/* ─── tokens ───────────────────────────────────────────────────────── */
:root {
  /* Modern minimal / Linear / Vercel palette - Light mode */
  --bg:      oklch(99% 0.002 240);
  --surface: oklch(100% 0 0);
  --fg:      oklch(18% 0.012 250);
  --muted:   oklch(54% 0.012 250);
  --border:  oklch(92% 0.005 250);
  --accent:  oklch(58% 0.18 255);

  --accent-soft: color-mix(in oklch, var(--accent) 14%, transparent);
  --fg-soft:     color-mix(in oklch, var(--fg) 6%, transparent);

  /* type — display = serif, body = sans */
  --font-display: 'Iowan Old Style', 'Charter', Georgia, 'Times New Roman', serif;
  --font-body:    -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono:    ui-monospace, 'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* scale */
  --fs-h1: clamp(44px, 6vw, 76px);
  --fs-h2: clamp(32px, 4vw, 48px);
  --fs-h3: 22px;
  --fs-lead: 19px;
  --fs-body: 16px;
  --fs-meta: 13px;

  /* spacing */
  --gap-xs: 8px;
  --gap-sm: 12px;
  --gap-md: 20px;
  --gap-lg: 32px;
  --gap-xl: 56px;
  --gap-2xl: 96px;
  --container: 1120px;
  --gutter: 32px;

  --radius: 10px;
  --radius-lg: 16px;
}

/* Dark mode */
[data-theme="dark"] {
  --bg:      oklch(15% 0.015 250);
  --surface: oklch(18% 0.015 250);
  --fg:      oklch(94% 0.005 250);
  --muted:   oklch(65% 0.01 250);
  --border:  oklch(28% 0.015 250);
  --accent:  oklch(65% 0.18 255);
  --accent-soft: color-mix(in oklch, var(--accent) 18%, transparent);
  --fg-soft:     color-mix(in oklch, var(--fg) 8%, transparent);
}

/* ─── reset & base ──────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.55;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; background: none; border: none; }
p { text-wrap: pretty; }
h2, h3, h4 { text-wrap: balance; }

/* ─── layout primitives ─────────────────────────────────────────── */
.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.section {
  padding-block: clamp(32px, 6vw, 64px);
}
.section + .section { border-top: 1px solid var(--border); }
.row-between { display: flex; align-items: center; justify-content: space-between; gap: var(--gap-md); }

/* ─── type ──────────────────────────────────────────────────────── */
.meta { font-family: var(--font-mono); font-size: var(--fs-meta); color: var(--muted); }

/* ─── theme toggle button (filter-tag style) ─────────────────────────── */
.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0;
}
.theme-toggle-btn .theme-icon-light { display: block; }
.theme-toggle-btn .theme-icon-dark { display: none; }
[data-theme="dark"] .theme-toggle-btn .theme-icon-light { display: none; }
[data-theme="dark"] .theme-toggle-btn .theme-icon-dark { display: block; }

/* ─── module list (single column, wider for desktop) ─────────────── */
.module-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
  max-width: 860px;
  margin-inline: auto;
}
.module {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0;
  padding: 28px 32px;
  transition: all 0.2s ease;
}
.module:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.06);
}
.module-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.module-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--accent-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  font-size: 16px;
}
.module-title {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}
.module-content {
  padding-top: 16px;
  min-height: 60px;
}
.module-content h3 {
  font-size: 18px;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--fg);
}
.module-content p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}
.module-content .meta { font-size: 12px; }
.module-footer {
  display: flex;
  align-items: center;
  padding-top: 16px;
  margin-top: 16px;
  border-top: 1px solid var(--border);
}
.module-link-text {
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  transition: color 0.15s ease;
}
a:hover .module-link-text {
  color: var(--accent);
}

/* ─── intro module (first module, compact) ────────────────────────── */
.module-intro {
  text-align: center;
  padding: 36px 32px;
}
.module-intro .module-header {
  display: none;
}
.module-intro .module-content {
  padding-top: 0;
  min-height: auto;
}
.module-intro .module-content h3 {
  font-family: var(--font-display);
  font-size: clamp(18px, 2.5vw, 22px);
  font-weight: 400;
  line-height: 1.6;
  margin-bottom: 0;
  color: var(--fg);
}
.module-intro .module-content p {
  font-family: var(--font-display);
  font-size: clamp(18px, 2.5vw, 22px);
  font-weight: 400;
  line-height: 1.6;
  color: var(--fg);
  margin: 0;
}
.module-intro .module-content p + p {
  margin-top: 0.6em;
}
.module-intro:hover {
  transform: none;
  border-color: var(--border);
  box-shadow: none;
}

