@charset "UTF-8";
/**
 * Skin — 012-graphpaper
 *
 * Archetype: blueprint-technical
 * Primary:   #1d4ed8 (Blueprint Blue)
 * Accent:    #64748b (Slate/Graphite)
 *
 * Visual identity: Moleskine meets Figma — precise, clean, print-ready.
 * All color values reference tokens.css — zero hardcoded hex outside
 * the dark-mode overrides block (which must override variables by value).
 *
 * @layer skin
 */

/* ========================================
   Base
   ======================================== */

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--site-background-alt);
  background-image: radial-gradient(var(--bg-dot-color) 1px, transparent 1px);
  background-size: var(--bg-dot-size) var(--bg-dot-size);
  color: var(--site-text);
  font-family: var(--font-body);
}

/* Reduced motion — mandatory accessibility */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Text selection */
::selection      { background: var(--site-primary-light); color: var(--site-primary-dark); }
::-moz-selection { background: var(--site-primary-light); color: var(--site-primary-dark); }

/* Focus ring — WCAG 2.1 AA */
*:focus-visible {
  outline: 3px solid var(--site-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
  box-shadow: 0 0 0 6px rgba(29, 78, 216, 0.10);
}

/* ========================================
   Scrollbar
   ======================================== */

::-webkit-scrollbar       { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--site-primary-light); }
::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--site-primary) 0%, var(--site-primary-hover) 100%);
  border-radius: 5px;
  border: 2px solid var(--site-primary-light);
}
::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(180deg, var(--site-primary-hover) 0%, var(--site-primary-dark) 100%);
}

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

.page-header h1,
.hero h1 {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--site-primary-dark);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.page-header h1 {
  font-size: 2rem;
}

/* ========================================
   Hero — blueprint-clean
   ======================================== */

.page-header {
  background: linear-gradient(180deg, #ffffff 0%, var(--site-primary-light) 100%);
  border-bottom: 2px solid var(--site-primary-border);
  padding: 1.5rem 2rem 1.25rem;
}

.hero {
  background: #ffffff;
  background-image: radial-gradient(var(--bg-dot-color) 1px, transparent 1px);
  background-size: var(--bg-dot-size) var(--bg-dot-size);
  border-bottom: 2px solid var(--site-primary-border);
  padding: 4rem 2rem 3rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

/* Subtle blueprint-corner glow */
.hero::before {
  content: '';
  position: absolute;
  top: -80px;
  right: -80px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(29, 78, 216, 0.05) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
}
.hero::after {
  content: '';
  position: absolute;
  bottom: -60px;
  left: -60px;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(29, 78, 216, 0.04) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
}
.hero > * { position: relative; z-index: 1; }

.hero h1 {
  font-size: 2.75rem;
  font-weight: 700;
  color: var(--site-primary-dark);
  font-family: var(--font-heading);
  letter-spacing: -0.025em;
  line-height: 1.15;
}

.hero .subtitle {
  font-size: 1.1rem;
  color: var(--site-text-muted);
  margin-top: 1rem;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.6;
  letter-spacing: 0.01em;
}

/* Hero stats */
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}

.stat-item {
  text-align: center;
  padding: 1rem 1.5rem;
  background: #ffffff;
  border: 1.5px solid var(--site-primary-border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-sm);
  min-width: 120px;
  transition: box-shadow var(--dur-normal) var(--ease), transform var(--dur-normal) var(--ease);
}

.stat-item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.stat-number {
  display: block;
  font-size: 1.75rem;
  font-weight: 700;
  font-family: var(--font-heading);
  background: linear-gradient(135deg, var(--site-primary) 0%, var(--site-primary-hover) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  display: block;
  font-size: 0.8rem;
  color: var(--site-text-muted);
  margin-top: 0.25rem;
  letter-spacing: 0.02em;
}

/* ========================================
   Breadcrumb
   ======================================== */

.breadcrumb {
  padding: 0.6rem 1rem;
  margin-bottom: 1rem;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.875rem;
  color: var(--site-text-muted);
}

