:root {
    --text-main: #000000;
    --accent-dark: #000000;
    --title-blue: #1d4ed8;
    --grid-line: #cbd5e1;
    --border-light: #e2e8f0;
    --bg-subtle: #f8fafc;
    --bg-paper: #ffffff;
    --cell-size: 20px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
    background-color: #e0e0e0;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    font-family: 'Rubik', sans-serif;
    color: var(--text-main);
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

.a4-page {
    width: 210mm;
    height: 297mm;
    background: var(--bg-paper);
    padding: 10mm 18mm;
    box-shadow: 0 0 10px rgba(0,0,0,0.15);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    page-break-after: always;
    position: relative;
    margin: 30px;
    overflow: hidden;
}

/* קרדיט קבוע — חובה בכל דף עבודה. שכבת נושא רשאית לדרוס את הסגנון, לא את הנוסח. */
.a4-page > .gz-footer {
    flex: 0 0 auto;
    margin-top: 4px;
    /* הקו הכחול נמתח לכל רוחב דף ה־A4: מבטל את padding הצד (18mm) של .a4-page */
    margin-inline: -18mm;
    padding-top: 3px;
    border-top: 1px solid var(--title-blue);
    text-align: center;
    line-height: 1.2;
}

.a4-page > .gz-footer .f1 {
    font-size: 10.5px;
    font-weight: 500;
    color: #1f2a44;
}

.a4-page > .gz-footer .f2 {
    font-size: 9.5px;
    color: #475569;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    margin-bottom: 8px;
    padding-bottom: 6px;
    border-bottom: 4px double var(--title-blue);
}

.page-title { color: var(--title-blue); font-size: 26px; font-weight: 400; }
.page-number {
    width: 32px;
    height: 32px;
    border: 2px solid var(--title-blue);
    color: var(--title-blue);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
}

.question-block { flex-grow: 1; display: flex; flex-direction: column; justify-content: space-between; }
/* Book-grade instruction typography: bullets align to the first text baseline, not to an arbitrary box height. */
.q-main, .q-sub { display: flex; align-items: baseline; margin-bottom: 5px; }
.bullet-container { flex-shrink: 0; margin-left: 10px; width: 10px; height: auto; display: flex; align-items: flex-end; justify-content: center; }
.bullet-large { width: 8px; height: 8px; background-color: var(--accent-dark); border-radius: 50%; flex: 0 0 auto; }
.bullet-small { width: 5px; height: 5px; background-color: var(--accent-dark); border-radius: 50%; flex: 0 0 auto; }
.q-text { line-height: 22px; flex: 1; min-width: 0; }

@supports (align-items: first baseline) {
    .q-main, .q-sub { align-items: first baseline; }
}

.answer-box {
    display: inline-block;
    border: 1px solid var(--grid-line);
    border-radius: 4px;
    height: 22px;
    margin: 0 5px;
    position: relative;
    vertical-align: middle;
    transform: translateY(-2px);
}
.answer-box::before { content: ""; position: absolute; bottom: 3px; left: 5px; right: 5px; border-bottom: 1.5px dotted var(--grid-line); }
.box-sm { width: 60px; }
.box-md { width: 140px; }

.explain-box {
    margin-top: 5px;
    height: 38px;
    border: 1px solid var(--border-light);
    border-radius: 4px;
    width: 100%;
    background-image: linear-gradient(transparent 32px, var(--border-light) 32px, var(--border-light) 33.5px, transparent 33.5px);
}

.math-table {
    border-collapse: collapse;
    margin: 6px 0;
    text-align: center;
    table-layout: fixed;
    direction: ltr;
}

.math-table td { border: 1px solid var(--accent-dark); height: 40px; vertical-align: middle; }
.label-cell { background-color: var(--bg-subtle); width: 150px; direction: rtl; text-align: right; padding-right: 10px; }

.page-3-table td { width: 48px; }

.row-subtle { background-color: var(--bg-subtle); }

.visual-container { display: flex; justify-content: center; margin: 6px 0; width: 100%; }

