body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    color: #333;
    background-color: #f9f9f9; /* 背景色をTOPページのスタイルに合わせる */
}

header {
    background-color: #0078d4;
    color: white;
    text-align: center;
    padding: 20px;
}

h1 {
    margin: 0;
}

.presentation-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 20px;
}

.presentation {
    width: 80%;
    margin: 20px 0;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.slideshow-container {
    position: relative;
    width: 100%;
}

.slide {
    display: none;
    width: 100%;
    height: auto;
}

.controls {
    position: absolute;
    top: 50%;
    width: 100%;
    display: flex;
    justify-content: space-between;
    transform: translateY(-50%);
}

.prev, .next {
    background-color: rgba(0, 0, 0, 0.5);
    color: white;
    border: none;
    border-radius: 50%;
    padding: 10px;
    font-size: 24px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.3s;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.prev:hover, .next:hover {
    background-color: rgba(0, 0, 0, 0.8);
    transform: scale(1.1);
}

.slider {
    width: 100%;
    margin-top: 10px;
}

.back-button {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 10px 20px;
    background-color: #0078d4;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}