/* ============================================================
   Embedded Mastery Tutorial — Light Theme (Base Styles)
   ============================================================ */

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

:root {
  /* Light theme colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f6f8fa;
  --bg-tertiary: #eef1f4;
  --bg-code: #f0f2f5;
  --bg-code-block: #f6f8fa;
  --bg-sidebar: #1a1e24;
  --bg-topbar: #ffffff;
  --bg-hover: #e8eaed;
  --bg-active: #d2d6db;
  --bg-callout-tip: #e8f5e9;
  --bg-callout-warning: #fff8e1;
  --bg-callout-note: #e3f2fd;
  --bg-table-header: #f0f2f5;
  --bg-table-stripe: #f8f9fa;
  --bg-checkbox: #e0e0e0;

  --text-primary: #1a1a2e;
  --text-secondary: #4a4a5a;
  --text-tertiary: #6b7280;
  --text-link: #2563eb;
  --text-link-hover: #1d4ed8;
  --text-sidebar: #e2e8f0;
  --text-sidebar-hover: #ffffff;
  --text-sidebar-active: #60a5fa;
  --text-code: #e83e8c;
  --text-code-block: #24292e;
  --text-callout-tip: #2e7d32;
  --text-callout-warning: #f57f17;
  --text-callout-note: #1565c0;
  --text-topbar: #1a1a2e;
  --text-checkbox: #ffffff;

  --border-primary: #e2e5e9;
  --border-secondary: #d1d5db;
  --border-code: #e5e7eb;
  --border-callout-tip: #a5d6a7;
  --border-callout-warning: #ffe082;
  --border-callout-note: #90caf9;
  --border-table: #e2e5e9;

  --accent: #2563eb;
  --accent-light: #dbeafe;
  --accent-dark: #1d4ed8;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  --shadow-sidebar: 2px 0 8px rgba(0, 0, 0, 0.15);

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "Cascadia Code", "Source Code Pro", "Consolas", "Monaco", monospace;
  --font-serif: "Georgia", "Times New Roman", serif;

  --sidebar-width: 280px;
  --topbar-height: 56px;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --- Sidebar --- */
#sidebar {
  position: fixed;
  top: 0;
  left: calc(-1 * var(--sidebar-width));
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-sidebar);
  color: var(--text-sidebar);
  z-index: 1000;
  transition: left 0.3s ease;
  overflow-y: auto;
  box-shadow: var(--shadow-sidebar);
}

#sidebar.open {
  left: 0;
}

#sidebar-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 999;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

#sidebar-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.sidebar-header {
  padding: 1.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  position: relative;
}

.sidebar-header h2 {
  color: #ffffff;
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.sidebar-subtitle {
  color: #94a3b8;
  font-size: 0.85rem;
  letter-spacing: 0.05em;
}

.sidebar-close-btn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  color: #94a3b8;
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
  line-height: 1;
}

.sidebar-close-btn:hover {
  color: #ffffff;
}

.sidebar-content {
  padding: 1rem 0;
}

.sidebar-section {
  padding: 0.75rem 1.5rem;
}

.sidebar-section h3 {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #64748b;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.sidebar-section ul {
  list-style: none;
}

.sidebar-section li {
  margin-bottom: 0;
}

.sidebar-section a {
  display: block;
  color: var(--text-sidebar);
  text-decoration: none;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  transition: all 0.15s ease;
}

.sidebar-section a:hover {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-sidebar-hover);
}

.sidebar-section a.active {
  background: rgba(96, 165, 250, 0.15);
  color: var(--text-sidebar-active);
  font-weight: 500;
}

/* --- On This Page TOC --- */
.sidebar-toc {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  margin-top: 0.5rem;
  padding-top: 0.75rem;
}

.sidebar-toc h3 {
  color: #94a3b8;
}

#toc-list {
  list-style: none;
}

#toc-list a {
  font-size: 0.8rem;
  padding: 0.25rem 0.75rem;
  color: #94a3b8;
  line-height: 1.4;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  display: block;
  text-decoration: none;
  transition: all 0.15s ease;
}

#toc-list a:hover {
  color: var(--text-sidebar-hover);
  background: rgba(255, 255, 255, 0.05);
}

#toc-list a.active {
  color: var(--text-sidebar-active);
  background: rgba(96, 165, 250, 0.1);
  font-weight: 500;
}

#toc-list a.toc-h3 {
  padding-left: 1.5rem;
  font-size: 0.75rem;
}

/* --- Top Bar --- */
#topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-height);
  background: var(--bg-topbar);
  border-bottom: 1px solid var(--border-primary);
  display: flex;
  align-items: center;
  padding: 0 1.5rem;
  z-index: 100;
  box-shadow: var(--shadow-sm);
  gap: 1rem;
}

