/* TodoApp — Base Scaffold Styles */

/* Light theme (default) */
:root {
  --bg-body: #f5f5f5;
  --bg-card: #fff;
  --bg-input: #fff;
  --bg-filter: #f0f0f0;
  --bg-filter-hover: #e0e0e0;
  --bg-filter-active: #4a90d9;
  --color-text: #333;
  --color-heading: #222;
  --color-muted: #888;
  --color-placeholder: #999;
  --color-completed: #aaa;
  --color-border: #ddd;
  --color-border-light: #eee;
  --color-accent: #4a90d9;
  --color-accent-hover: #357abd;
  --color-danger: #cc4444;
  --color-danger-hover: #a00;
  --color-footer: #bbb;
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* Dark theme */
[data-theme="dark"] {
  --bg-body: #1a1a2e;
  --bg-card: #16213e;
  --bg-input: #0f3460;
  --bg-filter: #0f3460;
  --bg-filter-hover: #1a4a7a;
  --bg-filter-active: #4a90d9;
  --color-text: #e0e0e0;
  --color-heading: #f0f0f0;
  --color-muted: #8899aa;
  --color-placeholder: #7788aa;
  --color-completed: #667788;
  --color-border: #2a3a5e;
  --color-border-light: #1e2d4d;
  --color-accent: #4a90d9;
  --color-accent-hover: #5da0e9;
  --color-danger: #e05555;
  --color-danger-hover: #ff6b6b;
  --color-footer: #556677;
  --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.4);
}

/* Screen reader only utility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

/* Focus-visible styles for keyboard navigation */
*:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus-visible,
input:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
    Ubuntu, Cantarell, sans-serif;
  background-color: var(--bg-body);
  color: var(--color-text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 2rem 1rem;
}

.app-container {
  width: 100%;
  max-width: 520px;
  background: var(--bg-card);
  border-radius: 8px;
  box-shadow: var(--shadow-card);
  padding: 2rem;
}

header {
  text-align: center;
  margin-bottom: 1.5rem;
  position: relative;
}

header h1 {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--color-heading);
}

/* Theme Toggle */
.theme-toggle {
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-size: 1.2rem;
  cursor: pointer;
  padding: 0.3rem 0.5rem;
  line-height: 1;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.theme-toggle:hover {
  border-color: var(--color-accent);
  transform: translateY(-50%) scale(1.1);
}

/* Task Input */
.task-input {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.task-input input {
  flex: 1;
  padding: 0.6rem 0.8rem;
  font-size: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  outline: none;
  transition: border-color 0.2s;
  background: var(--bg-input);
  color: var(--color-text);
}

.task-input input:focus {
  border-color: var(--color-accent);
}

.task-input input.invalid {
  border-color: var(--color-danger);
  animation: shake 0.3s ease;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}

.task-input button {
  padding: 0.6rem 1.2rem;
  font-size: 1rem;
  background: var(--color-accent);
  color: #fff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
}

.task-input button:hover {
  background: var(--color-accent-hover);
}

/* Filter Bar */
.filter-bar {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.filter-btn {
  flex: 1;
  padding: 0.4rem 0.8rem;
  font-size: 0.85rem;
  background: var(--bg-filter);
  color: var(--color-muted);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.filter-btn:hover {
  background: var(--bg-filter-hover);
}

.filter-btn.active {
  background: var(--bg-filter-active);
  color: #fff;
  border-color: var(--bg-filter-active);
}

/* Toggle All */
.toggle-all-container {
  margin-bottom: 0.5rem;
  padding: 0.4rem 0;
  border-bottom: 1px solid var(--color-border-light);
}

.toggle-all-container.hidden {
  display: none;
}

.toggle-all-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--color-muted);
}

.toggle-all-checkbox {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

/* Task List */
.task-list {
  list-style: none;
  max-height: 400px;
  overflow-y: auto;
}

.task-list li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--color-border-light);
}

.task-list li:last-child {
  border-bottom: none;
}

/* Animations — fade-in for new tasks */
@keyframes task-fade-in {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.task-list li.task-adding {
  animation: task-fade-in 0.3s ease forwards;
}

/* Animations — fade-out for deleted tasks */
@keyframes task-fade-out {
  from {
    opacity: 1;
    transform: translateX(0);
  }
  to {
    opacity: 0;
    transform: translateX(30px);
  }
}

.task-list li.task-deleting {
  animation: task-fade-out 0.3s ease forwards;
}

.task-list li.completed .task-text {
  text-decoration: line-through;
  color: var(--color-completed);
}

.task-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.task-text {
  flex: 1;
  font-size: 1rem;
  cursor: text;
  transition: color 0.3s ease;
}

.task-timestamp {
  font-size: 0.75rem;
  color: var(--color-completed);
}

.edit-input {
  flex: 1;
  font-size: 1rem;
  padding: 0.2rem 0.4rem;
  border: 1px solid var(--color-accent);
  border-radius: 3px;
  outline: none;
  background: var(--bg-input);
  color: var(--color-text);
}

.task-list input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.delete-btn {
  background: none;
  border: none;
  color: var(--color-danger);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 0 0.3rem;
  line-height: 1;
  opacity: 0;
  transition: color 0.15s ease, opacity 0.15s ease, transform 0.15s ease;
}

.task-list li:hover .delete-btn,
.task-list li:focus-within .delete-btn,
.delete-btn:focus-visible {
  opacity: 1;
}

