body {
    font-family: "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
    background-color: #f0f8ff;
    color: #333;
    display: flex;
    justify-content: center;
    padding: 20px;
}

.container {
    background-color: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    max-width: 600px;
    width: 100%;
    text-align: center;
}

h1 { color: #2c3e50; border-bottom: 3px solid #3498db; padding-bottom: 10px; }

.setup-area {
    display: flex;
    justify-content: space-around;
    align-items: center;
    margin-bottom: 20px;
}

label { font-weight: bold; font-size: 1.2rem; }

input, select {
    font-size: 1.2rem;
    padding: 5px;
}

button {
    font-size: 1.2rem;
    font-weight: bold;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 8px;
    border: none;
    transition: 0.3s;
}

#btnStart { background-color: #3498db; color: white; }
#btnHide { background-color: #e67e22; color: white; }
#btnAnswer { background-color: #27ae60; color: white; }
button:hover { opacity: 0.8; }

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    font-size: 1.5rem; /* 文字を大きく */
}

th, td {
    border: 2px solid #bdc3c7;
    padding: 15px;
    text-align: center;
}

th { background-color: #ecf0f1; }

.blank {
    color: #ccc;
    background-color: #fafafa;
}

.correct {
    color: #e74c3c;
    font-weight: bold;
    animation: fadeIn 0.5s;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}