.math-grid-bg {
    width: 100%;
    padding: 12px;
    background-image: linear-gradient(rgba(203, 213, 225, 0.4) 1px, transparent 1px), linear-gradient(90deg, rgba(203, 213, 225, 0.4) 1px, transparent 1px);
    background-size: var(--cell-size) var(--cell-size);
    border: 1px solid var(--border-light);
    border-bottom: 2px solid var(--accent-dark);
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    direction: ltr;
    border-radius: 6px;
}

.cell { width: var(--cell-size); height: var(--cell-size); border-radius: 2px; box-shadow: inset 1px 1px 2px rgba(255,255,255,0.4); }
.cell.red { background: linear-gradient(135deg, #ef4444, #991b1b); }
.cell.blue { background: linear-gradient(135deg, #3b82f6, #1e40af); }

.showcase-container {
    width: 100%;
    padding: 15px;
    background-color: var(--bg-subtle);
    border: 1px solid var(--border-light);
    border-bottom: 2px solid var(--accent-dark);
    border-radius: 6px;
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    direction: ltr;
}

.tactile-block { width: 22px; height: 22px; background: linear-gradient(135deg, #fff, #cbd5e1); border: 1px solid #000; border-radius: 2px; }
.tactile-circle { width: 22px; height: 22px; border-radius: 50%; background: radial-gradient(circle at 30% 30%, #475569, #000); border: 1px solid #000; }
.shape-placeholder { width: 90px; height: 90px; border: 2px dashed #94a3b8; border-radius: 6px; position: relative; }

.coordinate-system {
    width: 440px;
    height: 440px;
    border: 1px solid var(--border-light);
    background-color: #fff;
    position: relative;
    background-image: linear-gradient(rgba(203, 213, 225, 0.4) 1px, transparent 1px), linear-gradient(90deg, rgba(203, 213, 225, 0.4) 1px, transparent 1px);
    background-size: 22px 22px;
    background-position: 0 0;
    margin: 0 auto;
}

.axis { position: absolute; background-color: black; z-index: 2; }
.axis-x { width: 100%; height: 1px; top: 50%; left: 0; }
.axis-y { height: 100%; width: 1px; left: 50%; top: 0; }
.axis-x::after { content: ''; position: absolute; right: -8px; top: -5px; border: 6px solid transparent; border-left-color: black; }
.axis-y::after { content: ''; position: absolute; top: -8px; left: -5px; border: 6px solid transparent; border-bottom-color: black; }
.axis-label { position: absolute; font-size: 13px; font-weight: bold !important; }
.label-x { top: 50%; right: -25px; transform: translateY(-50%); }
.label-y { left: 50%; top: -25px; transform: translateX(-50%); }

.symmetry-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    padding-right: 35px;
    margin: 5px 0;
    direction: ltr;
}

.sym-item { display: flex; align-items: center; gap: 8px; font-size: 16px; }
.ordered-pair { direction: ltr; unicode-bidi: isolate; display: inline-block; margin-right: 5px; font-weight: 500 !important; }

.multiple-choice {
    display: flex;
    justify-content: space-around;
    width: 100%;
    background: var(--bg-paper);
    border: 1px solid var(--border-light);
    border-radius: 6px;
    padding: 8px;
    direction: rtl;
}

.mc-option { display: flex; align-items: center; gap: 6px; }
.mc-circle { width: 14px; height: 14px; border: 1.5px solid var(--grid-line); border-radius: 50%; }

.stack-col { display: flex; flex-direction: column; gap: 1px; }
.stack-row { display: flex; gap: 1px; }

hr { border: 0; border-top: 1px solid var(--border-light); margin: 6px 0; }

/* Preview-only navigation (hidden in print) */
.preview-nav {
    width: 210mm;
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 10px 18mm;
    margin: 18px 0 10px;
    background: var(--bg-paper);
    border: 1px solid var(--border-light);
    border-radius: 6px;
}

.preview-nav-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

.preview-nav .nav-side {
    display: flex;
    align-items: center;
    gap: 8px;
}

.preview-nav .nav-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 96px;
    height: 32px;
    padding: 0 10px;
    border: 1px solid var(--grid-line);
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-main);
    background: var(--bg-subtle);
}

