/* ============================================
   Fonts
   ============================================ */

@font-face {
  font-family: "Inter";
  src: url("/assets/fonts/InterVariable.woff2") format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Inter";
  src: url("/assets/fonts/InterVariable-Italic.woff2") format("woff2");
  font-weight: 100 900;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "JetBrains Mono";
  src: url("/assets/fonts/JetBrainsMono-Regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "JetBrains Mono";
  src: url("/assets/fonts/JetBrainsMono-Bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

/* ============================================
   Reset & Base
   ============================================ */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Curated Premium Color Schemes */
  --bg-light: #faf9f6;          /* Architectural warm off-white */
  --bg-dark: #0b0f19;           /* Deep academic night blue-gray */
  
  --text-light: #1c1917;        /* Crisp deep charcoal */
  --text-dark: #e5e8f0;         /* Ice silver-gray */
  
  --text-secondary-light: #5f5a54; /* Warm slate secondary */
  --text-secondary-dark: #8c97a8;  /* Silver-blue secondary */
  
  --border-light: #e6e4e0;      /* Rigid warm grid gray */
  --border-dark: #1f293d;       /* Crisp steel dark grid */
  
  --accent-light: #1a73e8;      /* Google Research blue */
  --accent-dark: #8ab4f8;       /* Tech-silver blue */
  
  --code-bg-light: #f4f3f0;     /* Code block off-white */
  --code-bg-dark: #141a29;      /* Code block deep space */
  
  --link-light: #1c1917;
  --link-dark: #ffffff;
  
  --link-hover-light: #1a73e8;
  --link-hover-dark: #8ab4f8;

  --font-body: "Inter", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "Cascadia Code", monospace;

  --line-height: 1.6;
  --max-width: 720px;
  --sidebar-width: 220px;
  --gap: 2.5rem; /* Slightly larger gap for editorial feel */

  /* Fallback defaults (system matches prefers-color-scheme automatically) */
  --color-bg: var(--bg-light);
  --color-text: var(--text-light);
  --color-text-secondary: var(--text-secondary-light);
  --color-border: var(--border-light);
  --color-accent: var(--accent-light);
  --color-code-bg: var(--code-bg-light);
  --color-link: var(--link-light);
  --color-link-hover: var(--link-hover-light);

  @media (prefers-color-scheme: dark) {
    --color-bg: var(--bg-dark);
    --color-text: var(--text-dark);
    --color-text-secondary: var(--text-secondary-dark);
    --color-border: var(--border-dark);
    --color-accent: var(--accent-dark);
    --color-code-bg: var(--code-bg-dark);
    --color-link: var(--link-dark);
    --color-link-hover: var(--link-hover-dark);
  }

  color-scheme: light dark;
}

/* Explicit class override for light/dark pinning via javascript */
html.dark {
  --color-bg: var(--bg-dark);
  --color-text: var(--text-dark);
  --color-text-secondary: var(--text-secondary-dark);
  --color-border: var(--border-dark);
  --color-accent: var(--accent-dark);
  --color-code-bg: var(--code-bg-dark);
  --color-link: var(--link-dark);
  --color-link-hover: var(--link-hover-dark);
  
  color-scheme: dark;
}

html:not(.dark)[data-theme="light"] {
  --color-bg: var(--bg-light);
  --color-text: var(--text-light);
  --color-text-secondary: var(--text-secondary-light);
  --color-border: var(--border-light);
  --color-accent: var(--accent-light);
  --color-code-bg: var(--code-bg-light);
  --color-link: var(--link-light);
  --color-link-hover: var(--link-hover-light);
  
  color-scheme: light;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: var(--color-bg);
  color: var(--color-text);
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-body);
  font-weight: 600;
  line-height: 1.25;
  color: var(--color-text);
}

h1 { font-size: 2rem; margin-bottom: 1rem; }
h2 { font-size: 1.5rem; margin-top: 2.5rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.175rem; margin-top: 2rem; margin-bottom: 0.5rem; }

p {
  margin-bottom: 1rem;
}

a {
  color: var(--color-link);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color 0.15s ease;
}

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

strong {
  font-weight: 600;
}

ul, ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.25rem;
}

blockquote {
  border-left: 3px solid var(--color-border);
  padding-left: 1rem;
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
}

hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2rem 0;
}

/* ============================================
   Code
   ============================================ */

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--color-code-bg);
  padding: 0.15em 0.35em;
  border-radius: 3px;
}

pre {
  background-color: var(--color-code-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  font-size: 0.85rem;
}

/* ============================================
   Tables
   ============================================ */

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}

th, td {
  padding: 0.6rem 0.85rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

th {
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
  border-bottom: 2px solid var(--color-border);
}

td {
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

tr:last-child td {
  border-bottom: none;
}

/* ============================================
   Site Header
   ============================================ */

