html {
  font-size: 14px;
}

@media (min-width: 768px) {
  html { font-size: 16px; }
}

.btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
  box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem #258cfb;
}

html { position: relative; min-height: 100%; }
body { margin: 0; }

/* Layout structure */
.layout-wrapper {
  display: flex;
  min-height: calc(100vh - 140px); /* header + footer approx */
  position: relative;
}

.app-header {
  text-align: center;
  padding: 1rem 0 0.75rem;
  background: #ffffff;
  border-bottom: 1px solid #e5e5e5;
}
.app-title {
  margin: 0;
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: .5px;
}

.sidebar {
  width: 250px;
  background: #f8f9fa;
  border-right: 1px solid #e2e2e2;
  display: flex;
  flex-direction: column;
  transition: transform .25s ease-in-out;
  z-index: 1035;
}
.sidebar-scroll {
  overflow-y: auto;
  padding: .75rem .5rem 2rem;
  height: 100%;
}
.sidebar-nav > li + li {
  margin-top: .35rem;
}

.sidebar-link {
  display: block;
  padding: .4rem .2rem .4rem 0;
  text-decoration: none;
  color: #212529;
  font-size: .9375rem;
}
.sidebar-link:hover,
.sidebar-link:focus {
  color: #0d6efd;
}

.sidebar-dropdown-btn {
  background: #ffffff;
  border: 1px solid #dcdcdc;
  border-radius: .375rem;
  padding: .55rem .75rem;
  font-size: .9rem;
  font-weight: 600;
  position: relative;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.sidebar-dropdown-btn:focus {
  outline: 2px solid #258cfb;
  outline-offset: 2px;
}

.dropdown-caret {
  display: inline-block;
  width: .75rem;
  height: .75rem;
  border-right: 2px solid #555;
  border-bottom: 2px solid #555;
  transform: rotate(45deg);
  transition: transform .2s ease;
  margin-left: .5rem;
}
.sidebar-dropdown-btn[aria-expanded="true"] .dropdown-caret {
  transform: rotate(225deg);
}

.main-content {
  flex: 1;
  padding: 1.25rem 1.5rem 2.5rem;
  background: #ffffff;
  min-width: 0;
}

.app-footer {
  border-top: 1px solid #e5e5e5;
  padding: .75rem 1rem;
  background: #ffffff;
  font-size: .85rem;
}

/* Mobile / small screens */
.sidebar-toggle-btn {
  position: fixed;
  top: .6rem;
  left: .65rem;
  z-index: 1100;
  background: #ffffff;
  border: 1px solid #d0d0d0;
  border-radius: 50%;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 6px rgba(0,0,0,.12);
  cursor: pointer;
  transition: background .2s;
}
.sidebar-toggle-btn:hover {
  background: #f1f1f1;
}
.caret-icon {
  width: 10px;
  height: 10px;
  border-right: 3px solid #333;
  border-bottom: 3px solid #333;
  transform: rotate(45deg);
  transition: transform .25s ease;
}
.sidebar-open .caret-icon {
  transform: rotate(225deg);
}

@media (max-width: 767.98px) {
  .layout-wrapper {
    flex-direction: column;
    min-height: calc(100vh - 140px);
  }
  .sidebar {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    transform: translateX(-100%);
    box-shadow: 4px 0 14px -4px rgba(0,0,0,.18);
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .sidebar-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.4);
    opacity: 0;
    pointer-events: none;
    transition: opacity .25s;
  }
  .sidebar-overlay.visible {
    opacity: 1;
    pointer-events: auto;
  }
  body.sidebar-open {
    overflow: hidden;
  }
}

/* Medium+ keep sidebar fixed */
@media (min-width: 768px) {
  .sidebar-toggle-btn { display: none; }
  .sidebar-overlay { display: none; }
}

/* Optional scrollbar styling */
.sidebar-scroll::-webkit-scrollbar {
  width: 8px;
}
.sidebar-scroll::-webkit-scrollbar-track {
  background: transparent;
}
.sidebar-scroll::-webkit-scrollbar-thumb {
  background: #c8c8c8;
  border-radius: 4px;
}
.sidebar-scroll::-webkit-scrollbar-thumb:hover {
  background: #b0b0b0;
}

