html, body {
    width: 100%;
    height: 100%;
    min-height: 450px;
    margin: 0;
    padding: 0;
    background-color: #404040;
}

body {
    font-family: sans-serif;
    font-size: 13px;
    background-image: url('/img/bg.webp');
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
}

.main {
    box-sizing: border-box;
    width: 100%;
    height: 100%;
    min-height: 450px;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
}

.contents-box {
    box-sizing: border-box;
    width: min(350px, calc(100vw - 20px));
    aspect-ratio: 840 / 1070;
    padding-top: 134px;
    background: url('/img/box.png') no-repeat top center;
    background-size: 100% 100%;
}

.contents-desc {
    color: #fff;
    text-align: center;
    width: 90%;
    margin: 8px auto 0;
}

.contents-box h2.title {
    font-size: 1.5em;
    margin-top: 0;
    margin-bottom: 10px;
}

.contents-box p.desc {
    font-size: 1.05em;
    line-height: 1.6;
    margin-top: 0;
    margin-bottom: 10px;
    word-break: keep-all;
}

.result-msg {
    font-size: 1em;
    font-weight: bold;
    margin-bottom: 6px;
}

.result-msg.success {
    color: #7fffb2;
}

.result-msg.error {
    color: #ff7f7f;
}

.btn-group {
    box-sizing: border-box;
    width: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.btn-group input[type="text"] {
    box-sizing: border-box;
    display: block;
    border: none;
    height: 34px;
    width: 90%;
    padding: 0 10px;
    font-size: 1.1em;
    margin-bottom: 8px;
    border-radius: 6px;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.3);
}

.btn-group .btn-submit {
    width: 50%;
    height: 34px;
    line-height: 34px;
    display: block;
    font-size: 1.3em;
    font-weight: bold;
    color: #fff;
    border: none;
    cursor: pointer;
    background: url('/img/btn.png') no-repeat center center;
    background-size: 100% 100%;
    border-radius: 6px;
    margin-top: 6px;
}

@media screen and (min-width: 767px) {
    html, body {
        min-height: 900px;
    }

    body {
        font-size: 20px;
    }

    .main {
        min-height: 900px;
    }

    .contents-box {
        width: 600px;
        aspect-ratio: 840 / 1070;
        padding-top: 230px;
    }

    .contents-desc {
        margin-top: 24px;
    }

    .btn-group {
        padding: 20px 40px 0;
    }

    .btn-group input[type="text"] {
        height: 60px;
        margin-bottom: 16px;
        font-size: 1.5em;
        border-radius: 8px;
    }

    .btn-group .btn-submit {
        height: 60px;
        line-height: 60px;
        font-size: 1.8em;
    }
}