* {
    margin: 0;
    box-sizing: border-box;
    font-family: sans-serif;
}

body {
    min-height: 100vh;
    min-height: 100svh;
}

header, footer, #main {
    width: 90%;
    max-width: 720px;
    margin: 0 auto;
}

header h1 {
    border-bottom: solid 2px black;
}

header h1 a {
    color: black;
    text-decoration: none;
}

footer {
    position: sticky;
    top: 100vh;
    background-color: var(--PUT_COLOR);
    margin: 64px auto 0 auto;
    padding: 4px 0;
}

#main {
    margin: 16px auto;
}

.link_card {
    display: block;
    color: black;
    margin: 4px 0;
    padding: 4px 8px;
    border: solid 2px black;
    border-radius: 4px;
    text-align: center;
    text-decoration: none;
    font-size: 24px;
    font-weight: bold;
}

.input_block {
    display: flex;
    flex-direction: column;
    margin: 8px 0;
}