* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f4f4; 
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh; 
    padding: 20px; 
}

#app {
    width: 100%;
    max-width: 420px;
    text-align: center; 
}

h1 {
    margin-bottom: 20px;
    font-size: 1.6rem;
    color: #333;
    font-weight: 600;
}

#calc-card {
    background: #ffffff;
    padding: 25px;
    border-radius: 40px; 
    box-shadow: 
        0 4px 12px rgba(0, 0, 0, 0.08),
        0 2px 4px rgba(0, 0, 0, 0.04);
    display: flex;
    flex-direction: column;
    gap: 16px; 
}

label {
    text-align: left;
    font-size: 0.95rem;
    font-weight: 500;
    color: #444;
}

input {
    padding: 12px;
    border-radius: 12px;
    border: 1px solid #ccc;
    font-size: 1rem;
    outline: none;
    transition: 0.2s;
}

input:focus {
    border-color: #4a90e2;
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.25);
}

button {
    background: #4a90e2;     
    color: white;
    padding: 14px;
    border: none;
    border-radius: 25px;
    font-size: 1.1rem;
    cursor: pointer;
    font-weight: 600;
    transition: 0.2s;
}

button:hover {
    background: #3b7fce;
}

.btn-primario {
    width: 100%;         
    border-radius: 25px;   
}

.btn-primario:hover {
    background: #3b7fce;
}

.btn-secundario {
    background: #bdbdbd; 
    color: #333;
    padding: 12px;
    border: none;
    border-radius: 25px;
    font-size: 1rem;
    cursor: pointer;
    font-weight: 600;
    transition: 0.2s;
    width: 100%;
    margin-top: 10px;
}

.btn-secundario:hover {
    background: #a5a5a5;
}

#btnReiniciar {
    display: none;
}

#resultado {
    margin-top: 10px;
    font-size: 1.05rem;
    color: #222;
    line-height: 1.5;
    font-weight: 500;
}

@media (max-width: 350px) {
    #calc-card {
        padding: 18px;
        border-radius: 25px; 
    }
    h1 {
        font-size: 1.3rem;
    }
}