body {
    background-color: #222;
    color: #fff;
    margin: 0;
    font-size: 2.5vw;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

button {
    background: #000;
    border: none;
    cursor: pointer;
    color: white;
    transition: background 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

button:active, button:focus {
    background: #333;
}

input, textarea {
    background: #000;
    color: #fff;
    padding: 0.5em;
    border: none;
    border-radius: 0.5em;
    box-sizing: border-box;
}

h1 {
    font-size: 4vw;
    margin: 1vw 0;
}

label {
    font-size: 2vw;
}

.flex-col {
    display: flex;
    flex-direction: column;
}

.flex-center {
    display: flex;
    align-items: center;
    justify-content: center;
}

.box {
    box-sizing: border-box;
}