/* Reset Minimalista */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

/* Variáveis de Cores - Padrão Dark Mode Premium */
:root {
    --bg-principal: #0f172a;
    --bg-card: #1e293b;
    --texto-principal: #f8fafc;
    --texto-secundario: #94a3b8;
    --cor-accent: #3b82f6; /* Azul Tech */
    --cor-sucesso: #10b981;
    --borda: #334155;
    --sidebar-width: 260px;
}

/* Modificadores para Light Clean (Ativado via classe no body) */
body.light-mode {
    --bg-principal: #f8fafc;
    --bg-card: #ffffff;
    --texto-principal: #0f172a;
    --texto-secundario: #64748b;
    --cor-accent: #2563eb;
    --borda: #e2e8f0;
}

body {
    background-color: var(--bg-principal);
    color: var(--texto-principal);
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
}

/* Layout Estrutural (Grid Responsivo) */
#app-container {
    display: grid;
    grid-template-columns: 1fr; /* Mobile First: Ocupa a tela toda */
    grid-template-rows: 60px 1fr;
    grid-template-areas: 
        "topo"
        "conteudo";
    min-height: 100vh;
}

/* Topo do Sistema */
.navbar {
    grid-area: topo;
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--borda);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.brand {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--cor-accent);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

/* Menu Lateral (Sidebar) */
.sidebar {
    background-color: var(--bg-card);
    border-right: 1px solid var(--borda);
    padding: 20px;
    display: none; /* Escondido por padrão no mobile */
}

.sidebar ul {
    list-style: none;
}

.sidebar a {
    display: block;
    color: var(--texto-secundario);
    text-decoration: none;
    padding: 12px 15px;
    border-radius: 8px;
    margin-bottom: 5px;
    transition: 0.2s;
    font-weight: 500;
}

.sidebar a:hover, .sidebar a.active {
    background-color: var(--bg-principal);
    color: var(--cor-accent);
}

/* Área de Conteúdo */
.main-content {
    grid-area: conteudo;
    padding: 20px;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
}

/* Elementos de UI comuns (Cards e Botões) */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--borda);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 20px;
}

.btn {
    background-color: var(--cor-accent);
    color: #ffffff;
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: opacity 0.2s;
}

.btn:hover { opacity: 0.9; }

.btn-theme {
    background: none;
    border: 1px solid var(--borda);
    color: var(--texto-principal);
    padding: 8px;
    border-radius: 50%;
    cursor: pointer;
    width: 35px;
    height: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Media Query para Telas Maiores (Desktop) */
@media (min-width: 768px) {
    #app-container {
        grid-template-columns: var(--sidebar-width) 1fr;
        grid-template-areas: 
            "topo topo"
            "menu conteudo";
    }
    
    .sidebar {
        grid-area: menu;
        display: block; /* Exibe o menu lateral na esquerda */
        height: calc(100vh - 60px);
        position: sticky;
        top: 60px;
    }
    
    .menu-toggle { display: none; } /* Esconde o botão hambúrguer */
}

@media (max-width: 767px) {
    .sidebar.show-mobile {
        display: block;
        position: fixed;
        top: 60px;
        left: 0;
        width: 100%;
        height: calc(100vh - 60px);
        z-index: 99;
    }