/* ============================================
   The Solution Architect - Style Sheet
   thesolutionarchitect.uk
   ============================================ */

/* --- Custom Properties --- */
:root {
  --color-primary-bg: #1a1a2e;
  --color-secondary-bg: #2a2a3e;
  --color-accent-blue: #4a6cf7;
  --color-accent-amber: #f59e0b;
  --color-white: #ffffff;
  --color-light-grey: #cccccc;
  --color-light-bg: #f8f9fa;
  --color-card-bg: #ffffff;
  --color-text-dark: #1a1a2e;
  --color-text-body: #333333;
  --color-border: #e2e8f0;
  --color-shadow: rgba(0, 0, 0, 0.1);
  --color-shadow-hover: rgba(74, 108, 247, 0.15);
  --color-badge-foundation: #4a6cf7;
  --color-badge-intermediate: #f59e0b;
  --color-badge-advanced: #7c3aed;

  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-base: 1rem;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3.5rem;

  --line-height-tight: 1.2;
  --line-height-normal: 1.6;
  --line-height-relaxed: 1.8;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  --spacing-4xl: 6rem;

  --max-width: 1200px;
  --max-width-content: 720px;
  --border-radius: 8px;
  --border-radius-lg: 12px;
  --transition: all 0.3s ease;
  --header-height: 72px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-body);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-accent-blue);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--color-accent-amber);
}

a:focus-visible {
  outline: 3px solid var(--color-accent-blue);
  outline-offset: 2px;
  border-radius: 2px;
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  line-height: var(--line-height-tight);
  color: var(--color-text-dark);
  font-weight: 700;
}

h1 { font-size: var(--font-size-5xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }


/* --- Layout --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-4xl) 0;
}

.section--dark {
  background-color: var(--color-primary-bg);
  color: var(--color-white);
}

.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: var(--color-white);
}

.section--alt {
  background-color: var(--color-light-bg);
}

.content-wrapper {
  max-width: var(--max-width-content);
  margin: 0 auto;
}

/* --- Header & Navigation --- */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-primary-bg);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  height: var(--header-height);
  display: flex;
  align-items: center;
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header__logo {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-white);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.header__logo:hover {
  color: var(--color-accent-blue);
}

.header__logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-accent-blue), var(--color-accent-amber));
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: white;
  font-weight: 800;
}

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

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

.nav__link {
  color: var(--color-light-grey);
  font-size: var(--font-size-sm);
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.nav__link:hover,
.nav__link--active {
  color: var(--color-white);
  background-color: rgba(255, 255, 255, 0.1);
}

.nav__toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
  color: var(--color-white);
}

.nav__toggle-icon {
  display: block;
  width: 24px;
  height: 2px;
  background-color: currentColor;
  position: relative;
  transition: var(--transition);
}

.nav__toggle-icon::before,
.nav__toggle-icon::after {
  content: '';
  position: absolute;
  width: 24px;
  height: 2px;
  background-color: currentColor;
  left: 0;
  transition: var(--transition);
}

.nav__toggle-icon::before { top: -7px; }
.nav__toggle-icon::after { top: 7px; }

/* Mobile nav open state */
.nav--open .nav__toggle-icon {
  background-color: transparent;
}

.nav--open .nav__toggle-icon::before {
  transform: rotate(45deg);
  top: 0;
}

.nav--open .nav__toggle-icon::after {
  transform: rotate(-45deg);
  top: 0;
}


/* --- Hero Section --- */
.hero {
  background-color: var(--color-primary-bg);
  padding: var(--spacing-4xl) 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at center, rgba(74, 108, 247, 0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
}

.hero__title {
  font-size: var(--font-size-5xl);
  color: var(--color-white);
  margin-bottom: var(--spacing-lg);
  font-weight: 800;
}

.hero__subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-accent-blue);
  margin-bottom: var(--spacing-xl);
  font-weight: 500;
}

