body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
    overflow: hidden; /* ドップラー効果の要素がはみ出してもスクロールバーが出ないように */
}

.container {
    text-align: center;
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1 {
    color: #333;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    margin-bottom: 20px;
    border: none;
    border-radius: 5px;
    background-color: #007bff;
    color: white;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #0056b3;
}

.road {
    width: 100%;
    max-width: 600px;
    height: 50px;
    background-color: #333;
    margin: 20px auto;
    position: relative;
    overflow: hidden;
    border-radius: 5px;
}

#ambulance {
    position: absolute;
    top: 5px;
    width: 80px;
    height: 40px;
    background-color: red;
    border-radius: 5px;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-weight: bold;
    font-size: 12px;
    animation: moveAmbulance 10s linear infinite;
    left: -100px; /* 初期位置を画面外に設定 */
}

@keyframes moveAmbulance {
    0% {
        left: -100px; /* 左から出現 */
    }
    100% {
        left: calc(100% + 100px); /* 右に移動して画面外へ */
    }
}