/* CSS Variables for Theme Management */
:root {
  --header-height: 120px;
  --nav-height: 68px;
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  /* Light Theme Colors */
  --color-primary: #8B4513;
  --color-secondary: #D2691E;
  --color-accent: #FF8C00;
  --color-warning: #FFA500;
  --color-success: #FFD700;
  
  /* Background Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  
  /* Text Colors */
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-light: #ffffff;
  
  /* Border Colors */
  --border-color: #dee2e6;
  --border-focus: var(--color-primary);
  
  /* Shadow */
  --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
  --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
  
  /* Transitions */
  --transition: all 0.3s ease;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-xxl: 3rem;
  
  /* Border Radius */
  --border-radius: 0.375rem;
  --border-radius-lg: 0.5rem;
  --border-radius-xl: 1rem;
  
  /* Font Sizes */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-xxl: 1.5rem;
  --font-size-xxxl: 2rem;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #1a1a1a;
  --bg-secondary: #2d2d2d;
  --bg-tertiary: #404040;
  
  --text-primary: #ffffff;
  --text-secondary: #cccccc;
  
  --border-color: #555555;
  
  --shadow-sm: 0 0.125rem 0.25rem rgba(255, 255, 255, 0.075);
  --shadow-md: 0 0.5rem 1rem rgba(255, 255, 255, 0.15);
  --shadow-lg: 0 1rem 3rem rgba(255, 255, 255, 0.175);
}

/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: var(--transition);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding-top: var(--header-height);
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* Header */
.header {
  background-color: var(--color-primary);
  color: var(--text-light);
  padding: var(--spacing-md) 0;
  box-shadow: var(--shadow-md);
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 200;
}

.header__inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.header__brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  min-width: 0;
}

.header__logo {
  width: 96px;
  height: 96px;
  object-fit: contain;
  border-radius: var(--border-radius);
}

.header__titles {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.header__title {
  font-size: var(--font-size-xxl);
  font-weight: 600;
  margin: 0;
  line-height: 1.2;
}

.header__subtitle {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.85);
  line-height: 1.3;
}

.header__controls {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: flex-end;
  margin-left: auto;
  align-items: center;
}

.header__controls .btn {
  height: 38px;
  min-width: 52px;
  padding: 0 var(--spacing-xs);
  justify-content: center;
}

/* Navigation */
.nav {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: var(--spacing-sm) 0;
  position: sticky;
  top: var(--header-height);
  z-index: 150;
  min-height: var(--nav-height);
}

.nav__list {
  display: flex;
  list-style: none;
  gap: var(--spacing-xs);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.nav__item {
  flex-shrink: 0;
}

.nav__link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm);
  background: none;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  border-radius: var(--border-radius);
  min-width: 80px;
  color: var(--text-secondary);
}

.nav__link:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.nav__link--active {
  background-color: var(--color-primary);
  color: var(--text-light);
}

.nav__text {
  font-size: var(--font-size-xs);
  font-weight: 500;
}

/* Main Content */
.main {
  flex: 1;
  padding: var(--spacing-lg) 0;
}

/* Sections */
.section {
  display: none;
  animation: fadeIn 0.3s ease-in-out;
}

.section--active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Cards */
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
}

.section__title {
  font-size: var(--font-size-xxl);
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary);
  text-align: center;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm) var(--spacing-md);
  border: none;
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
  min-height: 44px;
  gap: var(--spacing-xs);
}

.btn--primary {
  background-color: var(--color-primary);
  color: var(--text-light);
}

.btn--primary:hover {
  background-color: var(--color-secondary);
  transform: translateY(-1px);
}

.btn--secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn--secondary:hover {
  background-color: var(--color-accent);
  color: var(--text-light);
}

/* Icons */
.icon {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  stroke-width: 1.8;
  fill: none;
  display: inline-block;
}

.icon--solid {
  fill: currentColor;
  stroke: none;
}

.btn--small {
  padding: var(--spacing-xs) var(--spacing-sm);
  font-size: var(--font-size-sm);
  min-height: 36px;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

