/* 1. Variáveis de Design - Paleta refinada e espaçamentos */
:root {
    --primary-color: #6c5ce7;
    --primary-hover: #5b4bc4;
    --bg-color: #f0f2f5;
    --card-bg: #ffffff;
    --text-main: #2d3436;
    --text-muted: #636e72;
    
    --priority-high: #ff7675;
    --priority-medium: #fdcb6e;
    --priority-low: #55efc4;
    
    --radius: 12px;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 10px 25px rgba(0, 0, 0, 0.08);
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 2. Reset e Layout Base */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
    background: var(--bg-color);
    background-image: radial-gradient(#d1d1d1 0.5px, transparent 0.5px); /* Detalhe sutil no fundo */
    background-size: 20px 20px;
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    padding: 40px 20px;
}

.todo-container {
    width: 100%;
    max-width: 480px;
    background: var(--card-bg);
    padding: 2.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
}

/* 3. Tipografia e Cabeçalho */
header h1 {
    font-size: 1.8rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    text-align: center;
}

h2 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text-main);
}

/* 4. Formulário e Inputs */
.todo-form {
    display: grid;
    gap: 1.2rem;
}

.field-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
}

input[type="text"], select {
    padding: 12px 16px;
    border: 2px solid #edf2f7;
    border-radius: 8px;
    font-size: 1rem;
    transition: var(--transition);
    outline: none;
}

input[type="text"]:focus, select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(108, 92, 231, 0.1);
}

.btn-add {
    background: var(--primary-color);
    color: white;
    padding: 14px;
    border: none;
    border-radius: 8px;
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 0.5rem;
}

.btn-add:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(108, 92, 231, 0.2);
}

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

hr {
    border: 0;
    border-top: 1px solid #edf2f7;
    margin: 2rem 0;
}

/* 5. Estilização da Lista de Tarefas */
.task-list {
    list-style: none;
}

.task-item {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    margin-bottom: 12px;
    background: #fff;
    border-radius: 10px;
    border: 1px solid #f1f3f5;
    border-left: 5px solid #dfe6e9;
    transition: var(--transition);
}

.task-item:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-sm);
}

/* Cores de Prioridade com gradientes suaves */
.task-item.priority-alta { border-left-color: var(--priority-high); }
.task-item.priority-media { border-left-color: var(--priority-medium); }
.task-item.priority-baixa { border-left-color: var(--priority-low); }

/* Checkbox Customizado (Visual mais limpo) */
.task-item input[type="checkbox"] {
    appearance: none;
    width: 20px;
    height: 20px;
    border: 2px solid #cbd5e0;
    border-radius: 6px;
    margin-right: 12px;
    cursor: pointer;
    position: relative;
    transition: var(--transition);
}

.task-item input[type="checkbox"]:checked {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.task-item input[type="checkbox"]:checked::after {
    content: '✓';
    position: absolute;
    color: white;
    font-size: 14px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.task-item input[type="checkbox"]:checked + label {
    text-decoration: line-through;
    color: var(--text-muted);
    opacity: 0.5;
}

.task-content {
    font-weight: 500;
    flex-grow: 1;
}

/* Badge de Prioridade */
.badge-priority {
    font-size: 0.65rem;
    padding: 4px 8px;
    border-radius: 20px;
    background: #f8f9fa;
    color: var(--text-muted);
    border: 1px solid #e9ecef;
    margin-left: 10px;
}

/* Botão Deletar */
.btn-delete {
    background: transparent;
    border: none;
    color: #fab1a0;
    font-size: 1.2rem;
    cursor: pointer;
    margin-left: 10px;
    padding: 4px 8px;
    border-radius: 6px;
    transition: var(--transition);
}

.btn-delete:hover {
    color: var(--priority-high);
    background: #fff5f5;
}

/* Rodapé */
footer {
    margin-top: 2rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: center;
}

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