@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

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

:root {
  /* Fonts */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-title: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  /* Theme Defaults (Dark Mode) */
  --bg-color: #060913;
  --bg-gradient: radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 45%),
                 radial-gradient(circle at 90% 80%, rgba(20, 184, 166, 0.08) 0%, transparent 45%);
  --card-bg: rgba(15, 23, 42, 0.45);
  --card-border: rgba(255, 255, 255, 0.06);
  --card-border-hover: rgba(99, 102, 241, 0.4);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-tertiary: #64748b;
  
  --accent: #6366f1;
  --accent-rgb: 99, 102, 241;
  --accent-secondary: #14b8a6;
  
  --shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 25px rgba(99, 102, 241, 0.15);
  --separator: rgba(255, 255, 255, 0.06);
  
  --highlight-bg: rgba(99, 102, 241, 0.25);
  --highlight-text: #a5b4fc;

  --ambient-glow-1: rgba(99, 102, 241, 0.15);
  --ambient-glow-2: rgba(20, 184, 166, 0.12);
}

/* Light Mode Variables Override */
[data-theme="light"] {
  --bg-color: #f8fafc;
  --bg-gradient: radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.06) 0%, transparent 45%),
                 radial-gradient(circle at 90% 80%, rgba(20, 184, 166, 0.06) 0%, transparent 45%);
  --card-bg: rgba(255, 255, 255, 0.7);
  --card-border: rgba(0, 0, 0, 0.06);
  --card-border-hover: rgba(79, 70, 229, 0.4);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;
  
  --accent: #4f46e5;
  --accent-rgb: 79, 70, 229;
  --accent-secondary: #0d9488;
  
  --shadow: 0 8px 32px 0 rgba(15, 23, 42, 0.05);
  --shadow-glow: 0 0 25px rgba(79, 70, 229, 0.08);
  --separator: rgba(0, 0, 0, 0.06);
  
  --highlight-bg: rgba(79, 70, 229, 0.15);
  --highlight-text: #4f46e5;

  --ambient-glow-1: rgba(99, 102, 241, 0.08);
  --ambient-glow-2: rgba(20, 184, 166, 0.06);
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 100px;
}

body {
  background-color: var(--bg-color);
  background-image: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Smooth Theme Transitions */
body,
header.app-header,
.hero-card,
.sidebar-card,
.glass-card,
.search-input,
.toc-item a,
.drawer-toc-item a,
.row,
.row-block,
.mobile-drawer,
footer.app-footer {
  transition: background-color 0.3s ease, 
              color 0.3s ease, 
              border-color 0.3s ease, 
              box-shadow 0.3s ease,
              opacity 0.3s ease;
}

/* General link styling inside cards */
.glass-card a,
.card-intro-text a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease;
}

.glass-card a:hover,
.card-intro-text a:hover {
  color: var(--accent-secondary);
  text-decoration: underline;
}

/* ─── AMBIENT GLOW BACKDROPS ─────────────────────────────────── */
body::before,
body::after {
  content: '';
  position: fixed;
  width: 40vw;
  height: 40vw;
  border-radius: 50%;
  filter: blur(100px);
  z-index: -1;
  pointer-events: none;
  opacity: 0.6;
}

body::before {
  top: -10%;
  left: -10%;
  background: radial-gradient(circle, var(--ambient-glow-1) 0%, transparent 70%);
  animation: drift-glow 15s ease-in-out infinite alternate;
}

body::after {
  bottom: -10%;
  right: -10%;
  background: radial-gradient(circle, var(--ambient-glow-2) 0%, transparent 70%);
  animation: drift-glow-reverse 20s ease-in-out infinite alternate;
}

@keyframes drift-glow {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(5%, 10%) scale(1.1); }
}

@keyframes drift-glow-reverse {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(-10%, -5%) scale(1.15); }
}

