:root {
  /* Core Design System - Premium Light with Gradients */
  --bg-main: linear-gradient(135deg, #f8fafc 0%, #eef2ff 45%, #e0f2fe 100%);
  --bg-sidebar: rgba(255, 255, 255, 0.78);
  --bg-card: rgba(255, 255, 255, 0.82);
  --text-main: #0b1220;
  --text-muted: #5b6b84;
  --accent: #4f46e5;
  --accent-secondary: #0891b2;
  --accent-glow: rgba(79, 70, 229, 0.14);
  --border: rgba(148, 163, 184, 0.35);
  --ring: rgba(79, 70, 229, 0.25);
  --sidebar-width: 280px;
  --toc-width: 230px;
  --header-height: 80px;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);
}

[data-theme='dark'] {
  --bg-main: linear-gradient(135deg, #020617 0%, #0b1220 45%, #111827 100%);
  --bg-sidebar: rgba(15, 23, 42, 0.72);
  --bg-card: rgba(30, 41, 59, 0.72);
  --text-main: #f8fafc;
  --text-muted: #9aa9c2;
  --accent: #818cf8;
  --accent-secondary: #22d3ee;
  --accent-glow: rgba(129, 140, 248, 0.14);
  --border: rgba(148, 163, 184, 0.22);
  --ring: rgba(129, 140, 248, 0.22);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, sans-serif;
  background: var(--bg-main);
  background-attachment: fixed;
  color: var(--text-main);
  line-height: 1.5;
  overflow-x: hidden;
  transition: all 0.3s ease;
  position: relative;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-kerning: normal;
}

body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at 18% 40%, rgba(79, 70, 229, 0.06) 0%, transparent 52%),
              radial-gradient(circle at 84% 78%, rgba(8, 145, 178, 0.06) 0%, transparent 52%);
  animation: bgFloat 18s ease-in-out infinite;
  pointer-events: none;
  z-index: 0;
}

@keyframes bgFloat {
  0%, 100% {
    transform: translate3d(0, 0, 0);
    opacity: 1;
  }
  50% {
    transform: translate3d(0, -8px, 0);
    opacity: 0.95;
  }
}

.app-container {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr var(--toc-width);
  grid-template-areas: "left main right";
  min-height: 100vh;
  width: 100%;
}

/* Sidebar Styling */
.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  padding: 2rem 1.5rem;
  padding-bottom: calc(2rem + env(safe-area-inset-bottom));
  overflow: hidden;
  display: flex;
  flex-direction: column;
  z-index: 50;
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  box-shadow: 0 10px 40px rgba(2, 6, 23, 0.06);
}

.sidebar:focus-within {
  box-shadow: 0 10px 40px rgba(2, 6, 23, 0.08), 0 0 0 3px var(--ring);
}

.left-sidebar {
  grid-area: left;
}

.left-sidebar nav {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-y: contain;
  scroll-behavior: smooth;
}

.right-sidebar {
  grid-area: right;
  border-left: 1px solid var(--border);
  border-right: none;
  padding: 1rem 0.75rem;
  font-size: 12px;
  line-height: 1.35;
  overflow: hidden !important;
  display: flex;
  flex-direction: column;
}

.right-sidebar .right-sidebar-scroll {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-y: contain;
}

.sidebar::-webkit-scrollbar {
  width: 10px;
}

.sidebar::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
  background: rgba(148, 163, 184, 0.35);
  border-radius: 999px;
  border: 3px solid transparent;
  background-clip: padding-box;
}

[data-theme='dark'] .sidebar::-webkit-scrollbar-thumb {
  background: rgba(148, 163, 184, 0.22);
  border: 3px solid transparent;
  background-clip: padding-box;
}

.sidebar:hover::-webkit-scrollbar-thumb {
  background: rgba(79, 70, 229, 0.32);
  border: 3px solid transparent;
  background-clip: padding-box;
}

.custom-scrollbar {
  scrollbar-width: thin;
  scrollbar-color: rgba(79, 70, 229, 0.35) transparent;
}

