* {
    box-sizing: border-box;
}

body {
    text-align: center;
}

section {
    width: 70%;
    margin: auto;
    margin-top: 50px;
    margin-bottom: 50px;
    border: 5px solid rgb(100, 100, 100);
}

    #header {
        background: rgb(148, 45, 45);
        margin: auto;
        padding: 30px 40px;
        text-align: center;
    }
        .section-header {
            color: white;
            font-size: 30px;
            font-weight: bold;
            margin-bottom: 50px;
        }
            input {
                border: none;
                width: 75%;
                padding: 10px;
                float: left;
                font-size: 16px;
            }
            #add-button {
                padding: 10px;
                width: 25%;
                background: #d9d9d9;
                color: #555;
                float: right;
                text-align: center;
                font-size: 16px;
                cursor: pointer;
                transition: 0.3s;
            }
    
    #list-container {
        width: 100%;
        margin: auto;
        max-height: 467px;
        overflow: auto;
    }
        #list {
            list-style: none;
            padding: 0;
            margin: 0;
        }
            #list li {
                position: relative;
                cursor: pointer;
                padding: 12px 8px 12px 40px;
                text-align: left;
                background: rgb(250, 250, 250);
            }
            #list li:nth-child(odd) {
                background: rgb(230, 230, 230);
            }
                li:nth-child(odd).done {
                    background: rgb(60, 60, 60);
                }
            #list li:hover {
                background: rgb(64, 73, 133);
                color: white;
                transition: 0.5s;
            }

            .close {
                position: absolute;
                right: 0;
                top: 0;
                padding: 12px;
            }
                .close:hover {
                    background: red;
                    color: white;
                    transition: 0.5s;
                }

            #list li.done {
                background: rgb(60, 60, 60);
                color: white;
                text-decoration: line-through;
            }
            #list li.done::before {
                content: '';
                position: absolute;
                border-color: #fff;
                border-style: solid;
                border-width: 0 2px 2px 0;
                top: 10px;
                left: 16px;
                transform: rotate(45deg);
                height: 15px;
                width: 7px;
            }