/* ==========================================================================
   Calculent.com - Professional Finance-First Global Design System
   ========================================================================== */

:root {
  /* Theme Variables (Light Mode by Default) */
  --bg-primary: #f8fafc;
  --bg-card: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --success: #10b981;
  --success-bg: #ecfdf5;
  --error: #ef4444;
  --error-bg: #fef2f2;
  --border: #e2e8f0;
  --accent: #4f46e5;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.08), 0 2px 4px -2px rgb(0 0 0 / 0.08);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.08), 0 4px 6px -4px rgb(0 0 0 / 0.08);
  --radius: 12px;
  --radius-lg: 16px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-title: 'Outfit', var(--font-sans);
}

/* Native Dark Theme overrides */
body.dark {
  --bg-primary: #090d16;
  --bg-card: #131b2e;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --primary: #3b82f6;
  --primary-hover: #60a5fa;
  --success: #34d399;
  --success-bg: #064e3b;
  --error: #f87171;
  --error-bg: #7f1d1d;
  --border: #1e293b;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.5);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.4);
}

/* CSS Reset for Core Web Vitals (prevents layout shifting) */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

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

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

input, button, select, textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

input::placeholder, select::placeholder, textarea::placeholder {
  color: var(--text-secondary);
  opacity: 0.6;
}

/* ==========================================================================
   Header and Navigation Layout
   ========================================================================== */
header {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: background-color 0.3s ease, border-color 0.3s ease;
  padding-top: env(safe-area-inset-top, 0px);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: nowrap !important;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-title);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  flex-shrink: 0 !important;
  transition: opacity 0.3s cubic-bezier(0.16, 1, 0.3, 1), transform 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.brand-dot {
  color: var(--primary);
  font-size: 1.75rem;
  line-height: 1;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
}

.nav-link:hover, .nav-link.active {
  color: var(--primary);
}

.action-buttons {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-shrink: 0 !important;
}

/* Theme Toggle Button Style */
.theme-toggle-btn {
  background: none;
  border: 1px solid var(--border);
  width: 40px;
  height: 40px;
  border-radius: var(--radius);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  color: var(--text-secondary);
}

.theme-toggle-btn:hover {
  background-color: var(--bg-primary);
  color: var(--primary);
  border-color: var(--primary);
}

.theme-toggle-btn svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Hide inactive theme icon */
body.dark .theme-toggle-btn .sun-icon { display: block; }
body.dark .theme-toggle-btn .moon-icon { display: none; }
body:not(.dark) .theme-toggle-btn .sun-icon { display: none; }
body:not(.dark) .theme-toggle-btn .moon-icon { display: block; }

/* ==========================================================================
   Hero and Layout Grids
   ========================================================================== */
.hero {
  text-align: center;
  padding: 4rem 1.5rem 3rem;
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-family: var(--font-title);
  font-size: 2.75rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.hero p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* Global Search Input Box */
.search-container {
  max-width: 600px;
  margin: 2rem auto 0;
  position: relative;
}

.search-box {
  width: 100%;
  padding: 1rem 1.25rem 1rem 3rem;
  font-size: 1.05rem;
  border: 1px solid var(--border);
  background-color: var(--bg-card);
  border-radius: var(--radius-lg);
  outline: none;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.search-box:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.search-icon {
  position: absolute;
  left: 1.125rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
  width: 20px;
  height: 20px;
}

/* ==========================================================================
   Category & Tool Grid Systems
   ========================================================================== */
.content-wrapper {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
  flex: 1;
  width: 100%;
}

.category-section {
  margin-bottom: 3.5rem;
}

.category-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  border-bottom: 2px solid var(--border);
  padding-bottom: 0.5rem;
}

.category-title {
  font-family: var(--font-title);
  font-size: 1.5rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.category-count {
  font-size: 0.85rem;
  background-color: var(--border);
  color: var(--text-secondary);
  padding: 0.15rem 0.5rem;
  border-radius: 20px;
  font-weight: 600;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
}

.tool-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

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

.tool-card h3 {
  font-family: var(--font-title);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.tool-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  flex: 1;
}

.tool-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
}

.tool-tag {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--primary);
  letter-spacing: 0.05em;
}

.tool-go-arrow {
  color: var(--text-secondary);
  font-weight: bold;
  font-size: 1.1rem;
  transition: var(--transition);
}

.tool-card:hover .tool-go-arrow {
  color: var(--primary);
  transform: translateX(3px);
}

/* ==========================================================================
   AdSense Placement Layouts
   ========================================================================== */
.adsense-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  background-color: var(--bg-primary);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  margin: 1.5rem auto;
  overflow: hidden;
  box-sizing: border-box;
  width: 100%;
}

