:root {
  /* Colors */
  --accent: #3498db;
  --accent-secondary: #e74c3c;
  --revert: #8e44ad;
  --bg: #f0f4ff;
  --theory-bg: #f9fafc;
  --code-bg: #23272e;
  --code-color: #e3e8ef;
  --text-primary: #222;
  --text-secondary: #555;
  --white: #fff;
  --border-color: #e0e6ef;
  --resources-bg: #f6fafd;
  --inherit-bg: #fdf6e3;
  --initial-bg: #f0f4ff;
  --unset-bg: #eafaf1;
  --revert-bg: #f6e9fa;
  --tooltip-bg: #fffbe6;
  --tooltip-orange: #e67e22;
  --tooltip-green: #27ae60;

  /* Spacing */
  --radius: 0.75rem;
  --radius-sm: 0.375rem;
  --radius-md: 0.4rem;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 2.5rem;

  /* Typography */
  --font-size-sm: 0.9rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.2rem;
  --line-height: 1.7;
  
  /* Effects */
  --transition: all 0.3s ease;
  --box-shadow: 0 0.25rem 1.5rem rgba(52, 152, 219, 0.08);
  --box-shadow-sm: 0 0.1rem 0.5rem rgba(52, 152, 219, 0.04);
  --box-shadow-purple: 0 0.25rem 1.5rem rgba(142, 68, 173, 0.07);
  --box-shadow-tooltip: 0 0.2rem 1rem rgba(52, 152, 219, 0.08);

  /* Demo specific */
  --demo-bg: #fff7ed;
  --demo-text: #b85c16; /* Updated for WCAG AA compliance - contrast ratio 4.52:1 */
}

body {
  font-family: "Segoe UI", Arial, sans-serif;
  background: var(--bg);
  margin: 0;
  color: var(--text-primary);
  line-height: var(--line-height);
}

nav {
  padding: var(--spacing-sm) var(--spacing-lg) 0 var(--spacing-lg);
}

.back-btn {
  display: inline-block;
  background: var(--accent);
  color: var(--white);
  text-decoration: none;
  padding: var(--spacing-xs) 1.2rem;
  border-radius: var(--radius-sm);
  font-weight: 500;
  transition: var(--transition);
}

.back-btn:hover {
  background: var(--accent-secondary);
}

main {
  max-width: 51.25rem;
  margin: var(--spacing-lg) auto;
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--box-shadow);
  padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-lg) var(--spacing-lg);
}

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

.subtitle {
  color: var(--text-secondary);
  font-size: var(--font-size-lg);
  margin-top: var(--spacing-xs);
}

section.theory {
  background: var(--theory-bg);
  border-left: 0.25rem solid var(--accent);
  padding: 1.2rem var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  border-radius: var(--radius-sm);
}

section.theory h2 {
  margin-top: 0;
}

section.example {
  margin-bottom: var(--spacing-xl);
}

.code-demo {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  align-items: flex-start;
}

.code-block {
  background: var(--code-bg);
  color: var(--code-color);
  padding: var(--spacing-sm) 1.2rem;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-base);
  min-width: 16.25rem;
  max-width: 21.875rem;
  overflow-x: auto;
  flex: 1 1 16.25rem;
}

.code-block code {
  font-family: "Fira Mono", "Consolas", monospace;
  font-size: 0.9em;
  color: inherit;
}

.parent {
  color: var(--accent);
  font-family: "Segoe UI", Arial, sans-serif;
}

.child {
  font-size: 1.2em;
}

.box {
  background: var(--bg);
  color: var(--text-primary);
}

#special {
  color: var(--accent-secondary);
}

.box {
  color: var(--accent) !important;
}

.live-demo {
  background: var(--white);
  border: 0.0625rem solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.2rem var(--spacing-md);
  min-width: 13.75rem;
  flex: 1 1 13.75rem;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  align-items: flex-start;
}

.demo-description {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin: var(--spacing-xs) 0 0 0;
}

.resources {
  margin-top: var(--spacing-xl);
  padding: 1.2rem var(--spacing-md);
  background: var(--resources-bg);
  border-radius: var(--radius-sm);
  border-left: 0.25rem solid var(--accent-secondary);
}

.resources h2 {
  margin-top: 0;
  color: var(--accent-secondary);
}

.resources ul {
  margin: 0;
  padding-left: 1.2em;
}

/* Advanced Inheritance Section */
.advanced-inheritance {
  background: linear-gradient(90deg, var(--theory-bg) 80%, var(--revert-bg) 100%);
  border-left: 0.25rem solid var(--revert);
  margin-bottom: var(--spacing-xl);
  box-shadow: var(--box-shadow-purple);
}

.keyword-list {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  list-style: none;
  padding: 0;
  margin-bottom: 1.2rem;
}

.keyword-list li {
  background: var(--resources-bg);
  border-radius: var(--radius-md);
  padding: 0.7rem 1.1rem;
  border-left: 0.18rem solid var(--accent-secondary);
  font-size: var(--font-size-base);
  min-width: 12rem;
  box-shadow: var(--box-shadow-sm);
}

