/* ============================================================
   Apple-Style Personal Site — Design System
   Persona: 林宇辰 (Yu Chen Lin)
   ============================================================ */

/* ----------------------------------------------------------
   CSS Custom Properties
   ---------------------------------------------------------- */
:root {
  /* Colors — Light Theme */
  --bg-primary: #f5f5f7;
  --bg-secondary: #ffffff;
  --bg-tertiary: #fafafa;
  --text-primary: #1d1d1f;
  --text-secondary: #86868b;
  --text-tertiary: #aeaeb2;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-light: rgba(0, 113, 227, 0.08);
  --border: #d2d2d7;
  --border-light: rgba(0, 0, 0, 0.06);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.08);
  --glass-bg: rgba(255, 255, 255, 0.72);
  --glass-border: rgba(0, 0, 0, 0.08);
  --code-bg: #f4f4f5;
  --code-color: #d63384;
  --pre-bg: #1d1d1f;
  --pre-color: #f5f5f7;
  --tag-bg: rgba(0, 113, 227, 0.06);
  --tag-color: #0071e3;
  --divider: rgba(0, 0, 0, 0.06);

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
    sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Cascadia Code", "JetBrains Mono",
    Menlo, Consolas, monospace;

  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;
  --spacing-4xl: 96px;
  --spacing-5xl: 120px;

  /* Layout */
  --max-width: 980px;
  --content-width: 720px;
  --nav-height: 52px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;

  /* Transitions */
  --ease-out: cubic-bezier(0.25, 0.1, 0.25, 1);
  --ease-spring: cubic-bezier(0.25, 0.1, 0.07, 1.23);
  --duration-fast: 0.15s;
  --duration-base: 0.3s;
  --duration-slow: 0.6s;
}

/* ----------------------------------------------------------
   Dark Theme
   ---------------------------------------------------------- */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #1d1d1f;
    --bg-secondary: #2d2d2f;
    --bg-tertiary: #252527;
    --text-primary: #f5f5f7;
    --text-secondary: #98989d;
    --text-tertiary: #6e6e73;
    --accent: #2997ff;
    --accent-hover: #40a9ff;
    --accent-light: rgba(41, 151, 255, 0.12);
    --border: #424245;
    --border-light: rgba(255, 255, 255, 0.08);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.4);
    --glass-bg: rgba(29, 29, 31, 0.72);
    --glass-border: rgba(255, 255, 255, 0.08);
    --code-bg: #3a3a3c;
    --code-color: #ff6b9d;
    --pre-bg: #0d0d0f;
    --pre-color: #f5f5f7;
    --tag-bg: rgba(41, 151, 255, 0.12);
    --tag-color: #2997ff;
    --divider: rgba(255, 255, 255, 0.06);
  }
}

[data-theme="light"] {
  --bg-primary: #f5f5f7;
  --bg-secondary: #ffffff;
  --bg-tertiary: #fafafa;
  --text-primary: #1d1d1f;
  --text-secondary: #86868b;
  --text-tertiary: #aeaeb2;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-light: rgba(0, 113, 227, 0.08);
  --border: #d2d2d7;
  --border-light: rgba(0, 0, 0, 0.06);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.08);
  --glass-bg: rgba(255, 255, 255, 0.72);
  --glass-border: rgba(0, 0, 0, 0.08);
  --code-bg: #f4f4f5;
  --code-color: #d63384;
  --pre-bg: #1d1d1f;
  --pre-color: #f5f5f7;
  --tag-bg: rgba(0, 113, 227, 0.06);
  --tag-color: #0071e3;
  --divider: rgba(0, 0, 0, 0.06);
}

[data-theme="dark"] {
  --bg-primary: #1d1d1f;
  --bg-secondary: #2d2d2f;
  --bg-tertiary: #252527;
  --text-primary: #f5f5f7;
  --text-secondary: #98989d;
  --text-tertiary: #6e6e73;
  --accent: #2997ff;
  --accent-hover: #40a9ff;
  --accent-light: rgba(41, 151, 255, 0.12);
  --border: #424245;
  --border-light: rgba(255, 255, 255, 0.08);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.4);
  --glass-bg: rgba(29, 29, 31, 0.72);
  --glass-border: rgba(255, 255, 255, 0.08);
  --code-bg: #3a3a3c;
  --code-color: #ff6b9d;
  --pre-bg: #0d0d0f;
  --pre-color: #f5f5f7;
  --tag-bg: rgba(41, 151, 255, 0.12);
  --tag-color: #2997ff;
  --divider: rgba(255, 255, 255, 0.06);
}

