body {
    font-family: 'Noto Sans JP', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
}
.container {
    max-width: 800px;
    width: 100%;
    padding: 40px 20px;
    background-color: #fff;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    margin: 40px 20px;
    border-radius: 8px;
    box-sizing: border-box;
}
h1 {
    color: #2c3e50;
    text-align: center;
    border-bottom: 2px solid #3498db;
    padding-bottom: 10px;
    margin-bottom: 30px;
}
h2 {
    color: #2980b9;
    margin-top: 40px;
}
h3, h4 {
    color: #34495e;
}
p {
    margin-bottom: 15px;
}
a {
    color: #3498db;
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}
.play-badge {
    display: inline-block;
    transition: opacity 0.3s;
}
.play-badge:hover {
    opacity: 0.8;
}
.play-badge img {
    width: 200px;
    height: auto;
    border-radius: 8px;
}
.video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    margin-top: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}
.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
ul {
    list-style-type: none;
    padding-left: 0;
}
ul li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 10px;
}
ul li::before {
    content: "•";
    color: #3498db;
    position: absolute;
    left: 0;
    font-weight: bold;
}