* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: sans-serif;
}

#app {
    max-width: 720px;
    margin: 0 auto;
    padding: 0 1em 3em;
}

h1 {
    margin: 1em 0;
}

.date {
    display: flex;
    flex-direction: row;
}

.date .input-group {
    flex: 1;
}

.input-group {
    margin-bottom: 1em;
    padding: 0.25em;
}

label {
    display: block;
}

input,
select,
textarea {
    display: block;
    width: 100%;
    padding: 0.5em;
    font-size: 1em;
}

input[type=date] {
    padding: 7.5px;
}

.all-day * {
    display: inline-block;
    width: auto;
}

.output {
    display: flex;
}

.output button {
    min-width: 100px;
    margin-left: 1em;
    cursor: pointer;
}

@media screen and (max-width: 720px) {
    .date,
    .output {
        display: block;
    }
    .output button {
        display: block;
        width: 100%;
        padding: 0.5em;
        font-size: 1em;
        margin-left: 0;
        margin-top: 1em;
    }
}