.breadcrumb a { color: var(--site-primary); text-decoration: none; }
.breadcrumb a:hover { color: var(--site-primary-hover); text-decoration: underline; }
.breadcrumb li:not(:last-child)::after { content: '/'; color: var(--site-border-dark); margin-left: 0.3rem; }
.breadcrumb li:last-child { color: var(--site-text); font-weight: 600; }

/* ========================================
   Variant Chips
   ======================================== */

.variant-chip {
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-pill);
  color: var(--site-primary);
  background: var(--site-primary-light);
  border: 1px solid var(--site-primary-border);
  letter-spacing: 0.02em;
}

/* ========================================
   Set Switcher
   ======================================== */

.set-switcher {
  background: #ffffff;
  border: 1.5px solid var(--site-border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-sm);
}

.set-switcher-label {
  font-size: 1rem;
  font-weight: 600;
  color: var(--site-text);
  font-family: var(--font-heading);
}

.set-btn {
  background: #ffffff;
  border: 2px solid var(--site-border);
  border-radius: var(--radius-button);
  color: var(--site-text);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition:
    border-color var(--dur-fast) var(--ease),
    background var(--dur-fast) var(--ease),
    box-shadow var(--dur-fast) var(--ease);
}

.set-btn:hover  { border-color: var(--site-primary); background: var(--site-primary-light); }
.set-btn.active {
  background: var(--site-primary);
  color: #ffffff;
  border-color: var(--site-primary-dark);
  box-shadow: var(--shadow-sm);
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: var(--radius-button);
  background: #ffffff;
  color: var(--site-text);
  box-shadow: var(--shadow-sm);
  font-family: var(--font-heading);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition:
    background var(--dur-fast) var(--ease),
    box-shadow var(--dur-normal) var(--ease),
    transform var(--dur-fast) var(--ease),
    border-color var(--dur-fast) var(--ease);
}

.btn:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.btn:active {
  transform: translateY(0) scale(0.97);
  box-shadow: var(--shadow-sm);
  transition-duration: 80ms;
}

/* Primary blueprint button */
.btn-primary {
  background: var(--site-primary);
  color: #ffffff;
  border-color: var(--site-primary-dark);
}
.btn-primary:hover {
  background: var(--site-primary-hover);
  box-shadow: 0 6px 20px rgba(29, 78, 216, 0.28);
}

/* Print / Download — prominent, blueprint blue (center-stage) */
.btn-print,
.btn-download {
  background: var(--site-primary);
  color: #ffffff;
  border-color: var(--site-primary-dark);
  font-size: 1.05rem;
  padding: 0.7rem 1.5rem;
}
.btn-print:hover,
.btn-download:hover {
  background: var(--site-primary-hover);
  box-shadow: 0 6px 20px rgba(29, 78, 216, 0.30);
}

/* Success / Answers — slate accent */
.btn-success,
.btn-answers {
  background: var(--site-accent);
  color: #ffffff;
  border-color: var(--site-accent-dark);
}
.btn-success:hover,
.btn-answers:hover {
  background: var(--site-accent-hover);
  box-shadow: 0 6px 16px rgba(100, 116, 139, 0.24);
}

.btn-check       { background: var(--site-accent); color: #ffffff; border-color: var(--site-accent-dark); }
.btn-check:hover { background: var(--site-accent-hover); }

.btn:focus-visible { outline: 3px solid var(--site-primary); outline-offset: 3px; }

/* ========================================
   Body Content & Sheet Preview
   ======================================== */

.body-content {
  background: #ffffff;
  border-radius: 0 0 var(--radius-card) var(--radius-card);
  border: 1px solid var(--site-border);
  border-top: none;
}

/* Sheet preview: white paper with print-preview drop shadow */
.sheet-preview {
  background: #ffffff;
  border: 1px solid var(--site-border-dark);
  box-shadow: 0 2px 8px rgba(29, 78, 216, 0.07), 0 8px 24px rgba(0, 0, 0, 0.06);
  border-radius: var(--radius-card);
  margin: 1rem;
  padding: 1rem;
  transition:
    box-shadow var(--dur-normal) var(--ease),
    transform var(--dur-normal) var(--ease);
}

