/* ============================================================
   ULTRA PREMIUM ANIMATION SYSTEM
   Inspired by Linear, Vercel, Stripe, Apple design language
   ============================================================ */

/* ─── 1. KEYFRAME LIBRARY ─────────────────────────────────── */

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(28px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeDown {
  from { opacity: 0; transform: translateY(-20px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.92); }
  to   { opacity: 1; transform: scale(1); }
}

@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-24px); }
  to   { opacity: 1; transform: translateX(0); }
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(24px); }
  to   { opacity: 1; transform: translateX(0); }
}

/* Shimmer sweep — runs on glass cards */
@keyframes shimmer {
  0%   { background-position: -200% center; }
  100% { background-position: 200% center; }
}

/* Aurora orb float */
@keyframes auroraFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33%       { transform: translate(60px, -40px) scale(1.08); }
  66%       { transform: translate(-40px, 30px) scale(0.94); }
}

@keyframes auroraFloat2 {
  0%, 100% { transform: translate(0, 0) scale(1); }
  40%       { transform: translate(-70px, 50px) scale(1.12); }
  70%       { transform: translate(50px, -30px) scale(0.92); }
}

/* Pulse glow ring */
@keyframes pulseGlow {
  0%, 100% { box-shadow: 0 0 0 0 rgba(108, 92, 231, 0.4); }
  50%       { box-shadow: 0 0 0 12px rgba(108, 92, 231, 0); }
}

/* Spinning gradient border */
@keyframes rotateBorder {
  from { --border-angle: 0turn; }
  to   { --border-angle: 1turn; }
}

/* Count-up number tick */
@keyframes numberTick {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Badge pop */
@keyframes badgePop {
  0%   { transform: scale(0.7); opacity: 0; }
  70%  { transform: scale(1.12); opacity: 1; }
  100% { transform: scale(1); }
}

/* Loading skeleton pulse */
@keyframes skeletonPulse {
  0%, 100% { opacity: 0.5; }
  50%       { opacity: 1; }
}

/* Chevron bounce hint on first load */
@keyframes chevronBounce {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(4px); }
}

/* Magnetic button hover wiggle */
@keyframes buttonWiggle {
  0%   { transform: rotate(0deg); }
  25%  { transform: rotate(-1.5deg); }
  75%  { transform: rotate(1.5deg); }
  100% { transform: rotate(0deg); }
}

/* Gradient text animation */
@keyframes gradientShift {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* ─── 2. AURORA BACKGROUND ────────────────────────────────── */

.aurora-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}

.aurora-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.12;
  will-change: transform;
}

.theme-dark .aurora-orb { opacity: 0.10; }
.theme-light .aurora-orb { opacity: 0.08; }

.aurora-orb-1 {
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, hsl(245, 85%, 65%) 0%, transparent 70%);
  top: -100px;
  left: -100px;
  animation: auroraFloat 18s ease-in-out infinite;
}

.aurora-orb-2 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, hsl(160, 90%, 45%) 0%, transparent 70%);
  bottom: -80px;
  right: -80px;
  animation: auroraFloat2 22s ease-in-out infinite;
}

.aurora-orb-3 {
  width: 350px;
  height: 350px;
  background: radial-gradient(circle, hsl(280, 80%, 60%) 0%, transparent 70%);
  top: 40%;
  right: 20%;
  animation: auroraFloat 28s ease-in-out infinite reverse;
}

/* ─── 3. SCROLL-DRIVEN ENTRY REVEALS ─────────────────────── */

/*
  Elements with .reveal-on-scroll start invisible.
  IntersectionObserver in animations.js adds .is-visible.
  Scroll-driven animation used where supported as progressive enhancement.
*/

.reveal-on-scroll {
  opacity: 0;
  transform: translateY(32px);
  transition:
    opacity 0.65s cubic-bezier(0.16, 1, 0.3, 1),
    transform 0.65s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal-on-scroll.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger delays for sibling elements */
.reveal-on-scroll:nth-child(1)  { transition-delay: 0ms; }
.reveal-on-scroll:nth-child(2)  { transition-delay: 60ms; }
.reveal-on-scroll:nth-child(3)  { transition-delay: 120ms; }
.reveal-on-scroll:nth-child(4)  { transition-delay: 180ms; }
.reveal-on-scroll:nth-child(5)  { transition-delay: 240ms; }
.reveal-on-scroll:nth-child(6)  { transition-delay: 300ms; }
.reveal-on-scroll:nth-child(7)  { transition-delay: 360ms; }
.reveal-on-scroll:nth-child(8)  { transition-delay: 420ms; }

