*{
    margin: 0;
    padding: 0;
}
body{
    height: 100vh;
    width: 100%;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    display: flex;
}
.container{
    background: linear-gradient(#868f96, #596164);
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    justify-content: center;
    align-items: center;
}

.todo-list{
    background-color: white;
    display: flex;
    flex-direction: column;
    min-width: 400px;
    max-width: 600px;
    height: 500px;
    box-shadow: 0px 0px 20px white;
    border: 1px solid #838383;
    border-radius: 10px;
}
.header{
    padding: 2em;
    text-align: center;
}
.list{
    flex-grow: 1;
    padding: 1em;
    overflow-y: auto;
}
.add-task{
    padding: 2em;
    display: flex;
}
.add-task input{
    padding: 1em;
    flex-grow: 1;
}
.add-task button{
    padding: 1em;
    color: white;
    background-color: #3498db;
}
#box{
    list-style-type: none;
}
#box li{
    border-bottom: 1px solid #99f9f9;
    padding: 1em 0;
    color: crimson;
    font-weight: bold;
}
#box li a{
    float: right;
    cursor: pointer;
}