/* ─── HEADER / NAVIGATION ───────────────────────────────────── */
header.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  background: rgba(var(--accent-rgb), 0.02);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--card-border);
  padding: 16px 24px;
  /* iOS app-shell spacing: clears the status bar / notch, then adds 24px
     of extra clearance above the brand name + theme toggle. env() resolves
     to 0px on non-iOS/older browsers, so this is a no-op there and the
     24px alone still applies. */
  padding-top: calc(env(safe-area-inset-top, 0px) + 24px);
  transition: background 0.3s, border 0.3s;
}

header.app-header .header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header.app-header .brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

header.app-header .brand-logo {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-title);
  font-weight: 800;
  color: #ffffff;
  font-size: 18px;
  box-shadow: 0 4px 12px rgba(var(--accent-rgb), 0.3);
}

header.app-header .brand-logo-img {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 4px 12px rgba(var(--accent-rgb), 0.2);
}

header.app-header .brand-name {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 19px;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

header.app-header .header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* ─── ANIMATED THEME TOGGLE SWITCH ──────────────────────────── */
.theme-toggle-btn {
  position: relative;
  width: 72px;
  height: 36px;
  border-radius: 50px;
  border: none;
  cursor: pointer;
  outline: none;
  padding: 0;
  background: linear-gradient(135deg, #1e1b4b, #312e81);
  box-shadow: 0 0 0 1px rgba(99, 102, 241, 0.3),
              0 4px 16px rgba(0, 0, 0, 0.35),
              inset 0 1px 0 rgba(255,255,255,0.08);
  transition: background 0.4s ease, box-shadow 0.4s ease;
  overflow: hidden;
}

/* Stars in dark mode bg */
.theme-toggle-btn::before {
  content: '✦ ✦ ✦';
  position: absolute;
  left: 6px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 6px;
  letter-spacing: 2px;
  color: rgba(255, 255, 255, 0.5);
  transition: opacity 0.3s ease;
  pointer-events: none;
}

/* Sun rays in light mode bg */
.theme-toggle-btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #fbbf24, #f59e0b);
  border-radius: inherit;
  opacity: 0;
  transition: opacity 0.4s ease;
}

[data-theme="light"] .theme-toggle-btn {
  box-shadow: 0 0 0 1px rgba(251, 191, 36, 0.4),
              0 4px 16px rgba(245, 158, 11, 0.2),
              inset 0 1px 0 rgba(255,255,255,0.3);
}

[data-theme="light"] .theme-toggle-btn::after {
  opacity: 1;
}

[data-theme="light"] .theme-toggle-btn::before {
  opacity: 0;
}

/* The sliding knob */
.theme-toggle-knob {
  position: absolute;
  top: 4px;
  left: 4px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #ffffff;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  transition: transform 0.45s cubic-bezier(0.34, 1.56, 0.64, 1),
              box-shadow 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  line-height: 1;
}

[data-theme="light"] .theme-toggle-knob {
  transform: translateX(36px);
  box-shadow: 0 2px 8px rgba(245, 158, 11, 0.4);
}

/* ─── LAYOUT CONTAINER ───────────────────────────────────────── */
.main-layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

/* ─── HERO SECTION ──────────────────────────────────────────── */
.hero-card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 24px;
  padding: 48px 32px;
  text-align: center;
  margin-bottom: 40px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  animation: fade-in-up 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.hero-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), var(--accent-secondary));
}

.hero-card h1 {
  font-family: var(--font-title);
  font-weight: 800;
  font-size: 42px;
  letter-spacing: -1px;
  margin-bottom: 8px;
  background: linear-gradient(135deg, var(--text-primary) 30%, var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-card .app-subtitle {
  font-size: 16px;
  font-weight: 500;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 12px;
}

.hero-card .update-date {
  font-size: 13px;
  color: var(--text-tertiary);
  background: rgba(255, 255, 255, 0.04);
  padding: 4px 12px;
  border-radius: 20px;
  display: inline-block;
  border: 1px solid var(--card-border);
}

/* ─── DUAL GRID LAYOUT ──────────────────────────────────────── */
.grid-container {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 40px;
  align-items: start;
}

/* ─── SIDE NAVIGATION (TOC) ─────────────────────────────────── */
.sidebar {
  position: sticky;
  top: 90px;
  animation: fade-in-left 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.sidebar-card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: 24px;
  box-shadow: var(--shadow);
}

