* {
    box-sizing: border-box;
}

body {
    background-color: aquamarine;
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

/* Container holds the two columns side-by-side */
.container {
    display: flex;
    width: 100vw;
    height: 100vh;
}

/* Each column takes exactly 50% of the screen */
.column {
    width: 50vw;
    padding: 20px;
    overflow-y: auto;
    border-right: thin solid black;
}

/* Specific backgrounds */
#output.column {
    background-color: yellow;
}

#completed.column {
    background-color: lightgreen;
}

/* Headings */
h2 {
    margin-top: 0;
}

/* Tasks */
.task {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 8px 0;
    padding: 8px;
    background: white;
    border-radius: 4px;
    box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

/* Buttons */
button {
    margin-left: 6px;
    font-size: 13px;
    padding: 4px 10px;
    cursor: pointer;
}

.delete {
    background: crimson;
    color: white;
    border: none;
}

.undo {
    background: dodgerblue;
    color: white;
    border: none;
}

#todo {
    position: absolute;
    top: 10px;
    left: 10px;
    font-size: 18px;
    padding: 6px 12px;
    z-index: 10;
    background: black;
    color: white;
}

#date {
    position: absolute;
    top: 16px;
    left: 70px;
    font-size: 16px;
}