/* ============================================
   TI84 CALCULATO - MAIN STYLESHEET
   ============================================ */

/* 1. GOOGLE FONTS IMPORT */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* 2. CSS VARIABLES */
:root {
  --color-primary:       #2563EB;
  --color-primary-dark:  #1D4ED8;
  --color-primary-light: #EFF6FF;
  --color-secondary:     #10B981;
  --color-dark:          #1E293B;
  --color-gray-700:      #374151;
  --color-gray-500:      #6B7280;
  --color-gray-200:      #E5E7EB;
  --color-gray-100:      #F3F4F6;
  --color-white:         #FFFFFF;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.10);
  --shadow-lg: 0 8px 40px rgba(37,99,235,0.15);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  --transition: all 0.2s ease;
}

/* 3. RESET */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }
input, textarea { font-family: inherit; }

/* 4. BASE */
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--color-gray-700);
  background: #fff;
  line-height: 1.75;
  font-size: 1rem;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 { color: var(--color-dark); line-height: 1.3; }
h1 { font-size: clamp(2rem, 5vw, 3rem); font-weight: 700; }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); font-weight: 600; }
h3 { font-size: 1.25rem; font-weight: 600; }
h4 { font-size: 1rem; font-weight: 600; }
small, .caption { font-size: 0.875rem; color: var(--color-gray-500); }

/* 5. LAYOUT UTILITIES */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-alt { background: var(--color-gray-100); }
.section-blue { background: var(--color-primary-light); }

/* 6. TYPOGRAPHY UTILITIES */
.section-eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  margin-bottom: 12px;
}
.section-title { margin-bottom: 12px; }
.section-subtitle {
  font-size: 1.05rem;
  color: var(--color-gray-500);
  max-width: 720px;
  margin: 0 auto 8px;
}
.text-center { text-align: center; }
.text-muted { color: var(--color-gray-500); }

/* 7. BUTTON STYLES */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 600;
  transition: var(--transition);
  border: 1px solid transparent;
  white-space: nowrap;
}
.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-secondary { background: #fff; color: var(--color-dark); border-color: var(--color-gray-200); }
.btn-secondary:hover { background: var(--color-gray-100); border-color: var(--color-gray-500); }
.btn-ghost { background: transparent; color: var(--color-primary); }
.btn-ghost:hover { background: var(--color-primary-light); }
.btn-sm { padding: 8px 16px; font-size: 0.85rem; }
.btn-lg { padding: 14px 28px; font-size: 1rem; }

/* 8. BADGE STYLES */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 500;
}
.badge-blue  { background: var(--color-primary-light); color: var(--color-primary); }
.badge-green { background: #D1FAE5; color: #047857; }
.badge-gray  { background: var(--color-gray-100); color: var(--color-gray-700); }

/* 9. CARD STYLES */
.card {
  background: #fff;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 24px;
  transition: var(--transition);
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.card-icon {
  width: 48px; height: 48px;
  border-radius: 50%;
  background: var(--color-primary-light);
  color: var(--color-primary);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 16px;
}

/* 10. HEADER */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-gray-200);
  height: 64px;
  transition: var(--transition);
}
.site-header.scrolled { box-shadow: var(--shadow-sm); }
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.nav-logo { display: flex; align-items: center; }
.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-link {
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-gray-700);
  transition: var(--transition);
}
.nav-link:hover { color: var(--color-primary); background: var(--color-primary-light); }
.nav-link.active { color: var(--color-primary); background: var(--color-primary-light); }
.nav-hamburger { display: none; flex-direction: column; gap: 5px; padding: 4px; }
.nav-hamburger span { width: 24px; height: 2px; background: var(--color-dark); border-radius: 2px; transition: var(--transition); }

/* 11. MOBILE MENU OVERLAY */
.mobile-menu {
  position: fixed; inset: 0; z-index: 200;
  background: white;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  display: flex; flex-direction: column;
  padding: 24px;
  overflow-y: auto;
}
.mobile-menu.open { transform: translateX(0); }
.mobile-menu-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 32px; }
.mobile-menu-close { font-size: 1.5rem; color: var(--color-dark); padding: 8px; }
.mobile-menu ul { display: flex; flex-direction: column; gap: 8px; }
.mobile-menu a {
  display: block;
  padding: 14px 16px;
  border-radius: var(--radius-md);
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--color-dark);
  border: 1px solid var(--color-gray-200);
}
.mobile-menu a:hover { background: var(--color-primary-light); color: var(--color-primary); border-color: var(--color-primary); }