.hero__description {
  font-size: var(--font-size-lg);
  color: var(--color-light-grey);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-2xl);
}

.hero__cta {
  display: inline-flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
  justify-content: center;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: var(--transition);
}

.btn--primary {
  background-color: var(--color-accent-blue);
  color: var(--color-white);
}

.btn--primary:hover {
  background-color: #3b5de8;
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(74, 108, 247, 0.4);
}

.btn--secondary {
  background-color: transparent;
  color: var(--color-white);
  border: 2px solid rgba(255, 255, 255, 0.3);
}

.btn--secondary:hover {
  border-color: var(--color-accent-blue);
  color: var(--color-accent-blue);
}

.btn--amber {
  background-color: var(--color-accent-amber);
  color: var(--color-text-dark);
}

.btn--amber:hover {
  background-color: #e08e0a;
  color: var(--color-text-dark);
  transform: translateY(-2px);
}

/* --- Cards --- */
.card {
  background-color: var(--color-card-bg);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  box-shadow: 0 2px 8px var(--color-shadow);
  transition: var(--transition);
  border: 1px solid var(--color-border);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px var(--color-shadow-hover);
}

.card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-md);
  color: var(--color-text-dark);
}

.card__description {
  color: var(--color-text-body);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-lg);
}

.card__link {
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.card__link::after {
  content: '→';
  transition: var(--transition);
}

.card__link:hover::after {
  transform: translateX(4px);
}

/* --- Grid Layouts --- */
.grid {
  display: grid;
  gap: var(--spacing-xl);
}

.grid--2 { grid-template-columns: repeat(1, 1fr); }
.grid--3 { grid-template-columns: repeat(1, 1fr); }
.grid--4 { grid-template-columns: repeat(1, 1fr); }


/* --- Badges --- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: 20px;
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-transform: capitalize;
}

.badge--foundation {
  background-color: rgba(74, 108, 247, 0.1);
  color: var(--color-badge-foundation);
}

.badge--intermediate {
  background-color: rgba(245, 158, 11, 0.1);
  color: var(--color-badge-intermediate);
}

.badge--advanced {
  background-color: rgba(124, 58, 237, 0.1);
  color: var(--color-badge-advanced);
}

.badge--category {
  background-color: rgba(74, 108, 247, 0.1);
  color: var(--color-accent-blue);
}

/* --- Section Headers --- */
.section-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section-header__title {
  margin-bottom: var(--spacing-md);
}

.section-header__subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-body);
  max-width: 600px;
  margin: 0 auto;
  line-height: var(--line-height-relaxed);
}

.section--dark .section-header__subtitle {
  color: var(--color-light-grey);
}

/* --- Lesson Cards --- */
.lesson-card {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-lg);
  padding: var(--spacing-xl);
  background: var(--color-card-bg);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--color-border);
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
}

.lesson-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--color-shadow-hover);
  border-color: var(--color-accent-blue);
  color: inherit;
}

.lesson-card__number {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--color-accent-blue), #6366f1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: var(--font-size-lg);
}

.lesson-card__content {
  flex: 1;
}

.lesson-card__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-dark);
}

.lesson-card__meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

/* --- Infographic Gallery --- */
.gallery-filters {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
  margin-bottom: var(--spacing-xl);
  justify-content: center;
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  border: 2px solid var(--color-border);
  border-radius: 20px;
  background: var(--color-white);
  color: var(--color-text-body);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.filter-btn:hover,
.filter-btn--active {
  border-color: var(--color-accent-blue);
  background-color: var(--color-accent-blue);
  color: var(--color-white);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(1, 1fr);
  gap: var(--spacing-xl);
}

.gallery-item {
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  cursor: pointer;
  transition: all 0.3s ease, opacity 0.3s ease;
  border: 1px solid var(--color-border);
  background: var(--color-card-bg);
}

.gallery-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px var(--color-shadow-hover);
}

