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

:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --border-color: #30363d;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;
  --accent-blue: #58a6ff;
  --accent-green: #3fb950;
  --accent-yellow: #d29922;
  --accent-orange: #db6d28;
  --accent-red: #f85149;
  --accent-purple: #a371f7;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
}

/* Header */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 600;
}

/* Buttons */
.btn-primary {
  background: var(--accent-blue);
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  transition: opacity 0.2s;
}

.btn-primary:hover {
  opacity: 0.9;
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.875rem;
}

.btn-danger {
  background: var(--accent-red);
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.875rem;
}

.btn-small {
  padding: 0.375rem 0.75rem;
  font-size: 0.8125rem;
}

/* Board */
.board {
  display: flex;
  gap: 1rem;
  padding: 1.5rem;
  overflow-x: auto;
  min-height: calc(100vh - 65px);
}

/* Columns */
.column {
  flex: 0 0 280px;
  background: var(--bg-secondary);
  border-radius: 8px;
  border: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  max-height: calc(100vh - 100px);
}

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

.column-header h2 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.count {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  padding: 0.125rem 0.5rem;
  border-radius: 10px;
  font-size: 0.75rem;
}

.tasks {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem;
  min-height: 100px;
}

.tasks.drag-over {
  background: var(--bg-tertiary);
}

/* Task Cards */
.task-card {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.75rem;
  margin-bottom: 0.5rem;
  cursor: grab;
  transition: transform 0.1s, box-shadow 0.1s;
}

.task-card:hover {
  border-color: var(--accent-blue);
}

.task-card.dragging {
  opacity: 0.5;
  cursor: grabbing;
}

.task-card-title {
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

.task-card-meta {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  flex-wrap: wrap;
}

.priority-badge {
  font-size: 0.6875rem;
  padding: 0.125rem 0.375rem;
  border-radius: 4px;
  font-weight: 500;
}

.priority-low { background: #238636; color: white; }
.priority-medium { background: #9e6a03; color: white; }
.priority-high { background: #bd5b00; color: white; }
.priority-urgent { background: #da3633; color: white; }

.update-count {
  font-size: 0.6875rem;
  color: var(--text-muted);
}

.latest-update {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border-color);
  font-style: italic;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Modals */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  z-index: 1000;
  justify-content: center;
  align-items: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  width: 90%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
}

.modal-large {
  max-width: 600px;
}

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

.modal-header h2 {
  font-size: 1.125rem;
}

.close-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.5rem;
  cursor: pointer;
  line-height: 1;
}

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

/* Forms */
form {
  padding: 1rem;
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.375rem;
  color: var(--text-secondary);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.5rem 0.75rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  color: var(--text-primary);
  font-size: 0.875rem;
  font-family: inherit;
}

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

.form-actions {
  display: flex;
  gap: 0.5rem;
  justify-content: flex-end;
  padding-top: 0.5rem;
}

/* Task Detail */
.task-detail {
  padding: 1rem;
}

.detail-meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.status-badge {
  background: var(--bg-tertiary);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.created-by {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.detail-description {
  margin-bottom: 1.5rem;
}

.detail-description h3,
.detail-updates h3 {
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.detail-description p {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--text-primary);
}

/* Updates */
.updates-list {
  max-height: 200px;
  overflow-y: auto;
  margin-bottom: 1rem;
}

.update-item {
  background: var(--bg-tertiary);
  padding: 0.75rem;
  border-radius: 6px;
  margin-bottom: 0.5rem;
  border-left: 3px solid var(--accent-purple);
}

.update-item-text {
  font-size: 0.875rem;
  margin-bottom: 0.375rem;
}

.update-item-meta {
  font-size: 0.6875rem;
  color: var(--text-muted);
}

.add-update-form {
  display: flex;
  gap: 0.5rem;
  padding: 0;
}

.add-update-form textarea {
  flex: 1;
  padding: 0.5rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  color: var(--text-primary);
  font-size: 0.875rem;
  font-family: inherit;
  resize: none;
}

.detail-actions {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: flex-end;
}

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

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

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

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

/* Responsive */
@media (max-width: 768px) {
  header {
    padding: 1rem;
  }
  
  .board {
    padding: 1rem;
  }
  
  .column {
    flex: 0 0 260px;
  }
}