:root {
    --cor: #2a2a2a;
    --bg: #f6f7f8;
    --card: #fff;
    --card-borda: 00.5rem;
    --card-sombra: 0px 1px 4px #cfcfcf;
    --erro:#dc3545; 
    --sucesso:#28a745; 
    --aviso:#ffc107;
}
    * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
        color: var(--cor);
        font-family: Arial, Helvetica, sans-serif;
    }

body{
    max-width: 800px;
    min-height: 800px;
    margin: 0 auto;
    background-color: var(--bg);
}
header, footer{
    display: flex;
    flex-wrap: wrap;
    height: 70px;
    align-items: center;
    padding: 0 20px;
    background-color: var(--bg);
}
header{
    position: sticky;
    top: 0;
    z-index: 1000;
    justify-content: space-between;
}
footer{
    justify-content: center;
}
section{
    align-items: center;
    background: var(--card);
    border-radius: var(--card-borda);
    box-shadow: var(--card-sombra);
    padding: 20px;
    margin: 50px 20px;
}
input,select, #prompt_usuario{
    width: 100%;
    padding: 12px;
    margin-bottom: 20px;
    border: 0.5px solid var(--cor);
    border-radius: 4px;
    font-size: 16px;
}
#prompt_usuario{
    height: 150px;
}
#resposta{
    background:#eef;
    padding:15px;
    border-radius:6px;
    margin:20px 0;
}
#btn_login, #btn_gerar{
    width: 100%;
    padding: 14px;
    margin: 15px 0;
    background-color: var(--cor);
    color: #fff;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
}
#btn_logout{
    padding: 10px;
    margin: 0;
    background-color: var(--cor);
    color: #fff;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
}

.mensagem.erro{color:var(--erro)}
.mensagem.aviso{color:var(--aviso)}
button:disabled{opacity:.6;cursor:not-allowed;}
h1{ margin-bottom: 20px;  }
h2{ text-align: center; margin-bottom: 20px; }
p{ margin-bottom: 20px; }
.hidden{ display:none }
.historico-item {
  cursor: pointer;
}