/* ========================================
   VARIÁVEIS DE CORES E ESPAÇAMENTO
   ======================================== */
:root {
    --primary-color: #6366f1;
    --secondary-color: #ec4899;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --bg-dark: #0f172a;
    --bg-light: #f8fafc;
    --text-dark: #1e293b;
    --text-light: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
}

/* ========================================
   RESET E ESTILOS GLOBAIS
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: var(--text-dark);
}

/* ========================================
   CONTAINER PRINCIPAL
   ======================================== */
.container {
    max-width: 700px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: var(--shadow);
    overflow: hidden;
    animation: slideIn 0.3s ease-out;
}

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

/* ========================================
   CABEÇALHO
   ======================================== */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    font-size: 1rem;
    opacity: 0.9;
    font-weight: 300;
}

/* ========================================
   SEÇÃO DE ENTRADA
   ======================================== */
.input-section {
    padding: 30px;
    border-bottom: 1px solid var(--border-color);
}

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

.task-input {
    flex: 1;
    padding: 14px 18px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.task-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

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

/* ========================================
   BOTÕES
   ======================================== */
.btn {
    padding: 14px 24px;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-add {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-add:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

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

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

.btn-clear:hover {
    background: #dc2626;
    transform: translateY(-2px);
}

.btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
    font-size: 1.2rem;
    transition: all 0.2s ease;
}

.btn-icon:hover {
    transform: scale(1.2);
}

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

.btn-delete:hover {
    color: #dc2626;
}

.btn-edit {
    color: var(--warning-color);
}

.btn-edit:hover {
    color: #d97706;
}

/* ========================================
   FILTROS
   ======================================== */
.filters {
    display: flex;
    gap: 10px;
    padding: 20px 30px;
    border-bottom: 1px solid var(--border-color);
}

.filter-btn {
    padding: 8px 16px;
    border: 2px solid var(--border-color);
    background: white;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.3s ease;
    color: var(--text-light);
}

.filter-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.filter-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* ========================================
   ESTATÍSTICAS
   ======================================== */
.task-stats {
    display: flex;
    gap: 30px;
    padding: 15px 30px;
    background: var(--bg-light);
    font-size: 0.9rem;
}

.stat-item {
    color: var(--text-light);
}

.stat-item strong {
    color: var(--primary-color);
    font-weight: 700;
}

/* ========================================
   LISTA DE TAREFAS
   ======================================== */
.tasks-section {
    padding: 20px 30px;
    min-height: 200px;
}

.task-list {
    list-style: none;
}

.task-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: var(--bg-light);
    border-radius: 10px;
    margin-bottom: 12px;
    transition: all 0.3s ease;
    animation: fadeIn 0.3s ease-out;
}

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

.task-item:hover {
    background: #f1f5f9;
    transform: translateX(5px);
}

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

/* Checkbox customizado */
.checkbox {
    appearance: none;
    width: 24px;
    height: 24px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
}

.checkbox:hover {
    border-color: var(--primary-color);
}

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

.checkbox:checked::after {
    content: '✓';
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    color: white;
    font-size: 0.8rem;
    font-weight: bold;
}

/* Texto da tarefa */
.task-text {
    flex: 1;
    font-size: 1rem;
    color: var(--text-dark);
    word-break: break-word;
}

/* Ações */
.task-actions {
    display: flex;
    gap: 8px;
}

/* ========================================
   MENSAGEM VAZIA
   ======================================== */
.empty-message {
    text-align: center;
    padding: 60px 30px;
    color: var(--text-light);
}

.empty-message p {
    font-size: 1.2rem;
    margin-bottom: 8px;
}

.empty-message .text-small {
    font-size: 0.9rem;
    opacity: 0.7;
}

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

/* ========================================
   RODAPÉ
   ======================================== */
.footer {
    padding: 20px 30px;
    border-top: 1px solid var(--border-color);
}

/* ========================================
   RESPONSIVIDADE
   ======================================== */
@media (max-width: 600px) {
    .header h1 {
        font-size: 2rem;
    }

    .input-group {
        flex-direction: column;
    }

    .btn-add {
        width: 100%;
    }

    .filters {
        flex-wrap: wrap;
    }

    .task-stats {
        flex-direction: column;
        gap: 10px;
    }

    .task-item {
        padding: 12px;
    }

    .container {
        border-radius: 15px;
    }
}

@media (max-width: 400px) {
    .container {
        margin: 0;
        border-radius: 0;
    }

    body {
        padding: 0;
    }

    .input-section,
    .tasks-section,
    .filters,
    .task-stats,
    .footer {
        padding: 15px 20px;
    }
}

/* ========================================
   ANIMAÇÕES UTILITÁRIAS
   ======================================== */
.fade-out {
    animation: fadeOut 0.3s ease-out forwards;
}

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