.site-header {
  border-bottom: 1px solid var(--color-border);
  padding: 1.25rem 2rem;
}

.nav {
  max-width: calc(var(--max-width) + var(--sidebar-width) + var(--gap));
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-weight: 700;
  font-size: 1.1rem;
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 1.75rem;
  padding: 0;
  margin: 0;
}

.nav-links a {
  text-decoration: none;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  font-weight: 450;
}

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

/* ============================================
   Main Content
   ============================================ */

.main {
  flex: 1;
  max-width: calc(var(--max-width) + var(--sidebar-width) + var(--gap));
  width: 100%;
  margin: 0 auto;
  padding: 3rem 2rem;
}

/* ============================================
   Post Layout (two-column with ToC)
   ============================================ */

.post-layout {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  gap: var(--gap);
  align-items: start;
}

.post-header {
  margin-bottom: 2rem;
}

.post-header h1 {
  margin-bottom: 0.5rem;
}

.post-meta {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.post-status,
.post-category {
  font-weight: 500;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.post-content {
  min-width: 0;
  max-width: var(--max-width);
}

.post-content::after {
  content: "";
  display: block;
  height: 70vh; /* Allow short bottom sections to scroll enough for ToC scrollspy */
  pointer-events: none;
}

/* ============================================
   Table of Contents Sidebar
   ============================================ */

.toc-sidebar {
  position: sticky;
  top: 2rem;
  align-self: start;
}

.toc-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
  margin: 0 0 0.75rem 0;
}

.toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
  border-left: 1px solid var(--color-border);
}

.toc-item a {
  display: block;
  padding: 0.25rem 0 0.25rem 0.85rem;
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  text-decoration: none;
  line-height: 1.4;
}

.toc-item a:hover {
  color: var(--color-text);
}

.toc-item--h3 a {
  padding-left: 1.5rem;
  font-size: 0.775rem;
}

/* ============================================
   List Pages (Projects & Blog index)
   ============================================ */

.post-list {
  list-style: none;
  padding: 0;
}

.post-item {
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

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

.post-item a {
  text-decoration: none;
  display: block;
}

.post-item a:hover h2 {
  color: var(--color-link-hover);
}

.post-item h2 {
  font-size: 1.25rem;
  margin-bottom: 0.35rem;
  transition: color 0.15s ease;
}

.post-item p {
  color: var(--color-text-secondary);
  font-size: 0.925rem;
  margin-bottom: 0;
}

.post-item .post-meta {
  margin-bottom: 0.35rem;
}

/* ============================================
   Home — Hero
   ============================================ */

.hero {
  padding: 4rem 0 3rem;
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
  max-width: 580px;
}

/* ============================================
   Home — Sections
   ============================================ */

.home-section {
  margin-top: 3rem;
  padding-top: 3rem;
  border-top: 1px solid var(--color-border);
}

.home-section-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
  margin: 0 0 1.25rem 0;
}

/* ============================================
   Home — Project Ledger
   ============================================ */

.project-ledger {
  list-style: none;
  padding: 0;
  margin: 0;
}

.ledger-row {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
}

.ledger-row:hover .ledger-title {
  color: var(--color-link-hover);
}

.project-ledger li:last-child .ledger-row {
  border-bottom: none;
}

.ledger-year {
  font-family: var(--font-mono);
  font-size: 0.825rem;
  color: var(--color-text-secondary);
  flex-shrink: 0;
  width: 3rem;
}

.ledger-title {
  font-weight: 600;
  font-size: 0.95rem;
  flex: 1;
  transition: color 0.15s ease;
}

.ledger-tag {
  font-family: var(--font-mono);
  font-size: 0.775rem;
  color: var(--color-text-secondary);
  flex-shrink: 0;
  text-align: right;
}

/* ============================================
   Home — Writing Feed
   ============================================ */

.writing-feed {
  list-style: none;
  padding: 0;
  margin: 0;
}

.feed-row {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
}

.feed-row:hover .feed-title {
  color: var(--color-link-hover);
}

.writing-feed li:last-child .feed-row {
  border-bottom: none;
}

.feed-date {
  font-family: var(--font-mono);
  font-size: 0.825rem;
  color: var(--color-text-secondary);
  flex-shrink: 0;
  width: 6.5rem;
}

.feed-title {
  font-weight: 500;
  font-size: 0.95rem;
  flex: 1;
  transition: color 0.15s ease;
}

.feed-tag {
  font-family: var(--font-mono);
  font-size: 0.775rem;
  color: var(--color-text-secondary);
  flex-shrink: 0;
  text-align: right;
}

/* ============================================
   Home — Quick About
   ============================================ */

.home-about {
  padding-bottom: 2rem;
}

.home-about p {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  max-width: 480px;
}

