html,
body {
    height: 100%;
    margin: 0;
}

article {
    width: 80%;
    padding: 20px;
    margin: auto;
}


.app-header {
    display: flex;
    align-items: center;
    padding-left: 10px;
}

.app-icon {
    height: 50px;
    margin-right: 10px;
}

.app-name {
    font-weight: bold;
    font-size: 20px;
}

header,
footer {
    display: flex;
    justify-content: space-between;
    background-color: #f8f9fa;
    padding: 10px;
    padding-left: 50px;
    padding-right: 50px;
    text-align: center;
}

nav ul {
    list-style-type: none;
    padding: 0;
    display: flex;
    align-items: center;
}

nav ul li {
    margin: 0 10px;
}

a {
    text-decoration: none;
    color: #007bff;
}

a:hover {
    text-decoration: underline;
}

/* indexのモック画像とキャッチコピー */
.promo-section {
    display: flex;
    align-items: center;
    justify-content: space-around;
    margin-bottom: 20px;
}

.app-mockup {
    width: 70%;
    max-width: 400px;
}

.catchphrase {
    font-size: 24px;
    font-weight: bold;
    color: #333;
    width: 50%;
    text-align: center;
}

@media (max-width: 768px) {

    /* 768px以下の画面幅で適用されるスタイル */
    .promo-section {
        flex-direction: column;
        /* 横並びから縦並びに変更 */
    }

    .app-mockup,
    .catchphrase {
        width: 100%;
    }

    .catchphrase {
        margin-top: 20px;
    }
}



/* how-to.htmlの手順ステップ */
.step {
    margin-top: 20px;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
}

.step h2 {
    font-size: 20px;
}

.step img {
    width: 100%;
    max-width: 600px;
    height: auto;
}

.step p {
    font-size: 16px;
}