/* --- Search Bar --- */
.topbar-search {
  position: relative;
  flex: 1;
  max-width: 420px;
  margin: 0 1rem;
}

#search-input {
  width: 100%;
  height: 34px;
  padding: 0 0.75rem 0 2.25rem;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.875rem;
  font-family: var(--font-sans);
  outline: none;
  transition: all 0.15s ease;
}

#search-input::placeholder {
  color: var(--text-tertiary);
}

#search-input:focus {
  border-color: var(--accent);
  background: var(--bg-primary);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.topbar-search::before {
  content: '\1F50D';
  position: absolute;
  left: 0.65rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.85rem;
  pointer-events: none;
  opacity: 0.5;
}

.search-results {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  background: var(--bg-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  max-height: 420px;
  overflow-y: auto;
  z-index: 200;
  box-shadow: var(--shadow-lg);
}

.search-result-item {
  display: block;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-primary);
  text-decoration: none;
  color: var(--text-primary);
  transition: background 0.1s ease;
}

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

.search-result-item:hover,
.search-result-item:focus {
  background: var(--bg-secondary);
  text-decoration: none;
}

.search-result-page {
  font-size: 0.75rem;
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.15rem;
}

.search-result-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.search-result-excerpt {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.search-result-excerpt mark {
  background: var(--accent-light);
  color: var(--accent-dark);
  padding: 0 2px;
  border-radius: 2px;
}

.search-no-results {
  padding: 1.5rem 1rem;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

.search-loading {
  padding: 1rem;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 0.8rem;
}

.search-kbd-hint {
  position: absolute;
  right: 0.5rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.7rem;
  color: var(--text-tertiary);
  background: var(--bg-tertiary);
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  pointer-events: none;
}

#sidebar-toggle {
  background: none;
  border: none;
  font-size: 1.35rem;
  cursor: pointer;
  color: var(--text-topbar);
  padding: 0.5rem;
  margin-right: 1rem;
  border-radius: var(--radius-sm);
  transition: background 0.15s ease;
}

#sidebar-toggle:hover {
  background: var(--bg-hover);
}

.topbar-title {
  flex: 1;
  font-weight: 600;
  font-size: 1rem;
  color: var(--text-topbar);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

#theme-toggle {
  background: none;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  transition: background 0.15s ease;
}

#theme-toggle:hover {
  background: var(--bg-hover);
}

/* --- Main Content --- */
#content {
  margin-top: var(--topbar-height);
  min-height: calc(100vh - var(--topbar-height));
}

#main-article {
  max-width: 820px;
  margin: 0 auto;
  padding: 2.5rem 2rem 4rem;
}

/* --- Typography --- */
.article-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 2px solid var(--border-primary);
}

h1.title {
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.2;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.author, .date {
  color: var(--text-tertiary);
  font-size: 0.95rem;
}

h1 { font-size: 1.875rem; font-weight: 700; margin: 2.5rem 0 1rem; line-height: 1.3; }
h2 { font-size: 1.5rem; font-weight: 600; margin: 2rem 0 0.75rem; line-height: 1.35; }
h3 { font-size: 1.25rem; font-weight: 600; margin: 1.5rem 0 0.5rem; }
h4 { font-size: 1.1rem; font-weight: 600; margin: 1.25rem 0 0.5rem; }

p {
  margin-bottom: 1rem;
  color: var(--text-primary);
}

a {
  color: var(--text-link);
  text-decoration: none;
  transition: color 0.15s ease;
}

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

/* --- Code --- */
code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-code);
  color: var(--text-code);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-code);
}

pre {
  background: var(--bg-code-block);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin: 1.25rem 0;
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.6;
  box-shadow: var(--shadow-sm);
}

pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--text-code-block);
  font-size: inherit;
}

/* --- Tables --- */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  border: 1px solid var(--border-table);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

thead {
  background: var(--bg-table-header);
}

th {
  text-align: left;
  padding: 0.75rem 1rem;
  font-weight: 600;
  color: var(--text-primary);
  border-bottom: 2px solid var(--border-table);
}

td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border-table);
  color: var(--text-secondary);
}

tbody tr:nth-child(even) {
  background: var(--bg-table-stripe);
}

tbody tr:hover {
  background: var(--bg-hover);
}

/* --- Lists --- */
ul, ol {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.35rem;
}

li > ul, li > ol {
  margin-top: 0.25rem;
  margin-bottom: 0.25rem;
}

/* --- Checklists --- */
ul:has(input[type="checkbox"]) {
  list-style: none;
  padding-left: 0;
}

ul:has(input[type="checkbox"]) li {
  padding-left: 0.25rem;
}

input[type="checkbox"] {
  margin-right: 0.5rem;
  accent-color: var(--accent);
}

