/* Books shares the catalogue proportions while keeping its amber palette. */
body[data-track-section="books"] {
  --books-gutter: clamp(22px, 3.7vw, 72px);
  background: radial-gradient(ellipse at 0 10%, #f8e6c8, transparent 65%), linear-gradient(140deg, #fff8ed, #f7eddd 65%, #fff3e0);
}
body[data-track-section="books"] .shell { padding: 112px var(--books-gutter) 32px; }
.books-catalogue .shell-lines, .books-catalogue .ambient-strip,
.books-catalogue::before, .books-catalogue::after { display: none; }
.books-sticky-header { position: sticky; top: var(--books-nav-height, 72px); z-index: 30; padding: 8px 0 12px; margin-bottom: 12px; isolation: isolate; }
.books-sticky-header::before { content: ""; position: absolute; inset: 0 calc(-1 * var(--books-gutter)); z-index: -1; background: #fbf1e3ed; -webkit-backdrop-filter: blur(12px); backdrop-filter: blur(12px); }
.books-sticky-header::after { content: ""; position: absolute; bottom: 0; left: calc(-1 * var(--books-gutter)); right: calc(-1 * var(--books-gutter)); height: 2px; background: #cfac7b; }
body[data-track-section="books"] .hero { display: flex; align-items: center; justify-content: space-between; gap: 28px; min-height: 0; margin: 0 0 14px; padding: 24px 28px; border: 1px solid #b38345; border-radius: 18px; background: url('/static/img/listening-preview/header-waves.svg') center / 100% 320px no-repeat, radial-gradient(ellipse at 10% 0, #ffffff12, transparent 55%), linear-gradient(130deg, #70421d, #996027 46%, #bd8838); box-shadow: 0 10px 25px #77522212; animation: none; }
.books-catalogue .hero::before, .books-catalogue .hero::after { display: none; }
.books-catalogue .hero h1 { display: flex; align-items: center; gap: 16px; margin: 0 0 9px; color: #fff; font-size: clamp(30px, 2.6vw, 38px); line-height: 1.16; }
.books-catalogue .hero h1 svg { width: 44px; height: 48px; flex-shrink: 0; fill: none; stroke: #ffeac6; stroke-width: 1.3; stroke-linejoin: round; }
.books-catalogue .hero p { max-width: 650px; font-size: 14px; line-height: 1.6; color: #fff1db; }
.books-progress { width: 265px; flex: 0 0 265px; font-size: 12px; font-weight: 700; color: #fff4df; }
.books-progress-label { display: flex; justify-content: space-between; gap: 16px; margin-bottom: 9px; }
.books-progress-track { height: 5px; background: #ffffff30; border-radius: 8px; overflow: hidden; }
.books-progress-fill { height: 100%; width: 0; background: #ffe5af; border-radius: inherit; }
.books-toolbar { display: flex; gap: 22px; align-items: center; padding: 12px 16px; }
.books-search { display: flex; flex: 1; align-items: center; gap: 11px; height: 46px; padding: 0 15px; border: 1px solid transparent; border-radius: 7px; background: #fffaf1; }
.books-search svg { width: 19px; height: 19px; flex-shrink: 0; fill: none; stroke: #9b7847; stroke-width: 1.7; }
.books-search:focus-within { outline: 3px solid #f4dfbd; border-color: #b78645; }
.books-search input { width: 100%; min-width: 0; border: 0; outline: 0; background: transparent; font: inherit; font-size: 14px; color: #60421f; }
.books-search input::placeholder { color: #947b5b; }
.books-filters { display: flex; gap: 8px; }
.books-filter { min-height: 44px; padding: 10px 24px; border: 1px solid #dac39e; border-radius: 8px; background: #fff8ed; box-shadow: 0 2px 0 #e7d6bc; color: #76552b; font: inherit; font-size: 13px; font-weight: 700; cursor: pointer; }
.books-filter:hover { background: #f7e8d0; }
.books-filter[aria-pressed="true"] { color: #fff; background: #a06a29; border-color: #87571e; box-shadow: 0 2px 0 #734b1d; }
.books-filter:focus-visible, .books-catalogue .book-use:focus-visible { outline: 3px solid #c99653; outline-offset: 3px; }