/* 12. HERO SECTION */
.hero {
  background: linear-gradient(135deg, var(--color-primary-light) 0%, #fff 60%);
  padding: 64px 0 48px;
}
.hero-badges { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.hero h1 { margin-bottom: 16px; }
.hero-subtitle {
  font-size: 1.125rem;
  color: var(--color-gray-500);
  max-width: 600px;
  margin-bottom: 32px;
}
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--color-gray-200);
}
.hero-stat-num { font-size: 1.5rem; font-weight: 700; color: var(--color-primary); }
.hero-stat-label { font-size: 0.8rem; color: var(--color-gray-500); margin-top: 2px; }

/* 13. CALCULATOR SECTION */
.calc-section { padding: 0 0 60px; margin-top: -20px; }
.calc-wrapper {
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  border: 1px solid #BFDBFE;
  background: #fff;
}
.calc-toolbar {
  background: var(--color-dark);
  padding: 12px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.calc-toolbar-left { display: flex; align-items: center; gap: 10px; }
.calc-dots { display: flex; gap: 6px; }
.calc-dot { width: 12px; height: 12px; border-radius: 50%; }
.calc-dot.red    { background: #FF5F57; }
.calc-dot.yellow { background: #FEBC2E; }
.calc-dot.green  { background: #28C840; }
.calc-title-text { color: #94A3B8; font-size: 0.8rem; font-weight: 500; }
.calc-controls { display: flex; align-items: center; gap: 8px; }
.ctrl-btn {
  background: rgba(255,255,255,0.1);
  color: #CBD5E1;
  border: 1px solid rgba(255,255,255,0.15);
  padding: 5px 12px;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 500;
  transition: var(--transition);
}
.ctrl-btn:hover { background: rgba(255,255,255,0.2); color: white; }
.zoom-label { color: #94A3B8; font-size: 0.8rem; min-width: 36px; text-align: center; }
.calc-container { position: relative; width: 100%; min-height: 680px; background: #f8f9fa; }
.calc-container iframe { width: 100%; height: 680px; border: none; display: block; }
.calc-skeleton {
  position: absolute; inset: 0;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 16px;
  background: #f8fafc;
  transition: opacity 0.3s ease;
}
.calc-skeleton-icon {
  width: 64px; height: 64px;
  border-radius: 50%;
  background: #BFDBFE;
  display: flex; align-items: center; justify-content: center;
  font-size: 2rem;
}
.calc-skeleton-text { color: var(--color-gray-500); font-size: 0.9rem; }
.calc-skeleton-bar {
  width: 200px; height: 6px;
  border-radius: 3px;
  background: linear-gradient(90deg, #e2e8f0 25%, #cbd5e1 50%, #e2e8f0 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}
@keyframes shimmer {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
.calc-note {
  text-align: center;
  margin-top: 16px;
  font-size: 0.875rem;
  color: var(--color-gray-500);
}
.calc-fullscreen .calc-wrapper {
  position: fixed; inset: 0; z-index: 999;
  border-radius: 0; border: none;
}
.calc-fullscreen .calc-container iframe { height: calc(100vh - 52px); }

/* 14. FEATURES GRID */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 48px;
}
.feature-card .feature-icon { font-size: 2rem; margin-bottom: 16px; }
.feature-card h3 { margin-bottom: 8px; }
.feature-card p { font-size: 0.95rem; color: var(--color-gray-500); }

/* 15. HOW TO USE — STEPS */
.steps {
  display: flex; flex-direction: column; gap: 0;
  margin: 48px auto 0;
  max-width: 700px;
}
.step { display: flex; gap: 24px; position: relative; padding-bottom: 40px; }
.step:last-child { padding-bottom: 0; }
.step::before {
  content: '';
  position: absolute;
  left: 19px; top: 44px;
  width: 2px; height: calc(100% - 44px);
  background: var(--color-gray-200);
}
.step:last-child::before { display: none; }
.step-num {
  width: 40px; height: 40px; border-radius: 50%; flex-shrink: 0;
  background: var(--color-primary); color: white;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 1rem; z-index: 1;
}
.step-content h3 { margin-bottom: 8px; padding-top: 6px; }
.step-content p { color: var(--color-gray-500); font-size: 0.95rem; }

