:root {
  --primary-color: #4f46e5;
  --primary-hover: #4338ca;
  --danger-color: #ef4444;
  --danger-hover: #dc2626;
  --success-color: #10b981;
  --text-dark: #1f2937;
  --text-light: #6b7280;
  --bg-light: #f9fafb;
  --bg-white: #ffffff;
  --border-color: #e5e7eb;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: linear-gradient(135deg, #66beea 0%, #725fdd 100%);
  color: var(--text-dark);
  line-height: 1.6;
  min-height: 100vh;
  padding: 20px;
}

.container {
  max-width: 600px;
  margin: 0 auto;
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-lg);
}

.header {
  text-align: center;
  margin-bottom: 40px;
}

.title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 8px;
  letter-spacing: -0.5px;
}

.subtitle {
  font-size: 1rem;
  color: var(--text-light);
  font-weight: 400;
}

.form-section {
  margin-bottom: 40px;
  padding-bottom: 30px;
  border-bottom: 2px solid var(--bg-light);
}

.task-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.input-field {
  padding: 12px 16px;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-white);
  color: var(--text-dark);
  transition: var(--transition);
  font-family: inherit;
}

.input-field:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
  background: var(--bg-light);
}

.input-field::placeholder {
  color: var(--text-light);
}

.btn {
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
  width: 100%;
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

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

.btn-small {
  padding: 8px 12px;
  font-size: 0.875rem;
  min-width: auto;
}

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

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

.btn-success {
  background: var(--success-color);
  color: white;
}

.tasks-section {
  display: flex;
  flex-direction: column;
}

.tasks-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.tasks-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-dark);
}

.task-count {
  background: var(--bg-light);
  color: var(--text-light);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.875;
  font-weight: 500;
}

.task-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.task-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 16px;
  background: var(--bg-light);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.task-item:hover {
  border-color: var(--primary-color);
  box-shadow: var(--shadow-sm);
  background: var(--bg-white);
}

.task-item.completed {
  opacity: 0.7;
}

.task-item.completed .task-title {
  text-decoration: line-through;
  color: var(--text-light);
}

.task-checkbox {
  width: 20px;
  height: 20px;
  min-width: 20px;
  cursor: pointer;
  accent-color: var(--success-color);
  margin-top: 2px;
}

.task-content {
  flex: 1;
  min-width: 0;
}

.task-title {
  font-weight: 500;
  color: var(--text-dark);
  word-break: break-word;
  margin-bottom: 4px;
}

.task-note {
  font-size: 0.875rem;
  color: var(--text-light);
  word-break: break-word;
}

.task-due-date {
  font-size: 0.8rem;
  color: var(--primary-color);
  font-weight: 500;
  margin-bottom: 4px;
}

.task-actions {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-light);
  font-size: 1.1rem;
}

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

@media (max-width: 640px) {
  .container {
    padding: 24px;
  }

  .title {
    font-size: 2rem;
  }

  .subtitle {
    font-size: 0.95rem;
  }

  .task-item {
    flex-direction: column;
    gap: 8px;
  }

  .task-actions {
    width: 100%;
    margin-top: 8px;
  }

  .btn-small {
    flex: 1;
  }

  .tasks-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.task-item {
  animation: slideIn 0.3s ease-out;
}

@keyframes fadeOut {
  from {
    opacity: 1;
    transform: translateX(0);
  }
  to {
    opacity: 0;
    transform: translateX(10px);
  }
}

.task-item.removing {
  animation: fadeOut 0.3s ease-out forwards;
}

.hidden {
  display: none !important;
}

.flex {
  display: flex;
}

.gap-2 {
  gap: 8px;
}

.mt-2 {
  margin-top: 8px;
}

.mb-2 {
  margin-bottom: 8px;
}