#home-ads-hero {
  height: 90px;
}

@media (max-width: 768px) {
  #home-ads-hero {
    height: 100px;
  }
}

.ads-label {
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
  display: block;
}

/* ==========================================================================
   Footer Layout
   ========================================================================== */
footer {
  background-color: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 3rem 1.5rem 2rem;
  margin-top: auto;
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr repeat(4, 1fr);
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-brand p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  max-width: 280px;
}

.footer-col h4 {
  font-family: var(--font-title);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: var(--primary);
  padding-left: 2px;
}

.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.footer-bottom p {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin: 0;
}

/* E-E-A-T Zero Server Footprint Pill */
.trust-pill {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
}

/* Creator link subtle, calm premium styling */
.creator-link {
  color: var(--text-primary);
  font-weight: 500;
  position: relative;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  transition: var(--transition);
}

.creator-link::after {
  content: '';
  position: absolute;
  width: 100%;
  transform: scaleX(0);
  height: 1.5px;
  bottom: -1px;
  left: 0;
  background-color: var(--primary);
  transform-origin: bottom right;
  transition: transform 0.25s ease-out;
}

.creator-link:hover {
  color: var(--primary);
}

.creator-link:hover::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}

.creator-link:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 4px;
  border-radius: 4px;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 768px) {
  .footer-container {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  .hero {
    padding: 2.5rem 1rem 1.5rem;
  }
  .hero h1 {
    font-size: 2rem;
  }
  .nav-menu {
    display: none; /* Can expand to slide-out later if needed */
  }
  .footer-bottom {
    flex-direction: column;
    text-align: center;
    padding-top: 1.25rem;
    gap: 0.85rem;
  }
  .footer-bottom p {
    justify-content: center;
    line-height: 1.6;
  }
}

/* Accessibility Skip Link (WCAG 2.2 AA Compliance) */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1.5rem;
  background-color: var(--primary);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 var(--radius) var(--radius);
  z-index: 9999;
  font-weight: 600;
  transition: top 0.2s ease;
}

.skip-link:focus-visible {
  top: 0;
  outline: none;
  box-shadow: var(--shadow-lg);
}

/* ==========================================================================
   Print Stylesheet Override (Calculent.com High-Trust Print Engine)
   ========================================================================== */
@media print {
  header, footer, .theme-toggle-btn, .btn-row, .btn-submit, .action-buttons, .adsense-placeholder, .category-section, .hero, .search-container, .related-section, #currency-toggle, #tenure-unit-toggle, #btn-show-full-amort, .calculator-card, .results-header, .results-actions, .btn-add, .action-cell, .delete-btn, .delete-item-btn, .edit-indicator, .currency-disclaimer {
    display: none !important;
  }
  body {
    background-color: #ffffff !important;
    color: #000000 !important;
    font-size: 11pt !important;
  }
  .content-wrapper, .calculator-container {
    max-width: 100% !important;
    margin: 0 !important;
    padding: 0 !important;
    box-shadow: none !important;
    border: none !important;
    display: block !important;
  }
  .results-card, .invoice-preview-card {
    box-shadow: none !important;
    border: none !important;
    background: #ffffff !important;
    color: #000000 !important;
    padding: 0 !important;
    margin: 0 !important;
    page-break-inside: avoid;
  }
  .table-scroll-container {
    overflow: visible !important;
    width: 100% !important;
  }
  table.item-table {
    min-width: 100% !important;
    width: 100% !important;
    border-collapse: collapse !important;
    page-break-inside: auto;
  }
  table.item-table tr {
    page-break-inside: avoid !important;
    page-break-after: auto !important;
  }
  table.item-table th, table.item-table td {
    padding: 0.5rem 0.25rem !important;
    font-size: 8.5pt !important;
    border-bottom: 1px solid #cbd5e1 !important;
  }
  .item-table th {
    background-color: #f8fafc !important;
    color: #475569 !important;
    -webkit-print-color-adjust: exact !important;
    print-color-adjust: exact !important;
  }
  input, select, textarea {
    border: none !important;
    background: transparent !important;
    color: #000000 !important;
    padding: 0 !important;
    min-height: auto !important;
    box-shadow: none !important;
    pointer-events: none !important;
  }
}

/* ==========================================================================
   Calculent PWA System Styles (Install Button & SW Update Toast Alerts)
   ========================================================================== */
.install-pwa-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background-color: var(--primary);
  color: white;
  border: none;
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  margin-right: 0.5rem;
}

.install-pwa-btn:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  color: white;
}