/* Scale variant */
.reveal-scale {
  opacity: 0;
  transform: scale(0.94);
  transition:
    opacity 0.55s cubic-bezier(0.16, 1, 0.3, 1),
    transform 0.55s cubic-bezier(0.16, 1, 0.3, 1);
}
.reveal-scale.is-visible {
  opacity: 1;
  transform: scale(1);
}

/* ─── 4. NATIVE SCROLL-DRIVEN (progressive enhancement) ──── */

@supports ((animation-timeline: view()) and (animation-range: entry)) {
  .scroll-reveal-native {
    animation: fadeUp linear both;
    animation-timeline: view();
    animation-range: entry 0% entry 35%;
  }
}

/* ─── 5. PAGE / VIEW TRANSITIONS ─────────────────────────── */

/* Wrap content sections in .view-transition-wrap for morphing */
.page-view {
  animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1) both;
}

/* View Transitions API (Same-document) */
::view-transition-old(root) {
  animation: 280ms cubic-bezier(0.4, 0, 1, 1) both fadeOut;
}
::view-transition-new(root) {
  animation: 380ms cubic-bezier(0.16, 1, 0.3, 1) both fadeIn;
}

@keyframes fadeOut {
  to { opacity: 0; transform: scale(0.98); }
}

/* ─── 6. CARD HOVER — PREMIUM LIFT EFFECT ────────────────── */

.concept-accordion-card,
.unified-section-wrapper,
.stat-card,
.personalised-card,
.niche-card,
.cheatsheet-card {
  transition:
    transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),
    box-shadow 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),
    border-color 0.2s ease;
}

.concept-accordion-card:hover:not(.expanded),
.stat-card:hover,
.personalised-card:hover,
.niche-card:hover {
  transform: translateY(-4px) scale(1.005);
  box-shadow:
    0 12px 40px rgba(0, 0, 0, 0.35),
    0 0 0 1px rgba(108, 92, 231, 0.25),
    inset 0 1px 0 rgba(255, 255, 255, 0.07);
}

/* Active press micro-feedback */
.concept-accordion-card:active,
.stat-card:active,
.qa-sidebar-btn:active {
  transform: scale(0.98) !important;
  transition-duration: 0.1s !important;
}

/* ─── 7. SIDEBAR NAV ITEM ANIMATIONS ─────────────────────── */

.nav-item {
  position: relative;
  transition:
    background 0.22s ease,
    color 0.22s ease,
    transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.nav-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%) scaleY(0);
  width: 3px;
  height: 70%;
  background: var(--primary);
  border-radius: 0 3px 3px 0;
  transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.nav-item.active::before,
.nav-item:hover::before {
  transform: translateY(-50%) scaleY(1);
}

.nav-item:hover {
  transform: translateX(3px);
}

/* ─── 8. FILTER CHIP ANIMATIONS ──────────────────────────── */

.qa-sidebar-btn {
  transition:
    background 0.18s ease,
    border-color 0.18s ease,
    color 0.18s ease,
    transform 0.18s cubic-bezier(0.34, 1.56, 0.64, 1),
    box-shadow 0.18s ease;
}

.qa-sidebar-btn:hover:not(.active) {
  transform: translateY(-1px);
}

.qa-sidebar-btn.active {
  animation: badgePop 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.qa-btn-count-badge {
  transition: background 0.2s ease, color 0.2s ease;
}

/* ─── 9. SECTION HEADER EXPAND ───────────────────────────── */

.unified-section-header {
  transition: background 0.2s ease;
}

/* The chevron has a springy rotation */
.level-chevron {
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1) !important;
  flex-shrink: 0;
}

/* Card body slide-open — max-height transition for smooth accordion */
.level-card-body {
  transition:
    max-height 0.45s cubic-bezier(0.16, 1, 0.3, 1),
    opacity 0.35s ease,
    padding 0.35s ease;
  overflow: hidden;
}