/* Forms */
.form__group {
  margin-bottom: var(--spacing-md);
}

.form__label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  color: var(--text-primary);
}

.form__input,
.form__select,
.form__textarea {
  width: 100%;
  padding: var(--spacing-sm);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: var(--transition);
}

.form__input:focus,
.form__select:focus,
.form__textarea:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(139, 69, 19, 0.1);
}

.form__textarea {
  resize: vertical;
  min-height: 80px;
}

.form__actions {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: flex-end;
  margin-top: var(--spacing-lg);
}

/* Pet Selector */
.pet-selector {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  align-items: end;
  margin-bottom: var(--spacing-lg);
}

.pet-selector .form__group {
  flex: 1;
  min-width: 200px;
  margin-bottom: 0;
}

/* Mood Grid */
.mood-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.mood-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--spacing-lg);
  background-color: var(--bg-primary);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  cursor: pointer;
  transition: var(--transition);
  min-height: 100px;
}

.mood-btn:hover {
  border-color: var(--color-accent);
  background-color: var(--bg-tertiary);
  transform: translateY(-2px);
}

.mood-btn--selected {
  border-color: var(--color-primary);
  background-color: var(--color-primary);
  color: var(--text-light);
}

.mood-btn .icon {
  width: 28px;
  height: 28px;
  margin-bottom: var(--spacing-xs);
}

.mood-label {
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-align: center;
}

/* Mood Notes */
.mood-notes {
  margin-bottom: var(--spacing-lg);
}

/* Recent Items */
.recent-moods,
.recent-events {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  max-height: 400px;
  overflow-y: auto;
}

.mood-item,
.event-item {
  display: flex;
  align-items: center;
  padding: var(--spacing-sm);
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.mood-item:hover,
.event-item:hover {
  background-color: var(--bg-tertiary);
}

.item__icon {
  width: 28px;
  height: 28px;
  margin-right: var(--spacing-sm);
  flex-shrink: 0;
  stroke: var(--text-primary);
  stroke-width: 1.8;
}

.mood-item__content,
.event-item__content {
  flex: 1;
}

.mood-item__pet,
.event-item__pet {
  font-weight: 600;
  color: var(--color-primary);
}

.mood-item__date,
.event-item__date {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

.mood-item__notes,
.event-item__description {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-top: var(--spacing-xs);
}

/* Charts */
.pattern-charts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.chart-container {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-md);
}

.chart__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
  text-align: center;
}

.chart {
  width: 100%;
  height: 200px;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
}

/* Statistics */
.pattern-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-md);
}

.stat-card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-md);
  text-align: center;
}

.stat__title {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
}

.stat__value {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-primary);
}

/* Factor Analysis */
.factor-analysis {
  display: grid;
  gap: var(--spacing-lg);
}

.factor-card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-md);
}

.factor__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
}

.factor__content {
  color: var(--text-secondary);
}

.factor-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-sm);
  margin-bottom: var(--spacing-xs);
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius);
}

.factor-item__name {
  font-weight: 500;
}

.factor-item__value {
  font-weight: 600;
  color: var(--color-primary);
}

/* Modal */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.modal--active {
  opacity: 1;
  visibility: visible;
}

.modal__overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
}

.modal__content {
  position: relative;
  background-color: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  max-width: 500px;
  width: 90%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  transform: scale(0.9);
  transition: var(--transition);
}

.modal--active .modal__content {
  transform: scale(1);
}

.modal__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
}

.modal__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-primary);
}

.modal__close {
  background: none;
  border: none;
  font-size: var(--font-size-xl);
  cursor: pointer;
  color: var(--text-secondary);
  transition: var(--transition);
}

.modal__close:hover {
  color: var(--text-primary);
}

.modal__body {
  padding: var(--spacing-lg);
}

/* Loading */
.loading {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.loading--active {
  opacity: 1;
  visibility: visible;
}