/* --- Blockquotes / Callouts --- */
blockquote {
  border-left: 4px solid var(--border-secondary);
  padding: 1rem 1.25rem;
  margin: 1.25rem 0;
  background: var(--bg-secondary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

blockquote p:last-child {
  margin-bottom: 0;
}

/* Tip callout */
blockquote:has(strong:contains("Tip")),
blockquote.tip {
  border-left-color: var(--border-callout-tip);
  background: var(--bg-callout-tip);
}

/* Warning callout */
blockquote:has(strong:contains("Warning")),
blockquote.warning {
  border-left-color: var(--border-callout-warning);
  background: var(--bg-callout-warning);
}

/* Note callout */
blockquote:has(strong:contains("Note")),
blockquote.note {
  border-left-color: var(--border-callout-note);
  background: var(--bg-callout-note);
}

/* --- Horizontal Rule --- */
hr {
  border: none;
  height: 2px;
  background: var(--border-primary);
  margin: 2rem 0;
  border-radius: 1px;
}

/* --- Images --- */
img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
  box-shadow: var(--shadow-md);
}

/* --- Page Navigation --- */
.page-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 2px solid var(--border-primary);
}

.nav-prev, .nav-next {
  display: inline-flex;
  align-items: center;
  padding: 0.75rem 1.25rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  color: var(--text-link);
  font-weight: 500;
  text-decoration: none;
  transition: all 0.15s ease;
}

.nav-prev:hover, .nav-next:hover {
  background: var(--accent-light);
  border-color: var(--accent);
  text-decoration: none;
}

/* --- Footer --- */
#footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-tertiary);
  font-size: 0.85rem;
  border-top: 1px solid var(--border-primary);
  background: var(--bg-secondary);
}

/* --- Syntax Highlighting (pandoc default light) --- */
span.kw { color: #d73a49; font-weight: 500; }    /* keywords */
span.dt { color: #d73a49; }                       /* types */
span.dv { color: #005cc5; }                       /* values/numbers */
span.bn { color: #005cc5; }                       /* base-N numbers */
span.fl { color: #005cc5; }                       /* floats */
span.ch { color: #032f62; }                       /* chars */
span.st { color: #032f62; }                       /* strings */
span.co { color: #6a737d; font-style: italic; }   /* comments */
span.ot { color: #22863a; }                       /* other */
span.al { color: #b31d28; font-weight: 500; }     /* alerts */
span.fu { color: #6f42c1; }                       /* functions */
span.re { color: #005cc5; }                       /* environment names */
span.er { color: #b31d28; font-weight: 500; }     /* error */
span.cn { color: #005cc5; font-weight: 500; }     /* constants */
span.sc { color: #032f62; }                       /* special chars */
span.ss { color: #032f62; }                       /* special strings */
span.im { color: #22863a; }                       /* imports */
span.va { color: #e36209; }                       /* variables */
span.cf { color: #d73a49; font-weight: 500; }     /* control flow */
span.op { color: #24292e; }                       /* operators */
span.pp { color: #d73a49; }                       /* preprocessor */

/* --- Responsive --- */
@media (min-width: 1024px) {
  #sidebar {
    left: calc(-1 * var(--sidebar-width));
    top: var(--topbar-height);
    height: calc(100vh - var(--topbar-height));
  }

  #sidebar.open {
    left: 0;
  }

  #sidebar-overlay {
    display: none;
  }

  #sidebar-close {
    display: none;
  }

  #content {
    margin-left: 0;
    transition: margin-left 0.3s ease;
  }

  #content.sidebar-open {
    margin-left: var(--sidebar-width);
  }

  #topbar {
    left: 0;
  }

  #main-article {
    padding: 3rem 3rem 4rem;
  }
}

@media (max-width: 640px) {
  #main-article {
    padding: 1.5rem 1rem 3rem;
  }

  h1.title {
    font-size: 1.75rem;
  }

  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
  h3 { font-size: 1.1rem; }

  pre {
    padding: 1rem;
    font-size: 0.8rem;
  }

  table {
    font-size: 0.8rem;
  }

  th, td {
    padding: 0.5rem 0.65rem;
  }

  .topbar-search {
    max-width: 180px;
    margin: 0 0.5rem;
  }

  .search-kbd-hint {
    display: none;
  }
}

/* --- Print --- */
@media print {
  #sidebar, #topbar, #sidebar-overlay, #footer, .page-nav {
    display: none !important;
  }

  #content {
    margin-left: 0;
    margin-top: 0;
  }

  #main-article {
    max-width: 100%;
    padding: 0;
  }

  body {
    background: white;
    color: black;
  }

  pre, code {
    border: 1px solid #ccc;
  }

  a {
    color: black;
    text-decoration: underline;
  }
}