:root {
  --sb-width: 250px;
  --sb-mini-width: 68px;
  --sb-bg: #f8f9fa;
  --sb-border: #e2e2e2;
  --sb-accent: #0d6efd;
  --sb-accent-rgb: 13,110,253;
  --sb-link-color: #212529;
  --sb-link-hover: #0d6efd;
  --sb-link-active-bg: rgba(var(--sb-accent-rgb), .10);
  --sb-link-active-bar: var(--sb-accent);
  --sb-radius: .5rem;
  --transition-fast: .18s cubic-bezier(.4,0,.2,1);
  --transition-med: .28s cubic-bezier(.4,0,.2,1);
}

/* Dark mode opt-in (add .theme-dark to <body>) */
body.theme-dark {
  --sb-bg: #1e242b;
  --sb-border: #2d353d;
  --sb-link-color: #e5e8eb;
  --sb-link-hover: #62a8ff;
  --sb-link-active-bg: rgba(98,168,255,.15);
  --sb-link-active-bar: #62a8ff;
  background: #12171c;
  color: #e5e8eb;
}
body.theme-dark .app-header,
body.theme-dark .app-footer {
  background: #1c2228;
  border-color: #2d353d;
}

/* Sidebar base */
.sidebar {
  width: var(--sb-width);
  background: var(--sb-bg);
  border-right: 1px solid var(--sb-border);
  transition: width var(--transition-med), transform var(--transition-med), background var(--transition-fast);
  will-change: width, transform;
}

/* Mini (collapsed) variant (apply .sidebar-mini to body at md+) */
@media (min-width: 768px) {
  body.sidebar-mini .sidebar {
    width: var(--sb-mini-width);
  }
  body.sidebar-mini .sidebar .sidebar-dropdown-btn span.label,
  body.sidebar-mini .sidebar .sidebar-link span.label,
  body.sidebar-mini .sidebar .collapse.show {
    opacity: 0;
    pointer-events: none;
  }
  body.sidebar-mini .sidebar .collapse {
    display: none !important;
  }
  body.sidebar-mini .main-content {
    transition: margin-left var(--transition-med);
  }
}

/* Optional: shift content when fixed positioning used */
/* .main-content { margin-left: var(--sb-width); } */

/* Improve scroll area */
.sidebar-scroll {
  scrollbar-width: thin;
  scrollbar-color: #b8b8b8 transparent;
}
.sidebar-scroll::-webkit-scrollbar { width: 8px; }
.sidebar-scroll::-webkit-scrollbar-thumb {
  background: #c5c5c5;
  border-radius: 4px;
}
body.theme-dark .sidebar-scroll::-webkit-scrollbar-thumb {
  background: #394651;
}

/* Dropdown button refinement */
.sidebar-dropdown-btn {
  background: linear-gradient(#ffffff, #f3f4f5);
  border: 1px solid var(--sb-border);
  border-radius: var(--sb-radius);
  font-size: .8rem;
  letter-spacing: .5px;
  text-transform: uppercase;
  color: #555;
  position: relative;
  transition: background var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}
body.theme-dark .sidebar-dropdown-btn {
  background: linear-gradient(#262e36,#1e242b);
  color: #9aa6b2;
  border-color: #2d353d;
}
.sidebar-dropdown-btn:hover {
  background: #ffffff;
  color: #000;
}
body.theme-dark .sidebar-dropdown-btn:hover {
  background: #273039;
  color: #cfd7dd;
}

/* Caret animation */
.dropdown-caret {
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}
.sidebar-dropdown-btn[aria-expanded="true"] .dropdown-caret {
  transform: rotate(225deg) translateY(-1px);
}

/* Collapsing UL smooth reveal (height animation helper) */
.collapse {
  overflow: hidden;
  transition: height var(--transition-med);
}

