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

:root {
  --primary-color: #667eea;
  --secondary-color: #764ba2;
  --accent-color: #f093fb;
  --success-color: #26de81;
  --warning-color: #ffc048;
  --danger-color: #ff3838;
  --text-color: #333;
  --text-light: #666;
  --bg-color: #f5f7fa;
  --white: #ffffff;
  --border-color: #e1e8ed;
  --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  --gradient: linear-gradient(
    135deg,
    var(--primary-color),
    var(--secondary-color)
  );
}

body {
  font-family: "Arial", sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
}

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  background: var(--white);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1.5rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header h1 {
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-size: 2rem;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.btn {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.3s ease;
  text-decoration: none;
}

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

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.3);
}

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

.btn-secondary:hover {
  background: #d1d9e6;
}

.view-toggle {
  display: flex;
  background: var(--bg-color);
  border-radius: 8px;
  padding: 0.25rem;
}

.view-btn {
  padding: 0.5rem;
  border: none;
  background: transparent;
  cursor: pointer;
  border-radius: 6px;
  color: var(--text-light);
  transition: all 0.3s ease;
}

.view-btn.active {
  background: var(--white);
  color: var(--primary-color);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* Main Content */
.main-content {
  flex: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem;
  width: 100%;
}

/* Filters */
.filters {
  background: var(--white);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow);
  display: flex;
  gap: 2rem;
  align-items: center;
  flex-wrap: wrap;
}

.filter-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.filter-group label {
  font-weight: 500;
  color: var(--text-color);
  font-size: 0.9rem;
}

.filter-group select {
  padding: 0.5rem;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  background: var(--white);
  color: var(--text-color);
  min-width: 150px;
}

.search-group {
  position: relative;
  flex: 1;
  max-width: 300px;
}

.search-group input {
  width: 100%;
  padding: 0.75rem 2.5rem 0.75rem 1rem;
  border: 2px solid var(--border-color);
  border-radius: 25px;
  background: var(--white);
  font-size: 1rem;
}

.search-group i {
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-light);
}

/* Task Board */
.task-board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-bottom: 2rem;
}

.column {
  background: var(--white);
  border-radius: 12px;
  box-shadow: var(--shadow);
  min-height: 500px;
}

.column-header {
  padding: 1.5rem;
  border-bottom: 2px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.column-header h3 {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-color);
}

.task-count {
  background: var(--bg-color);
  color: var(--text-color);
  padding: 0.25rem 0.5rem;
  border-radius: 12px;
  font-size: 0.8rem;
  font-weight: 600;
}

.task-list {
  padding: 1rem;
  min-height: 400px;
}

/* Task Cards */
.task-card {
  background: var(--white);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  padding: 1rem;
  margin-bottom: 1rem;
  cursor: grab;
  transition: all 0.3s ease;
  position: relative;
}

.task-card:hover {
  border-color: var(--primary-color);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.task-card.dragging {
  opacity: 0.5;
  transform: rotate(5deg);
}

.task-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

.task-description {
  color: var(--text-light);
  font-size: 0.9rem;
  margin-bottom: 1rem;
  line-height: 1.4;
}

.task-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.priority-badge {
  padding: 0.25rem 0.5rem;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
}

.priority-high {
  background: var(--danger-color);
  color: white;
}

.priority-medium {
  background: var(--warning-color);
  color: white;
}

.priority-low {
  background: var(--success-color);
  color: white;
}

.task-due {
  font-size: 0.8rem;
  color: var(--text-light);
}

.task-actions {
  display: flex;
  gap: 0.5rem;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.task-card:hover .task-actions {
  opacity: 1;
}

.action-btn {
  padding: 0.25rem;
  border: none;
  background: none;
  cursor: pointer;
  border-radius: 4px;
  color: var(--text-light);
  transition: all 0.3s ease;
}

.action-btn:hover {
  background: var(--bg-color);
  color: var(--primary-color);
}

/* List View */
.task-list-view {
  background: var(--white);
  border-radius: 12px;
  box-shadow: var(--shadow);
  overflow: hidden;
}

.list-header {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 1rem;
  padding: 1rem 1.5rem;
  background: var(--bg-color);
  font-weight: 600;
  color: var(--text-color);
  border-bottom: 2px solid var(--border-color);
}

.list-body {
  max-height: 600px;
  overflow-y: auto;
}

.list-row {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 1rem;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  align-items: center;
  transition: background 0.3s ease;
}

.list-row:hover {
  background: var(--bg-color);
}

/* Stats Panel */
.stats-panel {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.stat-item {
  background: var(--white);
  padding: 1.5rem;
  border-radius: 12px;
  box-shadow: var(--shadow);
  text-align: center;
}

.stat-number {
  font-size: 2rem;
  font-weight: bold;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.stat-label {
  color: var(--text-light);
  font-size: 0.9rem;
}

/* Modal */
.modal {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0);
  background: var(--white);
  border-radius: 12px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
  z-index: 1001;
  width: 90%;
  max-width: 500px;
  transition: all 0.3s ease;
}

.modal.active {
  transform: translate(-50%, -50%) scale(1);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem;
  border-bottom: 2px solid var(--border-color);
}

.close-btn {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-light);
  padding: 0.25rem;
  border-radius: 4px;
  transition: all 0.3s ease;
}

.close-btn:hover {
  background: var(--bg-color);
  color: var(--danger-color);
}

.modal-content form {
  padding: 1.5rem;
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-color);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.75rem;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary-color);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-actions {
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
  padding-top: 1rem;
  border-top: 2px solid var(--border-color);
}

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

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

/* Drag and Drop */
.task-list.drag-over {
  background: rgba(102, 126, 234, 0.1);
  border: 2px dashed var(--primary-color);
  border-radius: 8px;
}

/* Status Colors */
.column[data-status="todo"] .column-header h3 i {
  color: var(--warning-color);
}

.column[data-status="in-progress"] .column-header h3 i {
  color: var(--primary-color);
}

.column[data-status="done"] .column-header h3 i {
  color: var(--success-color);
}

/* Responsive Design */
@media (max-width: 1200px) {
  .task-board {
    grid-template-columns: 1fr 1fr;
  }

  .stats-panel {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    gap: 1rem;
    padding: 1rem;
  }

  .main-content {
    padding: 1rem;
  }

  .task-board {
    grid-template-columns: 1fr;
  }

  .stats-panel {
    grid-template-columns: 1fr;
  }

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

  .search-group {
    max-width: none;
  }

  .list-header,
  .list-row {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }

  .list-header {
    display: none;
  }

  .list-row {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .form-actions {
    flex-direction: column;
  }
}

/* Animation Classes */
.fade-in {
  animation: fadeIn 0.3s ease-in;
}

.slide-up {
  animation: slideUp 0.3s ease-out;
}

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

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

/* Loading State */
.loading {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 2rem;
  color: var(--text-light);
}

.loading i {
  margin-right: 0.5rem;
  animation: spin 1s linear infinite;
}

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

/* Empty State */
.empty-state {
  text-align: center;
  padding: 3rem 2rem;
  color: var(--text-light);
}

.empty-state i {
  font-size: 3rem;
  margin-bottom: 1rem;
  color: var(--border-color);
}

.empty-state h3 {
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

.empty-state p {
  font-size: 0.9rem;
}