/* ----------------------------------------------------------
   CSS Reset & Base
   ---------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-sans);
  font-weight: 400;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  min-height: 100vh;
  transition: background-color var(--duration-base) var(--ease-out),
    color var(--duration-base) var(--ease-out);
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

a:hover {
  color: var(--accent-hover);
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--text-primary);
}

h1 { font-size: 3rem; letter-spacing: -0.025em; }
h2 { font-size: 2.25rem; letter-spacing: -0.02em; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem; }

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--code-bg);
  color: var(--code-color);
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 400;
}

pre {
  font-family: var(--font-mono);
  background: var(--pre-bg);
  color: var(--pre-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.65;
  margin: var(--spacing-lg) 0;
}

pre code {
  background: none;
  color: inherit;
  padding: 0;
  border-radius: 0;
  font-size: inherit;
}

blockquote {
  border-left: 3px solid var(--accent);
  padding: var(--spacing-sm) 0 var(--spacing-sm) var(--spacing-lg);
  margin: var(--spacing-lg) 0;
  color: var(--text-secondary);
  font-style: italic;
}

hr {
  border: none;
  border-top: 1px solid var(--divider);
  margin: var(--spacing-2xl) 0;
}

::selection {
  background: rgba(0, 113, 227, 0.2);
  color: var(--text-primary);
}

/* ----------------------------------------------------------
   Layout Utilities
   ---------------------------------------------------------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.container-narrow {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-5xl) 0;
}

.section-sm {
  padding: var(--spacing-3xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section-header h2 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  margin-bottom: var(--spacing-sm);
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.125rem;
  max-width: 560px;
  margin: 0 auto;
}

/* ----------------------------------------------------------
   Navigation
   ---------------------------------------------------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: var(--glass-bg);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid transparent;
  transition: border-color var(--duration-base) var(--ease-out),
    background-color var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
}

.nav.scrolled {
  border-bottom-color: var(--glass-border);
  box-shadow: var(--shadow-sm);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  transition: color var(--duration-fast) var(--ease-out);
}

.nav-brand:hover {
  color: var(--accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--duration-fast) var(--ease-out);
  letter-spacing: -0.005em;
}

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

.nav-links .active {
  color: var(--accent);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 1.125rem;
  transition: background var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out);
}

.theme-toggle:hover {
  background: var(--accent-light);
  color: var(--accent);
}

.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
  font-size: 1.25rem;
}

/* ----------------------------------------------------------
   Hero Section
   ---------------------------------------------------------- */
.hero {
  padding: var(--spacing-5xl) 0 var(--spacing-4xl);
  text-align: center;
}

.hero-avatar {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  margin: 0 auto var(--spacing-lg);
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: white;
  font-weight: 700;
  box-shadow: 0 8px 32px rgba(102, 126, 234, 0.3);
  user-select: none;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: var(--spacing-md);
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .subtitle {
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto var(--spacing-xl);
  line-height: 1.5;
}

.hero-social {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
}

.hero-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 1.125rem;
  transition: all var(--duration-base) var(--ease-out);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
}

.hero-social a:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  color: var(--accent);
  border-color: var(--accent);
}

/* ----------------------------------------------------------
   Cards
   ---------------------------------------------------------- */
.card {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  transition: transform var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out),
    border-color var(--duration-base) var(--ease-out);
}

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

.card-glass {
  background: var(--glass-bg);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  transition: transform var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
}

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

/* Card Grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
}

.card-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

/* Blog Card */
.blog-card {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  transition: transform var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
  display: flex;
  flex-direction: column;
}

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

.blog-card-date {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  font-weight: 500;
  margin-bottom: var(--spacing-sm);
  letter-spacing: 0.01em;
}

.blog-card-title {
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: var(--spacing-sm);
  letter-spacing: -0.01em;
}

.blog-card-title a {
  color: var(--text-primary);
}

.blog-card-title a:hover {
  color: var(--accent);
}

.blog-card-excerpt {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
  flex-grow: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.blog-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--divider);
}