/* Links */
.sidebar-link {
  position: relative;
  padding: .45rem .65rem .45rem .75rem;
  border-radius: .4rem;
  line-height: 1.3;
  font-size: .9rem;
  font-weight: 500;
  color: var(--sb-link-color);
  transition: background var(--transition-fast), color var(--transition-fast), padding var(--transition-fast);
  display: flex;
  align-items: center;
  gap: .5rem;
}
.sidebar-link:hover {
  color: var(--sb-link-hover);
  background: rgba(var(--sb-accent-rgb), .08);
}
body.theme-dark .sidebar-link:hover {
  background: rgba(255,255,255,.06);
}

/* Active state */
.sidebar-link.active {
  background: var(--sb-link-active-bg);
  color: var(--sb-accent);
  font-weight: 600;
}
.sidebar-link.active::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 4px;
  border-radius: 3px;
  background: var(--sb-link-active-bar);
}

/* Focus ring unified */
.sidebar-link:focus-visible,
.sidebar-dropdown-btn:focus-visible,
.sidebar-toggle-btn:focus-visible {
  outline: 2px solid var(--sb-accent);
  outline-offset: 2px;
}

/* Icon slot example (add <i class="icon icon-home"></i> etc.) */
.sidebar-link .icon {
  width: 1rem;
  height: 1rem;
  opacity: .7;
  flex-shrink: 0;
}
.sidebar-link.active .icon,
.sidebar-link:hover .icon {
  opacity: 1;
}

/* Transition for open state (mobile) */
.sidebar.open {
  box-shadow: 4px 0 18px -6px rgba(0,0,0,.28);
}

/* Toggle button theming */
.sidebar-toggle-btn {
  transition: background var(--transition-fast), border-color var(--transition-fast);
}
body.theme-dark .sidebar-toggle-btn {
  background: #1e242b;
  border-color: #2d353d;
  color: #e5e8eb;
}
body.theme-dark .sidebar-toggle-btn:hover {
  background: #273039;
}

/* Header & footer subtle elevation */
.app-header,
.app-footer {
  backdrop-filter: saturate(180%) blur(4px);
}

/* Utility: gradient accent (use on header or somewhere) */
.gradient-accent {
  background: linear-gradient(135deg, var(--sb-accent) 0%, #6f42c1 100%);
  color: #fff;
}

/* Responsive, colorful site title */
.app-title {
    margin: 0;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: .3px;
    font-size: clamp(1.25rem, 2.2vw + .5rem, 2.25rem);
    /* Fallback solid color */
    color: #0ea5e9;
    /* Gradient text */
    background: linear-gradient(90deg, #0ea5e9, #22c55e, #f59e0b, #ef4444);
    background-size: 200% 100%;
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 1px 0 rgba(255,255,255,.4);
}

@media (max-width: 575.98px) {
    .app-header {
        text-align: center;
    }
}

@media (prefers-reduced-motion: no-preference) {
    .app-title {
        animation: titleGradientShift 8s ease-in-out infinite alternate;
    }
}

@keyframes titleGradientShift {
    0% {
        background-position: 0% 50%;
    }

    100% {
        background-position: 100% 50%;
    }
}

/* === Contrast & darker text (global) === */
:root {
  --text-strong: #111111;
  --text-muted-strong: #495057;
  --link-strong: #0b5ed7;         /* darker than default bootstrap blue */
  --link-strong-hover: #084298;   /* darker hover */
  --focus-ring: #0b5ed7;
}

/* Base text color */
body {
  color: var(--text-strong);
}

/* Links: darker + visible underline */
a {
  color: var(--link-strong);
  text-decoration: underline;
  text-decoration-thickness: .08em;
  text-underline-offset: 3px;
}
a:hover,
a:focus {
  color: var(--link-strong-hover);
}

/* Sidebar links darker, with clearer hover */
.sidebar-link {
  color: var(--text-strong);
}
.sidebar-link:hover,
.sidebar-link:focus {
  color: var(--link-strong);
  background: rgba(var(--sb-accent-rgb, 13,110,253), .10);
  text-decoration: underline;
  text-decoration-thickness: .08em;
  text-underline-offset: 3px;
}