.loading__spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--bg-tertiary);
  border-top: 4px solid var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: var(--spacing-md);
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.loading__text {
  color: var(--text-light);
  font-size: var(--font-size-base);
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  top: calc(var(--header-height) + var(--spacing-sm));
  right: var(--spacing-md);
  z-index: 1500;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.toast {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-md);
  max-width: 350px;
  opacity: 0;
  transform: translateX(100%);
  transition: var(--transition);
}

.toast--active {
  opacity: 1;
  transform: translateX(0);
}

.toast--success {
  border-left: 4px solid var(--color-success);
}

.toast--error {
  border-left: 4px solid #dc3545;
}

.toast--warning {
  border-left: 4px solid var(--color-warning);
}

.toast__message {
  font-size: var(--font-size-sm);
  color: var(--text-primary);
}

/* Empty State */
.empty-state {
  text-align: center;
  color: var(--text-secondary);
  font-style: italic;
  padding: var(--spacing-lg);
}

/* Footer */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-md) 0 calc(var(--spacing-md) + var(--safe-bottom));
  margin-top: auto;
}

.footer__text {
  text-align: center;
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
  body {
    padding-bottom: calc(var(--nav-height) + var(--safe-bottom));
  }

  .main {
    padding-bottom: calc(var(--nav-height) + var(--spacing-md));
  }

  .header__logo {
    width: 84px;
    height: 84px;
  }

  .nav {
    position: fixed;
    bottom: 0;
    top: auto;
    left: 0;
    width: 100%;
    border-top: 1px solid var(--border-color);
    border-bottom: none;
    box-shadow: 0 -4px 12px rgba(0,0,0,0.08);
  }

  .nav__list {
    justify-content: space-between;
  }

  .nav__item {
    flex: 1;
  }

  .nav__link {
    width: 100%;
    min-width: auto;
  }

  .container {
    padding: 0 var(--spacing-sm);
  }
  
  .header__title {
    font-size: var(--font-size-xl);
  }

  .header__inner {
    align-items: center;
    gap: var(--spacing-sm);
    flex-direction: row;
  }

  .header__controls {
    width: auto;
    justify-content: flex-end;
    margin-left: auto;
    align-items: center;
  }
  
  .section__title {
    font-size: var(--font-size-xl);
  }
  
  .mood-grid {
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: var(--spacing-sm);
  }
  
  .mood-btn {
    padding: var(--spacing-md);
    min-height: 80px;
  }
  
  .mood-emoji {
    font-size: 1.5rem;
  }
  
  .pattern-charts {
    grid-template-columns: 1fr;
  }
  
  .pattern-stats {
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  }
  
  .pet-selector {
    flex-direction: column;
    align-items: stretch;
  }
  
  .pet-selector .form__group {
    min-width: auto;
  }
  
  .form__actions {
    flex-direction: column;
  }
  
  .toast-container {
    right: var(--spacing-sm);
    left: var(--spacing-sm);
  }
  
  .toast {
    max-width: none;
  }
}

@media (max-width: 480px) {
  .nav__list {
    justify-content: space-between;
  }
  
  .nav__link {
    min-width: 60px;
    padding: var(--spacing-xs);
  }
  
  .nav__text {
    font-size: 0.625rem;
  }
  
  .card {
    padding: var(--spacing-md);
  }
  
  .mood-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .pattern-stats {
    grid-template-columns: 1fr;
  }
}

/* Print Styles */
@media print {
  .header,
  .nav,
  .footer,
  .modal,
  .loading,
  .toast-container {
    display: none;
  }
  
  .main {
    padding: 0;
  }
  
  .card {
    border: 1px solid #000;
    box-shadow: none;
    page-break-inside: avoid;
  }
  
  .section {
    display: block;
  }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
  :root {
    --border-color: #000000;
    --text-secondary: #000000;
  }
  
  [data-theme="dark"] {
    --border-color: #ffffff;
    --text-secondary: #ffffff;
  }
}

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

/* Focus Visible */
.btn:focus-visible,
.form__input:focus-visible,
.form__select:focus-visible,
.form__textarea:focus-visible,
.nav__link:focus-visible,
.mood-btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}