body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
}

.app-container {
    background: white;
    width: 100%;
    max-width: 550px;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    margin-top: 20px;
}

h1 {
    color: #333;
    text-align: center;
    margin: 0 0 10px 0;
    font-size: 1.8rem;
}

.subtitle {
    color: #666;
    text-align: center;
    margin: 0 0 30px 0;
    font-size: 1rem;
}

.config-box,
.add-todo-box {
    background: #f9f9f9;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 25px;
}

.config-box h2,
.add-todo-box h2 {
    color: #333;
    margin: 0 0 15px 0;
    font-size: 1.1rem;
}

.config-box label,
.add-todo-box label {
    display: block;
    color: #555;
    font-weight: 600;
    margin-bottom: 10px;
    font-size: 0.95rem;
}

.input-group {
    display: flex;
    gap: 10px;
}

.input-group input {
    flex: 1;
    padding: 10px;
    border: 2px solid #ddd;
    border-radius: 6px;
    font-size: 15px;
    font-family: inherit;
}

.input-group input:focus {
    outline: none;
    border-color: #007bff;
    box-shadow: 0 0 5px rgba(0, 123, 255, 0.2);
}

.input-group button {
    padding: 10px 20px;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 6px;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
    font-size: 15px;
}

.input-group button:hover {
    background: #0056b3;
}

.loading {
    text-align: center;
    color: #666;
    font-size: 1rem;
    padding: 30px;
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

.counter {
    background: #f0f8ff;
    color: #333;
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 20px;
    font-weight: 500;
    text-align: center;
    border-left: 4px solid #007bff;
}

.todos-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 30px;
}

.todo-item {
    background: white;
    padding: 15px;
    border-radius: 6px;
    display: flex;
    gap: 12px;
    align-items: center;
    border-left: 4px solid #007bff;
    animation: slideIn 0.2s ease-out;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.todo-item.completed {
    background: #f5f5f5;
    border-left-color: #28a745;
    opacity: 0.7;
}

.todo-item.completed .todo-title {
    text-decoration: line-through;
    color: #999;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.todo-checkbox {
    flex-shrink: 0;
}

.todo-checkbox input {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.todo-content {
    flex: 1;
}

.todo-title {
    color: #333;
    font-weight: 500;
    font-size: 1rem;
    margin: 0 0 4px 0;
}

.todo-id {
    color: #999;
    font-size: 0.8rem;
    margin: 0;
}

.btn-delete {
    padding: 6px 12px;
    background: #fee;
    color: #c00;
    border: 1px solid #fcc;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
    transition: background 0.2s;
}

.btn-delete:hover {
    background: #fcc;
    color: #800;
}

.empty {
    background: white;
    color: #999;
    padding: 30px;
    text-align: center;
    border-radius: 6px;
    border: 1px solid #eee;
}

.error {
    background: #fee;
    color: #c00;
    padding: 15px;
    border-radius: 6px;
    border-left: 4px solid #c00;
    font-weight: 500;
}

.instructions {
    background: #f9f9f9;
    padding: 20px;
    border-radius: 10px;
    border-left: 4px solid #007bff;
    margin-top: 30px;
}

.instructions h2 {
    color: #333;
    margin: 0 0 15px 0;
    font-size: 1.1rem;
}

.instructions h3 {
    color: #555;
    margin: 15px 0 10px 0;
    font-size: 1rem;
}

.instructions ol,
.instructions ul {
    margin-left: 20px;
    color: #555;
    line-height: 1.7;
}

.instructions li {
    margin-bottom: 8px;
}

.instructions code {
    background: white;
    padding: 2px 5px;
    border-radius: 3px;
    font-family: 'Courier New', monospace;
    color: #d63384;
    font-size: 0.9em;
}

.nascosto {
    display: none;
}