/* Back to Basics Cat Litter - Vanilla CSS */
/* Simple, honest, natural aesthetic */

/* ================================
   CSS Custom Properties (Variables)
   ================================ */
:root {
  /* Colors - Earthy, Natural Palette */
  --color-earth: #5D4E37;
  --color-earth-light: #7A6B52;
  --color-earth-dark: #3D3225;

  --color-sage: #7D8471;
  --color-sage-light: #9BA38F;
  --color-sage-dark: #5E6454;

  --color-cream: #F5F2EB;
  --color-parchment: #EDE8DC;
  --color-white: #FDFCFA;

  --color-text: #2D2A26;
  --color-text-secondary: #5A5651;
  --color-text-muted: #8A8580;

  /* Typography */
  --font-heading: Georgia, 'Times New Roman', serif;
  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.5rem;
  --text-5xl: 3rem;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Layout */
  --max-width: 1100px;
  --border-radius: 4px;

  /* Transitions */
  --transition: 200ms ease;
}

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

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

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-cream);
  min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 400;
  line-height: 1.3;
  color: var(--color-earth-dark);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }

@media (min-width: 768px) {
  h1 { font-size: var(--text-5xl); }
  h2 { font-size: var(--text-4xl); }
}

p {
  margin-bottom: var(--space-4);
  color: var(--color-text-secondary);
}

a {
  color: var(--color-earth);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-sage-dark);
}

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

ul, ol {
  list-style: none;
}

/* ================================
   Utility Classes
   ================================ */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section {
  padding: var(--space-16) 0;
}

@media (min-width: 768px) {
  .section {
    padding: var(--space-20) 0;
  }
}

.text-center { text-align: center; }
.text-muted { color: var(--color-text-muted); }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* ================================
   Buttons
   ================================ */
.btn {
  display: inline-block;
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 500;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all var(--transition);
}

.btn-primary {
  background-color: var(--color-earth);
  color: var(--color-cream);
  border-color: var(--color-earth);
}

.btn-primary:hover {
  background-color: var(--color-earth-dark);
  border-color: var(--color-earth-dark);
  color: var(--color-cream);
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-earth);
  border-color: var(--color-earth);
}

.btn-secondary:hover {
  background-color: var(--color-earth);
  color: var(--color-cream);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-lg);
}

/* ================================
   Header
   ================================ */
.header {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-parchment);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.header__logo {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  color: var(--color-earth-dark);
  text-decoration: none;
}

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

.header__nav {
  display: none;
}

@media (min-width: 768px) {
  .header__nav {
    display: flex;
    gap: var(--space-8);
  }
}

.header__nav a {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-2) 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
}

.header__nav a:hover,
.header__nav a.active {
  color: var(--color-earth);
  border-bottom-color: var(--color-sage);
}

.header__cta {
  display: none;
}

@media (min-width: 768px) {
  .header__cta {
    display: inline-block;
  }
}

.header__toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
}

@media (min-width: 768px) {
  .header__toggle {
    display: none;
  }
}

.header__toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-earth);
  transition: all var(--transition);
}

/* Mobile Nav */
.mobile-nav {
  display: none;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-parchment);
  padding: var(--space-6);
}

.mobile-nav.is-open {
  display: block;
}

@media (min-width: 768px) {
  .mobile-nav {
    display: none !important;
  }
}

.mobile-nav a {
  display: block;
  padding: var(--space-3) 0;
  color: var(--color-text-secondary);
  text-decoration: none;
  border-bottom: 1px solid var(--color-parchment);
}

.mobile-nav a:hover {
  color: var(--color-earth);
}

/* ================================
   Footer
   ================================ */
.footer {
  background-color: var(--color-earth-dark);
  color: var(--color-cream);
  padding: var(--space-16) 0 var(--space-8);
}

.footer__grid {
  display: grid;
  gap: var(--space-10);
  margin-bottom: var(--space-12);
}

@media (min-width: 768px) {
  .footer__grid {
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
  }
}

.footer__brand p {
  color: rgba(245, 242, 235, 0.7);
  font-size: var(--text-sm);
  margin-top: var(--space-4);
}

.footer__heading {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-sage-light);
  margin-bottom: var(--space-4);
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer__links a {
  font-size: var(--text-sm);
  color: rgba(245, 242, 235, 0.8);
  text-decoration: none;
  transition: color var(--transition);
}

