gap: 9px;
  white-space: nowrap;
}
.brand:hover { color: var(--text); text-decoration: none; }
.brand-dot {
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 18%, transparent);
}

.nav { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.nav a {
  color: var(--text-soft); font-size: 14.5px; font-weight: 500;
  padding: 7px 12px; border-radius: 8px; transition: var(--t);
}
.nav a:hover { color: var(--text); background: var(--bg-soft); text-decoration: none; }
.nav a[aria-current="page"] { color: var(--accent); background: var(--accent-soft); }

.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; padding: 0; margin-left: 4px;
  border: 1px solid var(--border); border-radius: 9px;
  background: var(--surface); color: var(--text-soft);
  cursor: pointer; transition: var(--t);
}
.icon-btn:hover { color: var(--text); border-color: var(--border-strong); background: var(--bg-soft); }
.icon-btn svg { width: 18px; height: 18px; display: block; }
/* 浅色时显示月亮（点击切到深色），深色时显示太阳 */
html:not([data-theme="dark"]) .icon-btn .i-sun,
html[data-theme="dark"] .icon-btn .i-moon { display: none; }

/* ---------- 4. 主体 ---------- */
main { flex: 1 0 auto; padding: 46px 0 72px; }

/* ---------- 5. 个人简介 Hero ---------- */
.hero { display: flex; gap: 26px; align-items: flex-start; margin-bottom: 12px; }

/* 内页标题 */
.page-title { margin: 0 0 6px; font-size: 27px; letter-spacing: -.02em; font-weight: 700; }
.page-sub { margin: 0 0 30px; color: var(--text-soft); font-size: 15px; }

.avatar {
  width: 92px; height: 92px; flex: 0 0 92px; border-radius: 50%;
  object-fit: cover; background: var(--bg-soft);
  border: 1px solid var(--border);
  box-shadow: 0 0 0 5px var(--bg), 0 0 0 6px var(--border), var(--shadow-sm);
}

.hero-body { min-width: 0; }
.hero h1 {
  margin: 0 0 6px; font-size: 30px; line-height: 1.25;
  letter-spacing: -.02em; font-weight: 700;
}
.hero .tagline {
  margin: 0 0 16px; color: var(--text-soft); font-size: 15px;
  font-weight: 500; letter-spacing: .005em;
}
.hero .bio { margin: 0 0 20px; color: var(--text-soft); font-size: 15.5px; max-width: 62ch; text-wrap: pretty; }
.hero .bio p { margin: 0 0 12px; }
.hero .bio p:last-child { margin-bottom: 0; }

.chips { display: flex; flex-wrap: wrap; gap: 10px 12px; }
.chips + .chips { margin-top: 14px; }
.chip {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 16px; border-radius: 999px;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text-soft); font-size: 13.5px; font-weight: 500;
  transition: var(--t);
}
.chip:hover {
  color: var(--accent); border-color: var(--accent-line);
  background: var(--accent-soft); text-decoration: none;
  transform: translateY(-1px);
}
.chip svg { width: 15px; height: 15px; flex: 0 0 15px; }

/* ---------- 6. 区块标题 ---------- */
.section { margin-top: 54px; }
.section-head {
  display: flex; align-items: baseline; gap: 12px;
  margin-bottom: 18px; padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}
.section-head h2 {
  margin: 0; font-size: 17px; font-weight: 650; letter-spacing: -.005em;
}
.section-head .more {
  margin-left: auto; font-size: 13.5px; color: var(--text-mute); font-weight: 500;
}
.section-head .more:hover { color: var(--accent); }

/* ---------- 7. 文章列表 ---------- */
.post-list { display: grid; gap: 2px; list-style: none; margin: 0; padding: 0; }

.post-item { border-radius: var(--radius-sm); transition: var(--t); }
.post-item > a {
  display: block; padding: 18px 16px; border-radius: var(--radius-sm);
  color: inherit;
}
.post-item > a:hover {
  background: var(--bg-soft); text-decoration: none;
}
.post-item h3 {
  margin: 0 0 7px; font-size: 17px; font-weight: 650;
  line-height: 1.45; letter-spacing: -.005em; color: var(--text);
}
.post-item > a:hover h3 { color: var(--accent); }
.post-item p { margin: 0 0 10px; color: var(--text-soft); font-size: 14.5px; line-height: 1.65; }

