/* =============================================================================
   CLEAN ENERGY WIKI - Main Stylesheet
   ============================================================================= */

/* -----------------------------------------------------------------------------
   Font Face Declarations
   ----------------------------------------------------------------------------- */

@font-face {
  font-family: 'Satoshi';
  src: url('/fonts/Satoshi-Variable.woff2') format('woff2');
  font-weight: 300 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Satoshi';
  src: url('/fonts/Satoshi-VariableItalic.woff2') format('woff2');
  font-weight: 300 900;
  font-style: italic;
  font-display: swap;
}

/* -----------------------------------------------------------------------------
   CSS Variables
   ----------------------------------------------------------------------------- */

:root {
  /* Colors */
  --color-text: #1a1a1a;
  --color-text-muted: #666;
  --color-background: #fff;
  --color-surface: #fff;
  --color-border: #e0e0e0;
  --color-border-light: #f0f0f0;
  --color-link: #0066cc;
  --color-link-hover: #004499;
  --color-accent: #0066cc;
  --color-accent-light: #e6f0ff;
  --color-warning: #fff8e6;
  --color-warning-border: #f0d060;
  --color-shadow: rgba(0, 0, 0, 0.1);
  --color-shadow-strong: rgba(0, 0, 0, 0.15);

  /* Typography */
  --font-sans: 'Satoshi', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'SF Mono', 'Consolas', 'Liberation Mono', monospace;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  /* Layout */
  --max-width-content: 680px;
  --width-toc: 180px;
  --width-margin: 240px;
  --gap-layout: 2rem;
}

/* Dark mode - explicit toggle */
:root[data-theme="dark"] {
  --color-text: #e8e8e8;
  --color-text-muted: #a0a0a0;
  --color-background: #121212;
  --color-surface: #1e1e1e;
  --color-border: #333;
  --color-border-light: #2a2a2a;
  --color-link: #6db3f2;
  --color-link-hover: #8ec5f5;
  --color-accent: #6db3f2;
  --color-accent-light: #1a2d3d;
  --color-warning: #2d2a1f;
  --color-warning-border: #8a7530;
  --color-shadow: rgba(0, 0, 0, 0.3);
  --color-shadow-strong: rgba(0, 0, 0, 0.5);
}

/* Dark mode - system preference (when no explicit choice) */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-text: #e8e8e8;
    --color-text-muted: #a0a0a0;
    --color-background: #121212;
    --color-surface: #1e1e1e;
    --color-border: #333;
    --color-border-light: #2a2a2a;
    --color-link: #6db3f2;
    --color-link-hover: #8ec5f5;
    --color-accent: #6db3f2;
    --color-accent-light: #1a2d3d;
    --color-warning: #2d2a1f;
    --color-warning-border: #8a7530;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-shadow-strong: rgba(0, 0, 0, 0.5);
  }

  /* Show sun icon by default in system dark mode */
  :root:not([data-theme]) .theme-toggle .icon-sun {
    display: block;
  }

  :root:not([data-theme]) .theme-toggle .icon-moon {
    display: none;
  }
}

/* Light mode - explicit toggle (overrides system dark preference) */
:root[data-theme="light"] {
  --color-text: #1a1a1a;
  --color-text-muted: #666;
  --color-background: #fff;
  --color-surface: #fff;
  --color-border: #e0e0e0;
  --color-border-light: #f0f0f0;
  --color-link: #0066cc;
  --color-link-hover: #004499;
  --color-accent: #0066cc;
  --color-accent-light: #e6f0ff;
  --color-warning: #fff8e6;
  --color-warning-border: #f0d060;
  --color-shadow: rgba(0, 0, 0, 0.1);
  --color-shadow-strong: rgba(0, 0, 0, 0.15);
}

:root[data-theme="light"] .theme-toggle .icon-sun {
  display: none;
}

:root[data-theme="light"] .theme-toggle .icon-moon {
  display: block;
}

/* -----------------------------------------------------------------------------
   Reset & Base
   ----------------------------------------------------------------------------- */

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

html {
  font-size: 16px;
  line-height: 1.6;
  color-scheme: light dark;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-background);
}

/* -----------------------------------------------------------------------------
   Skip Link (Accessibility)
   ----------------------------------------------------------------------------- */

.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--color-accent);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  z-index: 1000;
}

.skip-link:focus {
  top: 0;
}

/* -----------------------------------------------------------------------------
   Site Header
   ----------------------------------------------------------------------------- */

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) var(--spacing-lg);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-background);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
}

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

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

.site-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.875rem;
}

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

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  border: none;
  background: none;
  color: var(--color-text-muted);
  cursor: pointer;
  border-radius: 4px;
  transition: color 0.2s, background-color 0.2s;
}

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

/* Show sun icon in dark mode, moon icon in light mode */
.theme-toggle .icon-sun {
  display: none;
}