body[data-track-section="books"] .panel { margin: 0; padding: 0; border: 0; border-radius: 0; background: transparent; box-shadow: none; overflow: visible; animation: none; }
.books-catalogue .panel::before, .books-catalogue .panel::after { display: none; }
.books-help { margin: 8px 0 18px; color: #80694c; font-size: 14px; line-height: 1.6; }
.books-catalogue .book-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; margin: 0; }
.books-catalogue .book-item { display: grid; grid-template-columns: 84px minmax(0, 1fr); grid-template-rows: auto 1fr auto; column-gap: 18px; row-gap: 12px; min-width: 0; padding: 20px; border: 1px solid #e8d9c4; border-radius: 12px; background: #fff; box-shadow: 0 2px 8px #78532209; }
.books-catalogue .book-item:hover { border-color: #c7a36e; }
.book-cover { grid-row: 1 / 3; display: flex; flex-direction: column; justify-content: center; align-items: center; gap: 12px; width: 84px; height: 116px; border-radius: 6px 9px 9px 6px; border-left: 5px solid #ffffff20; background: linear-gradient(150deg, #bd8a42, #765020); box-shadow: 0 3px 7px #553b201a; color: #fff3d9; }
.book-cover svg { width: 36px; height: 36px; fill: none; stroke: currentColor; stroke-width: 1.3; stroke-linejoin: round; }
.book-cover span { font-size: 10px; letter-spacing: .12em; font-weight: 800; }
.book-cover-guide { background: linear-gradient(150deg, #aa7846, #6d4830); }
.book-cover-skills { background: linear-gradient(150deg, #b29961, #71613c); }
.book-cover-writing { background: linear-gradient(150deg, #af7855, #7f4f3a); }
.book-meta { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.book-category { padding: 5px 8px; border: 1px solid #ead7b5; border-radius: 4px; background: #fcf4e6; color: #855b25; font-size: 12px; font-weight: 700; }
.book-state { padding: 6px 10px; border: 1px solid #dfc69f; border-radius: 5px; background: #faf1e2; color: #805a2d; font-size: 12px; font-weight: 600; }
.book-state.is-used { background: #cdf1d8; border-color: #8dd6a1; color: #146a39; }
.books-catalogue .book-item h3 { margin: 0 0 8px; color: #49351e; font-size: 17px; line-height: 1.4; }
.books-catalogue .book-item p { margin: 0; color: #836f55; font-size: 14px; line-height: 1.6; }
.books-catalogue .book-use { grid-column: 2; justify-self: end; min-height: 44px; padding: 11px 20px; border: 1px solid #976125; border-radius: 8px; background: #ad7731; box-shadow: 0 3px 0 #83571e, 0 5px 10px #9d69221a; color: #fff; font-family: inherit; font-weight: 700; font-size: 13px; }
.books-catalogue .book-use:hover { background: #966122; }
.books-catalogue [hidden] { display: none !important; }
.books-empty { padding: 32px 16px; color: #82684a; text-align: center; }
.books-catalogue a.book-cover { display: block; overflow: hidden; border-left: 0; background: #faf7f1; }
.book-cover img { display: block; width: 100%; height: 100%; object-fit: contain; }
.book-copy h3 a { color: inherit; text-decoration: none; }
.book-copy h3 a:hover { text-decoration: underline; }
.books-catalogue .book-file-info { margin-top: 9px; font-size: 12px; color: #76552e; }
.book-actions { grid-column: 1 / -1; display: flex; align-items: center; flex-wrap: wrap; gap: 10px; margin-top: 8px; }
.book-actions a { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 10px 14px; border: 1px solid #bd925b; border-radius: 7px; font-size: 13px; font-weight: 700; text-decoration: none; }
.book-actions .book-open { background: #9b6528; color: #fff; }
.book-actions .book-download { background: #fff6e8; color: #70421d; }
.books-catalogue .book-actions .book-use { margin-left: auto; padding: 10px 12px; background: #fff; color: #805520; box-shadow: none; }
.book-breadcrumb { display: flex; align-items: center; gap: 14px; margin: 6px 0 22px; color: #756550; font-size: 13px; }
