/* CSS Variables for Theme Support */
:root {
  --color-primary: #1A1A2E;
  --color-secondary: #16213E;
  --color-accent: #0F3460;
  --color-highlight: #E94560;
  --color-white: #FFFFFF;
  --color-text: #1A1A2E;
  --color-text-light: #666;
  --color-background: #FFFFFF;
  --color-surface: #F8F9FA;
  --color-border: #E1E5E9;
  --color-shadow: rgba(26, 26, 46, 0.1);
  --color-success: #28A745;
  --color-warning: #FFC107;
  --color-danger: #DC3545;
  
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  --border-radius: 8px;
  --border-radius-lg: 12px;
  --transition: all 0.3s ease;
}

/* Dark Theme */
[data-theme="dark"] {
  --color-text: #FFFFFF;
  --color-text-light: #B0B0B0;
  --color-background: #1A1A2E;
  --color-surface: #16213E;
  --color-border: #0F3460;
  --color-shadow: rgba(0, 0, 0, 0.3);
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-background);
  transition: var(--transition);
}

/* App Container */
.app-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header Styles */
.header {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: var(--spacing-md) 0;
  box-shadow: 0 2px 4px var(--color-shadow);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header__content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header__title {
  font-size: var(--font-size-2xl);
  font-weight: 700;
}

.header__controls {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
}

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

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

.btn--primary:hover {
  background-color: #d73650;
  transform: translateY(-1px);
}

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

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

.btn--icon {
  padding: var(--spacing-sm);
  background: none;
  border: none;
  color: inherit;
  cursor: pointer;
  border-radius: var(--border-radius);
}

.btn--icon:hover {
  background-color: var(--color-surface);
}

.btn--large {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-lg);
}

/* Main Layout */
.main {
  flex: 1;
  display: flex;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

/* Sidebar */
.sidebar {
  width: 280px;
  background-color: var(--color-surface);
  border-right: 1px solid var(--color-border);
  padding: var(--spacing-lg);
  transition: var(--transition);
}

.sidebar__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.sidebar__header h2 {
  font-size: var(--font-size-lg);
  color: var(--color-text);
}

.groups-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.group-item {
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
}

.group-item:hover {
  background-color: var(--color-background);
  border-color: var(--color-border);
}

.group-item--active {
  background-color: var(--color-highlight);
  color: var(--color-white);
}

.group-item__name {
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.group-item__stats {
  font-size: var(--font-size-sm);
  opacity: 0.8;
}

/* Content Area */
.content {
  flex: 1;
  padding: var(--spacing-lg);
  overflow-y: auto;
}

/* Welcome Screen */
.welcome-screen {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  text-align: center;
}

.welcome-screen__content h2 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.welcome-screen__content p {
  font-size: var(--font-size-lg);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-xl);
}

/* Group Dashboard */
.group-dashboard {
  max-width: 100%;
}

.group-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-lg);
  background-color: var(--color-surface);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--color-border);
}

.group-header__info {
  display: flex;
  gap: var(--spacing-lg);
  align-items: flex-start;
}

.group-header__avatar {
  width: 60px;
  height: 60px;
  background-color: var(--color-highlight);
  border-radius: var(--border-radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-2xl);
  color: var(--color-white);
}

.group-header__name {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-xs);
  color: var(--color-text);
}

.group-header__description {
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
}

.group-header__stats {
  display: flex;
  gap: var(--spacing-lg);
}

.stat {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
}

.group-header__actions {
  display: flex;
  gap: var(--spacing-sm);
  align-items: center;
}

/* Progress Section */
.progress-section {
  margin-bottom: var(--spacing-xl);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.progress-bar {
  flex: 1;
  height: 8px;
  background-color: var(--color-border);
  border-radius: 4px;
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  background-color: var(--color-success);
  transition: width 0.3s ease;
  border-radius: 4px;
}

.progress-text {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text);
  min-width: 80px;
}

/* Kanban Board */
.kanban-board {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

.kanban-column {
  background-color: var(--color-surface);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
}

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

.kanban-column__header h3 {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text);
}

.kanban-column__count {
  background-color: var(--color-text-light);
  color: var(--color-white);
  padding: 2px 8px;
  border-radius: 12px;
  font-size: var(--font-size-sm);
  font-weight: 600;
}

.kanban-column__content {
  padding: var(--spacing-md);
  min-height: 200px;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

/* Topic Card */
.topic-card {
  background-color: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--spacing-md);
  cursor: pointer;
  transition: var(--transition);
}

.topic-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--color-shadow);
}

.topic-card__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--spacing-sm);
}

.topic-card__title {
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-xs);
}

.topic-card__description {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
  line-height: 1.4;
}

