style.css

/* Basic Style */
body {
    background-color: #f8f8f8;
    color: #333;
    font-family: Lato, sans-serif;
}
.aaa {
    width: 500px;
    margin: 0 auto;
    display: block;
    text-align: right;
}
.aaa img {
    width: 100%;
}
.aaa .more_inf {
    font-family: fantasy, cursive;
}

@media (max-width:768px) {
.aaa { text-align: center;
}
}
.centered-main-page-element {
    display: block;
    width: 500px;
    margin: 0 auto 0;
}
.task {
    width: 56%;
    display: inline-block;
    flex-grow: 1
}
.task-row-wrapper {
    display: flex;
}
ul {
    margin:0;
    padding: 0px;
}
li, h3 {
    list-style:none;
}
input,button{
    outline:none;
}
button {
    background: none;
    border: 0px;
    color: #888;
    font-size: 15px;
    width: 60px;
    font-family: Lato, sans-serif;
    cursor: pointer;
}
button:hover {
    color: #3a3A3a;
}
/* Heading */
h3,
label[for='new-task'] {
    color: #333;
    font-weight: 700;
    font-size: 15px;
    border-bottom: 2px solid #333;
    padding: 30px 0 10px;
    margin: 0;
    text-transform: uppercase;
}
input[type="text"] {
    margin: 0;
    font-size: 18px;
    line-height: 18px;
    height: 21px;
    padding: 0 9px;
    border: 1px solid #dDd;
    background: #FFF;
    border-radius: 6px;
    font-family: Lato, sans-serif;
    color: #888;
}
input[type="text"]:focus {
    color: #333;
}

/* New Task */
label[for='new-task'] {
    display: block;
    margin: 0 0 20px;
}
input#new-task {
    width: 318px;
}

/* Task list */
li {
    overflow: hidden;
    padding: 20px 0;
    border-bottom: 1px solid #eee;

    display: flex;
    justify-content: space-between;
    align-items: center;
}
li > * {
    vertical-align: middle;
}

li > input[type="checkbox"] {
    margin: 0 10px;
}
li > label {
    padding-left: 10px;
    box-sizing: border-box;
    font-size: 18px;
    width: 226px;
}
li >    input[type="text"] {
    width: 226px
}
button.delete img {
    height: 2em;
    transform: rotateZ(45deg);
    transition: transform 200ms ease-in;
}
button.delete img:hover {
    transform: rotateZ(0);
}

/* Completed */
ul#completed-tasks label {
    text-decoration: line-through
    color: #888;
}

/* Edit Task */
ul li input[type=text] {
    display:none
}

ul li.editMode input[type=text] {
    display:inline-block;
    width:224px
}

ul li.editMode label {
    display:none;
}