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

:root {
  --bg: #1e1e2e;
  --surface: #2a2a3e;
  --surface2: #33334d;
  --border: #3e3e5e;
  --text: #e0e0f0;
  --text-muted: #8888aa;
  --primary: #3b82f6;
  --danger: #ef4444;
  --radius: 8px;
}

[data-theme="light"] {
  --bg: #f0f2f5;
  --surface: #ffffff;
  --surface2: #e4e6eb;
  --border: #ccced4;
  --text: #1a1a2e;
  --text-muted: #6c6e80;
  --primary: #2563eb;
  --danger: #dc2626;
}

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

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

header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#board-title {
  font-size: 1.3rem;
  font-weight: 600;
  padding: 4px 8px;
  border-radius: 4px;
  outline: none;
  cursor: text;
  min-width: 100px;
}
#board-title:focus {
  background: var(--surface2);
}

#board-nav {
  display: flex;
  gap: 6px;
  flex: 1;
}
#board-nav button {
  background: var(--surface2);
  color: var(--text-muted);
  border: 1px solid var(--border);
  padding: 4px 12px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
}
#board-nav button.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

#header-actions {
  display: flex;
  gap: 8px;
}
#header-actions button {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 6px 14px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
}
#show-archived-btn {
  background: var(--surface2);
}
#delete-board-btn {
  background: var(--danger);
}

main {
  flex: 1;
  overflow-x: auto;
  overflow-y: hidden;
  padding: 20px;
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.column {
  background: var(--surface);
  border-radius: var(--radius);
  width: 280px;
  min-width: 280px;
  max-height: calc(100vh - 100px);
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
}

.column-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  cursor: grab;
}
.column-header h2 {
  font-size: 0.95rem;
  font-weight: 600;
}
.column-header-actions {
  display: flex;
  gap: 4px;
}
.column-header-actions button {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.8rem;
  padding: 2px 6px;
  border-radius: 4px;
}
.column-header-actions button:hover {
  background: var(--surface2);
  color: var(--text);
}

.column-cards {
  flex: 1;
  overflow-y: auto;
  padding: 8px;
  min-height: 60px;
}

.column-footer {
  padding: 8px;
  border-top: 1px solid var(--border);
}
.column-footer button {
  width: 100%;
  background: none;
  border: 1px dashed var(--border);
  color: var(--text-muted);
  padding: 6px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
}
.column-footer button:hover {
  background: var(--surface2);
  color: var(--text);
}

.card {
  background: var(--surface2);
  border-radius: 6px;
  padding: 10px;
  margin-bottom: 8px;
  cursor: grab;
  border: 1px solid var(--border);
  transition: box-shadow 0.15s;
}
.card:hover {
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
}
.card-title {
  font-size: 0.9rem;
  font-weight: 500;
  margin-bottom: 6px;
  word-break: break-word;
}
.card-labels {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 6px;
}
.card-label {
  font-size: 0.7rem;
  padding: 1px 6px;
  border-radius: 3px;
  color: #fff;
}
.card-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
}
.card-archived-badge {
  color: var(--text-muted);
  font-style: italic;
}
.card.dragging {
  opacity: 0.5;
}
.sortable-ghost {
  opacity: 0.3;
  background: var(--primary);
}

.modal {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}
.modal.hidden {
  display: none;
}
.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.5);
}
.modal-body {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: 90%;
  max-width: 560px;
  max-height: 85vh;
  overflow-y: auto;
  padding: 20px;
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}
.modal-header h3 {
  font-size: 1.1rem;
}
.modal-header input[type="text"] {
  flex: 1;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 10px;
  border-radius: 4px;
  outline: none;
}
.modal-header input[type="text"]:focus {
  border-color: var(--primary);
}

.modal-body label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 4px;
  margin-top: 14px;
}