.custom-scrollbar::-webkit-scrollbar {
  width: 10px;
}

.custom-scrollbar::-webkit-scrollbar-track {
  background: transparent;
}

.custom-scrollbar::-webkit-scrollbar-thumb {
  background: rgba(79, 70, 229, 0.28);
  border-radius: 999px;
  border: 3px solid transparent;
  background-clip: padding-box;
}

/* Main Content Layout */
.main-content {
  grid-area: main;
  padding: 2rem clamp(1rem, 4vw, 4rem);
  max-width: 100%;
  width: 100%;
  position: relative;
  min-width: 0;
}

.main-content::before {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(900px 500px at 35% 8%, rgba(79, 70, 229, 0.06), transparent 60%),
    radial-gradient(900px 500px at 65% 70%, rgba(8, 145, 178, 0.05), transparent 60%);
  z-index: 0;
}

.main-content > * {
  position: relative;
  z-index: 1;
}

/* Desktop Large (1281px+) - All 3 columns */
@media (min-width: 1281px) {
  .app-container {
    grid-template-columns: var(--sidebar-width) 1fr var(--toc-width);
    grid-template-areas: "left main right";
  }
}

/* iPad landscape and larger tablets (1025px - 1280px) - Narrower sidebars */
@media (min-width: 1025px) and (max-width: 1280px) {
  .app-container {
    grid-template-columns: 220px 1fr 180px;
    grid-template-areas: "left main right";
  }

  .main-content {
    padding: 2rem 2rem;
  }
}

/* iPad Portrait and Tablet (769px - 1024px) - Hide right sidebar */
@media (min-width: 769px) and (max-width: 1024px) {
  .app-container {
    grid-template-columns: 220px 1fr;
    grid-template-areas: "left main";
  }

  .right-sidebar {
    display: none;
  }

  .main-content {
    padding: 2rem 2rem;
  }
}

/* Mobile and iPad (768px and below) - Stack vertically */
@media (max-width: 768px) {
  .app-container {
    display: flex;
    flex-direction: column;
    grid-template-columns: none;
    grid-template-areas: none;
  }

  .left-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: 85%;
    max-width: 320px;
    height: 100vh;
    height: 100dvh;
    padding-bottom: calc(3rem + env(safe-area-inset-bottom));
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    z-index: 100;
    display: flex;
    flex-direction: column;
    overflow: hidden;
  }

  .left-sidebar.translate-x-0 {
    transform: translateX(0);
  }

  .right-sidebar {
    display: none;
  }

  .main-content {
    width: 100%;
    padding: 1rem;
    min-height: 100vh;
  }

  .article-card {
    padding: 1.25rem;
    border-radius: 1rem;
  }
}

/* Small Mobile and iPhone (640px and below) */
@media (max-width: 640px) {
  .main-content {
    padding: 0.75rem;
  }

  body {
    font-size: 15px;
  }

  .article-card {
    padding: 1rem;
    font-size: 14px;
  }

  .left-sidebar {
    width: 100%;
    max-width: 100%;
  }
}

/* Premium Typography */
h1,
h2,
h3,
h4,
.heading-font {
  font-family: 'Outfit', sans-serif;
  letter-spacing: -0.02em;
}

/* Components */
.nav-link {
  display: block;
  padding: 0.75rem 1rem;
  border-radius: 0.75rem;
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  border: 1px solid transparent;
}

.nav-link:hover {
  background: var(--bg-main);
  color: var(--accent);
  transform: translateX(4px);
}

.nav-link.active {
  background: var(--accent-glow);
  color: var(--accent);
  border-color: rgba(79, 70, 229, 0.1);
  box-shadow: var(--shadow-sm);
}

.nav-link.active:hover {
  transform: translateX(2px);
  box-shadow: var(--shadow), 0 0 0 3px var(--ring);
}

