body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background-color: #ffffff;
    color: #333;
    margin: 0;
    display: flex;
    flex-direction: column; /* 縦に並べる */
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    width: 100%;
    max-width: 480px;
    padding: 20px;
    box-sizing: border-box;
    text-align: center;
}

header h1 {
    font-size: 1.5rem;
    margin-bottom: 15px;
}

.mode-select {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 10px;
}

.order-select {
    margin-bottom: 8px;
}

#progress-text {
    font-size: 0.9rem;
    color: #666;
    font-weight: bold;
    margin-bottom: 15px;
}

#question-text {
    font-size: 1rem;
    font-weight: bold;
    color: #2c3e50;
    margin: 0 0 12px;
}

ruby {
    ruby-align: center;
}
rt {
    font-size: 0.55em;
    color: #888;
    font-weight: normal;
}

.finish-msg {
    font-size: 1.5rem;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 20px;
}

.seo-text-box {
    margin-top: 40px;
    background-color: #fff;
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.05);
    text-align: left;
    color: #555;
    font-size: 0.95rem;
    line-height: 1.6;
}
.seo-text-box h2 {
    font-size: 1.2rem;
    color: #333;
    margin-top: 0;
    margin-bottom: 12px;
    border-bottom: 2px solid #eee;
    padding-bottom: 8px;
}

.back-btn {
    display: inline-block;
    margin: 15px 0 0 15px;
    text-decoration: none;
    color: #555;
    font-weight: bold;
    background: white;
    padding: 8px 16px;
    border-radius: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.mode-select button {
    flex: 1;
    padding: 10px;
    font-size: 0.9rem;
    font-weight: bold;
    border: 2px solid #007bff;
    background-color: #fff;
    color: #007bff;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.mode-select button.active {
    background-color: #007bff;
    color: #fff;
}

/* カードデザイン */
.card {
    background-color: #ffffff;
    width: 100%;
    height: 320px;
    border-radius: 16px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
    box-sizing: border-box;
    cursor: pointer;
    position: relative;
    user-select: none;
    transition: transform 0.1s;
}

.card:active {
    transform: scale(0.98);
}

.card-front, .card-back {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.hidden {
    display: none !important;
}

/* 表示コンテンツのスタイル */
#display-area {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

#display-area svg {
    width: 1560px;
    height: 1560px;
    max-width: 100%;
    max-height: 100%;
    display: block;
}

.pref-name-large {
    font-size: 2.5rem;
    font-weight: bold;
    color: #2c3e50;
}

.answer-main {
    font-size: 2.2rem;
    font-weight: bold;
    color: #e74c3c;
    margin-bottom: 5px;
}

.answer-sub {
    font-size: 1.2rem;
    color: #7f8c8d;
}

/* フッター・ボタン */
footer {
    margin-top: 20px;
}

#hint-text {
    font-size: 0.85rem;
    color: #888;
    margin-bottom: 10px;
}

.card-back#finish-area {
    justify-content: center;
    align-items: center;
    display: none;
}
.card-back#finish-area:not(.hidden) {
    display: flex;
}

.next-btn {
    width: 100%;
    padding: 12px;
    font-size: 1rem;
    font-weight: bold;
    background-color: #28a745;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(40, 167, 69, 0.2);
}

.next-btn:hover {
    background-color: #218838;
}