.md-editor {
  display: flex;
  gap: 8px;
}
.md-editor textarea {
  flex: 1;
  height: 120px;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px;
  border-radius: 4px;
  resize: vertical;
  font-family: monospace;
  font-size: 0.85rem;
  outline: none;
}
.md-editor textarea:focus {
  border-color: var(--primary);
}
.markdown-preview {
  flex: 1;
  height: 120px;
  overflow-y: auto;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 8px;
  font-size: 0.85rem;
}
.markdown-preview p { margin-bottom: 6px; }
.markdown-preview ul { padding-left: 20px; }
.markdown-preview code {
  background: var(--surface2);
  padding: 1px 4px;
  border-radius: 3px;
  font-size: 0.8rem;
}
.markdown-preview pre {
  background: var(--surface2);
  padding: 8px;
  border-radius: 4px;
  overflow-x: auto;
  margin-bottom: 6px;
}

#checklist-area {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.checklist-row {
  display: flex;
  align-items: center;
  gap: 6px;
}
.checklist-row input[type="checkbox"] {
  accent-color: var(--primary);
}
.checklist-row input[type="text"] {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 0.85rem;
  outline: none;
}
.checklist-row input[type="text"]:focus {
  border-color: var(--primary);
}
.checklist-row .checklist-del {
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 0.9rem;
}

#labels-area {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 6px;
}
.label-tag {
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 3px;
  color: #fff;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.label-tag .label-del {
  cursor: pointer;
  opacity: 0.7;
  font-size: 0.8rem;
}
.label-tag .label-del:hover {
  opacity: 1;
}

.label-form {
  display: flex;
  gap: 6px;
  align-items: center;
}
.label-form input[type="text"] {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 0.85rem;
  outline: none;
}
.label-form input[type="text"]:focus {
  border-color: var(--primary);
}
.label-form input[type="color"] {
  width: 30px;
  height: 30px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  background: none;
}

.small-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.8rem;
  margin-top: 4px;
}
.small-btn:hover {
  background: var(--primary);
  border-color: var(--primary);
}

.modal-footer {
  display: flex;
  gap: 8px;
  margin-top: 20px;
}
.primary-btn {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 8px 20px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.9rem;
}
.danger-btn {
  background: transparent;
  color: var(--danger);
  border: 1px solid var(--danger);
  padding: 8px 20px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.9rem;
}
.danger-btn:hover {
  background: var(--danger);
  color: #fff;
}

#column-list {
  list-style: none;
  margin-bottom: 12px;
}
#column-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 4px;
  border-bottom: 1px solid var(--border);
}
#column-list li span {
  flex: 1;
}
#column-list li input {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 0.85rem;
  outline: none;
}
#column-list li button {
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 0.9rem;
  margin-left: 8px;
}

.column-add-form {
  display: flex;
  gap: 6px;
}
.column-add-form input {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 10px;
  border-radius: 4px;
  font-size: 0.85rem;
  outline: none;
}
.column-add-form input:focus {
  border-color: var(--primary);
}

#archived-list {
  list-style: none;
}
#archived-list li {
  padding: 8px 4px;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
#archived-list li button {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.8rem;
}

::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: var(--bg);
}
::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}

#theme-toggle {
  background: var(--surface2);
  font-size: 1rem;
  padding: 4px 10px;
  line-height: 1;
}

#manage-columns-btn {
  background: var(--surface2);
}

#column-list li {
  cursor: grab;
}
#column-list li.dragging {
  opacity: 0.5;
}
#column-list li.sortable-ghost {
  opacity: 0.3;
  background: var(--primary);
}

@media (max-width: 768px) {
  header {
    flex-wrap: wrap;
    gap: 6px;
    padding: 8px 10px;
  }
  #board-title {
    font-size: 1rem;
    min-width: 80px;
  }
  #board-nav {
    order: 3;
    flex: 0 0 100%;
    overflow-x: auto;
    gap: 4px;
  }
  #board-nav button {
    font-size: 0.75rem;
    padding: 3px 8px;
    white-space: nowrap;
  }
  #header-actions button {
    font-size: 0.75rem;
    padding: 4px 8px;
  }
  main {
    padding: 10px;
    gap: 10px;
  }
  .column {
    min-width: 240px;
    width: 240px;
    max-height: calc(100vh - 80px);
  }
  .modal-body {
    width: 95%;
    padding: 14px;
  }
  .md-editor {
    flex-direction: column;
  }
  .md-editor textarea,
  .md-editor .markdown-preview {
    height: 100px;
  }
}