.sheet-preview:hover {
  box-shadow: 0 4px 16px rgba(29, 78, 216, 0.12), 0 16px 40px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

.sheet-grid-container,
.sheet-dots-container,
.sheet-lines-container {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 1rem 0;
}

.sheet-grid-svg,
.sheet-dots-svg {
  border: 1px solid var(--site-border);
  background: #ffffff;
}

.sheet-header {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--site-text);
  font-family: var(--font-heading);
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--site-border);
}

.sheet-line    { border-color: var(--site-border-dark); }
.problems-grid { border-top: 2px solid var(--site-border); }
.problem       { border-bottom: 1px solid var(--site-background-alt); font-size: 1.125rem; color: var(--site-text); }

/* ========================================
   Intro Section
   ======================================== */

.intro,
.intro-section {
  background: var(--site-primary-light);
  border: 1px solid var(--site-primary-border);
  border-radius: var(--radius-card);
  padding: 1.25rem 1.5rem;
  margin: 1rem 0;
}

.intro h3, .intro-section h3 { font-weight: 600; color: var(--site-primary-dark); font-family: var(--font-heading); }
.intro p,  .intro-section p  { color: var(--site-text-muted); line-height: 1.65; }

/* ========================================
   Page Navigation
   ======================================== */

.page-nav,
.page-navigation {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1.5rem;
  padding: 1rem 1.5rem;
  background: #ffffff;
  border: 1px solid var(--site-border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-sm);
}

.page-nav a,
.btn-nav {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-button);
  color: var(--site-primary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: background var(--dur-fast) var(--ease);
}

.page-nav a:hover,
.btn-nav:hover { background: var(--site-primary-light); }
.btn-nav.disabled { color: var(--site-text-light); cursor: not-allowed; }

/* ========================================
   Section Headers
   ======================================== */

.section-header { margin: 1.5rem 0 1rem; }

.section-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--site-text);
  font-family: var(--font-heading);
  letter-spacing: -0.01em;
  position: relative;
  padding-bottom: 0.6rem;
}

.section-header h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 40px;
  height: 3px;
  background: var(--site-primary);
  border-radius: 2px;
}

.section-header p { color: var(--site-text-muted); margin-top: 0.25rem; }

/* ========================================
   Category Cards — icon-left archetype
   ======================================== */

.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
  margin: 1rem 0;
}

.category-card {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 1rem;
  padding: 1.5rem;
  background: #ffffff;
  border: 1.5px solid var(--site-border);
  border-left: 4px solid var(--site-primary);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-sm);
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
  transition:
    border-left-color var(--dur-normal) var(--ease),
    box-shadow var(--dur-normal) var(--ease),
    transform var(--dur-normal) var(--ease);
}

/* Blueprint accent stripe on hover */
.category-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 12px;
  right: 12px;
  height: 2px;
  background: var(--site-primary);
  border-radius: 2px 2px 0 0;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-normal) var(--ease);
}

.category-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 28px rgba(29, 78, 216, 0.12), 0 4px 8px rgba(0, 0, 0, 0.05);
  border-left-color: var(--site-primary-hover);
}

.category-card:hover::after { transform: scaleX(1); }

.category-icon    { font-size: 2.2rem; line-height: 1; flex-shrink: 0; }
.category-card h3 { font-weight: 600; font-size: 1rem; color: var(--site-text); margin: 0 0 0.25rem; font-family: var(--font-heading); }
.category-card p  { font-size: 0.85rem; color: var(--site-text-muted); line-height: 1.4; margin: 0; }
.category-meta    {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--site-primary);
  margin-top: 0.5rem;
  background: var(--site-primary-light);
  border-radius: var(--radius-sm);
  padding: 0.1rem 0.4rem;
  display: inline-block;
  letter-spacing: 0.01em;
}

/* ========================================
   Subcategory Cards — top-accent archetype
   ======================================== */