/* Project Card */
.project-card {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  transition: transform var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
}

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

.project-card-image {
  width: 100%;
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.5rem;
  color: white;
  position: relative;
  overflow: hidden;
}

.project-card-image.g1 { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
.project-card-image.g2 { background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%); }
.project-card-image.g3 { background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%); }
.project-card-image.g4 { background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%); }

.project-card-body {
  padding: var(--spacing-lg);
}

.project-card-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  letter-spacing: -0.01em;
}

.project-card-body p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.5;
}

.project-card-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

/* ----------------------------------------------------------
   Tags
   ---------------------------------------------------------- */
.tag {
  display: inline-block;
  padding: 3px 10px;
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: 20px;
  background: var(--tag-bg);
  color: var(--tag-color);
  letter-spacing: 0.005em;
  transition: background var(--duration-fast) var(--ease-out);
  text-decoration: none;
}

a.tag:hover {
  background: var(--accent);
  color: #fff;
}

/* ----------------------------------------------------------
   Buttons
   ---------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: 10px 22px;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: 24px;
  border: none;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-out);
  letter-spacing: -0.005em;
  font-family: var(--font-sans);
  text-decoration: none;
}

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

.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0, 113, 227, 0.3);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1.5px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #fff;
}

.btn-ghost {
  background: var(--accent-light);
  color: var(--accent);
}

.btn-ghost:hover {
  background: var(--accent);
  color: #fff;
}

/* ----------------------------------------------------------
   Footer
   ---------------------------------------------------------- */
.footer {
  padding: var(--spacing-2xl) 0;
  border-top: 1px solid var(--divider);
  text-align: center;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.footer-social {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.footer-social a {
  color: var(--text-secondary);
  font-size: 1.25rem;
  transition: color var(--duration-fast) var(--ease-out);
}

.footer-social a:hover {
  color: var(--accent);
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
}

.footer-nav a {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.footer-nav a:hover {
  color: var(--text-primary);
}

.footer-copyright {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

/* ----------------------------------------------------------
   About Page
   ---------------------------------------------------------- */
.about-header {
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.about-avatar-lg {
  width: 128px;
  height: 128px;
  border-radius: 50%;
  margin: 0 auto var(--spacing-lg);
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.5rem;
  color: white;
  font-weight: 700;
  box-shadow: 0 12px 40px rgba(102, 126, 234, 0.3);
}

.about-bio {
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.about-bio p {
  margin-bottom: var(--spacing-lg);
}

/* Skills */
.skills-grid {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.skill-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  transition: all var(--duration-fast) var(--ease-out);
}

.skill-tag:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: var(--spacing-xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-xl);
  padding-left: var(--spacing-lg);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -9px;
  top: 8px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg-primary);
  box-shadow: 0 0 0 2px var(--accent);
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-date {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 4px;
  letter-spacing: 0.02em;
}

.timeline-title {
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.timeline-desc {
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

/* ----------------------------------------------------------
   Blog Post (Article)
   ---------------------------------------------------------- */
.blog-post-header {
  text-align: center;
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.blog-post-header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  margin-bottom: var(--spacing-md);
}

.blog-post-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  color: var(--text-secondary);
  font-size: 0.9375rem;
  margin-bottom: var(--spacing-md);
}

.blog-post-meta .sep {
  color: var(--text-tertiary);
}

.blog-post-tags {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-lg);
}

.blog-post-content {
  font-size: 1.0625rem;
  line-height: 1.85;
}

.blog-post-content h2 {
  font-size: 1.75rem;
  margin-top: var(--spacing-3xl);
  margin-bottom: var(--spacing-md);
}

.blog-post-content h3 {
  font-size: 1.375rem;
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-sm);
}

.blog-post-content p {
  margin-bottom: var(--spacing-lg);
}

.blog-post-content ul,
.blog-post-content ol {
  margin: var(--spacing-md) 0 var(--spacing-lg) var(--spacing-lg);
}

.blog-post-content li {
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.blog-post-content ul li {
  list-style: disc;
}

.blog-post-content ol li {
  list-style: decimal;
}

.blog-post-content strong {
  font-weight: 600;
  color: var(--text-primary);
}

.blog-post-content img {
  border-radius: var(--radius-md);
  margin: var(--spacing-xl) auto;
  box-shadow: var(--shadow-md);
}

