/* Variáveis de Cores */
:root {
    --bg-body: #f4f4f4;
    --bg-calc: #2c3e50;
    --display-bg: #ecf0f1;
    --display-text: #2c3e50;
    --btn-num: #7f8c8d;
    --btn-apagar: #d35400;
    --symbol-opacity: 0.06;
}

/* Modo Escuro */
body.dark-mode {
    --bg-body: #1a1a1a;
    --bg-calc: #000000;
    --display-bg: #2c3e50;
    --display-text: #ffffff;
    --btn-num: #333333;
    --btn-apagar: #8e44ad;
    --symbol-opacity: 0.04;
}

/* Transições e Estilos Base */
body, .calculadora, #display, button {
    transition: all 0.3s ease;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: var(--bg-body);
    overflow: hidden;
    /* PROTEÇÃO CONTRA ZOOM: pan-x pan-y permite rolar se necessário, mas bloqueia o zoom de duplo toque */
    touch-action: pan-x pan-y; 
}

/* Fundo Animado com Símbolos */
body::before {
    content: '';
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    z-index: -1;
    pointer-events: none;
    transition: background-image 0.5s ease;
    animation: flutuar 80s linear infinite;
    
    background-image: 
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='150' height='150'%3E%3Ctext x='20' y='50' font-family='Georgia, serif' font-size='40' fill='rgba(0,0,0,0.06)'%3E%2B%3C/text%3E%3Ctext x='100' y='130' font-family='Georgia, serif' font-size='35' fill='rgba(0,0,0,0.06)'%3E%3D%3C/text%3E%3C/svg%3E"),
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Ctext x='150' y='60' font-family='Georgia, serif' font-size='30' fill='rgba(0,0,0,0.06)'%3E%25%3C/text%3E%3Ctext x='50' y='150' font-family='Georgia, serif' font-size='45' fill='rgba(0,0,0,0.06)'%3E%CF%80%3C/text%3E%3C/svg%3E"),
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Ctext x='30' y='160' font-family='Georgia, serif' font-size='35' fill='rgba(0,0,0,0.06)'%3E%E2%88%9A%3C/text%3E%3Ctext x='120' y='40' font-family='Georgia, serif' font-size='40' fill='rgba(0,0,0,0.06)'%3E%C3%B7%3C/text%3E%3C/svg%3E");
    background-size: 150px 150px, 200px 200px, 180px 180px;
}

body.dark-mode::before {
    background-image: 
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='150' height='150'%3E%3Ctext x='20' y='50' font-family='Georgia, serif' font-size='40' fill='rgba(255,255,255,0.04)'%3E%2B%3C/text%3E%3Ctext x='100' y='130' font-family='Georgia, serif' font-size='35' fill='rgba(255,255,255,0.04)'%3E%3D%3C/text%3E%3C/svg%3E"),
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Ctext x='150' y='60' font-family='Georgia, serif' font-size='30' fill='rgba(255,255,255,0.04)'%3E%25%3C/text%3E%3Ctext x='50' y='150' font-family='Georgia, serif' font-size='45' fill='rgba(255,255,255,0.04)'%3E%CF%80%3C/text%3E%3C/svg%3E"),
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Ctext x='30' y='160' font-family='Georgia, serif' font-size='35' fill='rgba(255,255,255,0.04)'%3E%E2%88%9A%3C/text%3E%3Ctext x='120' y='40' font-family='Georgia, serif' font-size='40' fill='rgba(255,255,255,0.04)'%3E%C3%B7%3C/text%3E%3C/svg%3E");
}

/* Calculadora e Botões */
.topo-acoes { display: flex; justify-content: flex-start; margin-bottom: 10px; }
#theme-toggle { background: transparent; border: none; font-size: 22px; cursor: pointer; touch-action: manipulation; }

.calculadora {
    width: 95%; max-width: 320px; background-color: var(--bg-calc);
    padding: 20px; border-radius: 15px; box-shadow: 0px 10px 30px rgba(0,0,0,0.4);
    box-sizing: border-box; position: relative;
}

#display {
    width: 100%; height: 60px; margin-bottom: 15px; font-size: 28px;
    text-align: right; padding: 10px; box-sizing: border-box;
    border: none; border-radius: 8px; background: var(--display-bg); color: var(--display-text);
}

.conteudo { display: flex; gap: 12px; }
.numeros { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; flex-grow: 1; }
.controles-laterais { display: flex; flex-direction: column; gap: 8px; width: 70px; }

button {
    height: 55px; border-radius: 8px; border: none; cursor: pointer;
    font-size: 20px; font-weight: bold; border-bottom: 4px solid rgba(0,0,0,0.2);
    /* PROTEÇÃO CONTRA ZOOM E SELEÇÃO */
    touch-action: manipulation;
    -webkit-user-select: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

button:active { transform: translateY(2px); border-bottom-width: 2px; }
button:hover { filter: brightness(1.2); }

.btn-num { background: var(--btn-num); color: white; }
.btn-op { background: #e67e22; color: white; }
.btn-limpar { background: #e74c3c; color: white; }
.btn-soma { grid-column: span 2; background: #e67e22; color: white; }
.btn-apagar { background: var(--btn-apagar); color: white; }
.btn-igual { background: #27ae60; color: white; flex-grow: 1; }

@media (max-width: 360px) {
    .calculadora { padding: 15px; }
    button { height: 50px; font-size: 18px; }
    #display { font-size: 24px; height: 50px; }
}

@keyframes flutuar {
    from { background-position: 0 0; }
    to { background-position: 1000px 1000px; }
}