/* ==========================================================================
   Windows 11 Screenshot Guide - Clean Native CSS3 Stylesheet
   Zero 3rd-Party Dependencies | Native Web Standards | Mobile Responsive
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Custom Properties (CSS Variables)
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette - Windows 11 Light Theme */
  --color-primary: #0078d4;
  --color-primary-hover: #005a9e;
  --color-primary-light: #e5f3ff;
  --color-accent: #0f6cbd;
  --color-bg-main: #f3f3f3;
  --color-bg-card: #ffffff;
  --color-bg-alt: #f9f9f9;
  --color-border: #e0e0e0;
  --color-border-strong: #c7c7c7;
  
  --color-text-main: #1c1c1c;
  --color-text-muted: #5e5e5e;
  --color-text-light: #767676;
  
  --color-success: #107c41;
  --color-success-bg: #dff6dd;
  --color-warning: #797775;
  --color-warning-bg: #fff4ce;
  --color-shortcut-kbd: #f3f2f1;
  
  /* Elevation & Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  
  /* Layout & Spacing */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-pill: 9999px;
  --max-width: 1200px;
  
  /* Typography */
  --font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'Cascadia Code', Consolas, 'Courier New', monospace;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

/* Dark Theme Overrides */
[data-theme="dark"] {
  --color-primary: #479ef5;
  --color-primary-hover: #6cb0f8;
  --color-primary-light: #162c40;
  --color-accent: #2886de;
  --color-bg-main: #1f1f1f;
  --color-bg-card: #2b2b2b;
  --color-bg-alt: #242424;
  --color-border: #3d3d3d;
  --color-border-strong: #525252;
  
  --color-text-main: #f3f3f3;
  --color-text-muted: #b0b0b0;
  --color-text-light: #888888;
  
  --color-shortcut-kbd: #3b3b3b;
  --color-success-bg: #0e3a1f;
  --color-warning-bg: #3e320d;
  
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.5);
}

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

html {
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  scroll-behavior: smooth;
  color: var(--color-text-main);
  background-color: var(--color-bg-main);
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  color: var(--color-text-main);
  background-color: var(--color-bg-main);
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Skip link for screen reader / keyboard accessibility */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--color-primary);
  color: #ffffff;
  padding: 0.75rem 1.25rem;
  z-index: 9999;
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 1rem;
  outline: 3px solid var(--color-text-main);
}

/* Focus styles */
:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   3. Header & Navigation (Responsive Flexbox)
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-bg-card);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--color-text-main);
  font-weight: 700;
  font-size: 1.25rem;
}

.brand-icon {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.brand-title span {
  color: var(--color-primary);
}

/* Navigation Links */
.main-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 0.5rem;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.5rem 0.85rem;
  color: var(--color-text-main);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.925rem;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.nav-link:hover {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.nav-link.active {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: 600;
}

/* Nav Actions (Theme Toggle & Menu Button) */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-icon {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-main);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.btn-icon:hover {
  background-color: var(--color-bg-alt);
  border-color: var(--color-border-strong);
}

.mobile-menu-btn {
  display: none;
}

/* --------------------------------------------------------------------------
   4. Page Layout & Container
   -------------------------------------------------------------------------- */
.main-content {
  flex: 1;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* Breadcrumb Navigation */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
  list-style: none;
}

.breadcrumb a {
  color: var(--color-primary);
  text-decoration: none;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

.breadcrumb-separator {
  color: var(--color-text-light);
}

/* Hero Header Banner */
.hero-section {
  background: linear-gradient(135deg, var(--color-bg-card) 0%, var(--color-primary-light) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  margin-bottom: 2.5rem;
  box-shadow: var(--shadow-sm);
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .hero-section.has-aside {
    grid-template-columns: 2fr 1fr;
    align-items: center;
  }
}

.hero-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 0.75rem;
  color: var(--color-text-main);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  max-width: 48ch;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.75rem;
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
}

/* --------------------------------------------------------------------------
   5. Grid Layouts & Cards
   -------------------------------------------------------------------------- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.card-hover:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.card-icon {
  width: 40px;
  height: 40px;
  padding: 8px;
  border-radius: var(--radius-md);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  flex-shrink: 0;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-main);
  line-height: 1.3;
}

.card-body {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  flex: 1;
}

.card-footer {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
  white-space: nowrap;
}

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

.btn-primary:hover {
  background-color: var(--color-primary-hover);
}

.btn-secondary {
  background-color: var(--color-bg-card);
  border-color: var(--color-border-strong);
  color: var(--color-text-main);
}

.btn-secondary:hover {
  background-color: var(--color-bg-alt);
}

/* --------------------------------------------------------------------------
   6. Key Combination Displays (<kbd>) & Code Snippets
   -------------------------------------------------------------------------- */
kbd {
  display: inline-block;
  padding: 0.2rem 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.85em;
  font-weight: 700;
  line-height: 1;
  color: var(--color-text-main);
  background-color: var(--color-shortcut-kbd);
  border: 1px solid var(--color-border-strong);
  border-bottom-width: 2px;
  border-radius: var(--radius-sm);
  box-shadow: 0 1px 0 rgba(0,0,0,0.2);
  white-space: nowrap;
}