/* ─── 10. SHIMMER SKELETON LOADER ────────────────────────── */

.skeleton {
  background:
    linear-gradient(
      90deg,
      rgba(255, 255, 255, 0.03) 0%,
      rgba(255, 255, 255, 0.12) 40%,
      rgba(255, 255, 255, 0.03) 100%
    );
  background-size: 200% 100%;
  animation: shimmer 1.6s ease-in-out infinite;
  border-radius: 8px;
}

/* ─── 11. GRADIENT ANIMATED HEADLINE ─────────────────────── */

.gradient-text {
  background: linear-gradient(
    135deg,
    hsl(245, 85%, 72%),
    hsl(280, 80%, 70%),
    hsl(200, 90%, 65%),
    hsl(160, 90%, 55%)
  );
  background-size: 300% 300%;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: gradientShift 6s ease infinite;
}

.theme-light .gradient-text {
  background: linear-gradient(
    135deg,
    hsl(245, 75%, 50%),
    hsl(280, 70%, 50%),
    hsl(200, 80%, 42%),
    hsl(160, 80%, 36%)
  );
  background-size: 300% 300%;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: gradientShift 6s ease infinite;
}

/* ─── 12. STAT CARD NUMBER TICK-UP ───────────────────────── */

.stat-value[data-animated] {
  animation: numberTick 0.45s cubic-bezier(0.16, 1, 0.3, 1) both;
}

/* ─── 13. MOBILE NAV TAB PRESS FEEDBACK ──────────────────── */

.mobile-nav-tab {
  transition:
    background 0.2s ease,
    color 0.2s ease,
    box-shadow 0.2s ease,
    transform 0.15s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.mobile-nav-tab:active {
  transform: scale(0.93);
}

.mobile-nav-tab.active {
  animation: scaleIn 0.28s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

/* ─── 14. SEARCH BOX FOCUS ANIMATION ─────────────────────── */

.qa-search-wrapper {
  transition:
    border-color 0.25s ease,
    box-shadow 0.35s cubic-bezier(0.16, 1, 0.3, 1),
    background 0.25s ease;
}

.qa-search-wrapper:focus-within {
  border-color: var(--primary) !important;
  box-shadow:
    0 0 0 3px rgba(108, 92, 231, 0.18),
    0 4px 16px rgba(108, 92, 231, 0.12) !important;
  transform: none;
}

/* ─── 15. TOPIC CHIP / SUBNAV HOVER ──────────────────────── */

.topic-chip {
  transition:
    background 0.2s ease,
    color 0.2s ease,
    border-color 0.2s ease,
    transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1),
    box-shadow 0.2s ease;
}

.topic-chip:hover:not(.active) {
  transform: translateY(-2px);
}

.topic-chip:active {
  transform: scale(0.95) !important;
  transition-duration: 0.08s !important;
}

/* ─── 16. GLASSMORPHISM GLOW BORDER ──────────────────────── */

/* Rotating hue border used on key highlighted cards */
@property --border-angle {
  syntax: '<angle>';
  initial-value: 0turn;
  inherits: false;
}

.glow-border {
  border: 1px solid transparent;
  background-clip: padding-box;
  background-image: var(--card-bg);
  position: relative;
}

.glow-border::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  padding: 1px;
  background: conic-gradient(
    from var(--border-angle),
    hsl(245, 85%, 65%),
    hsl(280, 80%, 65%),
    hsl(200, 90%, 60%),
    hsl(160, 90%, 50%),
    hsl(245, 85%, 65%)
  );
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  animation: rotateBorder 4s linear infinite;
  opacity: 0;
  transition: opacity 0.35s ease;
}

.glow-border:hover::before {
  opacity: 1;
}

/* ─── 17. SECTION APPEAR ANIMATION ───────────────────────── */

.prep-hub-subview {
  animation: fadeUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
}

/* DB-loader overlay fade */
#db-loader-overlay {
  transition: opacity 0.4s ease !important;
}

/* ─── 18. SIDEBAR BRAND ENTRANCE ─────────────────────────── */

.brand {
  animation: slideInLeft 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.1s both;
}

