.app-container {
  display: flex;
  flex-direction: column;
  min-height: 90vh;
  width: 100%;
  max-width: 600px;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 2rem;
  box-shadow: var(--glass-shadow);
  animation: slideIn 0.5s ease-out;
}

.main-content {
  flex-grow: 1;
}

.app-footer {
  margin-top: 2rem;
  padding-top: 1rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85em;
  border-top: 1px solid var(--border-color);
}

.app-footer code {
  background: rgba(139, 92, 246, 0.1);
  padding: 0.2rem 0.4rem;
  border-radius: 6px;
  margin: 0 0.2rem;
  color: var(--accent-primary);
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.title {
  font-size: 2.5rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 2rem;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.todo-form {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
}

.todo-input {
  flex: 1;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 1rem 1.5rem;
  border-radius: 12px;
  font-size: 1rem;
  transition: all 0.3s ease;
}

.todo-input:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 2px rgba(139, 92, 246, 0.2);
}

.todo-input::placeholder {
  color: var(--text-muted);
}

.add-btn {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: white;
  font-weight: 600;
  padding: 0 1.5rem;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.add-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(139, 92, 246, 0.4);
}

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

/* Todo List Styles */
.todo-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.todo-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: 12px;
  transition: all 0.3s ease;
  animation: fadeIn 0.4s ease;
}

.todo-item:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.2);
  transform: translateX(4px);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }

  to {
    opacity: 1;
    transform: scale(1);
  }
}

.todo-content {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex: 1;
}

.checkbox {
  appearance: none;
  width: 24px;
  height: 24px;
  border: 2px solid var(--text-muted);
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.checkbox:checked {
  background-color: var(--success);
  border-color: var(--success);
}

.checkbox:checked::after {
  content: "✔";
  color: white;
  font-size: 14px;
}

.todo-text {
  font-size: 1.1rem;
  color: var(--text-main);
  transition: color 0.3s ease;
}

.todo-text.completed {
  text-decoration: line-through;
  color: var(--text-muted);
}

.delete-btn {
  background: transparent;
  color: var(--text-muted);
  font-size: 1.2rem;
  padding: 0.5rem;
  border-radius: 8px;
}

.delete-btn:hover {
  background: rgba(239, 68, 68, 0.1);
  color: var(--danger);
}

.loading,
.error,
.empty {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 1.1rem;
}

.error {
  color: var(--danger);
}

/* --- Responsive Design --- */

/* Tablets and small desktops */
@media (max-width: 768px) {
  .app-container {
    padding: 1.75rem;
    width: 90%;
    max-width: 600px;
    min-height: 80vh;
  }

  .title {
    font-size: 2.25rem;
  }
}

/* Mobile phones */
@media (max-width: 480px) {
  .app-container {
    padding: 1.5rem 1rem;
    border-radius: 0;
    margin: 0;
    width: 100%;
    max-width: 100%;
    min-height: 100vh;
    border: none;
    box-shadow: none;
    display: flex;
    flex-direction: column;
  }

  .main-content {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
  }

  .todo-wrapper {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
  }

  .todo-list {
    flex-grow: 1;
  }

  .title {
    font-size: 1.75rem;
    margin-bottom: 1.25rem;
  }

  .todo-form {
    flex-direction: column;
    gap: 0.75rem;
  }

  .add-btn {
    padding: 1rem;
    width: 100%;
    font-size: 1.05rem;
    justify-content: center;
  }

  .todo-item {
    padding: 0.85rem 0.75rem;
    border-radius: 10px;
  }

  .todo-text {
    font-size: 1rem;
  }

  .app-footer {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-top: 2rem;
    padding-bottom: 1rem;
  }

  .app-footer code {
    display: inline-block;
  }
}