.book-breadcrumb [aria-current] { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.book-back { flex-shrink: 0; padding: 9px 13px; border: 1px solid #dfc9a7; border-radius: 8px; background: #fffcf7; text-decoration: none; font-weight: 700; }
.book-breadcrumb a, .book-detail a, .book-related a { color: #80501d; }
.book-detail { display: grid; grid-template-columns: minmax(210px, .75fr) minmax(0, 1.7fr); align-items: stretch; gap: clamp(26px, 4vw, 60px); padding: clamp(22px, 3vw, 42px); border: 1px solid #e4d6c0; border-radius: 22px; background: white; box-shadow: 0 14px 45px #72502b0a; }
.book-detail-art { display: flex; flex-direction: column; justify-content: center; align-items: center; gap: 25px; padding: 30px 22px; background: radial-gradient(ellipse at 50% 35%, #fffefb, #f4e7d3); border: 1px solid #efe2ce; border-radius: 15px; }
.book-detail-cover { display: block; width: 100%; max-width: 245px; height: auto; max-height: 365px; object-fit: contain; filter: drop-shadow(0 14px 12px #482b2530); }
.book-edition-label { color: #92744e; font-size: 10px; font-weight: 700; letter-spacing: .16em; }
.book-detail-body { min-width: 0; align-self: center; padding: 4px 0; }
.book-detail h1 { margin: 15px 0 12px; font-size: clamp(27px, 2.7vw, 39px); line-height: 1.18; letter-spacing: -.035em; color: #30261d; max-width: 800px; }
.book-detail p { margin: 12px 0; line-height: 1.65; color: #6c6052; }
.book-detail .book-author { font-size: 14px; margin: 0 0 20px; }
.book-author strong { font-weight: 600; color: #534331; }
.book-detail .book-description { font-size: 15px; max-width: 700px; margin-bottom: 24px; }
.book-facts { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; margin: 0 0 25px; }
.book-facts div { padding: 13px 12px; border: 1px solid #eee5d9; background: #fdfaf5; border-radius: 9px; }
.book-facts dt { color: #817262; font-size: 11px; margin-bottom: 7px; }
.book-facts dd { color: #3c3024; font-size: 17px; font-weight: 700; margin: 0; line-height: 1.3; }
.book-facts dd span { font-size: 12px; font-weight: 500; }
.book-detail-actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin: 0; max-width: 600px; }
.book-detail-actions a { min-height: 72px; justify-content: flex-start; gap: 15px; padding: 13px 18px; border-radius: 10px; font-size: 16px; }
.book-detail-actions svg { width: 25px; height: 25px; fill: none; stroke: currentColor; stroke-width: 1.6; flex-shrink: 0; }
.book-detail-actions small { display: block; margin-top: 5px; font-size: 11px; font-weight: 500; }
.book-detail-actions .book-open { background: #986127; color: #fff; border-color: #875320; box-shadow: 0 3px 0 #73471e; }
.book-detail-actions .book-open:hover { background: #81501f; }
.book-detail-actions .book-download { background: #fff9ee; color: #734516; border-color: #cba672; box-shadow: 0 3px 0 #ecddc5; }
.book-detail-actions .book-download:hover { background: #f6e7cb; }
.book-detail a:focus-visible, .book-related a:focus-visible, .book-back:focus-visible { outline: 3px solid #b67b35; outline-offset: 4px; }
.book-detail .book-signin { font-size: 12px; margin-top: 16px; }
.book-signin a { font-weight: 700; }
.book-channel-note { display: flex; align-items: center; gap: 11px; padding-top: 22px; margin-top: 25px; border-top: 1px solid #eee5d9; color: #726451; font-size: 12px; }
.book-channel-note a { font-weight: 700; text-decoration: none; }
.book-channel-note small { display: block; margin-top: 4px; font-size: 11px; color: #847866; }
.book-channel-icon { display: grid; place-items: center; width: 33px; height: 33px; border-radius: 50%; background: #f6ead8; font-size: 20px; color: #986127; }
.book-related { padding: 36px 0 12px; }
.book-related-heading { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin-bottom: 18px; }