.article-card {
  background: var(--bg-card);
  border-radius: 1.5rem;
  padding: 2.5rem;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
  animation: fadeIn 0.5s ease-out forwards;
  text-align: justify;
  line-height: 1.75;
  font-size: 16px;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  letter-spacing: 0.01em;
  word-break: normal;
  overflow-wrap: anywhere;
  -webkit-hyphens: auto;
  -ms-hyphens: auto;
  hyphens: auto;
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent);
}

.article-card:focus-within {
  box-shadow: var(--shadow-lg), 0 0 0 3px var(--ring);
  border-color: rgba(79, 70, 229, 0.5);
}

/* Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-6px); }
}

.animate-fade-in {
  animation: fadeIn 0.4s ease forwards;
}

.animate-slide-up {
  animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.animate-float {
  animation: float 3s ease-in-out infinite;
}

.animate-shimmer {
  background-size: 200% 100%;
  animation: shimmer 3s linear infinite;
}

.search-input:focus {
  outline: none;
  background: var(--bg-sidebar);
  box-shadow: 0 0 0 3px var(--ring);
  border-color: rgba(79, 70, 229, 0.35);
}

/* Glassmorphism */
.glass-header {
  background: rgba(var(--bg-main-rgb, 248, 250, 252), 0.8) !important;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  max-width: 100%;
  overflow: hidden;
}

[data-theme='dark'] .glass-header {
  background: rgba(2, 6, 23, 0.8) !important;
}

/* Mobile header adjustments */
@media (max-width: 768px) {
  .glass-header {
    width: 100%;
    max-width: 100%;
    margin-left: 0;
    margin-right: 0;
    border-radius: 1rem;
  }
}

/* Scroll to Top Button */
.scroll-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 3.5rem;
  height: 3.5rem;
  background: var(--accent);
  color: white;
  border-radius: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  border: none;
}

.scroll-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-to-top:hover {
  transform: translateY(-5px);
  background: var(--accent-glow);
  color: var(--accent);
  border: 1px solid var(--accent);
}

.legal-content {
  text-align: justify;
  -webkit-hyphens: auto;
  hyphens: auto;
  overflow-wrap: anywhere;
  word-break: break-word;
}

.legal-content * {
  max-width: 100%;
  overflow-wrap: anywhere;
  word-break: break-word;
}

/* iOS and Mobile Optimizations */
@supports (-webkit-touch-callout: none) {
  body {
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
  }

  .sidebar {
    -webkit-overflow-scrolling: touch;
    overflow: hidden;
    overscroll-behavior-y: contain;
  }

  .main-content {
    -webkit-overflow-scrolling: touch;
  }
}

/* Enhanced mobile sidebar scrolling */
@media (max-width: 768px) {
  .left-sidebar {
    overflow: hidden;
    display: flex;
    flex-direction: column;
    touch-action: manipulation;
    will-change: transform;
  }
  
  .left-sidebar nav {
    -webkit-overflow-scrolling: touch;
    overscroll-behavior-y: contain;
    padding-bottom: calc(2rem + env(safe-area-inset-bottom, 1rem));
  }
  
  .left-sidebar > div:last-child {
    margin-bottom: env(safe-area-inset-bottom, 1rem);
  }
}

/* Safe area for iOS notch */
@supports (padding: max(0px)) {
  .sidebar {
    padding-left: max(1rem, env(safe-area-inset-left));
    padding-right: max(1rem, env(safe-area-inset-right));
  }

  .main-content {
    padding-left: max(1rem, env(safe-area-inset-left));
    padding-right: max(1rem, env(safe-area-inset-right));
  }
}

/* Touch-friendly buttons on mobile */
@media (max-width: 768px) {
  button, a {
    min-height: 44px;
    min-width: 44px;
    -webkit-tap-highlight-color: rgba(79, 70, 229, 0.1);
    touch-action: manipulation;
  }

  .nav-link {
    padding: 1rem;
    font-size: 14px;
    -webkit-tap-highlight-color: rgba(79, 70, 229, 0.15);
    user-select: none;
    -webkit-user-select: none;
  }
  
  .nav-link:active {
    transform: scale(0.98);
    transition: transform 0.1s ease;
  }
}