/* =====================================================================
   Study Sphere AI - Premium Design System
   Enhanced CSS variables, animations, and component foundations
   ===================================================================== */

/* ===== PREMIUM DARK THEME ===== */
:root,
:root[data-theme='dark'] {
  /* Base Colors */
  --bg-0: #060814;
  --bg-1: #0b1022;
  --bg-2: #11173a;
  --bg-3: #1a1f3a;
  
  /* Glass & Transparency */
  --glass: rgba(255, 255, 255, 0.06);
  --glass-strong: rgba(255, 255, 255, 0.1);
  --glass-premium: rgba(255, 255, 255, 0.08);
  --border: rgba(255, 255, 255, 0.12);
  --border-light: rgba(255, 255, 255, 0.08);
  
  /* Text */
  --text: #e8ecff;
  --text-dim: #9aa3c7;
  --text-muted: #6b7280;
  
  /* Primary Colors */
  --primary: #6d7bff;
  --primary-2: #a855f7;
  --primary-light: #8b9eff;
  --primary-dark: #4f5fd9;
  
  /* Accent & Status */
  --accent: #22d3ee;
  --accent-light: #67e8f9;
  --success: #34d399;
  --warning: #fbbf24;
  --danger: #fb7185;
  --info: #60a5fa;
  
  /* Shadows */
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.15);
  --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.25);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.45);
  --shadow-xl: 0 30px 80px rgba(0, 0, 0, 0.55);
  --shadow-glow: 0 0 30px rgba(109, 123, 255, 0.3);
  
  /* Gradients */
  --grad: linear-gradient(135deg, #6d7bff 0%, #a855f7 50%, #22d3ee 100%);
  --grad-primary: linear-gradient(135deg, #6d7bff, #a855f7);
  --grad-accent: linear-gradient(135deg, #22d3ee, #06b6d4);
  --grad-warm: linear-gradient(135deg, #f97316, #fb923c);
  --grad-cool: linear-gradient(135deg, #3b82f6, #8b5cf6);
  
  /* Navigation */
  --nav-bg: rgba(6, 8, 20, 0.55);
  --menu-bg: rgba(11, 16, 34, 0.96);
  
  /* Page Background */
  --page-bg:
    radial-gradient(1200px 800px at 15% -10%, rgba(109, 123, 255, 0.18), transparent 55%),
    radial-gradient(1000px 700px at 110% 10%, rgba(168, 85, 247, 0.16), transparent 55%),
    var(--bg-0);
  
  /* Spacing (8px grid) */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 999px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
  --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== PREMIUM LIGHT THEME ===== */
:root[data-theme='light'] {
  --bg-0: #eef1fb;
  --bg-1: #ffffff;
  --bg-2: #f4f6ff;
  --bg-3: #f0f4ff;
  
  --glass: rgba(255, 255, 255, 0.72);
  --glass-strong: rgba(255, 255, 255, 0.9);
  --glass-premium: rgba(255, 255, 255, 0.85);
  --border: rgba(20, 30, 80, 0.12);
  --border-light: rgba(20, 30, 80, 0.08);
  
  --text: #16203f;
  --text-dim: #5a648a;
  --text-muted: #9ca3af;
  
  --primary: #5b67ff;
  --primary-2: #9333ea;
  --primary-light: #818cf8;
  --primary-dark: #3730a3;
  
  --accent: #0891b2;
  --accent-light: #06b6d4;
  --success: #059669;
  --warning: #d97706;
  --danger: #e11d48;
  --info: #2563eb;
  
  --shadow-sm: 0 4px 12px rgba(60, 70, 130, 0.08);
  --shadow-md: 0 10px 30px rgba(60, 70, 130, 0.12);
  --shadow-lg: 0 20px 50px rgba(60, 70, 130, 0.18);
  --shadow-xl: 0 30px 80px rgba(60, 70, 130, 0.22);
  --shadow-glow: 0 0 30px rgba(91, 103, 255, 0.25);
  