.gallery-item__image {
  width: 100%;
  aspect-ratio: 16/9;
  background-color: var(--color-secondary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-light-grey);
  font-size: var(--font-size-sm);
}

.gallery-item__info {
  padding: var(--spacing-lg);
}

.gallery-item__title {
  font-size: var(--font-size-base);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.gallery-item__series {
  font-size: var(--font-size-sm);
  color: var(--color-accent-blue);
}

/* --- Lightbox --- */
.lightbox {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.9);
  z-index: 2000;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-xl);
}

.lightbox--open {
  display: flex;
}

.lightbox__content {
  max-width: 90vw;
  max-height: 90vh;
  position: relative;
}

.lightbox__image {
  max-width: 100%;
  max-height: 80vh;
  border-radius: var(--border-radius);
}

.lightbox__close {
  position: absolute;
  top: -40px;
  right: 0;
  background: none;
  border: none;
  color: var(--color-white);
  font-size: var(--font-size-2xl);
  cursor: pointer;
  padding: var(--spacing-sm);
}

.lightbox__title {
  color: var(--color-white);
  text-align: center;
  margin-top: var(--spacing-lg);
  font-size: var(--font-size-lg);
}


/* --- Blog Cards --- */
.blog-card {
  display: flex;
  flex-direction: column;
  background: var(--color-card-bg);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
}

.blog-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px var(--color-shadow-hover);
  color: inherit;
}

.blog-card__image {
  width: 100%;
  aspect-ratio: 16/9;
  background-color: var(--color-secondary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
}

.blog-card__body {
  padding: var(--spacing-xl);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.blog-card__meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-body);
}

.blog-card__title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-text-dark);
}

.blog-card__excerpt {
  color: var(--color-text-body);
  line-height: var(--line-height-relaxed);
  flex: 1;
}

/* --- Article / Blog Post --- */
.article {
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: var(--spacing-3xl) var(--spacing-lg);
}

.article__header {
  margin-bottom: var(--spacing-3xl);
}

.article__category {
  margin-bottom: var(--spacing-md);
}

.article__title {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--spacing-lg);
}

.article__meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  color: var(--color-text-body);
  font-size: var(--font-size-sm);
  flex-wrap: wrap;
}

.article__content {
  line-height: var(--line-height-relaxed);
}

.article__content h2 {
  margin-top: var(--spacing-3xl);
  margin-bottom: var(--spacing-lg);
  font-size: var(--font-size-2xl);
}

.article__content h3 {
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-xl);
}

.article__content p {
  margin-bottom: var(--spacing-lg);
}

.article__content ul,
.article__content ol {
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-xl);
}

.article__content ul { list-style: disc; }
.article__content ol { list-style: decimal; }

.article__content li {
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-relaxed);
}

.article__content blockquote {
  border-left: 4px solid var(--color-accent-blue);
  padding: var(--spacing-lg) var(--spacing-xl);
  margin: var(--spacing-xl) 0;
  background-color: var(--color-light-bg);
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  font-style: italic;
  color: var(--color-text-body);
}

.article__content strong {
  font-weight: 600;
  color: var(--color-text-dark);
}

/* --- Lesson Page --- */
.lesson-hero {
  background-color: var(--color-primary-bg);
  padding: var(--spacing-3xl) 0;
}

.lesson-hero__meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}

.lesson-hero__title {
  font-size: var(--font-size-4xl);
  color: var(--color-white);
  margin-bottom: var(--spacing-lg);
}

.lesson-hero__description {
  color: var(--color-light-grey);
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
  max-width: var(--max-width-content);
}

.lesson-content {
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: var(--spacing-3xl) var(--spacing-lg);
}

.lesson-content h2 {
  margin-top: var(--spacing-3xl);
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 2px solid var(--color-accent-blue);
}

.lesson-content h3 {
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
}

.lesson-content p {
  margin-bottom: var(--spacing-lg);
  line-height: var(--line-height-relaxed);
}