.home-links {
  display: flex;
  gap: 1.5rem;
  margin-top: 0.75rem;
}

.home-links a {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  text-decoration: none;
}

.home-links a:hover {
  color: var(--color-text);
}

/* ============================================
   Footer
   ============================================ */

.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 2rem;
  text-align: center;
  font-size: 0.825rem;
  color: var(--color-text-secondary);
}

.site-footer a {
  color: var(--color-text-secondary);
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 768px) {
  .post-layout {
    grid-template-columns: 1fr;
  }

  .toc-sidebar {
    position: static;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--color-border);
  }

  .main {
    padding: 2rem 1.25rem;
  }

  .site-header {
    padding: 1rem 1.25rem;
  }

  h1 { font-size: 1.75rem; }

  .hero { padding: 2.5rem 0 2rem; }
  .hero h1 { font-size: 2rem; }

  .ledger-tag,
  .feed-tag {
    display: none;
  }
}

/* ==========================================================================
   Enhancements Block (Google Research Inspired Modern Dynamics)
   ========================================================================== */

/* 1. Native Cross-Document View Transitions */
@view-transition {
  navigation: auto;
}

::view-transition {
  background-color: var(--color-bg);
}

.nav-logo {
  view-transition-name: site-logo;
}

/* 2. Rigid Grid Border Aesthetics & Fine Layout Lines */
.nav-right {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

/* 3. Sleek Theme Toggle Button */
.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  padding: 0.5rem;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  outline: none;
}

.theme-toggle:hover {
  border-color: var(--color-accent);
  color: var(--color-text);
  background-color: var(--color-code-bg);
  transform: translateY(-1px);
}

.theme-toggle:focus-visible {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px var(--color-border);
}

/* Show Sun/Moon icons representing the current active theme */
html.dark .theme-toggle .sun-icon {
  display: none;
}
html:not(.dark) .theme-toggle .moon-icon {
  display: none;
}

.theme-toggle svg {
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.theme-toggle:hover svg {
  transform: rotate(15deg);
}

/* 4. Ledger Slide-on-Hover Interactions */
.ledger-row, .feed-row {
  position: relative;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1) !important;
  padding: 0.75rem 0.5rem;
  margin: 0 -0.5rem;
  border-radius: 4px;
}

.ledger-row:hover, .feed-row:hover {
  background-color: var(--color-code-bg);
  padding-left: 1.25rem !important;
  color: var(--color-accent) !important;
}

.ledger-row::before, .feed-row::before {
  content: "→";
  position: absolute;
  left: 0.25rem;
  opacity: 0;
  transform: translateX(-5px);
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  color: var(--color-accent);
  font-weight: bold;
}

.ledger-row:hover::before, .feed-row:hover::before {
  opacity: 1;
  transform: translateX(0);
}

/* 5. Dynamic Filtering Chips Component */
.filter-container {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 1.25rem;
}

.filter-chip {
  background: var(--color-code-bg);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  padding: 0.35rem 1rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: var(--font-body);
  outline: none;
}

.filter-chip:hover {
  border-color: var(--color-accent);
  color: var(--color-text);
  background: var(--color-bg);
}

.filter-chip:focus-visible {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px var(--color-border);
}

.filter-chip.active {
  background: var(--color-accent);
  color: var(--color-bg);
  border-color: var(--color-accent);
}

/* Smooth filtering item transitions */
.post-item, .project-ledger li, .writing-feed li {
  transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              max-height 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              padding 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              margin 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              border-color 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  opacity: 1;
  transform: scale(1);
  max-height: 500px;
  overflow: hidden;
}

.post-item.is-hidden, .project-ledger li.is-hidden, .writing-feed li.is-hidden {
  opacity: 0;
  transform: scale(0.95);
  max-height: 0;
  margin: 0 !important;
  padding: 0 !important;
  border: none !important;
  pointer-events: none;
}

/* 6. Active Scrollspy Table of Contents Indicator */
.toc-list {
  border-left: 1px solid var(--color-border);
  transition: border-color 0.3s;
}

.toc-item a {
  border-left: 2px solid transparent;
  margin-left: -1px; /* Align to overlap parent border line */
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

.toc-item a.active {
  color: var(--color-accent) !important;
  font-weight: 600;
  border-left-color: var(--color-accent) !important;
  background-color: var(--color-code-bg);
  border-top-right-radius: 4px;
  border-bottom-right-radius: 4px;
}

/* 7. Premium Custom Scrollbar Styling */
html {
  scrollbar-color: var(--color-border) var(--color-bg);
  scrollbar-width: thin;
}

@supports not (scrollbar-color: auto) {
  ::-webkit-scrollbar {
    width: 8px;
    height: 8px;
  }
  ::-webkit-scrollbar-track {
    background: var(--color-bg);
  }
  ::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 4px;
  }
  ::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-secondary);
  }
}