  --grad: linear-gradient(135deg, #5b67ff 0%, #9333ea 50%, #0891b2 100%);
  --grad-primary: linear-gradient(135deg, #5b67ff, #9333ea);
  --grad-accent: linear-gradient(135deg, #0891b2, #06b6d4);
  --grad-warm: linear-gradient(135deg, #f97316, #fb923c);
  --grad-cool: linear-gradient(135deg, #3b82f6, #8b5cf6);
  
  --nav-bg: rgba(255, 255, 255, 0.7);
  --menu-bg: rgba(255, 255, 255, 0.97);
  
  --page-bg:
    radial-gradient(1200px 800px at 15% -10%, rgba(91, 103, 255, 0.15), transparent 55%),
    radial-gradient(1000px 700px at 110% 10%, rgba(147, 51, 234, 0.12), transparent 55%),
    var(--bg-0);
  
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 999px;
  
  --transition-fast: 0.15s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
  --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== PREMIUM ANIMATIONS ===== */

/* Page Transitions */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes zoomIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* Component Animations */
@keyframes hoverGlow {
  0% {
    box-shadow: 0 0 20px rgba(109, 123, 255, 0.3);
  }
  50% {
    box-shadow: 0 0 40px rgba(109, 123, 255, 0.6);
  }
  100% {
    box-shadow: 0 0 20px rgba(109, 123, 255, 0.3);
  }
}

@keyframes cardLift {
  from {
    transform: translateY(0);
    box-shadow: var(--shadow-md);
  }
  to {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
  }
}

@keyframes buttonHover {
  from {
    transform: scale(1);
  }
  to {
    transform: scale(1.02);
  }
}

@keyframes shimmer {
  0% {
    background-position: -1000px 0;
  }
  100% {
    background-position: 1000px 0;
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

@keyframes bounce {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

@keyframes float {
  0%, 100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-20px);
  }
}

/* Loading Skeleton */
@keyframes skeletonLoading {
  0% {
    background-position: -1000px 0;
  }
  100% {
    background-position: 1000px 0;
  }
}

/* Typing Animation */
@keyframes typing {
  0% {
    width: 0;
  }
  100% {
    width: 100%;
  }
}

@keyframes blink {
  0%, 50% {
    opacity: 1;
  }
  51%, 100% {
    opacity: 0;
  }
}

/* Confetti Animation */
@keyframes confetti-fall {
  to {
    transform: translateY(100vh) rotate(360deg);
    opacity: 0;
  }
}

/* ===== UTILITY ANIMATIONS ===== */

.animate-fade-in-up {
  animation: fadeInUp var(--transition-smooth) ease-out;
}

.animate-fade-in-down {
  animation: fadeInDown var(--transition-smooth) ease-out;
}

.animate-slide-in-left {
  animation: slideInLeft var(--transition-smooth) ease-out;
}

.animate-slide-in-right {
  animation: slideInRight var(--transition-smooth) ease-out;
}

.animate-zoom-in {
  animation: zoomIn var(--transition-smooth) ease-out;
}

.animate-pulse {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

.animate-spin {
  animation: spin 1s linear infinite;
}

.animate-bounce {
  animation: bounce 1s ease-in-out infinite;
}

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

/* ===== PREMIUM COMPONENT FOUNDATIONS ===== */

/* Smooth Transitions */
* {
  transition: background-color var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

button, a, input, textarea, select {
  transition: all var(--transition-base);
}

/* Focus States */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

button:focus-visible {
  box-shadow: var(--shadow-glow);
}

input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(109, 123, 255, 0.1);
}

/* Scrollbar Styling */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-1);
}

::-webkit-scrollbar-thumb {
  background: var(--glass-strong);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--border);
}

/* Selection */
::selection {
  background: var(--primary);
  color: white;
}

/* Placeholder */
::placeholder {
  color: var(--text-muted);
}

/* ===== RESPONSIVE UTILITIES ===== */

@media (max-width: 1024px) {
  :root {
    --space-3xl: 2.5rem;
  }
}

@media (max-width: 768px) {
  :root {
    --space-2xl: 2rem;
    --space-3xl: 2.5rem;
  }
}