.nav-section {
  animation: slideInLeft 0.6s cubic-bezier(0.16, 1, 0.3, 1) both;
}
.nav-section:nth-child(1) { animation-delay: 0.15s; }
.nav-section:nth-child(2) { animation-delay: 0.22s; }
.nav-section:nth-child(3) { animation-delay: 0.29s; }

/* ─── 19. MOBILE TOP BAR ENTRANCE ────────────────────────── */

.mobile-top-bar {
  animation: fadeDown 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.mobile-bottom-nav {
  animation: fadeUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) 0.2s both;
}

/* ─── 20. UNIFIED SEARCH CONTAINER ───────────────────────── */

#unified-search-container .unified-section-wrapper {
  animation: fadeUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
}

#unified-search-container .unified-section-wrapper:nth-child(1) { animation-delay: 0ms; }
#unified-search-container .unified-section-wrapper:nth-child(2) { animation-delay: 50ms; }
#unified-search-container .unified-section-wrapper:nth-child(3) { animation-delay: 100ms; }
#unified-search-container .unified-section-wrapper:nth-child(4) { animation-delay: 150ms; }
#unified-search-container .unified-section-wrapper:nth-child(5) { animation-delay: 200ms; }
#unified-search-container .unified-section-wrapper:nth-child(6) { animation-delay: 250ms; }
#unified-search-container .unified-section-wrapper:nth-child(7) { animation-delay: 300ms; }
#unified-search-container .unified-section-wrapper:nth-child(8) { animation-delay: 350ms; }

/* ─── 21. BUTTON HOVER GLOW ──────────────────────────────── */

.control-btn {
  transition:
    background 0.2s ease,
    color 0.2s ease,
    border-color 0.2s ease,
    transform 0.18s cubic-bezier(0.34, 1.56, 0.64, 1),
    box-shadow 0.2s ease;
  position: relative;
  overflow: hidden;
}

.control-btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at var(--mx, 50%) var(--my, 50%),
    rgba(255, 255, 255, 0.12) 0%,
    transparent 60%
  );
  opacity: 0;
  transition: opacity 0.25s ease;
  pointer-events: none;
}

.control-btn:hover::after { opacity: 1; }
.control-btn:hover { transform: translateY(-2px); }
.control-btn:active { transform: scale(0.96) !important; }

/* ─── 22. PROGRESS BAR STRIPE ANIMATION ──────────────────── */

@keyframes progressStripe {
  from { background-position: 40px 0; }
  to   { background-position: 0 0; }
}

.progress-bar-fill {
  transition: width 0.8s cubic-bezier(0.16, 1, 0.3, 1);
  background-image: linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.1) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.1) 50%,
    rgba(255, 255, 255, 0.1) 75%,
    transparent 75%
  );
  background-size: 40px 40px;
  animation: progressStripe 0.8s linear infinite;
}

/* ─── 23. SCROLLBAR REVEAL ────────────────────────────────── */

/* Theme-aware custom scrollbar */
.main-content {
  scrollbar-gutter: stable;
}

.main-content::-webkit-scrollbar {
  width: 6px;
}

.main-content::-webkit-scrollbar-track {
  background: transparent;
}

.main-content::-webkit-scrollbar-thumb {
  background: rgba(108, 92, 231, 0.3);
  border-radius: 99px;
  transition: background 0.2s ease;
}

.main-content::-webkit-scrollbar-thumb:hover {
  background: rgba(108, 92, 231, 0.6);
}

/* ─── 24. COPY BUTTON FEEDBACK ────────────────────────────── */

.copy-btn {
  transition: color 0.2s ease, transform 0.18s cubic-bezier(0.34, 1.56, 0.64, 1) !important;
}

.copy-btn:hover {
  color: var(--primary) !important;
  transform: scale(1.1);
}

/* ─── 25. STAT BADGE HOVER RIPPLE ────────────────────────── */

.stats-badge {
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), background 0.2s ease;
}

.stats-badge:hover {
  transform: scale(1.08);
}

/* ─── 26. REDUCED MOTION — RESPECT USER PREF ─────────────── */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .aurora-orb { display: none; }
  .reveal-on-scroll { opacity: 1; transform: none; }
  .gradient-text { animation: none; background-position: 0 0; }
}