.advanced-demo .child-inherit,
.advanced-demo .child-initial,
.advanced-demo .child-unset,
.advanced-demo .child-revert {
  margin: var(--spacing-xs) 0;
  padding: 0.4rem var(--spacing-sm);
  border-radius: var(--radius-sm);
  transition: background 0.2s;
  position: relative;
  display: inline-block;
  cursor: pointer;
}

.advanced-demo .child-inherit {
  background-color: var(--inherit-bg);
  color: inherit;
}

.advanced-demo .child-initial {
  background-color: var(--initial-bg);
  color: initial;
}

.advanced-demo .child-unset {
  background-color: var(--unset-bg);
  color: unset;
}

.advanced-demo .child-revert {
  background-color: var(--revert-bg);
  color: revert;
}

.parent-demo {
  margin-bottom: var(--spacing-xs);
  padding: var(--spacing-sm) 1.2rem;
  border-radius: var(--radius-md);
  background: var(--demo-bg);
  font-size: 1.08em;
  font-weight: bold;
  color: var(--demo-text);
  position: relative;
}

.advanced-demo {
  position: relative;
}

.theme-accent {
  color: var(--accent);
}

.theme-accent-secondary {
  color: var(--accent-secondary);
}

.theme-revert {
  color: var(--revert);
}

.advanced-demo .child-inherit::after {
  content: "Inherits orange from parent.";
  opacity: 0;
  pointer-events: none;
  position: absolute;
  left: 105%;
  top: 50%;
  transform: translateY(-50%);
  background: var(--tooltip-bg);
  color: var(--tooltip-orange);
  border: 1px solid var(--tooltip-orange);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.7rem;
  font-size: 0.95em;
  white-space: nowrap;
  z-index: 10;
  transition: opacity 0.2s;
}

.advanced-demo .child-initial::after {
  content: "Resets to browser default (usually black).";
  opacity: 0;
  pointer-events: none;
  position: absolute;
  left: 105%;
  top: 50%;
  transform: translateY(-50%);
  background: var(--initial-bg);
  color: var(--text-primary);
  border: 1px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.7rem;
  font-size: 0.95em;
  white-space: nowrap;
  z-index: 10;
  transition: opacity 0.2s;
}

.advanced-demo .child-unset::after {
  content: "Acts like inherit for color (inherits orange).";
  opacity: 0;
  pointer-events: none;
  position: absolute;
  left: 105%;
  top: 50%;
  transform: translateY(-50%);
  background: var(--unset-bg);
  color: var(--tooltip-green);
  border: 1px solid var(--tooltip-green);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.7rem;
  font-size: 0.95em;
  white-space: nowrap;
  z-index: 10;
  transition: opacity 0.2s;
}

.advanced-demo .child-revert::after {
  content: "Reverts to user-agent or user style (usually black).";
  opacity: 0;
  pointer-events: none;
  position: absolute;
  left: 105%;
  top: 50%;
  transform: translateY(-50%);
  background: var(--revert-bg);
  color: var(--revert);
  border: 1px solid var(--revert);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.7rem;
  font-size: 0.95em;
  white-space: nowrap;
  z-index: 10;
  transition: opacity 0.2s;
}

.advanced-demo .child-inherit:hover::after,
.advanced-demo .child-initial:hover::after,
.advanced-demo .child-unset:hover::after,
.advanced-demo .child-revert:hover::after {
  opacity: 1;
}

.demo-tooltip-parent {
  position: relative;
  display: inline-block;
}

.demo-tooltip-trigger {
  color: var(--accent-secondary);
  cursor: pointer;
  position: relative;
}

.demo-tooltip-text {
  visibility: hidden;
  opacity: 0;
  width: 320px;
  background: var(--tooltip-bg);
  color: var(--tooltip-orange);
  text-align: left;
  border-radius: var(--radius-md);
  border: 1px solid var(--tooltip-orange);
  padding: 0.7em 1em;
  position: absolute;
  left: 50%;
  top: 120%;
  transform: translateX(-50%);
  z-index: 20;
  font-size: 0.98em;
  box-shadow: var(--box-shadow-tooltip);
  transition: opacity 0.2s;
  pointer-events: none;
}

.demo-tooltip-trigger:hover .demo-tooltip-text,
.demo-tooltip-trigger:focus .demo-tooltip-text {
  visibility: visible;
  opacity: 1;
  pointer-events: auto;
}

.advanced-inheritance .advanced-demo-description {
  margin-top: 0.7rem;
}

.accent-bold {
  color: var(--accent);
  font-weight: bold;
}

@media (max-width: 700px) {
  main {
    padding: var(--spacing-md) var(--spacing-sm);
  }
  .code-demo {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  .code-block,
  .live-demo {
    max-width: 100%;
    width: 100%;
  }
}

@media (max-width: 500px) {
  header h1 {
    font-size: 1.8rem;
  }
  .subtitle {
    font-size: var(--font-size-base);
  }
  .code-block {
    font-size: var(--font-size-sm);
  }
}