.lesson-content ul,
.lesson-content ol {
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-xl);
}

.lesson-content ul { list-style: disc; }
.lesson-content ol { list-style: decimal; }

.lesson-content li {
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-relaxed);
}

.lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--color-border);
  margin-top: var(--spacing-3xl);
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

/* --- Curriculum Banner --- */
.curriculum-banner {
  background: linear-gradient(135deg, var(--color-accent-blue), #6366f1);
  color: var(--color-white);
  text-align: center;
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: var(--font-size-sm);
  font-weight: 500;
}

/* --- Phase Cards (Lifecycle) --- */
.phase-card {
  background: var(--color-card-bg);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-2xl);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-accent-blue);
  margin-bottom: var(--spacing-xl);
}

.phase-card__title {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.phase-card__number {
  width: 36px;
  height: 36px;
  background: var(--color-accent-blue);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-sm);
  font-weight: 700;
  flex-shrink: 0;
}

.phase-card__description {
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-lg);
}

.phase-card__list {
  list-style: disc;
  padding-left: var(--spacing-xl);
}

.phase-card__list li {
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-relaxed);
}


/* --- Artifacts Table --- */
.artifacts-category {
  margin-bottom: var(--spacing-3xl);
}

.artifacts-category__title {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-md);
  border-bottom: 2px solid var(--color-accent-blue);
}

.artifact-item {
  padding: var(--spacing-lg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  margin-bottom: var(--spacing-md);
  transition: var(--transition);
}

.artifact-item:hover {
  border-color: var(--color-accent-blue);
  box-shadow: 0 2px 8px var(--color-shadow-hover);
}

.artifact-item__name {
  font-weight: 600;
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-dark);
}

.artifact-item__description {
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-relaxed);
}

.artifact-item__meta {
  font-size: var(--font-size-sm);
  color: var(--color-accent-blue);
  font-weight: 500;
}

/* --- Footer --- */
.footer {
  background-color: var(--color-primary-bg);
  color: var(--color-light-grey);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

.footer__brand {
  max-width: 300px;
}

.footer__brand-name {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: var(--spacing-md);
}

.footer__brand-tagline {
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
}

.footer__nav-title {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--spacing-md);
}

.footer__nav-list li {
  margin-bottom: var(--spacing-sm);
}

.footer__nav-list a {
  color: var(--color-light-grey);
  font-size: var(--font-size-sm);
  transition: var(--transition);
}

.footer__nav-list a:hover {
  color: var(--color-accent-blue);
}

.footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-xl);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  align-items: center;
  text-align: center;
  font-size: var(--font-size-sm);
}

.footer__tagline {
  color: var(--color-accent-amber);
  font-weight: 500;
}

/* --- Animations --- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in--visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Utility Classes --- */
.text-center { text-align: center; }
.text-left { text-align: left; }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }
.mt-2xl { margin-top: var(--spacing-2xl); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }
.mb-2xl { margin-bottom: var(--spacing-2xl); }
.mt-3xl { margin-top: var(--spacing-3xl); }
.mb-3xl { margin-bottom: var(--spacing-3xl); }

/* --- Key Takeaways Box --- */
.takeaways {
  background: linear-gradient(135deg, rgba(74, 108, 247, 0.05), rgba(99, 102, 241, 0.05));
  border: 1px solid rgba(74, 108, 247, 0.2);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-2xl);
  margin: var(--spacing-2xl) 0;
}

.takeaways__title {
  font-size: var(--font-size-xl);
  color: var(--color-accent-blue);
  margin-bottom: var(--spacing-lg);
}

.takeaways__list {
  list-style: none;
  padding: 0;
}

.takeaways__list li {
  padding: var(--spacing-sm) 0;
  padding-left: var(--spacing-xl);
  position: relative;
  line-height: var(--line-height-relaxed);
}