/* 16. FAQ ACCORDION */
.faq-list {
  max-width: 760px;
  margin: 48px auto 0;
  display: flex; flex-direction: column;
  gap: 12px;
}
.faq-item {
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.faq-question {
  width: 100%;
  display: flex; justify-content: space-between; align-items: center;
  padding: 20px 24px;
  font-size: 1rem; font-weight: 600;
  color: var(--color-dark);
  background: white;
  text-align: left;
  gap: 16px;
  transition: var(--transition);
}
.faq-question:hover { background: var(--color-primary-light); }
.faq-question[aria-expanded="true"] { background: var(--color-primary-light); color: var(--color-primary); }
.faq-icon {
  font-size: 1.25rem;
  font-weight: 300;
  flex-shrink: 0;
  transition: transform 0.2s ease;
  color: var(--color-primary);
}
.faq-question[aria-expanded="true"] .faq-icon { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; }
.faq-answer.open { max-height: 500px; }
.faq-answer-inner {
  padding: 0 24px 20px;
  color: var(--color-gray-500);
  font-size: 0.95rem;
  line-height: 1.75;
}

/* 17. RELATED CALCULATORS */
.related-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 40px;
}
.related-card {
  display: flex; flex-direction: column;
  align-items: center; text-align: center;
  padding: 24px 16px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  background: white;
  transition: var(--transition);
  gap: 10px;
}
.related-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.related-icon { font-size: 2rem; }
.related-card h3 { font-size: 0.95rem; color: var(--color-dark); }
.related-card p { font-size: 0.8rem; color: var(--color-gray-500); }

/* 18. CONTENT SECTION */
.content-section { padding: 60px 0; }
.content-grid { display: grid; grid-template-columns: 2fr 1fr; gap: 48px; }
.content-main h2 { margin-bottom: 16px; margin-top: 36px; }
.content-main h2:first-child { margin-top: 0; }
.content-main p { margin-bottom: 16px; color: var(--color-gray-500); }
.content-main ul {
  margin: 12px 0 16px 20px;
  list-style: disc;
  color: var(--color-gray-500);
}
.content-main ul li { margin-bottom: 6px; }
.content-main ol {
  margin: 12px 0 16px 20px;
  color: var(--color-gray-500);
}
.content-main ol li { margin-bottom: 8px; }
.content-sidebar { position: sticky; top: 84px; height: fit-content; }
.sidebar-card {
  background: var(--color-primary-light);
  border: 1px solid #BFDBFE;
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 20px;
}
.sidebar-card h4 { color: var(--color-primary); margin-bottom: 12px; }
.sidebar-card ul { display: flex; flex-direction: column; gap: 8px; list-style: none; margin: 0; }
.sidebar-card ul li a {
  font-size: 0.9rem;
  color: var(--color-primary);
  display: flex; align-items: center; gap: 6px;
}
.sidebar-card ul li a:hover { text-decoration: underline; }

/* 19. COMPARISON TABLE */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.comparison-table th {
  background: var(--color-dark);
  color: white;
  padding: 14px 20px;
  text-align: left;
  font-weight: 600;
}
.comparison-table td {
  padding: 14px 20px;
  border-bottom: 1px solid var(--color-gray-200);
  font-size: 0.95rem;
}
.comparison-table tr:last-child td { border-bottom: none; }
.comparison-table tr:nth-child(even) td { background: var(--color-gray-100); }
.comparison-table .check { color: var(--color-secondary); font-weight: 700; }
.comparison-table .cross { color: #EF4444; }