.shortcut-combo {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-weight: 600;
}

.shortcut-plus {
  color: var(--color-text-light);
  font-size: 0.85em;
}

/* Step-by-Step Guide List */
.step-list {
  list-style: none;
  counter-reset: step-counter;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin: 1.5rem 0;
}

.step-item {
  position: relative;
  padding-left: 3.25rem;
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.25rem 1.25rem 3.75rem;
}

.step-item::before {
  counter-increment: step-counter;
  content: counter(step-counter);
  position: absolute;
  left: 1rem;
  top: 1.25rem;
  width: 2rem;
  height: 2rem;
  background-color: var(--color-primary);
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
}

.step-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.35rem;
  color: var(--color-text-main);
}

.step-desc {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* Callout Box / Note */
.callout {
  padding: 1.25rem;
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-primary);
  background-color: var(--color-primary-light);
  margin: 1.5rem 0;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.callout-icon {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
  flex-shrink: 0;
  margin-top: 2px;
}

.callout-title {
  font-weight: 700;
  margin-bottom: 0.25rem;
  color: var(--color-text-main);
}

.callout-body {
  font-size: 0.925rem;
  color: var(--color-text-main);
}

/* --------------------------------------------------------------------------
   7. Tables & Data Comparisons
   -------------------------------------------------------------------------- */
.table-wrapper {
  width: 100%;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background-color: var(--color-bg-card);
  margin: 1.5rem 0;
  box-shadow: var(--shadow-sm);
}

table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.925rem;
}

th, td {
  padding: 0.9rem 1.25rem;
  border-bottom: 1px solid var(--color-border);
}

th {
  background-color: var(--color-bg-alt);
  font-weight: 700;
  color: var(--color-text-main);
  white-space: nowrap;
}

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

tr:hover td {
  background-color: var(--color-primary-light);
}

/* --------------------------------------------------------------------------
   8. Diagrams & Vector Graphic Cards
   -------------------------------------------------------------------------- */
.vector-illustration {
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  padding: 1rem;
  display: block;
}

/* Search Box Component */
.search-box {
  position: relative;
  margin-bottom: 2rem;
}

.search-input {
  width: 100%;
  padding: 0.85rem 1rem 0.85rem 2.8rem;
  font-size: 1rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-card);
  color: var(--color-text-main);
  transition: border-color var(--transition-fast);
}

.search-input:focus {
  border-color: var(--color-primary);
  outline: none;
}

.search-icon {
  position: absolute;
  left: 0.9rem;
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--color-text-light);
  pointer-events: none;
}

/* Accordion / FAQ Collapsible */
.accordion {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 1.5rem 0;
}

.accordion-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-card);
  overflow: hidden;
}

.accordion-header {
  width: 100%;
  padding: 1rem 1.25rem;
  background: transparent;
  border: none;
  text-align: left;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-main);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.accordion-header:hover {
  background-color: var(--color-bg-alt);
}

.accordion-icon {
  width: 20px;
  height: 20px;
  transition: transform var(--transition-fast);
}

.accordion-item.active .accordion-icon {
  transform: rotate(180deg);
}

.accordion-content {
  display: none;
  padding: 0 1.25rem 1.25rem 1.25rem;
  color: var(--color-text-muted);
  font-size: 0.95rem;
  border-top: 1px solid var(--color-border);
}

.accordion-item.active .accordion-content {
  display: block;
}

/* --------------------------------------------------------------------------
   9. Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background-color: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
  margin-top: auto;
  padding: 3rem 1.5rem 2rem 1.5rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-col h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--color-text-main);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  max-width: var(--max-width);
  margin: 0 auto;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.footer-bottom a {
  color: var(--color-primary);
  text-decoration: underline;
  font-weight: 600;
}

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

.footer-disclaimer {
  margin-top: 1.25rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  text-align: center;
}

/* --------------------------------------------------------------------------
   10. Mobile Responsiveness & Drawer Navigation
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .mobile-menu-btn {
    display: inline-flex;
  }
  
  .main-nav {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-bg-card);
    flex-direction: column;
    padding: 1.5rem;
    gap: 1rem;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition-normal), opacity var(--transition-normal), visibility var(--transition-normal);
    z-index: 999;
    border-bottom: 1px solid var(--color-border);
  }
  
  .main-nav.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav-list {
    flex-direction: column;
    width: 100%;
    align-items: stretch;
  }
  
  .nav-link {
    padding: 0.85rem 1rem;
    font-size: 1rem;
    border-radius: var(--radius-md);
  }
}

/* --------------------------------------------------------------------------
   11. Print Stylesheet
   -------------------------------------------------------------------------- */
@media print {
  .site-header, .site-footer, .header-actions, .mobile-menu-btn, .btn {
    display: none !important;
  }
  
  body {
    background: #ffffff;
    color: #000000;
  }
  
  .main-content {
    max-width: 100%;
    padding: 0;
  }
  
  .card, .hero-section, .table-wrapper {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}