.sidebar h3 {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-tertiary);
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--separator);
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.toc-item a,
.drawer-toc-item a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  border-radius: 10px;
  transition: all 0.25s ease;
  position: relative;
  overflow: hidden;
}

.toc-item a::before,
.drawer-toc-item a::before {
  content: '';
  position: absolute;
  left: 0;
  width: 3px;
  height: 40%;
  background: var(--accent);
  border-radius: 0 4px 4px 0;
  opacity: 0;
  transform: scaleY(0.3);
  transition: all 0.25s ease;
}

.toc-item.active a,
.drawer-toc-item.active a {
  color: var(--text-primary);
  background: rgba(var(--accent-rgb), 0.08);
}

.toc-item.active a::before,
.drawer-toc-item.active a::before {
  opacity: 1;
  height: 60%;
  transform: scaleY(1);
}

.toc-item a:hover,
.drawer-toc-item a:hover {
  color: var(--text-primary);
  background: rgba(var(--accent-rgb), 0.05);
  padding-left: 18px;
}

/* ─── SEARCH CONTAINER ──────────────────────────────────────── */
.search-container {
  position: relative;
  margin-bottom: 30px;
  animation: fade-in-up 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.1s;
  animation-fill-mode: both;
}

.search-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input {
  width: 100%;
  padding: 16px 20px 16px 48px;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 15px;
  outline: none;
  transition: all 0.3s ease;
  box-shadow: var(--shadow);
  -webkit-appearance: none;
}

.search-input:focus {
  border-color: var(--accent);
  box-shadow: var(--shadow-glow), var(--shadow);
}

.search-icon {
  position: absolute;
  left: 18px;
  width: 20px;
  height: 20px;
  color: var(--text-tertiary);
  pointer-events: none;
  transition: color 0.3s;
  z-index: 2;
}

.search-input:focus + .search-icon {
  color: var(--accent);
}

.search-clear {
  position: absolute;
  right: 18px;
  background: none;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.search-clear.visible {
  opacity: 1;
  visibility: visible;
}

.search-clear:hover {
  color: var(--accent);
}

/* ─── CONTENT COLUMN ────────────────────────────────────────── */
.content-area {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

/* ─── GLASS CARDS (SECTIONS) ────────────────────────────────── */
.group {
  opacity: 0;
  animation: fade-in-up 0.8s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.group-label {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--accent);
  margin-bottom: 12px;
  padding-left: 4px;
}

.glass-card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
  position: relative;
}

/* Dynamic glow effect setup */
.glass-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  border-radius: inherit;
  background: radial-gradient(600px circle at var(--mouse-x, 0) var(--mouse-y, 0), rgba(var(--accent-rgb), 0.06), transparent 40%);
  pointer-events: none;
  z-index: 1;
  opacity: 0;
  transition: opacity 0.5s ease;
}

.glass-card:hover::after {
  opacity: 1;
}

.glass-card:hover {
  border-color: var(--card-border-hover);
}

.card-intro-text {
  padding: 24px;
  font-size: 16px;
  color: var(--text-primary);
  line-height: 1.7;
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 24px;
  border-bottom: 1px solid var(--separator);
  min-height: 56px;
}

.row:last-child {
  border-bottom: none;
}

.row-label {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
}

.row-value {
  font-size: 15px;
  color: var(--text-secondary);
  text-align: right;
}

.row-value a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.row-value a:hover {
  color: var(--accent-secondary);
  text-decoration: underline;
}

/* Full block of description text inside cards */
.row-block {
  padding: 22px 24px;
  border-bottom: 1px solid var(--separator);
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.row-block:last-child {
  border-bottom: none;
}

.row-block strong {
  color: var(--text-primary);
  font-weight: 600;
  display: block;
  margin-bottom: 4px;
  font-size: 16px;
}

.row-block a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.row-block a:hover {
  color: var(--accent-secondary);
  text-decoration: underline;
}