.takeaways__list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-accent-blue);
  font-weight: 700;
}

/* --- Scenario Box --- */
.scenario-box {
  background-color: var(--color-light-bg);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-2xl);
  margin: var(--spacing-2xl) 0;
  border: 1px solid var(--color-border);
}

.scenario-box__title {
  font-size: var(--font-size-xl);
  color: var(--color-accent-amber);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.scenario-box__title::before {
  content: '🏛️';
}

/* --- Page Header (for inner pages) --- */
.page-header {
  background-color: var(--color-primary-bg);
  padding: var(--spacing-3xl) 0;
  text-align: center;
}

.page-header__title {
  font-size: var(--font-size-4xl);
  color: var(--color-white);
  margin-bottom: var(--spacing-md);
}

.page-header__subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-light-grey);
  max-width: 600px;
  margin: 0 auto;
  line-height: var(--line-height-relaxed);
}

/* --- Coming Soon Badge --- */
.coming-soon {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(245, 158, 11, 0.1);
  color: var(--color-accent-amber);
  border-radius: 20px;
  font-size: var(--font-size-sm);
  font-weight: 500;
}

/* --- Info Box --- */
.info-box {
  background: var(--color-light-bg);
  border-left: 4px solid var(--color-accent-blue);
  padding: var(--spacing-lg) var(--spacing-xl);
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  margin: var(--spacing-xl) 0;
}

.info-box--amber {
  border-left-color: var(--color-accent-amber);
}


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

/* Tablet (768px+) */
@media (min-width: 768px) {
  .grid--2 { grid-template-columns: repeat(2, 1fr); }
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }

  .gallery-grid { grid-template-columns: repeat(2, 1fr); }

  .footer__grid { grid-template-columns: repeat(2, 1fr); }

  .hero__title { font-size: var(--font-size-5xl); }

  .nav__toggle { display: none; }
}

/* Desktop (1200px+) */
@media (min-width: 1200px) {
  .grid--3 { grid-template-columns: repeat(3, 1fr); }
  .grid--4 { grid-template-columns: repeat(4, 1fr); }

  .gallery-grid { grid-template-columns: repeat(3, 1fr); }

  .footer__grid { grid-template-columns: 2fr 1fr 1fr 1fr; }
}

/* Mobile (below 768px) */
@media (max-width: 767px) {
  :root {
    --font-size-5xl: 2.25rem;
    --font-size-4xl: 1.875rem;
    --font-size-3xl: 1.5rem;
    --spacing-4xl: 3rem;
  }

  .nav__toggle {
    display: block;
  }

  .nav__list {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-primary-bg);
    flex-direction: column;
    padding: var(--spacing-lg);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  }

  .nav--open .nav__list {
    display: flex;
  }

  .nav__link {
    padding: var(--spacing-md);
    width: 100%;
    display: block;
  }

  .hero__cta {
    flex-direction: column;
    align-items: center;
  }

  .lesson-card {
    flex-direction: column;
  }

  .lesson-nav {
    flex-direction: column;
    align-items: stretch;
    text-align: center;
  }

  .article__title {
    font-size: var(--font-size-3xl);
  }

  .footer__bottom {
    flex-direction: column;
  }
}

/* --- Skip Link (Accessibility) --- */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--spacing-md);
  background: var(--color-accent-blue);
  color: var(--color-white);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--border-radius);
  z-index: 9999;
  font-weight: 600;
  transition: top 0.3s;
}

.skip-link:focus {
  top: var(--spacing-md);
  color: var(--color-white);
}

/* --- Print Styles --- */
@media print {
  .header,
  .footer,
  .nav,
  .hero__cta,
  .lightbox {
    display: none;
  }

  body {
    color: #000;
    background: #fff;
  }

  .section--dark {
    background: #fff;
    color: #000;
  }

  .section--dark h2,
  .section--dark h3 {
    color: #000;
  }
}