* {
    box-sizing: border-box;
}

.col-1 {width: 8.33%;}
.col-2 {width: 16.66%;}
.col-3 {width: 25%;}
.col-4 {width: 33.33%;}
.col-5 {width: 41.66%;}
.col-6 {width: 50%;}
.col-7 {width: 58.33%;}
.col-8 {width: 66.66%;}
.col-9 {width: 75%;}
.col-10 {width: 83.33%;}
.col-11 {width: 91.66%;}
.col-12 {width: 100%;}

body {
    padding: 1%;
    margin: 2%;
    border: 1px solid red;
    border-top-right-radius: 20px;
    border-bottom-left-radius: 20px;
}

.header {
    padding: 15px;
    color: white;
    background-color: rgb(138, 145, 52);
    background-image: linear-gradient(to bottom right, black, yellow);
    border-top-right-radius: 20px;
}

.footer {
    padding: 15px;
    background-color: rgb(138, 145, 52);
    background-image: linear-gradient(to bottom right,yellow, black);
    border-bottom-left-radius: 20px;
    text-align: right;
    color: white;
}

.row::after {
    content:"";
    clear: both;
    display: table;
}

[class*="col-"] {
    float: left;
    padding: 15px;
    
}

.main {
    background-color: rgb(204, 207, 206);
    height: 60vh;
}

.menu button {
    margin: 2px;
    padding: 3px;
}

.menu ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    padding-top: 10%;
}

.menu li {
    padding: 8px;
    margin: 5px;
    border-top-right-radius: 10px;
    border-bottom-left-radius: 10px;
    background-color: rgb(50, 140, 175);
    color: white;
    text-align: center;
    box-shadow: 2px 2px grey;
}

.menu li:hover {
    background-color: brown;
}

h3 {
    margin-bottom: 0;
}