* { box-sizing: border-box; }
:root { font-size: 21px; }

html, body { margin: 0; padding: 0; }
body { background-color: #221c63; color: white; font-family: sans-serif; }

.container { margin: 0 auto; width: 920px; display: flex; flex-direction: column; }
.main-header { display: flex; flex-direction: row; gap: 5rem; margin-top: 2rem; justify-content: flex-start; }

.tagline {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 2rem;
}

::placeholder {
    color: rgba(255,255,255,.6);
}

a {
    color: #3db28a;
}

input[type="email"] {
    background-color: transparent;
    border: none;
    border-bottom: 2px solid white;
    font-size: 1rem;
    color: white;
    padding: .5rem 0;
    transition: border 200ms ease;
}

button {
    font-size: 1rem;
    padding: .5rem 1rem;
    border: none;
    background-color: #3db28a;
}

input[type="email"]:active, input[type="email"]:focus {
    outline: none;
    border-bottom: 2px solid #3db28a;
}

form {
    display: flex;
    flex-direction: row;
    gap: 1rem;
    margin: 2rem 0;
}

@media screen and (max-width: 920px) {
    .container {
        width: 100%;
        padding: 1rem;
    }

    .main-header, form {
        flex-direction: column;
    }

    .main-header {
        justify-content: start;
        gap: 1rem;
    }

    img {
        width: 100%;
    }
}