.single-post .attachment-post-thumbnail{
    width: 100%;
    height: auto;
    margin: 20px 0px 40px 0px;
}

.single-post h1{
    border-bottom: 2px solid #c2c2c2;
    margin-top: 40px;
}

.single-post img {
    max-width: 100%;
    height: auto;
}