/* ═══════════════════════════════════════════════════════════════
   books-landing.css — /books course book discovery landing
   Prefix: vp-books__ (BEM)
   Loaded under _VerityMainLayout, so the verityprep_main_theme
   tokens (Layer B semantic --vp-*-color + --vp-*-rgb channels)
   are available and switch automatically via body.dark-theme.
   ═══════════════════════════════════════════════════════════════ */

/* ── Local surface tokens (light defaults + single dark override) ─── */
:root {
    --vp-books-shadow:        0 12px 32px rgb(var(--vp-shadow-rgb) / .12);
    --vp-books-shadow-hover:  0 22px 52px rgb(var(--vp-shadow-rgb) / .20);
    --vp-books-cover-bg:      rgb(var(--vp-navyline-rgb) / .06);
    --vp-books-cat-hover:     rgb(var(--vp-navyline-rgb) / .05);
    --vp-books-cat-active:    rgb(var(--vp-navyline-rgb) / .09);
    --vp-books-count-bg:      rgb(var(--vp-navyline-rgb) / .08);
    --vp-books-placeholder:   rgb(var(--vp-navyline-rgb) / .07);
}

body.dark-theme {
    --vp-books-shadow:        0 18px 44px rgb(var(--vp-ink-rgb) / .55);
    --vp-books-shadow-hover:  0 28px 66px rgb(var(--vp-ink-rgb) / .62);
    --vp-books-cover-bg:      rgb(var(--vp-white-rgb) / .06);
    --vp-books-cat-hover:     rgb(var(--vp-white-rgb) / .05);
    --vp-books-cat-active:    rgb(var(--vp-white-rgb) / .08);
    --vp-books-count-bg:      rgb(var(--vp-white-rgb) / .08);
    --vp-books-placeholder:   rgb(var(--vp-white-rgb) / .07);
}

/* ── Hero ─────────────────────────────────────────────────────── */
.vp-books__eyebrow {
    display: inline-block;
    margin: 0 0 12px;
    color: var(--vp-accent-primary-color);
    font-size: 0.82rem;
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.vp-books__title {
    max-width: 22ch;
}

.vp-books__lead {
    max-width: 60ch;
}

/* ── Two-column layout (side nav + panels) ────────────────────── */
.vp-books__layout {
    display: grid;
    grid-template-columns: minmax(180px, 220px) 1fr;
    gap: clamp(24px, 4vw, 48px);
    align-items: start;
}

/* ── Side category navigation ─────────────────────────────────── */
.vp-books__side {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.vp-books__cat {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    width: 100%;
    padding: 12px 14px;
    border: 1px solid transparent;
    border-radius: 10px;
    background: transparent;
    color: var(--vp-text-secondary-color);
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: background 180ms ease, color 180ms ease, border-color 180ms ease;
}

.vp-books__cat:hover {
    background: var(--vp-books-cat-hover);
    color: var(--vp-text-heading-color);
}

.vp-books__cat:focus-visible {
    outline: 2px solid var(--vp-accent-primary-color);
    outline-offset: 2px;
}

.vp-books__cat[aria-selected="true"] {
    background: var(--vp-books-cat-active);
    border-color: var(--vp-border-primary-color);
    color: var(--vp-text-heading-color);
    box-shadow: inset 3px 0 0 var(--vp-accent-primary-color);
}

.vp-books__cat-label {
    flex: 1 1 auto;
    min-width: 0;
}

.vp-books__cat-count {
    flex: 0 0 auto;
    min-width: 1.6em;
    padding: 2px 8px;
    border-radius: 999px;
    background: var(--vp-books-count-bg);
    color: var(--vp-text-secondary-color);
    font-size: 0.78rem;
    font-weight: 500;
    text-align: center;
}

.vp-books__cat[aria-selected="true"] .vp-books__cat-count {
    background: var(--vp-accent-primary-color);
    color: var(--vp-bg-primary-color);
}

/* ── Panels ───────────────────────────────────────────────────── */
.vp-books__panels {
    min-width: 0;
}

.vp-books__panel[hidden] {
    display: none;
}

/* Tinted banner: accent square badge + heading/blurb on a soft
   accent-tinted rounded panel */
.vp-books__panel-head {
    display: flex;
    align-items: center;
    gap: 18px;
    padding: clamp(16px, 2vw, 20px) clamp(18px, 2.2vw, 22px);
    border-radius: 16px;
    background: color-mix(in srgb, var(--vp-accent-primary-color) 8%, var(--vp-bg-primary-color));
    border: 1px solid color-mix(in srgb, var(--vp-accent-primary-color) 22%, var(--vp-border-primary-color));
    margin-bottom: clamp(22px, 3vw, 34px);
}