.post-meta {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px;
  font-size: 12.5px; color: var(--text-mute);
  font-variant-numeric: tabular-nums;
}
.post-meta .dot { opacity: .5; }
.tag {
  padding: 2px 8px; border-radius: 6px; font-size: 12px; font-weight: 500;
  background: var(--accent-soft); color: var(--accent);
  border: 1px solid var(--accent-line);
}

/* ---------- 8. 空状态 ---------- */
.empty {
  padding: 46px 24px; text-align: center;
  border: 1px dashed var(--border-strong); border-radius: var(--radius);
  background: var(--surface-2);
}
.empty svg { width: 34px; height: 34px; color: var(--text-mute); opacity: .55; margin-bottom: 12px; }
.empty p { margin: 0; color: var(--text-soft); font-size: 14.5px; }
.empty .sub { margin-top: 6px; color: var(--text-mute); font-size: 13px; }

/* ---------- 9. 文章页 ---------- */
.post-header { margin-bottom: 34px; padding-bottom: 22px; border-bottom: 1px solid var(--border); }
.post-header h1 {
  margin: 0 0 14px; font-size: clamp(25px, 4vw, 32px);
  line-height: 1.3; letter-spacing: -.02em; font-weight: 700;
}
.post-header .post-meta { font-size: 13px; }

.back-link {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 13.5px; color: var(--text-mute); margin-bottom: 22px; font-weight: 500;
}
.back-link:hover { color: var(--accent); text-decoration: none; }

/* 目录 */
.toc {
  margin: 0 0 32px; padding: 14px 18px;
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--radius-sm); font-size: 14px;
}
.toc-title {
  font-size: 12px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase;
  color: var(--text-mute); margin-bottom: 8px;
}
.toc ul { list-style: none; margin: 0; padding: 0; }
.toc li { margin: 3px 0; }
.toc a { color: var(--text-soft); }
.toc a:hover { color: var(--accent); text-decoration: none; }
.toc .lvl-3 { padding-left: 16px; font-size: 13.5px; }

/* ---------- 10. 正文排版（prose） ---------- */
.prose { font-size: 16.5px; line-height: 1.82; color: var(--text); }
.prose > *:first-child { margin-top: 0; }

.prose h2, .prose h3, .prose h4, .prose h5, .prose h6 {
  margin: 2em 0 .7em; line-height: 1.4; font-weight: 650; letter-spacing: -.01em;
}
.prose h2 { font-size: 23px; padding-bottom: .35em; border-bottom: 1px solid var(--border); }
.prose h3 { font-size: 19.5px; }
.prose h4 { font-size: 17px; }
.prose p { margin: 0 0 1.15em; }
.prose ul, .prose ol { margin: 0 0 1.15em; padding-left: 1.5em; }
.prose li { margin: .35em 0; }
.prose li > ul, .prose li > ol { margin: .35em 0; }

.prose blockquote {
  margin: 1.5em 0; padding: 4px 20px;
  border-left: 3px solid var(--accent-line);
  background: var(--surface-2);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-soft);
}
.prose blockquote p:last-child { margin-bottom: 0; }

.prose hr { height: 1px; margin: 2.4em 0; border: 0; background: var(--border); }

.prose img { border-radius: var(--radius-sm); box-shadow: var(--shadow-sm); }

.prose a { font-weight: 500; }

.prose code {
  font-family: var(--font-mono); font-size: .875em;
  padding: .16em .42em; border-radius: 5px;
  background: var(--bg-soft); border: 1px solid var(--border);
  color: var(--text); word-break: break-word;
}

.prose table {
  width: 100%; margin: 1.5em 0; border-collapse: collapse;
  font-size: 14.5px; display: block; overflow-x: auto;
}
.prose th, .prose td {
  padding: 9px 13px; border: 1px solid var(--border); text-align: left;
}
.prose th { background: var(--bg-soft); font-weight: 650; }