.footer__links a:hover {
  color: var(--color-cream);
}

.footer__bottom {
  padding-top: var(--space-8);
  border-top: 1px solid rgba(245, 242, 235, 0.1);
  text-align: center;
}

.footer__bottom p {
  font-size: var(--text-sm);
  color: rgba(245, 242, 235, 0.5);
  margin: 0;
}

/* ================================
   Hero Section
   ================================ */
.hero {
  background-color: var(--color-parchment);
  padding: var(--space-16) 0 var(--space-20);
}

@media (min-width: 768px) {
  .hero {
    padding: var(--space-20) 0 var(--space-24);
  }
}

.hero__content {
  max-width: 700px;
}

.hero__badge {
  display: inline-block;
  font-size: var(--text-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-sage-dark);
  margin-bottom: var(--space-4);
}

.hero__title {
  margin-bottom: var(--space-6);
}

.hero__subtitle {
  font-size: var(--text-lg);
  margin-bottom: var(--space-8);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

/* ================================
   Features Section
   ================================ */
.features__grid {
  display: grid;
  gap: var(--space-8);
}

@media (min-width: 768px) {
  .features__grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-card {
  background-color: var(--color-white);
  padding: var(--space-8);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-parchment);
}

.feature-card__icon {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

.feature-card h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-3);
}

.feature-card p {
  font-size: var(--text-sm);
  margin: 0;
}

/* ================================
   Section Headers
   ================================ */
.section-header {
  max-width: 600px;
  margin: 0 auto var(--space-12);
  text-align: center;
}

.section-header h2 {
  margin-bottom: var(--space-4);
}

.section-header p {
  font-size: var(--text-lg);
}

/* ================================
   Comparison Section
   ================================ */
.comparison {
  background-color: var(--color-white);
}

.comparison__grid {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 768px) {
  .comparison__grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.comparison-card {
  background-color: var(--color-cream);
  border-radius: var(--border-radius);
  overflow: hidden;
}

.comparison-card--highlight {
  border: 2px solid var(--color-sage);
}

.comparison-card__header {
  padding: var(--space-4);
  text-align: center;
  font-weight: 600;
  font-size: var(--text-sm);
}

.comparison-card:not(.comparison-card--highlight) .comparison-card__header {
  background-color: var(--color-text-muted);
  color: var(--color-white);
}

.comparison-card--highlight .comparison-card__header {
  background-color: var(--color-sage);
  color: var(--color-white);
}

.comparison-card__body {
  padding: var(--space-6);
}

.comparison-card__body li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-2);
  padding: var(--space-2) 0;
  font-size: var(--text-sm);
}

.comparison-card__body li::before {
  flex-shrink: 0;
  font-size: var(--text-base);
}

.comparison-card:not(.comparison-card--highlight) li::before {
  content: "×";
  color: var(--color-text-muted);
}

.comparison-card--highlight li::before {
  content: "✓";
  color: var(--color-sage-dark);
}

/* ================================
   CTA Section
   ================================ */
.cta-section {
  background-color: var(--color-earth);
  color: var(--color-cream);
  padding: var(--space-16) 0;
  text-align: center;
}

.cta-section h2 {
  color: var(--color-cream);
  margin-bottom: var(--space-4);
}

.cta-section p {
  color: rgba(245, 242, 235, 0.8);
  font-size: var(--text-lg);
  max-width: 600px;
  margin: 0 auto var(--space-8);
}

.cta-section .btn-primary {
  background-color: var(--color-cream);
  color: var(--color-earth-dark);
  border-color: var(--color-cream);
}

.cta-section .btn-primary:hover {
  background-color: var(--color-white);
  border-color: var(--color-white);
}

.cta-section .btn-secondary {
  color: var(--color-cream);
  border-color: var(--color-cream);
}

.cta-section .btn-secondary:hover {
  background-color: var(--color-cream);
  color: var(--color-earth-dark);
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  justify-content: center;
}

/* ================================
   Content Sections
   ================================ */
.content-grid {
  display: grid;
  gap: var(--space-12);
}

@media (min-width: 768px) {
  .content-grid {
    grid-template-columns: 2fr 1fr;
    gap: var(--space-16);
  }
}

.content-main h2 {
  margin-bottom: var(--space-6);
}

.content-main h3 {
  font-size: var(--text-xl);
  margin-top: var(--space-10);
  margin-bottom: var(--space-4);
  color: var(--color-sage-dark);
}

