* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;

}

body {
    background-color: #252525;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 3em;
    background-image: url('fundo\ louza.webp'); 
    background-repeat: no-repeat;
    background-size: cover;
    flex-direction: column;
}

#calculadora {
    width: 400px;
    padding: 0.5em;
    background-color: #4b4a49;
    color: black;
    display: flex;
    flex-direction: column;
    border-radius: 10px;
    border: 4px solid;
}

#calculadora h3 {
    font-size: 1em;
    font-weight: 300;
    color: #3d3b41;
    text-align: center;
}

#operations {
    text-align: right;
}

#current-operation,
#previus-operation {
    min-height: 1.6em;
    padding: 0.2em;
    overflow-wrap: break-word;
}

#previous-operation {
    color: #000000;
    font-size: 1.5em;
}    

#current-operation {
    font-size: 3em;
    font-weight: 700;
}

#buttons-container {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    gap: 3px;
}

#buttons-container button {
    border: 1px solid transparent;
    border-radius: 0;
    height: 4em;
    font-size: 1.2em;
    background-color: #dbdbdb;
    cursor: pointer;
    border-radius: 10px;
    border: 1px solid;
}

#buttons-container .number {
    background-color: #fefefe;
}

#buttons-container button:hover {
    background-color: #bababa;
    border-color: #999;
}

#buttons-container #equal-btn {
    grid-column: span 2;
    background-color: #75a5cb;
}

#buttons-container #equal-btn:hover {
    background-color: #3a91d8;
}


.glow-on-hover {
    width: 100%;
    height: 50px;
    border: none;
    outline: none;
    color: #fff;
    background: #fcce00;
    cursor: pointer;
    position: relative;
    z-index: 0;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden; 
    border-radius: 10px;
    border: 1px solid;
}

.glow-on-hover:before {
    content: '';
    background: linear-gradient(45deg, #ff0000, #ff7300, #fffb00, #48ff00, #00ffd5, #002bff, #7a00ff, #ff00c8, #ff0000);
    position: absolute;
    top: -2px;
    left: -2px;
    background-size: 400%;
    z-index: -1;
    filter: blur(5px);
    width: 100%; 
    height: calc(100% + 4px);
    animation: glowing 20s linear infinite alternate;
    opacity: 1;
    transition: opacity .3s ease-in-out;
    border-radius: 10px;
}

.glow-on-hover:active {
    color: black;
}

.glow-on-hover:active:after {
    background: transparent;
}

@keyframes glowing {
    0% { background-position: 0 0; opacity: 0; }
    50% { background-position: 400% 0; opacity: 1; }
    100% { background-position: 0 0; opacity: 0; }
}



#operations {
    text-align: right;
    border: 2px solid #000000;
    border-radius: 10px;
    padding: 10px;
    position: relative;
    background: linear-gradient(45deg, #ff0000, #ff7300, #fffb00, #48ff00, #00ffd5, #002bff, #7a00ff, #ff00c8, #ff0000);
    background-clip: text; 
    -webkit-background-clip: text; 
    color: transparent; 
    overflow: hidden;
    animation: gradientAnimation 10s linear infinite;
}

#operations:before {
    content: '';
    background: linear-gradient(45deg, #ff0000, #ff7300, #fffb00, #48ff00, #00ffd5, #002bff, #7a00ff, #ff00c8, #ff0000);
    position: absolute;
    top: -2px;
    left: -2px;
    background-size: 400%;
    z-index: -1;
    filter: blur(5px);
    width: calc(100% + 4px);
    height: calc(100% + 4px);
    animation: glowing 20s linear infinite alternate;
    opacity: 1;
    transition: opacity .3s ease-in-out;
    border-radius: 10px;
}

#operations:hover:before {
    opacity: 1;
}




nav a {
    color: #fcce00;
    text-decoration: none;
    padding: 10px 20px;
    margin: 0 10px;
    border-radius: 5px;
}

@media screen and (max-width: 768px) {
    .menu-icon {
        display: block;
    }

    nav {
        flex-direction: column;
        align-items: flex-start;
    }

    nav a {
        margin: 10px 0;
    }

    header {
        padding: 50px 0;
    }

    h1 {
        font-size: 6em;
    }
}



a {
    text-decoration: none;
    color: #333; 
    position: relative;
    overflow: hidden;
}

a::before {
    content: "";
    position: absolute;
    width: 0;
    height: 2px;
    background-color: #fcce00; 
    bottom: 0;
    left: 0;
    transition: width 0.3s ease; 
}

a:hover::before {
    width: 100%;
}

.back-button{
    padding: 25px;
}


header{
    padding: 5%  
}