.group-note {
  font-size: 13px;
  color: var(--text-tertiary);
  margin-top: 10px;
  padding: 0 4px;
  line-height: 1.5;
}

.group-note a {
  color: var(--accent);
  text-decoration: none;
}

.group-note a:hover {
  text-decoration: underline;
}

/* Search Highlights */
mark {
  background: var(--highlight-bg);
  color: var(--highlight-text);
  border-radius: 4px;
  padding: 0 3px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

/* ─── FOOTER ────────────────────────────────────────────────── */
footer.app-footer {
  margin-top: 60px;
  padding: 48px 24px;
  border-top: 1px solid var(--separator);
  text-align: center;
  position: relative;
  background: rgba(var(--accent-rgb), 0.01);
}

footer.app-footer p {
  font-size: 14px;
  color: var(--text-tertiary);
  margin-bottom: 12px;
}

footer.app-footer .footer-links {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

footer.app-footer a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}

footer.app-footer a:hover {
  color: var(--accent);
}

/* ─── SEARCH EMPTY STATE ─────────────────────────────────────── */
.search-empty {
  display: none;
  text-align: center;
  padding: 60px 24px;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  animation: fade-in 0.4s ease;
}

.search-empty.visible {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.search-empty-icon {
  font-size: 40px;
  color: var(--text-tertiary);
}

.search-empty h4 {
  font-family: var(--font-title);
  font-size: 18px;
  color: var(--text-primary);
  font-weight: 700;
}

.search-empty p {
  color: var(--text-tertiary);
  font-size: 14px;
  max-width: 320px;
}

/* ─── MOBILE STICKY FLOATING ACTION BUTTON ─────────────────── */
.mobile-nav-fab {
  display: none;
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 90;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  box-shadow: 0 8px 24px rgba(var(--accent-rgb), 0.35);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: white;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.mobile-nav-fab:hover {
  transform: scale(1.1);
}

/* ─── MOBILE DRAWER MENU ────────────────────────────────────── */
.mobile-drawer-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: 199;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

.mobile-drawer-overlay.open {
  opacity: 1;
  visibility: visible;
}

.mobile-drawer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--bg-color);
  border-top: 1px solid var(--card-border);
  border-radius: 24px 24px 0 0;
  z-index: 200;
  padding: 24px 24px 40px;
  transform: translateY(100%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: 0 -8px 32px rgba(0, 0, 0, 0.25);
  max-height: 75vh;
  overflow-y: auto;
}

.mobile-drawer.open {
  transform: translateY(0);
}

.mobile-drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--separator);
}

.mobile-drawer-title {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 16px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-primary);
}

.mobile-drawer-close {
  background: none;
  border: none;
  color: var(--text-tertiary);
  font-size: 20px;
  cursor: pointer;
}

/* ─── KEYFRAME ANIMATIONS ───────────────────────────────────── */
@keyframes fade-in-up {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fade-in-left {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Stagger card load animations using CSS transition delays in JS */

/* ─── RESPONSIVE STYLES ─────────────────────────────────────── */
@media (max-width: 992px) {
  .grid-container {
    grid-template-columns: 1fr;
    gap: 30px;
  }
  
  .sidebar {
    display: none; /* Collapses into mobile drawer FAB */
  }

  .mobile-nav-fab {
    display: flex;
  }
  
  .hero-card {
    padding: 36px 20px;
  }
  
  .hero-card h1 {
    font-size: 32px;
  }
}

@media (max-width: 600px) {
  header.app-header {
    padding: 12px 16px;
    padding-top: calc(env(safe-area-inset-top, 0px) + 24px);
  }
  
  .main-layout {
    padding: 20px 16px 60px;
  }
  
  .hero-card {
    border-radius: 16px;
    padding: 28px 16px;
  }
  
  .hero-card h1 {
    font-size: 26px;
  }
  
  .row {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    padding: 14px 16px;
  }
  
  .row-value {
    text-align: left;
  }
  
  .row-block {
    padding: 16px 16px;
  }
  
  .card-intro-text {
    padding: 16px 16px;
  }
  
  .glass-card {
    border-radius: 14px;
  }
}