.subcategories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
}

.subcategory-card {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  padding: 1.25rem 1.125rem;
  background: #ffffff;
  border: 1.5px solid var(--site-border);
  border-top: 3px solid var(--site-primary);
  border-radius: var(--radius-card);
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
  transition:
    border-top-color var(--dur-normal) var(--ease),
    box-shadow var(--dur-normal) var(--ease),
    transform var(--dur-normal) var(--ease);
}

.subcategory-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 12px;
  right: 12px;
  height: 2px;
  background: var(--site-primary);
  border-radius: 2px 2px 0 0;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-normal) var(--ease);
}

.subcategory-card:hover {
  transform: translateY(-3px);
  border-top-color: var(--site-primary-hover);
  box-shadow: 0 12px 28px rgba(29, 78, 216, 0.12), 0 4px 8px rgba(0, 0, 0, 0.05);
}

.subcategory-card:hover::after { transform: scaleX(1); }

.subcategory-card h3    { font-weight: 600; color: var(--site-text); font-family: var(--font-heading); }
.subcategory-card p     { font-size: 0.85rem; color: var(--site-text-muted); }
.subcategory-arrow      { font-size: 0.85rem; font-weight: 600; color: var(--site-primary); margin-top: auto; }

/* ========================================
   Worksheet Cards — wide-row archetype
   ======================================== */

.worksheets-grid { display: flex; flex-direction: column; gap: 0.4rem; }

.worksheet-card {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1.25rem;
  background: #ffffff;
  border: 1px solid var(--site-border);
  border-radius: var(--radius-button);
  text-decoration: none;
  color: inherit;
  transition:
    background var(--dur-fast) var(--ease),
    border-color var(--dur-fast) var(--ease),
    box-shadow var(--dur-fast) var(--ease),
    transform var(--dur-fast) var(--ease);
}

.worksheet-card:hover {
  background: var(--site-primary-light);
  border-color: var(--site-primary-border);
  box-shadow: var(--shadow-sm);
  transform: translateY(-1px);
}

.worksheet-number { font-weight: 700; font-size: 1rem; color: var(--site-primary); min-width: 60px; font-family: var(--font-heading); }
.worksheet-card h3 { font-size: 0.9rem; margin: 0; flex: 1; }
.worksheet-problems { font-size: 0.8rem; color: var(--site-text-light); }

/* ========================================
   Content Toggle
   ======================================== */

.body-content--collapsible {
  margin: 1rem 0;
  border: 1px solid var(--site-border);
  border-radius: var(--radius-card);
  overflow: hidden;
}

.content-toggle { border: none; }

.content-toggle summary {
  padding: 0.9rem 1.25rem;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--site-primary-dark);
  cursor: pointer;
  background: var(--site-primary-light);
  border-bottom: 1px solid transparent;
  transition: background var(--dur-fast) var(--ease);
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-heading);
}

.content-toggle summary::-webkit-details-marker { display: none; }
.content-toggle summary::after {
  content: '⌄';
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--site-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.5rem;
  height: 1.5rem;
  background: #ffffff;
  border-radius: 50%;
  transition: transform var(--dur-normal) var(--ease);
}

.content-toggle[open] summary::after { transform: rotate(180deg); }
.content-toggle summary:hover        { background: var(--site-primary-border); }
.content-toggle[open] summary        { border-bottom-color: var(--site-primary-border); }
.content-toggle-panel                { padding: 1.25rem 1.5rem; }

/* ========================================
   SEO Components
   ======================================== */

.seo-components {
  border-top: 1px solid var(--site-border);
  padding-top: 1rem;
  margin: 1.5rem 0;
}

.seo-components--primary { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.2rem; }
.seo-more-grid           { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1.2rem; }

.seo-block {
  background: #ffffff;
  border: 1px solid var(--site-border);
  border-radius: var(--radius-card);
  padding: 1.15rem 1.25rem;
  box-shadow: var(--shadow-sm);
  transition:
    box-shadow var(--dur-normal) var(--ease),
    transform var(--dur-normal) var(--ease);
}

.seo-block:hover { box-shadow: var(--shadow-md); transform: translateY(-1px); }

/* SEO card color band */
.seo-card { background: var(--site-background-alt); border-color: var(--site-border); border-top: none; }
.seo-card::before { background: var(--site-primary); }
.seo-card:hover   { box-shadow: 0 0 0 3px var(--site-primary-border); }