.theme-toggle .icon-moon {
  display: block;
}

:root[data-theme="dark"] .theme-toggle .icon-sun {
  display: block;
}

:root[data-theme="dark"] .theme-toggle .icon-moon {
  display: none;
}

/* -----------------------------------------------------------------------------
   Article Layout (Three Column)
   ----------------------------------------------------------------------------- */

.article-layout {
  display: grid;
  grid-template-columns: var(--width-toc) minmax(0, var(--max-width-content)) var(--width-margin);
  gap: var(--gap-layout);
  max-width: calc(var(--width-toc) + var(--max-width-content) + var(--width-margin) + var(--gap-layout) * 2);
  margin: 0 auto;
  padding: var(--spacing-lg);
}

/* Table of Contents */
.toc {
  position: sticky;
  top: calc(60px + var(--spacing-lg));
  height: calc(100vh - 60px - var(--spacing-lg) * 2);
  display: flex;
  flex-direction: column;
  font-size: 0.875rem;
}

.toc-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin: 0 0 var(--spacing-sm) 0;
  flex-shrink: 0;
}

.toc-nav {
  flex: 1;
  overflow-y: auto;
  min-height: 0;
}

.toc-nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc-nav li {
  margin: var(--spacing-xs) 0;
}

.toc-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  display: block;
  padding: var(--spacing-xs) 0;
}

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

.toc-nav .toc-sub {
  padding-left: var(--spacing-md);
}

/* Main Content */
.article-content {
  min-width: 0;
}

.article-content h1 {
  font-size: 2rem;
  margin: 0 0 var(--spacing-sm) 0;
  line-height: 1.2;
}

.lede {
  font-size: 1.25rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--spacing-xl) 0;
  line-height: 1.5;
}

.article-content h2 {
  font-size: 1.5rem;
  margin: var(--spacing-xl) 0 var(--spacing-md) 0;
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--color-border-light);
}

.article-content h3 {
  font-size: 1.25rem;
  margin: var(--spacing-lg) 0 var(--spacing-sm) 0;
}

.article-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: var(--spacing-md) 0 var(--spacing-sm) 0;
}

.article-content p {
  margin: 0 0 var(--spacing-md) 0;
  max-width: 65ch;
}

.article-content ul, .article-content ol {
  margin: 0 0 var(--spacing-md) 0;
  padding-left: var(--spacing-lg);
}

.article-content li {
  margin: var(--spacing-xs) 0;
  max-width: 65ch;
}

.article-content a {
  color: var(--color-link);
  text-decoration: none;
}

.article-content a:hover {
  text-decoration: underline;
}

/* Living Margin */
.margin {
  position: sticky;
  top: calc(60px + var(--spacing-lg));
  height: fit-content;
}

.margin-content {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.margin-fallback {
  font-style: italic;
}

.margin-facet {
  background: var(--color-border-light);
  padding: var(--spacing-md);
  border-radius: 4px;
}

.margin-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin: 0 0 var(--spacing-xs) 0;
}

.margin-value {
  font-weight: 600;
  margin: 0 0 var(--spacing-sm) 0;
  color: var(--color-text);
}

.margin-description {
  margin: 0 0 var(--spacing-sm) 0;
  line-height: 1.4;
}

.margin-compare {
  background: none;
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.875rem;
}

.margin-compare:hover {
  background: var(--color-accent);
  color: white;
}

/* -----------------------------------------------------------------------------
   Facet Blocks
   ----------------------------------------------------------------------------- */

.facet-block {
  border-left: 3px solid var(--color-border);
  padding-left: var(--spacing-md);
  margin-left: calc(-1 * var(--spacing-md) - 3px);
  margin-bottom: var(--spacing-md);
  transition: border-color 0.2s;
}

.facet-block.active {
  border-left-color: var(--color-accent);
}

/* -----------------------------------------------------------------------------
   Limitation Blocks
   ----------------------------------------------------------------------------- */

.limitation-block {
  background: var(--color-warning);
  border-left: 3px solid var(--color-warning-border);
  padding: var(--spacing-md);
  margin: var(--spacing-md) 0;
  border-radius: 0 4px 4px 0;
}

.limitation-block p:last-child {
  margin-bottom: 0;
}

/* -----------------------------------------------------------------------------
   Equations
   ----------------------------------------------------------------------------- */

.equation-block {
  margin: var(--spacing-lg) 0;
  overflow-x: auto;
}

/* -----------------------------------------------------------------------------
   Tables
   ----------------------------------------------------------------------------- */

.table-wrapper {
  overflow-x: auto;
  margin: var(--spacing-md) 0;
}

.article-content table {
  border-collapse: collapse;
  width: 100%;
  font-size: 0.875rem;
}

.article-content th, .article-content td {
  border: 1px solid var(--color-border);
  padding: var(--spacing-sm) var(--spacing-md);
  text-align: left;
}

.article-content th {
  background: var(--color-border-light);
  font-weight: 600;
}

