/* Dark mode styles */
body.dark-mode {
  background: linear-gradient(135deg, #181f2a 0%, #232b3a 100%);
  color: #e5e7eb;
}

.dark-mode .container {
  background: #232b3a;
  box-shadow: 0 4px 24px rgba(0,0,0,0.25);
}

.dark-mode h1 {
  color: #60a5fa;
}

.dark-mode #task-form button {
  background: #60a5fa;
  color: #181f2a;
}

.dark-mode #task-form button:hover,
.dark-mode #task-form button:focus {
  background: #2563eb;
  color: #fff;
}

.dark-mode #task-input {
  background: #181f2a;
  color: #e5e7eb;
  border: 1px solid #334155;
}

.dark-mode #task-input:focus {
  border-color: #60a5fa;
}

.dark-mode .task-item {
  background: #1e293b;
  color: #e5e7eb;
}

.dark-mode .task-item.completed {
  background: #334155;
  color: #64748b;
}

.dark-mode .task-actions button {
  color: #60a5fa;
}

.dark-mode .task-actions .delete-btn {
  color: #f87171;
}

.dark-mode .task-actions .delete-btn:hover {
  background: #7f1d1d;
  color: #fff;
}

.dark-mode .task-actions .complete-btn:hover {
  background: #1e40af;
  color: #fff;
}

.dark-mode .filters {
  background: transparent;
}

.dark-mode .filter-btn {
  background: #1e293b;
  color: #60a5fa;
}

.dark-mode .filter-btn.active, .dark-mode .filter-btn:focus {
  background: #60a5fa;
  color: #181f2a;
}

.dark-mode .filter-btn:hover:not(.active) {
  background: #2563eb;
  color: #fff;
}
/* Visually hidden utility for accessibility */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

body {
  font-family: 'Segoe UI', Arial, sans-serif;
  background: linear-gradient(135deg, #f8fafc 0%, #e0e7ef 100%);
  margin: 0;
  min-height: 100vh;
  color: #222;
}

.container {
  max-width: 400px;
  margin: 3rem auto;
  background: #fff;
  border-radius: 1rem;
  box-shadow: 0 4px 24px rgba(0,0,0,0.08);
  padding: 2rem 1.5rem 2.5rem 1.5rem;
}

h1 {
  text-align: center;
  margin-bottom: 1.5rem;
  font-size: 2rem;
  color: #2563eb;
}

#task-form {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

#task-input {
  flex: 1;
  padding: 0.75rem;
  border: 1px solid #cbd5e1;
  border-radius: 0.5rem;
  font-size: 1rem;
  outline: none;
  transition: border 0.2s;
}

#task-input:focus {
  border-color: #2563eb;
}

#task-form button {
  background: #2563eb;
  color: #fff;
  border: none;
  border-radius: 0.5rem;
  padding: 0 1.25rem;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

#task-form button:hover,
#task-form button:focus {
  background: #1d4ed8;
}

#task-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.task-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #f1f5f9;
  border-radius: 0.5rem;
  padding: 0.75rem 1rem;
  margin-bottom: 0.75rem;
  transition: background 0.2s;
}

.task-item.completed {
  text-decoration: line-through;
  color: #94a3b8;
  background: #e2e8f0;
}

.task-actions {
  display: flex;
  gap: 0.5rem;
}

.task-actions button {
  background: none;
  border: none;
  color: #2563eb;
  font-size: 1.1rem;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  border-radius: 0.3rem;
  transition: background 0.2s, color 0.2s;
}

.task-actions button:focus {
  outline: 2px solid #2563eb;
}

.task-actions .delete-btn {
  color: #ef4444;
}

.task-actions .delete-btn:hover {
  background: #fee2e2;
}

.task-actions .complete-btn:hover {
  background: #dbeafe;
}

@media (max-width: 500px) {
  .container {
    max-width: 98vw;
    padding: 1rem 0.5rem 1.5rem 0.5rem;
  }
  h1 {
    font-size: 1.3rem;
  }
  #task-form button {
    padding: 0 0.7rem;
    font-size: 0.95rem;
  }
  .task-item {
    padding: 0.6rem 0.7rem;
  }
}