/* Per-type band colors */
.seo-card.features::before       { background: var(--site-primary); }
.seo-card.benefits::before       { background: var(--site-accent); }
.seo-card.faq::before            { background: var(--site-primary-dark); }
.seo-card.tips::before           { background: #f59e0b; }
.seo-card.steps::before          { background: var(--site-accent-hover); }
.seo-card.tutorial::before       { background: var(--site-accent); }
.seo-card.examples::before       { background: #06b6d4; }
.seo-card.use-cases::before      { background: #ec4899; }
.seo-card.common-mistakes::before { background: #ef4444; }
.seo-card.practice::before       { background: #f97316; }
.seo-card.requirements::before   { background: #6366f1; }
.seo-card.resources::before      { background: #14b8a6; }
.seo-card.next-steps::before     { background: var(--site-primary); }
.seo-card.summary::before        { background: #64748b; }
.seo-card.related::before        { background: #a855f7; }

.seo-block h2, .seo-block h3 { font-weight: 700; color: var(--site-text); font-family: var(--font-heading); }
.seo-block p, .seo-block li  { font-size: 0.9375rem; color: var(--site-text-muted); line-height: 1.65; }
.seo-block a                 { color: var(--site-primary); text-decoration: none; }
.seo-block a:hover           { text-decoration: underline; }

/* FAQ details */
.seo-block details           { border-bottom: 1px solid var(--site-border); padding: 0.5rem 0; }
.seo-block details:last-child { border-bottom: none; }
.seo-block details summary   { font-weight: 600; font-size: 0.92rem; cursor: pointer; list-style: none; color: var(--site-primary-dark); font-family: var(--font-heading); }
.seo-block details summary::-webkit-details-marker { display: none; }
.seo-block details summary::before { content: "▸"; margin-right: 0.4rem; color: var(--site-primary); display: inline-block; transition: transform var(--dur-fast) var(--ease); }
.seo-block details[open] summary::before { transform: rotate(90deg); }
.seo-block details p { padding: 0.3rem 0 0.3rem 1rem; color: var(--site-text-muted); font-size: 0.88rem; }

/* Homepage content area */
.homepage > .content { background: #ffffff; border-color: var(--site-border); box-shadow: var(--shadow-sm); }
.homepage > .content h2 { color: var(--site-text); border-bottom-color: var(--site-border); font-weight: 700; font-family: var(--font-heading); }
.homepage > .content p, .homepage > .content li { color: var(--site-text-muted); }

/* ========================================
   Staggered card entrance
   ======================================== */

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

.category-card,
.subcategory-card,
.worksheet-card,
.seo-block {
  animation: fadeInUp 400ms var(--ease-out) backwards;
}

.category-card:nth-child(1), .subcategory-card:nth-child(1) { animation-delay: 50ms; }
.category-card:nth-child(2), .subcategory-card:nth-child(2) { animation-delay: 100ms; }
.category-card:nth-child(3), .subcategory-card:nth-child(3) { animation-delay: 150ms; }
.category-card:nth-child(4), .subcategory-card:nth-child(4) { animation-delay: 200ms; }
.category-card:nth-child(5), .subcategory-card:nth-child(5) { animation-delay: 250ms; }
.category-card:nth-child(6), .subcategory-card:nth-child(6) { animation-delay: 300ms; }
.category-card:nth-child(n+7), .subcategory-card:nth-child(n+7) { animation-delay: 350ms; }

@keyframes fadeIn  { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
.fade-in  { animation: fadeIn 300ms ease-out; }
.slide-up { animation: slideUp 300ms ease-out; }

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

@media (max-width: 768px) {
  .hero              { padding: 2.5rem 1rem 2rem; }
  .hero h1           { font-size: 2rem; }
  .hero .subtitle    { max-width: 100%; }
  .hero-stats        { gap: 1rem; }
  .stat-number       { font-size: 1.4rem; }
  .categories-grid   { grid-template-columns: 1fr; }
  .subcategories-grid { grid-template-columns: 1fr; }
  .seo-components--primary { grid-template-columns: 1fr; }
  .seo-more-grid     { grid-template-columns: 1fr; }
  .page-navigation   { flex-wrap: wrap; justify-content: center; }
}