.vp-books__panel-badge {
    flex: 0 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    width: clamp(48px, 6vw, 56px);
    height: clamp(48px, 6vw, 56px);
    border-radius: 14px;
    background: var(--vp-accent-primary-color);
    color: var(--vp-bg-primary-color);
    font-weight: 500;
    font-size: clamp(0.78rem, 1.3vw, 0.95rem);
    letter-spacing: 0.02em;
    line-height: 1;
    overflow: hidden;
    white-space: nowrap;
    padding: 0 4px;
    text-align: center;
}

.vp-books__panel-headtext {
    min-width: 0;
}

.vp-books__panel-title {
    margin: 0;
    color: var(--vp-text-heading-color);
    font-size: clamp(1.4rem, 2.6vw, 1.6rem);
    font-weight: var(--vp-text-heading-weight);
    line-height: 1.2;
    letter-spacing: -0.01em;
}

.vp-books__panel-blurb {
    max-width: 68ch;
    margin: clamp(4px, 0.8vw, 6px) 0 0;
    color: var(--vp-text-secondary-color);
    font-size: clamp(0.92rem, 1.3vw, 0.98rem);
    line-height: 1.5;
}

/* ── Card grid ────────────────────────────────────────────────── */
.vp-books__grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(min(220px, 100%), 1fr));
    gap: clamp(18px, 2.5vw, 28px);
}

.vp-books__card {
    display: flex;
    flex-direction: column;
    background: var(--vp-bg-secondary-color);
    border: 1px solid var(--vp-border-primary-color);
    border-radius: 14px;
    overflow: hidden;
    text-decoration: none;
    color: inherit;
    box-shadow: var(--vp-books-shadow);
    transition: transform 220ms ease, box-shadow 220ms ease, border-color 220ms ease;
}

.vp-books__card:hover,
.vp-books__card:focus-visible {
    transform: translateY(-6px);
    box-shadow: var(--vp-books-shadow-hover);
    border-color: var(--vp-accent-primary-color);
    text-decoration: none;
    color: inherit;
}

.vp-books__card:focus-visible {
    outline: 2px solid var(--vp-accent-primary-color);
    outline-offset: 3px;
}

.vp-books__cover-frame {
    display: block;
    width: 100%;
    background: var(--vp-books-cover-bg);
}

.vp-books__cover {
    display: block;
    width: 100%;
    max-width: 100%;
    aspect-ratio: 2 / 3;
    object-fit: cover;
}

/* ── Placeholder cover (no artwork) ───────────────────────────── */
.vp-books__cover--placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--vp-books-placeholder);
}

.vp-books__cover--placeholder > span {
    color: var(--vp-accent-primary-color);
    font-size: clamp(3rem, 8vw, 4.5rem);
    font-weight: var(--vp-text-heading-weight);
    line-height: 1;
    text-transform: uppercase;
}

.vp-books__card-body {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 16px 18px 20px;
}

.vp-books__card-title {
    margin: 0;
    color: var(--vp-text-heading-color);
    font-size: 1.05rem;
    font-weight: var(--vp-text-heading-weight);
    line-height: 1.35;
}

.vp-books__card-subject {
    color: var(--vp-text-secondary-color);
    font-size: 0.88rem;
    font-weight: 500;
    letter-spacing: 0.02em;
}

/* ── Empty state ──────────────────────────────────────────────── */
.vp-books__empty {
    margin: 0;
    padding: clamp(24px, 4vw, 40px);
    border: 1px dashed var(--vp-border-primary-color);
    border-radius: 14px;
    color: var(--vp-text-secondary-color);
    font-size: 1rem;
    text-align: center;
}

/* ── Responsive: collapse to horizontal tab strip ─────────────── */
@media (max-width: 820px) {
    .vp-books__layout {
        grid-template-columns: 1fr;
        gap: clamp(20px, 4vw, 28px);
    }

    .vp-books__side {
        flex-direction: row;
        flex-wrap: nowrap;
        gap: 8px;
        overflow-x: auto;
        padding-bottom: 6px;
        scrollbar-width: thin;
    }

    .vp-books__cat {
        width: auto;
        flex: 0 0 auto;
        border: 1px solid var(--vp-border-primary-color);
    }

    .vp-books__cat[aria-selected="true"] {
        box-shadow: none;
        border-color: var(--vp-accent-primary-color);
    }
}

/* ── Reduced motion ───────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
    .vp-books__card {
        transition: none;
    }

    .vp-books__card:hover,
    .vp-books__card:focus-visible {
        transform: none;
    }
}