/* Sidebar section button text slightly darker */
.sidebar-dropdown-btn {
  color: #333;
}

/* Kendo TOC links darker */
#toc .k-link {
  color: var(--link-strong);
}
#toc .k-link:hover,
#toc .k-link:focus {
  color: var(--link-strong-hover);
  text-decoration: underline;
}

/* Stronger focus outline site-wide */
.sidebar-link:focus-visible,
.sidebar-dropdown-btn:focus-visible,
.sidebar-toggle-btn:focus-visible,
button:focus-visible,
a:focus-visible {
  outline-color: var(--focus-ring);
}

/* Muted text with better contrast */
.text-muted {
  color: var(--text-muted-strong) !important;
}

/* Header/Footer text color */
.app-header,
.app-footer {
  color: var(--text-strong);
}

/* Dark theme adjustments for readability */
body.theme-dark {
  --text-strong: #e6e9ed;
  --text-muted-strong: #b7c1c9;
  --link-strong: #8fc2ff;
  --link-strong-hover: #cde2ff;
}
body.theme-dark { color: var(--text-strong); }
body.theme-dark a { color: var(--link-strong); }
body.theme-dark a:hover,
body.theme-dark a:focus { color: var(--link-strong-hover); }
body.theme-dark .sidebar-link:hover { background: rgba(255,255,255,.08); }
body.theme-dark .app-header,
body.theme-dark .app-footer { color: var(--text-strong); }

/* High-contrast user preference: simplify animated gradient title */
@media (prefers-contrast: more) {
  .app-title {
    background: none !important;
    -webkit-text-fill-color: currentColor !important;
    color: var(--link-strong) !important;
    text-shadow: none !important;
  }
}

/* Optional opt-in mode: add 'contrast-high' on <body> for even stronger scheme */
body.contrast-high {
  --sb-link-color: var(--text-strong);
  --sb-link-hover: var(--link-strong);
  --sb-link-active-bar: var(--link-strong);
}

/* === Menu contrast overrides (sidebar) === */
:root {
  --menu-text: #111111;
  --menu-hover: #0b5ed7;
  --menu-hover-bg: rgba(13,110,253,.12);
  --menu-active-bg: rgba(13,110,253,.18);
  --menu-border: #c7cbd1;
}

/* Section buttons */
.sidebar-dropdown-btn {
  color: var(--menu-text);
  border-color: var(--menu-border);
  background: linear-gradient(#ffffff, #f2f4f6);
}
.sidebar-dropdown-btn:hover {
  color: #0f172a;
  border-color: #b7bdc6;
  background: #ffffff;
}
/* Caret visibility */
.dropdown-caret {
  border-right-color: #1f2937;
  border-bottom-color: #1f2937;
}

/* Links inside the menu */
.sidebar-link {
  color: var(--menu-text);
}
.sidebar-link:hover,
.sidebar-link:focus {
  color: var(--menu-hover);
  background: var(--menu-hover-bg);
  text-decoration: underline;
  text-decoration-thickness: .08em;
  text-underline-offset: 3px;
}
.sidebar-link.active {
  background: var(--menu-active-bg);
  color: var(--menu-hover);
}
.sidebar-link.active::before {
  background: var(--menu-hover);
}

/* Dark theme equivalents */
body.theme-dark {
  --menu-text: #e7ebef;
  --menu-hover: #b6d5ff;
  --menu-hover-bg: rgba(255,255,255,.08);
  --menu-active-bg: rgba(255,255,255,.14);
  --menu-border: #39424a;
}
body.theme-dark .sidebar-dropdown-btn {
  color: var(--menu-text);
  border-color: var(--menu-border);
}
body.theme-dark .dropdown-caret {
  border-right-color: #d9e2ec;
  border-bottom-color: #d9e2ec;
}
body.theme-dark .sidebar-link.active::before {
  background: var(--menu-hover);
}