.ch1-structure { margin: 1.4rem auto 1.8rem; text-align: center; }
.ch1-structure img { display: block; max-width: 100%; height: auto; margin: 0 auto !important; padding: 12px; box-sizing: border-box; background: #fff; border-radius: 4px; }
.ch1-structure figcaption { margin-top: .5rem; font-size: .85em; color: #78838d; }