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

:root {
  --bg-primary: #c8c8c8;
  --bg-secondary: #d0d0d0;
  --bg-card: #f0f0f0;
  --bg-input: #f5f5f5;
  --bg-btn: #e8e8e8;
  --bg-modal: #e8e8e8;
  --text-primary: #333;
  --text-secondary: #555;
  --text-muted: #777;
  --border-color: #d8d8d8;
  --border-light: #ccc;
  --shadow: rgba(0,0,0,0.1);
  --shadow-strong: rgba(0,0,0,0.25);
  --danger: #c04040;
}

body.dark {
  --bg-primary: #1a1a1a;
  --bg-secondary: #2a2a2a;
  --bg-card: #333;
  --bg-input: #444;
  --bg-btn: #404040;
  --bg-modal: #333;
  --text-primary: #e0e0e0;
  --text-secondary: #ccc;
  --text-muted: #999;
  --border-color: #444;
  --border-light: #555;
  --shadow: rgba(0,0,0,0.3);
  --shadow-strong: rgba(0,0,0,0.5);
  --danger: #e05050;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  font-weight: 400;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 32px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-light);
  box-shadow: 0 2px 6px var(--shadow);
}

.header-title {
  font-size: 22px;
  font-weight: 500;
  letter-spacing: -0.5px;
}

.header-actions {
  display: flex;
  gap: 8px;
}

.btn {
  padding: 10px 20px;
  border: none;
  background: var(--bg-btn);
  border-radius: 20px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s ease;
  box-shadow: 0 2px 4px var(--shadow);
  color: var(--text-primary);
}

.btn:hover {
  background: var(--border-light);
  box-shadow: 0 4px 8px var(--shadow);
  transform: translateY(-1px);
}

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

.btn-danger:hover {
  background: var(--danger);
  color: #fff;
}

.btn-secondary {
  background: var(--bg-secondary);
  box-shadow: none;
}

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

.btn-icon {
  padding: 10px;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.main {
  display: flex;
  gap: 28px;
  padding: 28px;
  max-width: 1200px;
  margin: 0 auto;
}

.column {
  flex: 1;
  background: var(--bg-card);
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 12px var(--shadow);
}

.column-title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-light);
  letter-spacing: 0.5px;
  color: var(--text-secondary);
}

.tasks-container {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.bucket-section {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 8px;
}

.bucket-heading {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-top: 8px;
  margin-bottom: 12px;
  letter-spacing: 0.5px;
  text-align: center;
}

.task-section-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-top: 20px;
  padding-top: 12px;
  border-top: 1px solid var(--border-light);
  text-align: center;
}

.task-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  background: var(--bg-btn);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.task-row:hover {
  background: var(--bg-secondary);
  border-color: var(--border-light);
  box-shadow: 0 2px 6px var(--shadow);
}

.task-row.done {
  opacity: 0.6;
}

.task-row.done .task-title {
  text-decoration: line-through;
  font-style: italic;
}

.task-checkbox {
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--text-secondary);
}

.task-title {
  flex: 1;
  font-size: 14px;
}

.task-delete {
  padding: 4px 8px;
  border: none;
  background: transparent;
  color: var(--danger);
  cursor: pointer;
  font-size: 14px;
  opacity: 0;
  transition: opacity 0.2s;
}

.task-row:hover .task-delete {
  opacity: 1;
}

.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  justify-content: center;
  align-items: center;
}

.modal.hidden {
  display: none;
}

.modal-content {
  background: var(--bg-modal);
  padding: 28px;
  border-radius: 16px;
  width: 400px;
  max-width: 90%;
  box-shadow: 0 8px 32px var(--shadow-strong);
}

.modal-content h3 {
  margin-bottom: 16px;
  font-size: 18px;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  margin-bottom: 4px;
  font-size: 14px;
  font-weight: 500;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border-light);
  border-radius: 10px;
  font-size: 14px;
  transition: border-color 0.2s;
  background: var(--bg-input);
  color: var(--text-primary);
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--text-muted);
  background: var(--bg-btn);
}

.form-actions {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  margin-top: 20px;
}

@media (max-width: 768px) {
  .main {
    flex-direction: column;
  }
}