style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box; 
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}
html,body{
    height: 100%;
    overflow: hidden;

}
.center{
    display: flex;
    flex-wrap: wrap;
    max-width: 100%;
    margin: 0 auto;
    padding: 0 2%;
    margin-top: 10px;
    margin-right: 10%;
    margin-left: 10%;
}

header{
    height: 15%;
    padding: 20x 0;
}

.logo{ 
    width: 50%;
}

.menu{
    padding-top: 2%;
    width: 50%;
    text-align: right;
}

.menu a{
    color: black ;
    text-decoration: none;
    font-weight: bold;
    margin-left: 15px;

}

section.sobre{
    height: calc(100% - 15%);
    position: relative;
}

.extras{
    position: absolute;
    bottom: -10%;
    right: -15%;
    width: 50%;
    height: 100%;
    border-radius: 50%;
    background-color: #017143;
}

.extras img{
    bottom: 100px;
    right: 100px;
}

.texto-sobre{
    margin-top:100px;
}
.texto-sobre h1{
    font-size:50px;
    max-width: 60%;
    max-height: 60%;
}
.texto-sobre p{
    margin: 20px 0;
    color: black;
    font-size: 14;
    font-weight: bold;
    max-width: 60%;
}
.texto-sobre button{
    border: 0;
    background-color: #017143;
    color: white;
    border-radius: 10px;
    width: 100px;
    height: 30px;
    cursor: pointer;
}