.delete-btn:hover {
  color: var(--color-danger-hover);
  transform: scale(1.15);
}

/* Drag and Drop */
.task-list li[draggable="true"] {
  cursor: grab;
}

.task-list li.dragging {
  opacity: 0.4;
}

.task-list li.drag-over-top {
  border-top: 2px solid var(--color-accent);
  padding-top: calc(0.6rem - 2px);
}

.task-list li.drag-over-bottom {
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: calc(0.6rem - 2px);
}

/* Task Footer */
.task-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 0;
  margin-top: 0.5rem;
  border-top: 1px solid var(--color-border-light);
}

.task-footer.hidden {
  display: none;
}

.task-counter {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.clear-completed-btn {
  font-size: 0.85rem;
  color: var(--color-muted);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  transition: color 0.15s ease;
}

.clear-completed-btn:hover {
  color: var(--color-danger);
}

.clear-completed-btn.hidden {
  display: none;
}

/* Empty State */
.empty-state {
  text-align: center;
  color: var(--color-placeholder);
  padding: 2rem 0;
  font-size: 0.95rem;
}

.empty-state.hidden {
  display: none;
}

/* Export/Import Bar */
.export-import-bar {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
}

.ei-btn {
  flex: 1;
  padding: 0.5rem 0.8rem;
  font-size: 0.85rem;
  background: var(--bg-filter);
  color: var(--color-muted);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  cursor: pointer;
  text-align: center;
  transition: background 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
}

.ei-btn:hover {
  background: var(--bg-filter-hover);
}


.ei-import-label {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* Hover & Focus States */
.task-input button:hover {
  transform: translateY(-1px);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
}

.task-input button:active {
  transform: translateY(0);
  box-shadow: none;
}

.filter-btn:hover {
  transform: translateY(-1px);
}

.filter-btn:active {
  transform: translateY(0);
}

.ei-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.ei-btn:active {
  transform: translateY(0);
  box-shadow: none;
}

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

.toggle-all-label:hover {
  color: var(--color-text);
}

.task-list li:hover {
  background: rgba(0, 0, 0, 0.02);
}

[data-theme="dark"] .task-list li:hover {
  background: rgba(255, 255, 255, 0.03);
}

/* Footer */
footer {
  margin-top: 1.5rem;
  text-align: center;
}

.footer-text {
  font-size: 0.8rem;
  color: var(--color-footer);
}

/* Responsive Design */
@media (max-width: 600px) {
  body {
    padding: 1rem 0.5rem;
  }

  .app-container {
    padding: 1.25rem;
    border-radius: 0;
    box-shadow: none;
  }

  header h1 {
    font-size: 1.5rem;
  }

  .task-input input {
    padding: 0.75rem 0.8rem;
    font-size: 1rem;
    min-height: 44px;
  }

  .task-input button {
    padding: 0.75rem 1rem;
    font-size: 1rem;
    min-height: 44px;
    min-width: 44px;
  }

  .filter-btn {
    padding: 0.6rem 0.5rem;
    font-size: 0.85rem;
    min-height: 44px;
  }

  .task-list li {
    padding: 0.75rem 0;
    gap: 0.75rem;
  }

  .task-list input[type="checkbox"],
  .toggle-all-checkbox {
    width: 24px;
    height: 24px;
    min-width: 44px;
    min-height: 44px;
  }

  .delete-btn {
    font-size: 1.4rem;
    padding: 0.3rem 0.5rem;
    min-width: 44px;
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 1;
  }

  .task-footer {
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  .clear-completed-btn {
    min-height: 44px;
    padding: 0.5rem;
  }
}

@media (max-width: 360px) {
  .app-container {
    padding: 1rem 0.75rem;
  }

  .task-input {
    flex-direction: column;
  }

  .task-input button {
    width: 100%;
  }

  .filter-bar {
    flex-wrap: wrap;
  }

  .filter-btn {
    flex: 1 1 30%;
  }
}

/* Print Styles */
@media print {
  body {
    background: none;
    padding: 0;
    color: #000;
  }

  .app-container {
    box-shadow: none;
    background: none;
    padding: 0;
    max-width: 100%;
    border-radius: 0;
  }

  /* Hide interactive elements */
  .task-input,
  .filter-bar,
  .toggle-all-container,
  .theme-toggle,
  .export-import-bar,
  .clear-completed-btn,
  .delete-btn,
  .task-footer,
  footer {
    display: none !important;
  }

  /* Clean task list */
  .task-list {
    max-height: none;
    overflow: visible;
  }

  .task-list li {
    border-bottom: 1px solid #ccc;
    padding: 0.4rem 0;
    break-inside: avoid;
  }

  .task-list li.completed .task-text {
    text-decoration: line-through;
    color: #999;
  }

  .task-text {
    color: #000;
  }

  /* Show empty state only if relevant */
  .empty-state {
    color: #666;
  }

  /* Remove decorative elements */
  header {
    margin-bottom: 1rem;
  }

  header h1 {
    color: #000;
    font-size: 1.5rem;
  }

  /* Ensure checkboxes print */
  .task-list input[type="checkbox"] {
    -webkit-appearance: auto;
    appearance: auto;
  }

  /* Remove animations */
  .task-list li.task-adding,
  .task-list li.task-deleting {
    animation: none;
    opacity: 1;
    transform: none;
  }

  /* Remove hover backgrounds */
  .task-list li:hover {
    background: none;
  }
}