.install-pwa-btn svg {
  width: 14px;
  height: 14px;
  stroke: currentColor;
}

@media (max-width: 480px) {
  .install-pwa-btn span {
    display: none;
  }
  .install-pwa-btn {
    padding: 0.55rem;
    margin-right: 0.25rem;
  }
}

/* Glassmorphic Background Update Toast Notification */
#sw-update-toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: rgba(19, 27, 46, 0.88);
  backdrop-filter: blur(12px) saturate(185%);
  -webkit-backdrop-filter: blur(12px) saturate(185%);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  box-shadow: 0 10px 30px -5px rgba(0, 0, 0, 0.3), 0 0 1px 1px rgba(255, 255, 255, 0.05);
  z-index: 9999;
  opacity: 0;
  transform: translateY(20px) scale(0.95);
  transition: opacity 0.3s cubic-bezier(0.16, 1, 0.3, 1), transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  max-width: 380px;
  width: calc(100% - 48px);
}

body:not(.dark) #sw-update-toast {
  background: rgba(255, 255, 255, 0.88);
  border-color: rgba(0, 0, 0, 0.06);
  box-shadow: 0 10px 30px -5px rgba(0, 0, 0, 0.1), 0 0 1px 1px rgba(0, 0, 0, 0.02);
}

#sw-update-toast.visible {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.toast-content {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.toast-icon {
  font-size: 1.5rem;
  animation: bounce-slow 2s infinite;
}

.toast-text h4 {
  font-family: var(--font-title);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.15rem;
}

.toast-text p {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 0;
  white-space: nowrap;
}

.toast-btn {
  background-color: var(--primary);
  color: white;
  border: none;
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  flex-shrink: 0;
}

.toast-btn:hover {
  background-color: var(--primary-hover);
  transform: scale(1.02);
  color: white;
}

@keyframes bounce-slow {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}

@media (max-width: 500px) {
  #sw-update-toast {
    bottom: 16px;
    left: 16px;
    right: 16px;
    width: calc(100% - 32px);
    padding: 0.85rem 1rem;
    gap: 1rem;
  }
  .toast-text p {
    white-space: normal;
  }
}

/* Glassmorphic Cookie Consent Banner */
#cookie-consent-banner {
  position: fixed;
  bottom: -150px;
  left: 24px;
  right: 24px;
  background: rgba(19, 27, 46, 0.92);
  backdrop-filter: blur(12px) saturate(185%);
  -webkit-backdrop-filter: blur(12px) saturate(185%);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  box-shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.5), 0 0 1px 1px rgba(255, 255, 255, 0.05);
  z-index: 9998;
  transition: bottom 0.4s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.4s ease;
  max-width: 1152px;
  margin: 0 auto;
  opacity: 0;
}

body:not(.dark) #cookie-consent-banner {
  background: rgba(255, 255, 255, 0.92);
  border-color: rgba(0, 0, 0, 0.06);
  box-shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.15), 0 0 1px 1px rgba(0, 0, 0, 0.02);
}

#cookie-consent-banner.visible {
  bottom: 24px;
  opacity: 1;
}

.cookie-content {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  flex: 1;
  text-align: left;
}

.cookie-icon {
  font-size: 1.75rem;
  line-height: 1;
  flex-shrink: 0;
  animation: bounce-slow 3s infinite;
}

.cookie-content p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 0;
}

.cookie-policy-link {
  color: var(--primary);
  font-weight: 600;
  text-decoration: underline;
}

.cookie-policy-link:hover {
  color: var(--primary-hover);
}

.cookie-actions {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.cookie-btn {
  background-color: var(--primary);
  color: white;
  border: none;
  padding: 0.6rem 1.5rem;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  white-space: nowrap;
}

.cookie-btn:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  color: white;
}

@media (max-width: 768px) {
  #cookie-consent-banner {
    flex-direction: column;
    align-items: stretch;
    gap: 1.25rem;
    padding: 1.25rem;
    left: 16px;
    right: 16px;
  }
  #cookie-consent-banner.visible {
    bottom: 16px;
  }
  .cookie-actions {
    justify-content: flex-end;
  }
  .cookie-btn {
    width: 100%;
    text-align: center;
  }
}

/* Global Brand Header Logo Styles */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  flex-shrink: 0; /* Prevents brand logo and name from shrinking/collapsing on mobile viewports */
}
.brand-logo {
  width: 28px;
  height: 28px;
  display: block; /* Safe block display for images inside flex layouts */
  object-fit: contain;
  flex-shrink: 0;
  border-radius: 6px;
  transition: var(--transition);
}
.brand:hover .brand-logo {
  transform: scale(1.05);
}