.book-related-eyebrow { color: #92652f; font-size: 10px; letter-spacing: .12em; font-weight: 700; }
.book-related h2 { margin: 7px 0 0; font-size: clamp(21px, 2vw, 26px); color: #392b1f; }
.book-related-heading > a { font-size: 12px; font-weight: 600; text-decoration: none; }
.book-practice-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; }
.book-related .book-practice-link { display: flex; align-items: center; gap: 12px; padding: 18px 14px; border: 1px solid #e5d6be; border-radius: 12px; background: #fffdf9; color: #3d342b; text-decoration: none; }
.book-practice-link:hover { border-color: #b98c51; background: #fff; }
.book-practice-link strong { font-size: 14px; }
.book-practice-link small { display: block; margin-top: 5px; color: #7b7164; font-size: 11px; line-height: 1.4; }
.book-practice-link b { margin-left: auto; color: #927754; font-size: 16px; }
.book-practice-symbol { display: grid; place-items: center; flex-shrink: 0; width: 36px; height: 36px; border-radius: 9px; background: #e9efff; color: #315eac; font-size: 20px; font-weight: 700; }
.is-listening .book-practice-symbol { background: #e0f3f4; color: #137385; }
.is-writing .book-practice-symbol { background: #fae8f0; color: #9b4174; }
.is-speaking .book-practice-symbol { background: #e5f5e9; color: #278158; }
@media (max-width: 1000px) { .book-practice-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } .book-facts { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 600px) { .book-detail { grid-template-columns: 1fr; gap: 24px; padding: 18px; border-radius: 16px; } .book-detail-art { padding: 25px 15px 17px; gap: 18px; } .book-detail-cover { width: 170px; max-height: 245px; } .book-detail h1 { font-size: 27px; } .book-detail-actions { grid-template-columns: 1fr; } .book-detail-actions a { min-height: 66px; } .book-related-heading { align-items: start; flex-direction: column; gap: 12px; } .book-practice-grid { grid-template-columns: 1fr; } .book-related .book-practice-link { padding: 14px; } .book-breadcrumb { font-size: 11px; gap: 9px; } .books-catalogue .book-actions .book-use { margin-left: 0; } }
@media (min-width: 1801px) { .books-catalogue .book-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); } }
@media (min-width: 1025px) and (max-width: 1800px) { body[data-track-section="books"] { --books-gutter: clamp(14px, 2vw, 30px); } }
@media (max-width: 900px) {
  body[data-track-section="books"] { --books-gutter: 22px; }
  body[data-track-section="books"] .hero { flex-direction: column; align-items: stretch; gap: 20px; }
  .books-progress { width: 100%; flex-basis: auto; max-width: 350px; }
}
@media (max-width: 600px) {
  body[data-track-section="books"] { --books-gutter: 16px; }
  body[data-track-section="books"] .books-sticky-header > .hero { display: none; }
  body[data-track-section="books"] .shell { padding-top: 92px; }
  body[data-track-section="books"] .hero { padding: 20px 15px; gap: 18px; border-radius: 14px; margin-bottom: 12px; }
  .books-catalogue .hero h1 { font-size: 28px; gap: 10px; }
  .books-catalogue .hero h1 svg { width: 34px; height: 40px; }
  .books-catalogue .hero p { font-size: 13px; }
  .books-toolbar { flex-wrap: wrap; padding: 11px 0; gap: 10px; }
  .books-search { flex-basis: 100%; }
  .books-filters { width: 100%; }
  .books-filter { flex: 1; min-height: 40px; padding: 9px 12px; }
  .books-catalogue .book-grid { grid-template-columns: 1fr; gap: 14px; }
  .books-catalogue .book-item { padding: 16px; grid-template-columns: 72px minmax(0, 1fr); column-gap: 14px; }
  .book-cover { width: 72px; height: 104px; }
  .books-catalogue .book-item h3 { font-size: 16px; }
  .books-catalogue .book-item p { font-size: 13px; }
  .books-catalogue .book-use { padding-inline: 16px; }
}