.blog-post-footer {
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--divider);
  text-align: center;
}

/* Code block filename */
.code-filename {
  display: inline-block;
  padding: 6px 14px;
  background: #2d2d30;
  color: #aaa;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  margin-bottom: -1px;
}

/* ----------------------------------------------------------
   Blog Listing
   ---------------------------------------------------------- */
.blog-listing {
  padding: var(--spacing-3xl) 0;
}

.blog-listing-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.blog-listing-header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  margin-bottom: var(--spacing-sm);
}

.blog-listing-header p {
  color: var(--text-secondary);
  font-size: 1.125rem;
}

.blog-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  max-width: var(--content-width);
  margin: 0 auto;
}

.blog-list-item {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  transition: transform var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
}

.blog-list-item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.blog-list-item .blog-card-date {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-tertiary);
  margin-bottom: var(--spacing-xs);
  letter-spacing: 0.01em;
}

.blog-list-item .blog-card-title {
  font-size: 1.375rem;
  margin-bottom: var(--spacing-sm);
}

.blog-list-item .blog-card-title a {
  color: var(--text-primary);
}

.blog-list-item .blog-card-title a:hover {
  color: var(--accent);
}

/* ----------------------------------------------------------
   404 Page
   ---------------------------------------------------------- */
.error-page {
  min-height: calc(100vh - var(--nav-height) - 200px);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.error-page h1 {
  font-size: 8rem;
  font-weight: 700;
  letter-spacing: -0.05em;
  line-height: 1;
  background: linear-gradient(135deg, var(--accent) 0%, #a855f7 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-md);
}

.error-page p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
}

/* ----------------------------------------------------------
   Animations
   ---------------------------------------------------------- */
[data-animate] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--duration-slow) var(--ease-out),
    transform var(--duration-slow) var(--ease-out);
}

[data-animate].visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger delay for card grids */
[data-animate-delay="1"] { transition-delay: 0.05s; }
[data-animate-delay="2"] { transition-delay: 0.1s; }
[data-animate-delay="3"] { transition-delay: 0.15s; }
[data-animate-delay="4"] { transition-delay: 0.2s; }
[data-animate-delay="5"] { transition-delay: 0.25s; }
[data-animate-delay="6"] { transition-delay: 0.3s; }

/* Fade in only (no slide) */
[data-animate="fade"] {
  opacity: 0;
  transform: none;
  transition: opacity var(--duration-slow) var(--ease-out);
}

[data-animate="fade"].visible {
  opacity: 1;
}

/* ----------------------------------------------------------
   Responsive
   ---------------------------------------------------------- */
@media (max-width: 768px) {
  :root {
    --spacing-5xl: 80px;
    --spacing-4xl: 64px;
    --spacing-3xl: 48px;
  }

  h1 { font-size: 2.25rem; }
  h2 { font-size: 1.75rem; }

  .container,
  .container-narrow {
    padding: 0 var(--spacing-lg);
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .hero .subtitle {
    font-size: 1.0625rem;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2xl);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--duration-base) var(--ease-out);
    z-index: 99;
  }

  .nav-links.open {
    opacity: 1;
    pointer-events: auto;
  }

  .nav-links a {
    font-size: 1.5rem;
    font-weight: 600;
  }

  .menu-toggle {
    display: flex;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .card-grid-3 {
    grid-template-columns: 1fr;
  }

  .blog-post-header h1 {
    font-size: 1.75rem;
  }

  .blog-post-content {
    font-size: 1rem;
  }

  .blog-post-content h2 {
    font-size: 1.375rem;
  }

  .blog-post-content h3 {
    font-size: 1.125rem;
  }

  .error-page h1 {
    font-size: 5rem;
  }

  .about-header {
    padding: var(--spacing-xl) 0 var(--spacing-md);
  }

  .timeline {
    padding-left: var(--spacing-md);
  }

  .blog-list-item {
    padding: var(--spacing-lg);
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2rem;
  }

  .section-header h2 {
    font-size: 1.75rem;
  }

  .hero-social {
    gap: var(--spacing-md);
  }

  .footer-nav {
    flex-wrap: wrap;
    gap: var(--spacing-md);
  }
}