/* ==========================================================================
   Interactive Mobile Navigation Hamburger Toggle Button
   ========================================================================== */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  width: 40px;
  height: 40px;
  border-radius: var(--radius);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: var(--transition);
}

.mobile-menu-toggle:hover {
  background-color: var(--bg-primary);
  color: var(--primary);
  border-color: var(--primary);
}

.mobile-menu-toggle svg {
  width: 20px;
  height: 20px;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.mobile-menu-toggle line {
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  transform-origin: center;
}

/* Hamburger to X morphing animation */
.mobile-menu-toggle.open svg {
  transform: rotate(90deg);
}

.mobile-menu-toggle.open .line-mid {
  opacity: 0;
}

.mobile-menu-toggle.open .line-top {
  transform: translateY(6px) rotate(45deg);
}

.mobile-menu-toggle.open .line-bottom {
  transform: translateY(-6px) rotate(-45deg);
}

@media (max-width: 768px) {
  .mobile-menu-toggle {
    display: flex;
  }
}

/* ==========================================================================
   Premium Glassmorphic Mobile Slide-Out Navigation Drawer
   ========================================================================== */
#mobile-drawer {
  position: fixed;
  top: 0;
  right: -300px; /* Hidden off-screen by default */
  width: 280px;
  height: 100vh;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-left: 1px solid rgba(0, 0, 0, 0.08);
  z-index: 999;
  display: flex;
  flex-direction: column;
  padding: calc(5.5rem + env(safe-area-inset-top, 0px)) 1.5rem 2rem; /* space top for header */
  box-shadow: -10px 0 30px -10px rgba(0, 0, 0, 0.08);
  transition: right 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

body.dark #mobile-drawer {
  background: rgba(19, 27, 46, 0.9);
  border-left-color: rgba(255, 255, 255, 0.08);
  box-shadow: -10px 0 30px -10px rgba(0, 0, 0, 0.35);
}

#mobile-drawer.open {
  right: 0; /* Slide in */
}

/* Drawer overlay backdrop */
#mobile-drawer-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.15);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 998;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

body.dark #mobile-drawer-overlay {
  background: rgba(0, 0, 0, 0.35);
}

#mobile-drawer-overlay.visible {
  opacity: 1;
  pointer-events: auto;
}

/* Prevent body scroll and optimize header display when menu open */
body.drawer-open {
  overflow: hidden;
}

body.drawer-open header {
  background-color: transparent !important;
  border-bottom-color: transparent !important;
  box-shadow: none !important;
}

body.drawer-open .brand,
body.drawer-open .theme-toggle-btn {
  opacity: 0.15 !important;
  pointer-events: none !important;
  transition: opacity 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

body.drawer-open .mobile-menu-toggle {
  opacity: 1 !important;
}

/* Drawer links structure */
.mobile-drawer-links {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1rem;
}

.mobile-drawer-link {
  font-family: var(--font-title);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-secondary);
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: var(--transition);
  background-color: transparent;
  text-decoration: none;
}

.mobile-drawer-link:hover, 
.mobile-drawer-link.active {
  color: var(--primary);
  background-color: var(--bg-primary);
  padding-left: 1.25rem;
}

.mobile-drawer-link svg {
  width: 18px;
  height: 18px;
  color: var(--primary);
  opacity: 0;
  transform: translateX(-5px);
  transition: var(--transition);
}

.mobile-drawer-link:hover svg, 
.mobile-drawer-link.active svg {
  opacity: 1;
  transform: translateX(0);
}

/* ==========================================================================
   Edge-to-Edge Padding & Fluid Spacing Overrides (Pin-to-Pin Layout)
   ========================================================================== */
@media (max-width: 640px) {
  .nav-container {
    padding: 0.75rem 1rem;
  }
  .content-wrapper {
    padding: 0 1rem 3rem;
  }
}

@media (max-width: 576px) {
  .brand {
    font-size: 1.3rem; /* dynamic scale down on tight devices to prevent header wrap */
  }
  .brand-logo {
    width: 24px;
    height: 24px;
  }
  .action-buttons {
    gap: 0.5rem; /* reduce gap to keep elements inline */
  }
}

@media (max-width: 360px) {
  .nav-container {
    padding: 0.6rem 0.75rem;
  }
  .brand {
    font-size: 1.15rem;
    gap: 0.35rem;
  }
  .brand-logo {
    width: 20px;
    height: 20px;
  }
  .action-buttons {
    gap: 0.35rem;
  }
  .theme-toggle-btn, .mobile-menu-toggle {
    width: 36px;
    height: 36px;
  }
}