/* ========================================
   StudyGenius AI - Premium Design System
   ======================================= */

:root {
  /* Color Palette - Premium Education Theme */
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #818cf8;
  --secondary: #ec4899;
  --secondary-dark: #db2777;
  --accent: #10b981;
  --accent-dark: #059669;

  /* Dark Mode Optimized */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --bg-card: rgba(30, 41, 59, 0.6);
  --bg-glass: rgba(51, 65, 85, 0.3);

  /* Text Colors */
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #6366f1 0%, #ec4899 100%);
  --gradient-secondary: linear-gradient(135deg, #10b981 0%, #3b82f6 100%);
  --gradient-accent: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);

  /* Shadows & Effects */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.5);

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-heading: 'Outfit', 'Inter', sans-serif;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ========================================
   Reset & Base Styles
   ======================================== */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  min-height: 100vh;
}

/* ========================================
   Typography
   ======================================== */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--space-sm);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
}

h2 {
  font-size: clamp(2rem, 4vw, 3rem);
}

h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--space-sm);
  color: var(--text-secondary);
}

a {
  text-decoration: none;
  color: var(--primary-light);
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--primary);
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font-primary);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width var(--transition-slow), height var(--transition-slow);
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 2px solid var(--bg-tertiary);
}

.btn-secondary:hover {
  background: transparent;
  border-color: var(--primary);
  color: var(--primary);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover {
  background: var(--primary);
  color: white;
}

.btn-large {
  padding: 1.125rem 2.5rem;
  font-size: 1.125rem;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* ========================================
   Cards & Containers
   ======================================== */

.card {
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(99, 102, 241, 0.3);
}

.card-glass {
  background: var(--bg-glass);
  backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.container-wide {
  max-width: 1400px;
}

/* ========================================
   Navigation
   ======================================== */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  padding: var(--space-sm) 0;
  transition: all var(--transition-base);
}

.navbar.scrolled {
  box-shadow: var(--shadow-lg);
  padding: var(--space-xs) 0;
}

.nav-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  gap: var(--space-lg);
  list-style: none;
  align-items: center;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-links a:hover {
  color: var(--primary-light);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  padding: var(--space-2xl) 0;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, transparent 70%);
  border-radius: 50%;
  animation: float 20s ease-in-out infinite;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -50%;
  left: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(236, 72, 153, 0.15) 0%, transparent 70%);
  border-radius: 50%;
  animation: float 15s ease-in-out infinite reverse;
}

@keyframes float {

  0%,
  100% {
    transform: translate(0, 0) scale(1);
  }

  50% {
    transform: translate(50px, 50px) scale(1.1);
  }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 900px;
  margin: 0 auto;
}

.hero h1 {
  margin-bottom: var(--space-md);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.25rem;
  margin-bottom: var(--space-xl);
  color: var(--text-secondary);
}

.hero-buttons {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ========================================
   Features Section
   ======================================== */

.features {
  padding: var(--space-2xl) 0;
}

.section-title {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.125rem;
  margin-top: var(--space-sm);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-lg);
  margin-top: var(--space-xl);
}

.feature-card {
  text-align: center;
  padding: var(--space-xl);
}

.feature-icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
  display: inline-block;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.feature-card h3 {
  margin-bottom: var(--space-sm);
}

.feature-card p {
  color: var(--text-muted);
}

/* ========================================
   Pricing Section
   ======================================== */

.pricing {
  padding: var(--space-2xl) 0;
  background: var(--bg-secondary);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
  margin-top: var(--space-xl);
}

.pricing-card {
  position: relative;
  padding: var(--space-xl);
  text-align: center;
}

.pricing-card.featured {
  transform: scale(1.05);
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-xl), var(--shadow-glow);
}

.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-primary);
  color: white;
  padding: 0.375rem 1rem;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 600;
}

.pricing-tier {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pricing-price {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: var(--space-xs);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.pricing-period {
  color: var(--text-muted);
  margin-bottom: var(--space-lg);
}

.pricing-features {
  list-style: none;
  margin-bottom: var(--space-lg);
  text-align: left;
}

.pricing-features li {
  padding: var(--space-sm) 0;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.pricing-features li::before {
  content: '✓';
  color: var(--accent);
  font-weight: 700;
  font-size: 1.25rem;
}

/* ========================================
   Forms & Inputs
   ======================================== */

.form-group {
  margin-bottom: var(--space-md);
}

label {
  display: block;
  margin-bottom: var(--space-xs);
  color: var(--text-secondary);
  font-weight: 500;
}

input,
textarea,
select {
  width: 100%;
  padding: 0.875rem 1rem;
  background: var(--bg-tertiary);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-primary);
  font-size: 1rem;
  transition: all var(--transition-base);
}

input:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

textarea {
  resize: vertical;
  min-height: 120px;
}

/* ========================================
   Dashboard
   ======================================== */

.dashboard {
  padding: calc(70px + var(--space-xl)) var(--space-lg) var(--space-xl);
  min-height: 100vh;
}

.dashboard-header {
  margin-bottom: var(--space-xl);
}

.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.stat-card {
  padding: var(--space-lg);
  text-align: center;
}

.stat-value {
  font-size: 2.5rem;
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-xs);
}

.stat-label {
  color: var(--text-muted);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: var(--space-lg);
}

.tool-card {
  padding: var(--space-xl);
  text-align: center;
  cursor: pointer;
}

.tool-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-md);
}

/* ========================================
   Chat Interface
   ======================================== */

.chat-container {
  display: flex;
  flex-direction: column;
  height: calc(100vh - 140px);
  max-width: 900px;
  margin: 0 auto;
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.message {
  max-width: 80%;
  padding: var(--space-md);
  border-radius: var(--radius-lg);
  animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }

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

.message.user {
  align-self: flex-end;
  background: var(--gradient-primary);
  color: white;
  border-bottom-right-radius: 4px;
}

.message.ai {
  align-self: flex-start;
  background: var(--bg-card);
  border-bottom-left-radius: 4px;
}

.chat-input-container {
  padding: var(--space-lg);
  background: var(--bg-secondary);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.chat-input-wrapper {
  display: flex;
  gap: var(--space-sm);
}

.chat-input-wrapper input {
  flex: 1;
}

/* ========================================
   Loading & States
   ======================================== */

.loading {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.spinner-container {
  display: flex;
  justify-content: center;
  padding: var(--space-xl);
}

/* ========================================
   Utilities
   ======================================== */

.text-center {
  text-align: center;
}

.text-gradient {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.mt-sm {
  margin-top: var(--space-sm);
}

.mt-md {
  margin-top: var(--space-md);
}

.mt-lg {
  margin-top: var(--space-lg);
}

.mt-xl {
  margin-top: var(--space-xl);
}

.mb-sm {
  margin-bottom: var(--space-sm);
}

.mb-md {
  margin-bottom: var(--space-md);
}

.mb-lg {
  margin-bottom: var(--space-lg);
}

.mb-xl {
  margin-bottom: var(--space-xl);
}

.hidden {
  display: none;
}

.flex {
  display: flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.gap-sm {
  gap: var(--space-sm);
}

.gap-md {
  gap: var(--space-md);
}

.gap-lg {
  gap: var(--space-lg);
}

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

  .mobile-menu-btn {
    display: block;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: stretch;
  }

  .pricing-card.featured {
    transform: none;
  }

  .message {
    max-width: 90%;
  }

  .features-grid,
  .pricing-grid,
  .dashboard-grid,
  .tools-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  :root {
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 2.5rem;
  }

  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.75rem;
  }

  .pricing-price {
    font-size: 2.5rem;
  }
}