.article-content tr:hover {
  background: var(--color-border-light);
}

/* -----------------------------------------------------------------------------
   Citations
   ----------------------------------------------------------------------------- */

cite {
  cursor: help;
}

cite sup {
  color: var(--color-link);
}

/* Source List */
.source-list {
  font-size: 0.875rem;
  padding-left: var(--spacing-lg);
}

.source-list li {
  margin: var(--spacing-sm) 0;
}

.source-list em {
  font-style: italic;
}

/* -----------------------------------------------------------------------------
   Comparison Panel
   ----------------------------------------------------------------------------- */

.comparison-panel {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: min(600px, 90vw);
  background: var(--color-surface);
  box-shadow: -4px 0 20px var(--color-shadow-strong);
  overflow-y: auto;
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.25s ease-out;
}

.comparison-panel:not([hidden]) {
  transform: translateX(0);
}

.comparison-panel[hidden] {
  display: block;
  pointer-events: none;
}

.comparison-panel-content {
  padding: var(--spacing-lg);
}

.comparison-panel-close {
  position: absolute;
  top: var(--spacing-md);
  right: var(--spacing-md);
  width: 2rem;
  height: 2rem;
  border: none;
  background: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-text-muted);
}

.comparison-panel-close:hover {
  color: var(--color-text);
}

.comparison-table {
  width: 100%;
}

.comparison-table tr.current {
  background: var(--color-accent-light);
}

.comparison-group {
  margin: var(--spacing-lg) 0;
}

.comparison-group h3 {
  margin: 0 0 var(--spacing-sm) 0;
}

.comparison-group ul {
  list-style: none;
  padding: 0;
}

.comparison-group li {
  margin: var(--spacing-xs) 0;
}

.comparison-group li.current {
  font-weight: 600;
}

.comparison-groups {
  display: grid;
  gap: var(--spacing-md);
}

/* -----------------------------------------------------------------------------
   Index Page
   ----------------------------------------------------------------------------- */

.index-page {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

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

.index-header h1 {
  font-size: 2.5rem;
  margin: 0 0 var(--spacing-md) 0;
}

.index-lede {
  font-size: 1.25rem;
  color: var(--color-text-muted);
  max-width: 60ch;
  margin: 0 auto;
}

.filter-bar {
  margin-bottom: var(--spacing-lg);
}

.filter-bar label {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.filter-bar select {
  margin-left: var(--spacing-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-size: 0.875rem;
  background: var(--color-surface);
  color: var(--color-text);
}

.source-group {
  margin-bottom: var(--spacing-xl);
}

.source-group-title {
  font-size: 1.25rem;
  margin: 0 0 var(--spacing-md) 0;
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--color-border);
}

.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.tech-card {
  display: block;
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.tech-card:hover {
  border-color: var(--color-accent);
  box-shadow: 0 2px 8px var(--color-shadow);
}

.tech-card h3 {
  font-size: 1rem;
  margin: 0 0 var(--spacing-sm) 0;
  color: var(--color-link);
}

.tech-card p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--spacing-sm) 0;
  line-height: 1.4;
}

.tech-card-facets {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.tech-card-facets li {
  font-size: 0.75rem;
  background: var(--color-border-light);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 3px;
  color: var(--color-text-muted);
}

/* -----------------------------------------------------------------------------
   Responsive Design
   ----------------------------------------------------------------------------- */

@media (max-width: 1000px) {
  .article-layout {
    grid-template-columns: 1fr;
    max-width: var(--max-width-content);
  }

  .toc {
    display: none;
  }

  .margin {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    top: auto;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-md);
    transform: translateY(100%);
    transition: transform 0.2s;
    z-index: 50;
  }

  .margin.visible {
    transform: translateY(0);
  }

  .margin-description {
    display: none;
  }
}

@media (max-width: 600px) {
  .site-header {
    flex-direction: column;
    gap: var(--spacing-sm);
  }

  .site-title {
    max-height: 2rem;
    overflow: hidden;
    transition: max-height 0.2s ease-out, opacity 0.2s ease-out, margin 0.2s ease-out;
  }

  .site-header.collapsed .site-title {
    max-height: 0;
    opacity: 0;
    margin: 0;
  }

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

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

/* -----------------------------------------------------------------------------
   About Page
   ----------------------------------------------------------------------------- */

.about-page {
  max-width: 680px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

.about-content h1 {
  font-size: 2rem;
  margin: 0 0 var(--spacing-md) 0;
}

.about-content h2 {
  font-size: 1.5rem;
  margin: var(--spacing-xl) 0 var(--spacing-md) 0;
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--color-border-light);
}

.about-content p {
  margin: 0 0 var(--spacing-md) 0;
  line-height: 1.6;
}

.about-content ul {
  margin: 0 0 var(--spacing-md) 0;
  padding-left: var(--spacing-lg);
}

.about-content li {
  margin: var(--spacing-xs) 0;
}