html, body {
  height: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}
    .book-wrap{max-width:900px;margin:40px auto;padding:0 16px}
    .card{border:1px solid #ddd;border-radius:8px;background:#fff}
    .row{display:flex;justify-content:space-between;align-items:center;padding:18px 22px;border-bottom:1px solid #eee}
    .row:last-child{border-bottom:0}
    .btnSmall{padding:8px 14px;border:0;border-radius:6px;background:#111;color:#fff;cursor:pointer}
    .title{font-size:34px;text-align:center;margin:24px 0}
    .sub{font-size:22px;text-align:center;margin:34px 0 16px}