:root {
    --btb-book-bg: #ffffff;
    --btb-book-ink: #151515;
    --btb-book-muted: #666666;
    --btb-book-line: rgba(0,0,0,.10);
    --btb-book-soft: #f7f3ed;
    --btb-book-accent: #8a6a2f;
    --btb-book-accent-dark: #5b451e;
    --btb-book-radius: 18px;
}

.btb-book-summary-card,
.btb-book-details-wrap,
.btb-author-box,
.btb-book-card {
    box-sizing: border-box;
}

.btb-book-summary-card {
    margin: 18px 0 22px;
    padding: 20px;
    background: linear-gradient(135deg, var(--btb-book-soft), #fff);
    border: 1px solid var(--btb-book-line);
    border-radius: var(--btb-book-radius);
    box-shadow: 0 10px 30px rgba(0,0,0,.05);
}

.btb-book-badge,
.btb-card-badge,
.btb-loop-badge {
    display: inline-flex;
    align-items: center;
    width: fit-content;
    padding: 5px 10px;
    border-radius: 999px;
    background: var(--btb-book-accent);
    color: #fff;
    font-size: 12px;
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: .02em;
    text-transform: uppercase;
}

.btb-book-tax-inline {
    display: flex;
    flex-wrap: wrap;
    gap: 10px 18px;
    margin: 14px 0 8px;
    color: var(--btb-book-muted);
    font-size: 14px;
}

.btb-book-tax-inline a,
.btb-detail-row a,
.btb-card-author a,
.btb-author-box a {
    color: var(--btb-book-accent-dark);
    text-decoration: none;
}

.btb-book-tax-inline a:hover,
.btb-detail-row a:hover,
.btb-card-author a:hover,
.btb-author-box a:hover {
    text-decoration: underline;
}

.btb-book-hook p:last-child {
    margin-bottom: 0;
}

.btb-why-read {
    margin-top: 16px;
}

.btb-why-read h3 {
    margin: 0 0 8px;
    font-size: 16px;
}

.btb-why-read ul {
    margin: 0;
    padding-left: 20px;
}

.btb-why-read li {
    margin-bottom: 6px;
}

.btb-sample-button,
.btb-trailer-link,
.btb-author-link,
.btb-card-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-top: 16px;
    padding: 11px 16px;
    border-radius: 999px;
    background: var(--btb-book-ink);
    color: #fff !important;
    text-decoration: none !important;
    font-size: 14px;
    font-weight: 700;
    transition: transform .18s ease, background .18s ease;
}

.btb-sample-button:hover,
.btb-trailer-link:hover,
.btb-author-link:hover,
.btb-card-button:hover {
    transform: translateY(-1px);
    background: var(--btb-book-accent-dark);
}

.btb-book-details-wrap {
    margin: 20px 0;
}

.btb-book-details-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
}

.btb-detail-row {
    padding: 14px 16px;
    border: 1px solid var(--btb-book-line);
    border-radius: 14px;
    background: var(--btb-book-bg);
}

.btb-detail-row span {
    display: block;
    margin-bottom: 4px;
    color: var(--btb-book-muted);
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .04em;
}

.btb-detail-row strong {
    display: block;
    color: var(--btb-book-ink);
    font-size: 15px;
    line-height: 1.35;
}

.btb-note-box,
.btb-review-quote,
.btb-author-box {
    margin-top: 18px;
    padding: 18px;
    border-radius: var(--btb-book-radius);
    border: 1px solid var(--btb-book-line);
    background: var(--btb-book-soft);
}

.btb-note-box h3,
.btb-author-box h3 {
    margin-top: 0;
}

.btb-review-quote {
    font-size: 18px;
    line-height: 1.55;
    font-style: italic;
}

.btb-review-quote cite {
    display: block;
    margin-top: 10px;
    color: var(--btb-book-muted);
    font-size: 14px;
    font-style: normal;
}

.btb-loop-meta {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 6px;
    margin: 7px 0 3px;
}

.btb-loop-format {
    display: inline-flex;
    padding: 4px 9px;
    border: 1px solid var(--btb-book-line);
    border-radius: 999px;
    color: var(--btb-book-muted);
    font-size: 12px;
}

.btb-book-grid {
    display: grid;
    gap: 22px;
    margin: 24px 0;
}

.btb-book-grid-1 { grid-template-columns: 1fr; }
.btb-book-grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.btb-book-grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.btb-book-grid-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.btb-book-grid-5 { grid-template-columns: repeat(5, minmax(0, 1fr)); }
.btb-book-grid-6 { grid-template-columns: repeat(6, minmax(0, 1fr)); }

.btb-book-card {
    overflow: hidden;
    border: 1px solid var(--btb-book-line);
    border-radius: var(--btb-book-radius);
    background: var(--btb-book-bg);
    box-shadow: 0 12px 30px rgba(0,0,0,.06);
}

.btb-book-card-image {
    display: block;
    aspect-ratio: 3 / 4;
    background: var(--btb-book-soft);
    text-decoration: none;
}

.btb-book-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.btb-book-card-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--btb-book-muted);
    font-weight: 700;
}

.btb-book-card-body {
    padding: 16px;
}

.btb-book-card h3 {
    margin: 10px 0 6px;
    font-size: 18px;
    line-height: 1.25;
}

.btb-book-card h3 a {
    color: var(--btb-book-ink);
    text-decoration: none;
}

.btb-card-author {
    margin: 0 0 10px;
    color: var(--btb-book-muted);
    font-size: 14px;
}

.btb-card-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-top: 10px;
    color: var(--btb-book-muted);
    font-size: 14px;
}

.btb-card-meta .amount {
    color: var(--btb-book-ink);
    font-weight: 800;
}

.btb-no-books {
    padding: 16px;
    border-radius: 12px;
    background: var(--btb-book-soft);
}

@media (max-width: 900px) {
    .btb-book-grid-4,
    .btb-book-grid-5,
    .btb-book-grid-6 {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 640px) {
    .btb-book-details-grid,
    .btb-book-grid,
    .btb-book-grid-2,
    .btb-book-grid-3,
    .btb-book-grid-4,
    .btb-book-grid-5,
    .btb-book-grid-6 {
        grid-template-columns: 1fr;
    }

    .btb-book-summary-card,
    .btb-note-box,
    .btb-review-quote,
    .btb-author-box {
        border-radius: 14px;
    }
}