.content-main h3:first-of-type {
  margin-top: 0;
}

.content-main p {
  font-size: var(--text-lg);
}

.content-sidebar {
  position: sticky;
  top: 90px;
  height: fit-content;
}

.sidebar-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-parchment);
  border-radius: var(--border-radius);
  padding: var(--space-6);
}

.sidebar-card h4 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-4);
}

.sidebar-card ul li {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  font-size: var(--text-sm);
  border-bottom: 1px solid var(--color-parchment);
}

.sidebar-card ul li:last-child {
  border-bottom: none;
}

/* ================================
   Page Hero
   ================================ */
.page-hero {
  background-color: var(--color-parchment);
  padding: var(--space-12) 0 var(--space-16);
  text-align: center;
}

.page-hero__badge {
  display: inline-block;
  font-size: var(--text-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-sage-dark);
  margin-bottom: var(--space-4);
}

.page-hero h1 {
  margin-bottom: var(--space-4);
}

.page-hero p {
  font-size: var(--text-lg);
  max-width: 600px;
  margin: 0 auto;
}

/* ================================
   Benefits Grid
   ================================ */
.benefits-grid {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 640px) {
  .benefits-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .benefits-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.benefit-card {
  background-color: var(--color-white);
  padding: var(--space-6);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-parchment);
  text-align: center;
}

.benefit-card__icon {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-3);
}

.benefit-card h3 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-2);
}

.benefit-card p {
  font-size: var(--text-sm);
  margin: 0;
}

/* ================================
   Options Grid
   ================================ */
.options-grid {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 640px) {
  .options-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.option-card {
  background-color: var(--color-white);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-parchment);
  overflow: hidden;
}

.option-card--featured {
  border-color: var(--color-sage);
  border-width: 2px;
}

.option-card__header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--color-parchment);
}

.option-card__icon {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-3);
}

.option-card h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-2);
}

.option-card__intro {
  font-size: var(--text-sm);
  margin: 0;
}

.option-card__body {
  padding: var(--space-6);
}

.option-card__list {
  font-size: var(--text-sm);
}

.option-card__list li {
  padding: var(--space-2) 0;
  padding-left: var(--space-5);
  position: relative;
}

.option-card__list li::before {
  content: "•";
  position: absolute;
  left: 0;
  color: var(--color-sage);
}

.option-card__best {
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-parchment);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-sage-dark);
}

/* ================================
   Guide Steps
   ================================ */
.guide-section {
  padding: var(--space-12) 0;
  border-bottom: 1px solid var(--color-parchment);
}

.guide-section:last-of-type {
  border-bottom: none;
}

.guide-section__header {
  display: flex;
  align-items: baseline;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.guide-section__number {
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  color: var(--color-sage-light);
  line-height: 1;
}

.guide-section h2 {
  margin: 0;
}

.guide-content {
  max-width: 800px;
}

.guide-content p {
  font-size: var(--text-lg);
}

/* Lists with checks */
.check-list li,
.cross-list li {
  position: relative;
  padding-left: var(--space-6);
  margin-bottom: var(--space-3);
}

.check-list li::before,
.cross-list li::before {
  position: absolute;
  left: 0;
}

.check-list li::before {
  content: "✓";
  color: var(--color-sage-dark);
}

.cross-list li::before {
  content: "×";
  color: var(--color-text-muted);
}

/* ================================
   Ingredients Grid
   ================================ */
.ingredients-grid {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 768px) {
  .ingredients-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.ingredient-card {
  background-color: var(--color-white);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-parchment);
  padding: var(--space-6);
}

.ingredient-card--featured {
  background-color: var(--color-earth-dark);
  color: var(--color-cream);
  border: none;
}

@media (min-width: 768px) {
  .ingredient-card--featured {
    grid-column: span 2;
  }
}

.ingredient-card--featured h3 {
  color: var(--color-sage-light);
}

.ingredient-card--featured h4 {
  color: var(--color-sage-light);
}

.ingredient-card--featured p {
  color: rgba(245, 242, 235, 0.8);
}

.ingredient-card__icon {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

.ingredient-card h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-2);
}

.ingredient-card h4 {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: var(--space-5);
  margin-bottom: var(--space-2);
}

.ingredient-card p {
  font-size: var(--text-sm);
}

.ingredient-card ul {
  font-size: var(--text-sm);
}

.ingredient-card ul li {
  padding-left: var(--space-5);
  position: relative;
  margin-bottom: var(--space-2);
}

.ingredient-card ul li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-sage);
}

.ingredient-card--featured ul li::before {
  color: var(--color-sage-light);
}