/* ─── category filter module ────────────────────────────────────── */
.module-filter {
  padding: 14px 20px;
}
.module-filter .module-header {
  display: none;
}
.module-filter .module-content {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
  min-height: auto;
  padding-top: 0;
}
.filter-tag {
  display: inline-flex;
  align-items: center;
  padding: 7px 16px;
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 0;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}
.filter-tag:hover {
  border-color: var(--fg);
  color: var(--fg);
}
.filter-tag.active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--surface);
}
.module-filter:hover {
  transform: none;
  border-color: var(--border);
  box-shadow: none;
}

/* ─── article page styles ────────────────────────────────────────── */
.article-meta {
  display: flex;
  align-items: center;
  gap: var(--gap-md);
  flex-wrap: wrap;
  margin-bottom: var(--gap-md);
}
.article-tag {
  padding: 4px 12px;
  background: var(--accent-soft);
  border: 1px solid var(--accent);
  border-radius: 0;
  font-size: 12px;
  color: var(--accent);
}
.article-intro {
  font-size: 15px;
  color: var(--muted);
  margin: 0;
}

/* ─── article content ───────────────────────────────────────────── */
.article-content {
  font-size: 15px;
  line-height: 1.8;
}
.article-content p {
  color: var(--fg);
  margin-bottom: 1.2em;
}
.article-content a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.article-content a:hover {
  text-decoration-thickness: 2px;
}

/* headings */
.article-content h2 {
  font-family: var(--font-display);
  font-size: clamp(20px, 3vw, 26px);
  line-height: 1.2;
  margin-top: 2em;
  margin-bottom: 0.5em;
}
.article-content h3 {
  font-size: 18px;
  font-weight: 600;
  margin-top: 1.5em;
  margin-bottom: 0.5em;
}

/* code */
.article-content pre {
  background: var(--fg);
  color: var(--bg);
  padding: 20px 24px;
  border-radius: 0;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  margin: 1.5em 0;
}
.article-content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  padding: 2px 6px;
  background: var(--fg-soft);
  border-radius: 0;
}
.article-content pre code {
  padding: 0;
  background: transparent;
}

/* blockquote */
.article-content blockquote {
  border-left: 3px solid var(--accent);
  padding-left: var(--gap-md);
  margin: 1.5em 0;
  color: var(--muted);
  font-style: italic;
}

/* lists */
.article-content ul,
.article-content ol {
  padding-left: 1.5em;
  margin: 1em 0;
}
.article-content li {
  margin-bottom: 0.5em;
}

/* nav links */
.nav-links {
  display: flex;
  justify-content: space-between;
  gap: var(--gap-md);
  width: 100%;
}
.nav-links .filter-tag {
  flex: 0 1 auto;
  text-align: center;
  justify-content: center;
}
.nav-links a {
  font-size: 13px;
  color: var(--muted);
  transition: color 0.15s;
}
.nav-links a:hover {
  color: var(--accent);
}
.nav-placeholder {
  font-size: 13px;
  color: var(--muted);
  opacity: 0.6;
  cursor: default;
}
.nav-placeholder:hover {
  border-color: var(--border);
  color: var(--muted);
}

/* ─── nav bar (used in article/about pages) ─────────────────────── */
.module-filter.nav-bar .module-content {
  justify-content: space-between;
}

/* ─── about page specific ────────────────────────────────────────── */
.about-intro {
  display: flex;
  flex-direction: column;
  gap: var(--gap-md);
}
.about-intro h1 {
  font-family: var(--font-display);
  font-size: clamp(28px, 4vw, 36px);
  line-height: 1.2;
}
.about-intro .bio {
  font-size: 15px;
  color: var(--muted);
  line-height: 1.7;
  max-width: 60ch;
}

/* skills */
.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.skill-tag {
  padding: 6px 14px;
  background: var(--fg-soft);
  border: 1px solid var(--border);
  border-radius: 0;
  font-size: 13px;
  color: var(--fg);
  transition: all 0.15s;
}
.skill-tag:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

/* experience */
.experience-list {
  display: flex;
  flex-direction: column;
  gap: var(--gap-lg);
}
.experience-item {
  padding-bottom: var(--gap-lg);
  border-bottom: 1px solid var(--border);
}
.experience-item:last-child {
  padding-bottom: 0;
  border-bottom: none;
}
.experience-item h3 {
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 4px;
}
.experience-item .period {
  font-size: 12px;
}
.experience-item .desc {
  font-size: 14px;
  color: var(--muted);
  margin: 8px 0 0;
}

/* contact */
.contact-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.contact-link {
  display: flex;
  align-items: center;
  gap: var(--gap-md);
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  transition: border-color 0.15s;
}
.contact-link:hover {
  border-color: var(--accent);
}
.contact-link .label {
  flex: 1;
  font-size: 15px;
}
.contact-link .value {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--muted);
}

@media (max-width: 600px) {
  .module { padding: 20px 24px; }
  .module-intro { padding: 28px 20px; }
  .module-filter { padding: 12px 16px; }
  .filter-tag { padding: 6px 12px; font-size: 12px; }
  .module-list { gap: 16px; }
}

/* 返回时高亮显示的文章 */
.module.highlight {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}