/* ==========================================================================
   browse.css — MakerWorld's models-page layout, GDC's palette.
   Engine rail across the top, component filters down the left, card grid.
   ========================================================================== */

.browse {
    padding-top: 32px;
    padding-bottom: 64px;
}

/* --------------------------------------------------------- engine rail    */

.engine-rail {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 14px;
    margin-bottom: 22px;
    scrollbar-width: thin;
}

.engine-tab {
    flex: 0 0 auto;
    display: inline-flex;
    align-items: center;
    gap: 9px;
    border: 2px solid var(--gdc-border);
    background: var(--gdc-surface);
    color: var(--gdc-ink-muted);
    border-radius: 999px;
    padding: 11px 22px;
    font-family: var(--gdc-font-ui);
    font-weight: 700;
    font-size: 16px;
    cursor: pointer;
    white-space: nowrap;
    transition: all 0.2s;
}

.engine-tab:hover {
    border-color: var(--gdc-accent);
    background: var(--gdc-accent-tint);
    color: var(--gdc-navy);
}

.engine-tab.active {
    background: var(--gdc-navy);
    border-color: var(--gdc-navy);
    color: #fff;
}

.engine-count {
    display: inline-block;
    min-width: 24px;
    padding: 1px 7px;
    border-radius: 999px;
    background: var(--gdc-accent-tint);
    color: var(--gdc-accent);
    font-size: 13px;
    font-weight: 700;
    text-align: center;
}

.engine-tab.active .engine-count {
    background: rgba(255, 255, 255, 0.22);
    color: #fff;
}

.engine-tab.is-empty:not(.active) { opacity: 0.5; }

/* ------------------------------------------------------------- layout     */

.browse-body {
    display: grid;
    grid-template-columns: 264px minmax(0, 1fr);
    gap: 26px;
    align-items: start;
}

.filter-toggle { display: none; }

.sidebar {
    position: sticky;
    top: calc(var(--gdc-nav-h) + 16px);
    padding: 22px 20px;
    max-height: calc(100vh - var(--gdc-nav-h) - 40px);
    overflow-y: auto;
}

.filter-group { margin-bottom: 24px; }

.filter-title {
    font-family: var(--gdc-font-body);
    font-size: 20px;
    font-weight: 700;
    color: var(--gdc-navy);
    margin: 0 0 12px;
}

.filter-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.filter-option {
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    border: 0;
    background: transparent;
    color: var(--gdc-ink-muted);
    border-radius: 8px;
    padding: 9px 11px;
    font-family: var(--gdc-font-ui);
    font-size: 15px;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: all 0.15s;
}

.filter-option:hover {
    background: var(--gdc-surface-sunken);
    color: var(--gdc-navy);
}

.filter-option.active {
    background: var(--gdc-accent-tint);
    color: var(--gdc-navy);
    font-weight: 700;
}

.filter-icon {
    width: 18px;
    text-align: center;
    color: var(--gdc-accent);
    flex: 0 0 auto;
}

.filter-label { flex: 1 1 auto; }

.filter-count {
    font-size: 13px;
    font-weight: 600;
    color: var(--gdc-ink-faint);
    font-variant-numeric: tabular-nums;
}

.filter-option.active .filter-count { color: var(--gdc-accent); }

/* An empty category is dimmed, never hidden — a zero count is information. */
.filter-option.is-empty { opacity: 0.45; }

/* ------------------------------------------------------------- toolbar    */

.toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
    margin-bottom: 14px;
}

.search-wrap {
    position: relative;
    flex: 1 1 320px;
    min-width: 0;
}

.search-wrap > .fa-magnifying-glass {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gdc-ink-faint);
    pointer-events: none;
}

.search-input,
.sort-select {
    width: 100%;
    border: 2px solid var(--gdc-border);
    border-radius: 999px;
    background: var(--gdc-surface);
    color: var(--gdc-ink);
    font-family: var(--gdc-font-ui);
    font-size: 15px;
    padding: 12px 18px;
    transition: border-color 0.2s;
}

.search-input { padding-left: 44px; }

.search-input:focus,
.sort-select:focus {
    outline: none;
    border-color: var(--gdc-accent);
}

.sort-select {
    width: auto;
    min-width: 210px;
    cursor: pointer;
    padding-right: 38px;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%23445668'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 15px center;
    background-size: 14px;
}

/* ------------------------------------------------------- active filters   */

.active-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 12px;
}

.active-chip {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border: 0;
    background: var(--gdc-navy);
    color: #fff;
    border-radius: 999px;
    padding: 7px 14px;
    font-family: var(--gdc-font-ui);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.active-chip:hover { background: var(--gdc-accent); }

.active-chip.clear-all {
    background: transparent;
    color: var(--gdc-accent);
    border: 2px solid var(--gdc-border);
}

.active-chip.clear-all:hover {
    background: var(--gdc-accent-tint);
    border-color: var(--gdc-accent);
}

.result-count {
    font-family: var(--gdc-font-ui);
    font-size: 14px;
    color: var(--gdc-ink-faint);
    margin: 0 0 16px;
}

/* ---------------------------------------------------------- lesson grid   */

.lesson-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(272px, 1fr));
    gap: 22px;
}

/* --------------------------------------------------------- empty state    */

.empty-state {
    text-align: center;
    padding: 64px 24px;
    background: var(--gdc-surface);
    border-radius: var(--gdc-radius);
    box-shadow: var(--gdc-shadow-sm);
}

.empty-state i {
    font-size: 44px;
    color: var(--gdc-accent-soft);
    margin-bottom: 14px;
}

.empty-state h2 {
    font-size: 26px;
    font-weight: 700;
    color: var(--gdc-navy);
    margin: 0 0 10px;
}

.empty-state p {
    font-family: var(--gdc-font-ui);
    color: var(--gdc-ink-muted);
    max-width: 52ch;
    margin: 0 auto 20px;
    line-height: 1.6;
}

/* ------------------------------------------------------------- bottom cta */

.browse-cta {
    margin-top: 40px;
    padding: 26px 30px;
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
    align-items: center;
    justify-content: space-between;
}

.browse-cta h2 {
    font-size: 24px;
    font-weight: 700;
    color: var(--gdc-navy);
    margin: 0 0 6px;
}

.browse-cta p {
    font-family: var(--gdc-font-ui);
    font-size: 15px;
    color: var(--gdc-ink-muted);
    margin: 0;
    max-width: 62ch;
}

.browse-cta code {
    background: var(--gdc-surface-sunken);
    border-radius: 4px;
    padding: 1px 6px;
    color: var(--gdc-navy);
    font-size: 13.5px;
}

/* ------------------------------------------------------------ responsive  */

@media screen and (max-width: 900px) {
    .browse-body { grid-template-columns: minmax(0, 1fr); }

    .filter-toggle {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        margin-bottom: 14px;
    }

    .sidebar {
        display: none;
        position: static;
        max-height: none;
        margin-bottom: 18px;
    }

    .sidebar.open { display: block; }

    .toolbar { flex-direction: column; align-items: stretch; }
    /* In a column flex container flex-basis sets the HEIGHT — without this the
       search box grows to 320px tall. */
    .search-wrap { flex: 0 0 auto; }
    .sort-select { width: 100%; }
}

@media screen and (max-width: 560px) {
    .lesson-grid { grid-template-columns: minmax(0, 1fr); }
    .browse-cta { flex-direction: column; align-items: flex-start; }
}