@media (max-width: 480px) {
  :root {
    --space-lg: 1rem;
    --space-xl: 1.5rem;
    --space-2xl: 2rem;
  }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* =====================================================================
   PWA components — install button, update banner, network status,
   AI model selector, typing indicator (premium / glassmorphism)
   ===================================================================== */
.pwa-install-btn {
  position: fixed;
  right: 18px;
  bottom: calc(18px + env(safe-area-inset-bottom, 0px));
  z-index: 9000;
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .8rem 1.25rem;
  border: 1px solid rgba(255, 255, 255, .18);
  border-radius: 16px;
  font-weight: 600;
  font-size: .92rem;
  color: #fff;
  cursor: pointer;
  background: linear-gradient(135deg, #6d7bff, #a855f7);
  box-shadow: 0 12px 32px rgba(109, 123, 255, .45);
  transform: translateY(120%);
  opacity: 0;
  transition: transform .35s cubic-bezier(.16,1,.3,1), opacity .35s, box-shadow .2s;
}
.pwa-install-btn.show { transform: translateY(0); opacity: 1; }
.pwa-install-btn:hover { box-shadow: 0 16px 40px rgba(109, 123, 255, .6); transform: translateY(-2px); }

.pwa-update-banner {
  position: fixed;
  left: 50%;
  bottom: calc(18px + env(safe-area-inset-bottom, 0px));
  transform: translate(-50%, 140%);
  z-index: 9001;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: .75rem 1rem .75rem 1.25rem;
  border-radius: 14px;
  background: rgba(17, 23, 58, .92);
  backdrop-filter: blur(14px);
  border: 1px solid rgba(255, 255, 255, .14);
  color: #e8ecff;
  font-size: .9rem;
  box-shadow: 0 16px 40px rgba(0, 0, 0, .45);
  transition: transform .35s cubic-bezier(.16,1,.3,1);
}
.pwa-update-banner.show { transform: translate(-50%, 0); }
.pwa-update-banner button {
  border: 0; cursor: pointer; padding: .5rem .9rem; border-radius: 10px;
  font-weight: 600; color: #fff;
  background: linear-gradient(135deg, #6d7bff, #a855f7);
}

.pwa-net-banner {
  position: fixed; top: 0; left: 0; right: 0; z-index: 9002;
  text-align: center; padding: .6rem 1rem; font-size: .85rem; font-weight: 600;
  color: #fff; transform: translateY(-100%); transition: transform .3s ease;
}
.pwa-net-banner.show { transform: translateY(0); }
.pwa-net-banner.offline { background: linear-gradient(90deg, #f43f5e, #fb7185); }
.pwa-net-banner.online { background: linear-gradient(90deg, #10b981, #34d399); }

/* ---- Model selector (chat header + settings) ---- */
.model-selector {
  display: inline-flex; align-items: center; gap: .5rem;
  padding: .35rem .6rem; border-radius: 12px;
  background: var(--glass, rgba(255,255,255,.06));
  border: 1px solid var(--border, rgba(255,255,255,.12));
  font-size: .85rem;
}
.model-selector select {
  background: transparent; border: 0; color: var(--text, #e8ecff);
  font: inherit; font-weight: 600; cursor: pointer; outline: none;
}
.model-selector select option { background: #11173a; color: #e8ecff; }
.model-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: #10b981; box-shadow: 0 0 0 3px rgba(16,185,129,.2);
}
.model-dot.off { background: #6b7280; box-shadow: none; }
.model-badge {
  display: inline-flex; align-items: center; gap: .4rem;
  font-size: .72rem; font-weight: 600; color: var(--text-dim, #9aa3c7);
  padding: .15rem .5rem; border-radius: 999px;
  background: var(--glass, rgba(255,255,255,.06));
  border: 1px solid var(--border-light, rgba(255,255,255,.08));
}

.field-hint { display: block; margin-top: .35rem; font-size: .78rem; color: var(--text-muted, #6b7280); }
.provider-status { display: flex; flex-wrap: wrap; gap: .4rem; margin-top: .35rem; }