.preview-nav .nav-link:focus-visible {
    outline: 2px solid var(--title-blue);
    outline-offset: 2px;
}

.preview-nav .nav-link.is-disabled {
    opacity: 0.5;
    cursor: default;
}

.preview-nav .nav-meta {
    font-size: 14px;
    color: var(--text-main);
}

.preview-nav-topics {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.preview-nav-topics .topic-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    height: 34px;
    padding: 0 14px;
    border-radius: 999px;
    border: 2px solid var(--title-blue);
    text-decoration: none;
    color: var(--title-blue);
    background: var(--bg-paper);
    font-weight: 500 !important;
    transition: transform 120ms ease, background-color 120ms ease, color 120ms ease;
}

.preview-nav-topics .topic-link:hover {
    transform: translateY(-1px);
}

.preview-nav-topics .topic-link:focus-visible {
    outline: 2px solid var(--title-blue);
    outline-offset: 2px;
}

.preview-nav-topics .topic-link.is-active {
    background: var(--title-blue);
    color: var(--bg-paper);
}

/* Generic text blocks for rules pages (same tokens, no new colors) */
.rules-paragraph { margin-bottom: 6px; }
.rules-code {
    direction: ltr;
    unicode-bidi: isolate;
    background: var(--bg-subtle);
    border: 1px solid var(--border-light);
    border-radius: 6px;
    padding: 10px;
    white-space: pre-wrap;
    line-height: 20px;
    font-size: 14px;
}

/* Mobile preview for every standalone page: preserve the complete A4 layout and fit it as one unit. */
@media screen and (max-width: 820px) {
    html {
        width: 100%;
        max-width: 100vw;
        overflow-x: hidden !important;
        overscroll-behavior-x: none;
    }

    body:not(.pythagoras-workbook-shell) {
        width: 100%;
        max-width: 100vw;
        overflow-x: hidden !important;
        overscroll-behavior-x: none;
        touch-action: pan-y pinch-zoom;
        align-items: center;
    }

    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page {
        margin-left: 0;
        margin-right: 0;
        transform: none !important;
        transform-origin: center top !important;
    }
}

@media screen and (max-width: 350px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .42; }
}
@media screen and (min-width: 351px) and (max-width: 370px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .44; }
}
@media screen and (min-width: 371px) and (max-width: 390px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .46; }
}
@media screen and (min-width: 391px) and (max-width: 410px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .49; }
}
@media screen and (min-width: 411px) and (max-width: 430px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .51; }
}
@media screen and (min-width: 431px) and (max-width: 460px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .54; }
}
@media screen and (min-width: 461px) and (max-width: 500px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .59; }
}
@media screen and (min-width: 501px) and (max-width: 540px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .64; }
}
@media screen and (min-width: 541px) and (max-width: 590px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .70; }
}
@media screen and (min-width: 591px) and (max-width: 650px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .76; }
}
@media screen and (min-width: 651px) and (max-width: 720px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .84; }
}
@media screen and (min-width: 721px) and (max-width: 800px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .93; }
}
@media screen and (min-width: 801px) and (max-width: 820px) {
    body:not(.pythagoras-workbook-shell) .preview-nav,
    body:not(.pythagoras-workbook-shell) .a4-page { zoom: .99; }
}

@media print {
    @page { size: A4; margin: 0; }
    html, body { background: none; display: block; width: auto; height: auto; overflow-x: visible; }
    body { padding: 0; margin: 0; touch-action: auto; }
    .a4-page { box-shadow: none; margin: 0; width: 100%; zoom: 1 !important; -webkit-print-color-adjust: exact; print-color-adjust: exact; overflow: visible; }
    .preview-nav { display: none; }
}

/* --- Premium Math Visualization Rules --- */
.graph-label {
    font-family: 'Assistant', sans-serif;
    font-style: italic;
    font-size: 14px;
    fill: #2c3e50;
    dominant-baseline: hanging;
}

.math-line {
    stroke: #3498db;
    stroke-width: 2.5;
    fill: none;
}

.axis-line {
    stroke: #000;
    stroke-width: 1.5;
}