.toc {
    margin: 0 auto 2rem auto;
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
}

.toc-ios, .toc-android {
    margin: 0 1rem;
}

.os-contents {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin: 0 auto 2rem auto;
}

.os-title {
    text-align: center;
}

.os-subtitle {
    text-align: center;
    margin-bottom: 1rem;
}

.protocol {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin-bottom: 2rem;
}

.protocol-title {
    text-align: center;
}

.protocol-images {
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: flex-start;
}

.protocol-image {
    display: block;
    margin: 0 0.5rem;
    width: 100%;
    box-shadow: 0 0.5em 1em -0.125em rgba(10,10,10,.1), 0 0 0 1px rgba(10,10,10,.02);
}