/* 20. BLOG CARDS */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
}
.blog-card {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-gray-200);
  background: white;
  transition: var(--transition);
}
.blog-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.blog-card-img {
  height: 160px;
  background: linear-gradient(135deg, var(--color-primary-light), #DBEAFE);
  display: flex; align-items: center; justify-content: center;
  font-size: 3rem;
}
.blog-card-body { padding: 20px; }
.blog-card-meta { font-size: 0.8rem; color: var(--color-gray-500); margin-bottom: 8px; }
.blog-card-title {
  font-size: 1rem; font-weight: 600;
  color: var(--color-dark);
  margin-bottom: 8px;
  line-height: 1.4;
}
.blog-card-excerpt {
  font-size: 0.875rem;
  color: var(--color-gray-500);
  margin-bottom: 16px;
}
.blog-card-link {
  font-size: 0.875rem;
  color: var(--color-primary);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.blog-card-link:hover { text-decoration: underline; }

/* 21. DOCS CARDS */
.docs-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 40px;
}
.doc-card {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px 24px;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  background: white;
  transition: var(--transition);
}
.doc-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
  transform: translateX(4px);
}
.doc-card-icon { font-size: 1.75rem; flex-shrink: 0; }
.doc-card-body { flex: 1; }
.doc-card-title { font-weight: 600; color: var(--color-dark); margin-bottom: 4px; }
.doc-card-desc { font-size: 0.85rem; color: var(--color-gray-500); margin-bottom: 6px; }
.doc-card-arrow { margin-left: auto; color: var(--color-primary); font-size: 1.25rem; flex-shrink: 0; }

/* 22. FOOTER */
.site-footer {
  background: var(--color-dark);
  color: #94A3B8;
  padding: 64px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
}
.footer-logo { margin-bottom: 16px; }
.footer-desc { font-size: 0.9rem; line-height: 1.7; margin-bottom: 20px; }
.footer-col h4 {
  color: white;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.footer-col ul { display: flex; flex-direction: column; gap: 10px; }
.footer-col ul li a {
  font-size: 0.875rem;
  color: #94A3B8;
  transition: var(--transition);
}
.footer-col ul li a:hover { color: white; }
.footer-bottom {
  margin-top: 48px;
  padding: 20px 0;
  border-top: 1px solid #334155;
  display: flex; justify-content: space-between; align-items: center;
  font-size: 0.8rem;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-bottom a { color: #94A3B8; }
.footer-bottom a:hover { color: white; }

/* 23. TOAST NOTIFICATION */
.toast-container {
  position: fixed; bottom: 24px; right: 24px; z-index: 9999;
  display: flex; flex-direction: column; gap: 8px;
}
.toast {
  padding: 12px 20px;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  color: white;
  box-shadow: var(--shadow-md);
  animation: slideInRight 0.3s ease;
}
.toast-success { background: var(--color-secondary); }
.toast-error   { background: #EF4444; }
@keyframes slideInRight {
  from { transform: translateX(100%); opacity: 0; }
  to   { transform: translateX(0);    opacity: 1; }
}

/* 24. BREADCRUMB */
.breadcrumb {
  padding: 12px 0;
  font-size: 0.875rem;
  color: var(--color-gray-500);
}
.breadcrumb a { color: var(--color-primary); }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb span { margin: 0 6px; }

/* 25. 404 PAGE */
.error-page {
  min-height: 60vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  flex-direction: column;
  gap: 24px;
}
.error-code {
  font-size: clamp(4rem, 15vw, 8rem);
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
}

/* 26. MOBILE RESPONSIVE */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .content-grid { grid-template-columns: 1fr; }
  .content-sidebar { position: static; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .section { padding: 56px 0; }
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }
  .features-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: repeat(2, 1fr); }
  .blog-grid { grid-template-columns: 1fr; }
  .docs-grid { grid-template-columns: 1fr; }
  .hero-stats { gap: 20px; flex-wrap: wrap; }
  .calc-controls { gap: 4px; }
  .ctrl-btn { padding: 4px 8px; font-size: 0.75rem; }
  .zoom-label { display: none; }
  .comparison-table th, .comparison-table td { padding: 10px 12px; font-size: 0.85rem; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .related-grid { grid-template-columns: 1fr 1fr; gap: 12px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .hero-actions { flex-direction: column; width: 100%; }
  .hero-actions .btn { width: 100%; justify-content: center; }
  .calc-toolbar { padding: 10px 12px; }
  .calc-title-text { display: none; }
}