/* 代码块 */
.code-block {
  margin: 1.5em 0; border: 1px solid var(--border);
  border-radius: var(--radius-sm); overflow: hidden; background: var(--code-bg);
}
.code-bar {
  display: flex; align-items: center; gap: 10px;
  padding: 7px 12px 7px 14px;
  background: var(--code-bar); border-bottom: 1px solid var(--border);
}
.code-lang {
  font-family: var(--font-mono); font-size: 11.5px; font-weight: 600;
  letter-spacing: .06em; text-transform: uppercase; color: var(--text-mute);
}
.copy-btn {
  margin-left: auto; display: inline-flex; align-items: center; gap: 5px;
  padding: 4px 9px; border-radius: 6px; cursor: pointer;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text-mute); font-family: var(--font-sans); font-size: 12px; font-weight: 500;
  transition: var(--t);
}
.copy-btn:hover { color: var(--text); border-color: var(--border-strong); }
.copy-btn.done { color: #0a7d4f; border-color: #0a7d4f; }
.copy-btn svg { width: 13px; height: 13px; }

.code-block pre {
  margin: 0; padding: 16px 18px; overflow-x: auto;
  background: transparent; border: 0;
}
.code-block pre code {
  padding: 0; background: none; border: 0; border-radius: 0;
  font-size: 13.5px; line-height: 1.72; color: var(--code-text);
  display: block; white-space: pre;
}

/* 语法高亮 */
.tok-comment { color: var(--hl-comment); font-style: italic; }
.tok-string  { color: var(--hl-string); }
.tok-number  { color: var(--hl-number); }
.tok-keyword { color: var(--hl-keyword); font-weight: 600; }
.tok-func    { color: var(--hl-func); }
.tok-punct   { color: var(--hl-punct); }

/* 文末上下篇 */
.post-nav {
  display: grid; gap: 12px; grid-template-columns: 1fr 1fr;
  margin-top: 52px; padding-top: 26px; border-top: 1px solid var(--border);
}
.post-nav a {
  display: block; padding: 15px 17px; border-radius: var(--radius-sm);
  border: 1px solid var(--border); background: var(--surface);
  color: inherit; transition: var(--t);
}
.post-nav a:hover {
  border-color: var(--accent-line); background: var(--accent-soft);
  text-decoration: none; transform: translateY(-1px);
}
.post-nav .dir { display: block; font-size: 12px; color: var(--text-mute); margin-bottom: 5px; }
.post-nav .title { font-size: 14.5px; font-weight: 600; color: var(--text); }
.post-nav .next { text-align: right; grid-column: 2; }
.post-nav .spacer { visibility: hidden; }

/* 归档 */
.archive-year {
  margin: 34px 0 10px; font-size: 13px; font-weight: 700;
  letter-spacing: .1em; color: var(--text-mute);
  font-variant-numeric: tabular-nums;
}
.archive-year:first-child { margin-top: 0; }

/* ---------- 11. 页脚 ---------- */
.site-footer {
  flex: 0 0 auto; border-top: 1px solid var(--border);
  padding: 26px 0 34px; background: var(--bg-soft);
  color: var(--text-mute); font-size: 13.5px;
}
.site-footer .wrap { display: flex; flex-wrap: wrap; gap: 10px 20px; align-items: center; }
.site-footer a { color: var(--text-soft); }
.site-footer a:hover { color: var(--accent); }
.site-footer .spacer { margin-left: auto; }

/* ---------- 12. 加载态 ---------- */
.loading { padding: 34px 0; text-align: center; color: var(--text-mute); font-size: 14px; }
.spinner {
  width: 20px; height: 20px; margin: 0 auto 12px;
  border: 2px solid var(--border-strong); border-top-color: var(--accent);
  border-radius: 50%; animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 13. 响应式 ---------- */
@media (max-width: 720px) {
  main { padding: 30px 0 56px; }
  .hero { flex-direction: column; gap: 18px; }
  .avatar { width: 76px; height: 76px; flex-basis: 76px; }
  .hero h1 { font-size: 25px; }
  .hero .bio { font-size: 15px; }
  .wrap { padding: 0 17px; }
  .prose { font-size: 16px; }
  .prose h2 { font-size: 20.5px; }
  .prose h3 { font-size: 18px; }
  .post-nav { grid-template-columns: 1fr; }
  .post-nav .next { grid-column: 1; text-align: left; }
  .nav a { padding: 7px 9px; font-size: 14px; }
  .site-footer .spacer { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  html { scroll-behavior: auto; }
}

@media print {
  .site-header, .site-footer, .toc, .copy-btn, .post-nav { display: none !important; }
  body { background: #fff; }
}