.topic-card__meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--font-size-sm);
}

.topic-card__assignee {
  color: var(--color-text-light);
}

.topic-card__due-date {
  color: var(--color-text-light);
}

.topic-card__due-date--overdue {
  color: var(--color-danger);
  font-weight: 600;
}

.topic-card__due-date--soon {
  color: var(--color-warning);
  font-weight: 600;
}

/* Modal Styles */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.modal__content {
  background-color: var(--color-background);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 10px 25px var(--color-shadow);
  width: 90%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
  z-index: 1;
}

.modal__content--large {
  max-width: 700px;
}

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

.modal__header h3 {
  font-size: var(--font-size-xl);
  color: var(--color-text);
}

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

.modal__footer {
  padding: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: flex-end;
  gap: var(--spacing-md);
}

/* Form Styles */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 600;
  color: var(--color-text);
}

.form-group input,
.form-group textarea,
.form-group select,
.form-control {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  background-color: var(--color-background);
  color: var(--color-text);
  transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus,
.form-control:focus {
  outline: none;
  border-color: var(--color-highlight);
  box-shadow: 0 0 0 3px rgba(233, 69, 96, 0.1);
}

/* Topic Details */
.topic-details__info {
  margin-bottom: var(--spacing-xl);
}

.topic-details__description {
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
  line-height: 1.6;
}

.topic-details__meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

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

.meta-item strong {
  color: var(--color-text);
  font-size: var(--font-size-sm);
}

.meta-item span {
  color: var(--color-text-light);
}

.topic-details__actions {
  margin-bottom: var(--spacing-xl);
  display: flex;
  gap: var(--spacing-md);
  align-items: flex-end;
}

.topic-details__actions select {
  flex: 1;
}

.topic-details__notes h4 {
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.topic-details__notes textarea {
  margin-bottom: var(--spacing-md);
}

/* Utility Classes */
.hidden {
  display: none !important;
}

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

.text-success {
  color: var(--color-success);
}

.text-warning {
  color: var(--color-warning);
}

.text-danger {
  color: var(--color-danger);
}

/* Footer */
.footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-md);
  text-align: center;
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
}

/* Theme Toggle */
.theme-icon {
  font-size: var(--font-size-lg);
}

/* Responsive Design */
@media (max-width: 768px) {
  .header__content {
    padding: 0 var(--spacing-sm);
  }
  
  .header__title {
    font-size: var(--font-size-lg);
  }
  
  .header__controls {
    gap: var(--spacing-sm);
  }
  
  .main {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md);
  }
  
  .content {
    padding: var(--spacing-md);
  }
  
  .group-header {
    flex-direction: column;
    gap: var(--spacing-lg);
    align-items: stretch;
  }
  
  .group-header__info {
    flex-direction: column;
    text-align: center;
    gap: var(--spacing-md);
  }
  
  .group-header__actions {
    justify-content: center;
    flex-wrap: wrap;
  }
  
  .kanban-board {
    grid-template-columns: 1fr;
  }
  
  .progress-section {
    flex-direction: column;
    align-items: stretch;
    gap: var(--spacing-sm);
  }
  
  .progress-text {
    text-align: center;
    min-width: auto;
  }
  
  .modal__content {
    width: 95%;
    margin: var(--spacing-md);
  }
  
  .topic-details__actions {
    flex-direction: column;
    align-items: stretch;
  }
  
  .topic-details__meta {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .header__content {
    flex-direction: column;
    gap: var(--spacing-md);
  }
  
  .header__controls {
    width: 100%;
    justify-content: center;
  }
  
  .btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-sm);
  }
  
  .group-header__stats {
    flex-direction: column;
    gap: var(--spacing-xs);
    text-align: center;
  }
  
  .modal__header,
  .modal__body,
  .modal__footer {
    padding: var(--spacing-md);
  }
}

/* Sidebar Toggle for Mobile */
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    top: 0;
    left: -100%;
    width: 280px;
    height: 100vh;
    z-index: 1500;
    transition: left 0.3s ease;
    border-right: 1px solid var(--color-border);
    border-bottom: none;
  }
  
  .sidebar.sidebar--open {
    left: 0;
  }
  
  .sidebar__toggle-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1400;
    display: none;
  }
  
  .sidebar__toggle-overlay.active {
    display: block;
  }
}

/* Animation for smooth transitions */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.topic-card {
  animation: fadeIn 0.3s ease;
}

/* Focus styles for accessibility */
.btn:focus,
input:focus,
textarea:focus,
select:focus {
  outline: 2px solid var(--color-highlight);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --color-border: #000000;
    --color-text-light: #333333;
  }
}

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