body {
    font-family: 'Segoe UI', sans-serif;
    position: relative;
    margin: 0;
    align-items: center;
    justify-content: space-between;
    min-height: 100vh;
    font-size: 15pt;
    display: flex;
    flex-direction: column;
}
body::before {
    content: '';
    position: absolute;
    top: 0 ;
    left: 0 ;
    width: 100% ;
    height: 100%; 
    background-image: url('images/roi1.jpeg');
    background-size: cover ;
    background-position: center ;
    filter: blur(5px);
    opacity: 0.8;
    z-index: -1;
}

header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    font-weight: 700;
    font-size: 2.5rem;
    padding: 1rem;
    flex: 2;
}

header img {
    width: 90px ;
    height: 90px ;
    border-radius: 50%;
}

main {
    width: 100%;
    margin: 1rem auto;
}

.container {
    position: relative;
    margin: auto;
    padding: 30px 40px;
    border-radius: 10px;
    background: gray;
    width: 100%;
    max-width: 400px;
    color: white;
}

h2 {
    text-align: center;
    margin-bottom: 20px;
    color: #fff;
}
label {
    display: block;
    margin: 15px 0 5px;
}
input {
    width: 100%;
    padding: 10px;
    font-size: 16px;
    border: 1px solid #ccc;
    border-radius: 6px;
}
button {
    margin-top: 20px;
    width: 100%;
    background-color: #007BFF;
    color: white;
    border: none;
    padding: 12px;
    font-size: 16px;
    border-radius: 6px;
    cursor: pointer;
}
button:hover {
    background-color: #0056b3;
}
.result {
    margin-top: 20px;
    text-align: center;
    font-weight: bold;
    font-size: 28px;
}
.error {
    color: red;
}
.bonus {
    color: green ;
}

footer {
    width: 100%;
    line-height: .9;
    padding: 1.6rem 0;
    text-shadow: 1px 1px 2px purple;
    text-align: center;
}

footer .pair{
    display: flex;
    justify-content: space-evenly;
}

footer .footerlink {
    text-decoration: none;
    color: yellow;
    border-radius: 10px;
    padding: .3rem .8rem;
    font-size: 1.8rem;
    font-weight: 600;
}
footer .footerlink:hover {
    background-color: #fd8c7d;
}

footer p {
    display: inline-block;
    text-align: center;
    user-select: none;
    letter-spacing: 1px;
    font-size: 1.3rem;
    font-weight: 600;
    text-shadow: 1px 1px 2px rgba(255, 255, 255, .7);
}
footer p:hover {
    color: white;
    text-shadow: 2px 3px 6px rgba(0, 0, 0, .7);
}

footer .pair .footerbutton img {
    width: 40px;
    height: 40px;
    border-radius: 25%;
}
footer .pair .footerbutton:hover {
    transform: translateY(-3px);
    box-shadow: 0 7px 15px rgba(0, 200, 250, 0.4);
}









/* -------        MEDIA QUERIES FOR DEVICES WITH SMALL WIDTH   --------- */
@media (max-width: 768px) {
    .container {
        max-width: 250px;
    }
}