body {
    font-family: 'Arial', sans-serif;
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    background-color: #f0f0f0;
}
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 90%;
    padding: 20px 100px;
    background-color: #333;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #f0f0f0;
    z-index: 99;
}
.logo {
    font-size: 2em;
    color: #ffffff;
    user-select: none;
}
.navigation a {
    position: relative;
    font-size: 1.4em;
    color: #ffffff;
    text-decoration: none;
    font-weight: 500;
    margin-left: 50px;
    right: 40px;
}
.navigation a:after {
    content: '';
    position: absolute;
    left: 0;
    width: 100%;
    height: 3px;
    bottom: -6px;
    background-color: #ffffff;
    border-radius: 5px;
    transform: scaleX(0);
    transition: transform .5s;
}
.navigation a:hover::after {
    transform: scaleX(1);
}
.navigation button {
    width: 100px;
    height: 50px;
    font-size: 1.4em;
    background: transparent;
    border: 2px solid #ffffff;
    outline: none;
    border-radius: 6px;
    cursor: pointer;
    color: #ffffff;
    
}
.navigation button:hover {
    background-color: #ffffff;
    color: #333;
}
#about {
    margin: 0 auto;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}
.footer {
    text-align: center;
    padding: 10px;
    background-color: #333;
    color: #fff;
    position: fixed;
    bottom: 0;
    width: 100%;
}