@media (prefers-color-scheme: light) {
    body {
        background-color: hsl(60, 30%, 90%);
    }
}

@media (prefers-color-scheme: dark) {
    header img, footer img {
        filter: invert(100%);
    }
}

body {
    margin: 0 auto;
    padding: 4em 2em;
    max-width: 800px;
    font-size: 1.3em;
    line-height: 1.6;
}

* {
    font-family: system-ui, serif;
    box-sizing: border-box;
}
h1, h2, h3, h4, h5, h6 {
    font-family: sans-serif;
    line-height: 1.2;
    margin-top: 2em;
}

header {
    margin: 0 0 2em 0;
    text-align: center;
}
header img {
    width: 300px;
    max-width: 100%;
}

th, td {
    padding: 0.2em 0.5em;
}

footer {
    margin: 3em 0 0 0;
    text-align: center;
}
footer a {
    padding: 0 1em;
}
footer img {
    width: 36px;
}

summary {
    cursor: pointer;
    background-color: blueviolet;
    color: white;
    padding: 0.2em 0.8em;
    border-radius: 0.5em;
    font-weight: bold;
}
details:open summary {
    margin: 0 -1em 1em;
    border-radius: 0;
}
details:open summary:focus {
    outline: none;
}
details:open {
    border: 5px solid blueviolet;
    border-top: 0;
    padding: 0 1em 1em;
    border-radius: 0.5em;
    overflow: hidden;
}

label {
    cursor: pointer;
}
input {
    font-size: 1.2rem;
}
input[type="text"],
input[type="email"],
input[type="tel"],
input[type="submit"] {
    width: 100%;
    padding: 0.3em 0.4em;
    border-radius: 0.2em;
    margin-bottom: 1em;
    border: 1px solid grey;
}
input:required {
    background-image: url("/images/star.svg");
    background-repeat: no-repeat;
    background-position: right 5px center;
    background-size: 1.2em;
}
input:required:valid {
    background-image: url("/images/check-light.svg");
}
input:required:not(:focus):valid {
    border-color: forestgreen;
}
@media (prefers-color-scheme: dark) {
    input:required:valid {
        background-image: url("/images/check-dark.svg");
    }
    input:required:not(:focus):valid {
        border-color: lightgreen;
    }
}
input:required:user-invalid,
input:required:invalid:not(:placeholder-shown) {
    background-image: url('/images/cross.svg');
}
input:required:not(:focus):user-invalid,
input:required:not(:focus):invalid:not(:placeholder-shown) {
    border-color: red;
}
fieldset {
    margin-bottom: 1em;
}
fieldset.dates label {
    display: block;
    font-size: 1rem;
    margin-bottom: 0.5em;
}
details p {
    margin-top: 0;
}
input[type="submit"] {
    cursor: pointer;
    background-color: blueviolet;
    color: white;
    border: 0;
    margin-bottom: 0.3em;
}
.powered-by {
    text-align: right;
    margin-bottom: 0;
    font-size: 0.8em;
    opacity: 0.5;
}