@media (max-width: 480px) {
  .hero           { padding: 2rem 1rem; }
  .hero h1        { font-size: 1.6rem; }
  .hero-stats     { flex-direction: column; gap: 0.75rem; }
}

/* ========================================
   Print — maximize grid area, no UI chrome
   ======================================== */

@media print {
  @page {
    size: letter;
    margin: 8mm;
  }

  body {
    background: #ffffff !important;
    background-image: none !important;
    color: #000000 !important;
  }

  * {
    box-shadow: none !important;
    text-shadow: none !important;
    animation: none !important;
    transition: none !important;
  }

  .page-header,
  .hero,
  .breadcrumb,
  .btn,
  .set-switcher,
  .page-nav,
  .page-navigation,
  .seo-components,
  .content-toggle summary,
  .hero-stats,
  .categories-section,
  .worksheets-section,
  .subcategories-section {
    display: none !important;
  }

  .category-card,
  .subcategory-card,
  .worksheet-card,
  .seo-block {
    transform: none !important;
    box-shadow: none !important;
  }

  .category-card::after,
  .subcategory-card::after {
    display: none !important;
  }

  .hero::before,
  .hero::after { display: none !important; }

  .sheet-preview {
    border: 1pt solid #999 !important;
    box-shadow: none !important;
    page-break-inside: avoid;
    break-inside: avoid;
    transform: none !important;
  }

  .sheet-grid-svg,
  .sheet-dots-svg {
    border: 1pt solid #999 !important;
    box-shadow: none !important;
  }

  -webkit-print-color-adjust: exact;
  print-color-adjust: exact;
}

/* ========================================
   Dark Mode
   ======================================== */

@media (prefers-color-scheme: dark) {
  :root {
    --site-background:     #030b1a;
    --site-background-alt: #071224;
    --site-surface:        #0f1f3d;
    --site-text:           #e2e8f0;
    --site-text-muted:     #94a3b8;
    --site-text-light:     #64748b;
    --site-border:         #1e3a5f;
    --site-border-dark:    #1d4ed8;
    --bg-dot-color:        rgba(29, 78, 216, 0.18);
    --shadow-sm:           0 1px 3px rgba(0, 0, 0, 0.30);
    --shadow-md:           0 4px 8px rgba(0, 0, 0, 0.35);
    --shadow-lg:           0 10px 20px rgba(0, 0, 0, 0.40);
  }

  body {
    background-color: var(--site-background);
    background-image: radial-gradient(var(--bg-dot-color) 1px, transparent 1px);
    background-size: var(--bg-dot-size) var(--bg-dot-size);
    color: var(--site-text);
  }

  .page-header {
    background: linear-gradient(180deg, #071224 0%, #0f1f3d 100%);
    border-bottom-color: var(--site-primary-dark);
  }
  .page-header h1 { color: #dbeafe; }

  .hero {
    background: #071224;
    border-bottom-color: var(--site-primary-dark);
  }
  .hero h1      { color: #dbeafe; }
  .hero .subtitle { color: #93c5fd; }

  .stat-item { background: #0f1f3d; border-color: var(--site-primary-dark); }
  .stat-label { color: #94a3b8; }

  .breadcrumb   { }
  .breadcrumb a { color: #60a5fa; }
  .breadcrumb li:last-child { color: #e2e8f0; }

  .category-card { background: #0f1f3d; border-color: var(--site-primary-dark); border-left-color: #3b82f6; color: #e2e8f0; }
  .category-card:hover { border-left-color: #60a5fa; }
  .category-card h3 { color: #e2e8f0; }
  .category-card p  { color: #94a3b8; }
  .category-meta { color: #60a5fa; background: rgba(29, 78, 216, 0.15); }
  .category-card::after { background: #60a5fa; }

  .subcategory-card { background: #0f1f3d; border-color: var(--site-primary-dark); border-top-color: #3b82f6; color: #e2e8f0; }
  .subcategory-card:hover { border-top-color: #60a5fa; }
  .subcategory-card h3 { color: #e2e8f0; }
  .subcategory-card p  { color: #94a3b8; }
  .subcategory-card::after { background: #60a5fa; }
  .subcategory-arrow { color: #60a5fa; }

  .worksheet-card { background: #0f1f3d; border-color: #1e3a5f; color: #e2e8f0; }
  .worksheet-card:hover { background: #142545; border-color: #3b82f6; }
  .worksheet-number { color: #60a5fa; }
  .worksheet-problems { color: #94a3b8; }

  .btn { background: #0f1f3d; color: #e2e8f0; border-color: #1e3a5f; }
  .btn-primary { background: var(--site-primary); color: #fff; border-color: var(--site-primary-dark); }
  .btn-print, .btn-download { background: var(--site-primary); color: #fff; border-color: var(--site-primary-dark); }
  .btn-success, .btn-answers { background: #475569; color: #fff; border-color: #334155; }
  .btn-check { background: #475569; color: #fff; border-color: #334155; }

  .set-switcher { background: #0f1f3d; border-color: #1e3a5f; }
  .set-btn { background: #0f1f3d; border-color: #1e3a5f; color: #e2e8f0; }
  .set-btn:hover { background: #142545; border-color: #3b82f6; }
  .set-btn.active { background: var(--site-primary); color: #fff; }

  .body-content { background: var(--site-background); border-color: #1e3a5f; }

  .sheet-preview { background: #0f1f3d; border-color: #1e3a5f; }
  .sheet-header  { color: #e2e8f0; border-bottom-color: #1e3a5f; }
  .sheet-grid-svg, .sheet-dots-svg { background: #0f1f3d; border-color: #1e3a5f; }

  .intro, .intro-section { background: #0f1f3d; border-color: var(--site-primary-dark); }
  .intro h3, .intro-section h3 { color: #dbeafe; }
  .intro p, .intro-section p  { color: #94a3b8; }

  .content-toggle summary { background: #0f1f3d; color: #dbeafe; }
  .content-toggle summary:hover { background: #142545; }
  .content-toggle summary::after { background: #1e3a5f; color: #60a5fa; }
  .content-toggle[open] summary { border-bottom-color: #1e3a5f; }
  .content-toggle-panel { background: var(--site-background); }

  .page-navigation, .page-nav { background: #0f1f3d; border-color: #1e3a5f; }
  .btn-nav { color: #60a5fa; }
  .btn-nav:hover { background: #142545; }

  .seo-block { background: #0f1f3d; border-color: #1e3a5f; }
  .seo-block:hover { box-shadow: 0 4px 12px rgba(29, 78, 216, 0.20); }
  .seo-block h2, .seo-block h3 { color: #dbeafe; }
  .seo-block p, .seo-block li  { color: #94a3b8; }
  .seo-block a { color: #60a5fa; }
  .seo-block details { border-bottom-color: #1e3a5f; }
  .seo-block details summary { color: #93c5fd; }

  .seo-card { background: #071224; border-color: #1e3a5f; }

  .section-header h2 { color: #e2e8f0; }
  .section-header h2::after { background: #3b82f6; }
  .section-header p { color: #94a3b8; }

  .variant-chip { background: #142545; color: #93c5fd; border-color: var(--site-primary-dark); }

  .homepage > .content { background: #0f1f3d; border-color: #1e3a5f; }
  .homepage > .content h2 { color: #e2e8f0; }
  .homepage > .content p, .homepage > .content li { color: #94a3b8; }

  ::selection      { background: #1e3a8a; color: #dbeafe; }
  ::-moz-selection { background: #1e3a8a; color: #dbeafe; }
  ::-webkit-scrollbar-track { background: #030b1a; }
  ::-webkit-scrollbar-thumb { background: linear-gradient(180deg, #1d4ed8 0%, #1e40af 100%); border-color: #030b1a; }

  *:focus-visible { outline-color: #60a5fa; box-shadow: 0 0 0 6px rgba(96, 165, 250, 0.15); }
}