/* ══════════════════════════════════════════════════════════
   complex_arithmetic.html  ·  page-specific styles
   ══════════════════════════════════════════════════════════ */

:root {
    --bg: #0a0a10;
    --bg-2: #12131c;
    --bg-panel: rgba(22, 23, 32, 0.75);
    --fg: #eef0f5;
    --text: #eef0f5;
    --text-dim: #d4d7e0;
    --muted: #8b90a3;
    --border: rgba(255, 255, 255, 0.09);
    --border-hover: rgba(255, 255, 255, 0.18);

    /* page semantic palette */
    --z1-color: #58a6ff;          /* z₁ vector (blue, opaque) */
    --z2-color: #7be089;          /* z₂ vector (green, opaque) */
    --result-color: #ff5c7a;      /* result vector (red, semi-transparent) */
    --accent: var(--site-accent);
    --accent-soft: var(--site-accent-soft);
    --accent-soft-faint: var(--site-accent-soft-faint);
    --accent-soft-edge: var(--site-accent-soft-edge);

    --grid-line: rgba(255, 255, 255, 0.06);
    --grid-zero: rgba(255, 255, 255, 0.30);
    --tick-line: rgba(255, 255, 255, 0.25);
    --domain-line: rgba(255, 255, 255, 0.35);
    --slider-track: rgba(255, 255, 255, 0.12);
    --input-bg: rgba(255, 255, 255, 0.04);
    --pill-bg: rgba(255, 255, 255, 0.03);

    --body-size: 17px;
    --math-size: 18px;
    --hero-size: 60px;
}

[data-theme="light"] {
    --bg: #f5f5f7;
    --bg-2: #ffffff;
    --bg-panel: rgba(255, 255, 255, 0.92);
    --fg: #1a1a1e;
    --text: #1a1a1e;
    --text-dim: #2b2d38;
    --muted: #6a6f7c;
    --border: rgba(0, 0, 0, 0.10);
    --border-hover: rgba(0, 0, 0, 0.22);

    --z1-color: #1d4ed8;
    --z2-color: #2f8f3f;
    --result-color: #dc2626;
    --accent: var(--site-accent);
    --accent-soft: var(--site-accent-soft);
    --accent-soft-faint: var(--site-accent-soft-faint);
    --accent-soft-edge: var(--site-accent-soft-edge);

    --grid-line: rgba(0, 0, 0, 0.07);
    --grid-zero: rgba(0, 0, 0, 0.32);
    --tick-line: rgba(0, 0, 0, 0.22);
    --domain-line: rgba(0, 0, 0, 0.35);
    --slider-track: rgba(0, 0, 0, 0.12);
    --input-bg: rgba(0, 0, 0, 0.03);
    --pill-bg: rgba(0, 0, 0, 0.03);
}

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

html, body {
    background: var(--bg);
    color: var(--fg);
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    font-size: var(--body-size);
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

body {
    overflow-x: hidden;
    min-height: 100vh;
}

.katex { font-size: var(--math-size) !important; }
.katex-display { margin: 0.6em 0 !important; }
.katex-display > .katex { font-size: calc(var(--math-size) * 1.06) !important; }
h1 .katex, h2 .katex, h3 .katex { font-size: inherit !important; }

a { color: var(--accent); }

/* ─── Brand and back ─── */
.brand {
    position: fixed;
    top: 20px;
    left: 24px;
    z-index: 40;
    font-size: 12px;
    color: var(--muted);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
    display: flex;
    align-items: center;
    gap: 10px;
}

.brand .mark {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: conic-gradient(var(--z1-color), var(--z2-color), var(--result-color), var(--z1-color));
}

.back-btn {
    position: fixed;
    top: 14px;
    right: 56px;
    z-index: 9999;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 14px;
    border-radius: 999px;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    color: var(--fg);
    text-decoration: none;
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    backdrop-filter: blur(8px);
    transition: all 0.15s;
}
.back-btn:hover { border-color: var(--accent); color: var(--accent); }

/* ─── Landing hero ─── */
.landing {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 120px 56px 80px;
    text-align: center;
    position: relative;
}

.landing .meta {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--muted);
    letter-spacing: 0.2em;
    text-transform: uppercase;
    margin-bottom: 28px;
}

h1.hero {
    font-size: var(--hero-size);
    line-height: 1.02;
    font-weight: 600;
    letter-spacing: -0.025em;
    margin: 0 0 24px;
    max-width: 22ch;
    margin-left: auto;
    margin-right: auto;
}

h1.hero em {
    font-style: normal;
    background: linear-gradient(135deg, var(--z1-color), var(--result-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.landing .sub {
    color: var(--muted);
    font-size: 18px;
    max-width: 64ch;
    margin: 12px auto 0;
    line-height: 1.6;
}

.landing .tags {
    margin-top: 36px;
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
}

.field-tag {
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    color: var(--muted);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    display: inline-block;
    padding: 4px 10px;
    border: 1px solid var(--border);
    border-radius: 4px;
}

.scroll-hint {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    letter-spacing: 0.2em;
    color: var(--muted);
    text-transform: uppercase;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.scroll-hint .line {
    width: 1px;
    height: 32px;
    background: linear-gradient(var(--muted), transparent);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 1; }
}

/* ─── Scene layout ─── */
section.scene {
    min-height: 100vh;
    padding: 100px 40px 80px;
    display: grid;
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.5fr);
    gap: 28px;
    align-items: start;
    border-bottom: 1px solid var(--border);
}

section.scene .copy { max-width: 560px; }

.eyebrow {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 18px;
    display: flex;
    align-items: center;
    gap: 10px;
}
.eyebrow .num { color: var(--accent); }
.eyebrow .bar { flex: 0 0 28px; height: 1px; background: var(--accent); }

h2 {
    font-size: 34px;
    line-height: 1.12;
    font-weight: 600;
    letter-spacing: -0.02em;
    margin: 0 0 18px;
    color: var(--fg);
}
h2 em { font-style: normal; }
h2 em.z1 { color: var(--z1-color); }
h2 em.z2 { color: var(--z2-color); }
h2 em.r  { color: var(--result-color); }

h3 {
    font-size: 17px;
    font-weight: 600;
    margin: 22px 0 8px;
    color: var(--fg);
    letter-spacing: -0.01em;
}

p { margin: 0 0 14px; color: var(--text-dim); }
p.lead { font-size: calc(var(--body-size) + 1px); color: var(--fg); }
p.dim { color: var(--muted); }

strong { color: var(--fg); font-weight: 600; }

.eq-block {
    display: block;
    margin: 16px 0;
    padding: 14px 18px;
    background: var(--accent-soft-faint);
    border: 1px solid var(--accent-soft-edge);
    border-radius: 10px;
    text-align: center;
    color: var(--fg);
    overflow-x: auto;
}

.callout {
    margin-top: 18px;
    padding: 14px 18px;
    border-left: 2px solid var(--accent);
    background: var(--accent-soft-faint);
    border-radius: 0 8px 8px 0;
    font-size: 14px;
    color: var(--text-dim);
    line-height: 1.7;
}

/* ─── Plot stack ─── */
.plot-stack {
    display: flex;
    flex-direction: column;
    gap: 14px;
    width: 100%;
    max-width: 720px;
}

.plot-box {
    position: relative;
    border: 1px solid var(--border);
    border-radius: 12px;
    background: var(--bg-2);
    overflow: hidden;
    width: 100%;
    aspect-ratio: 1 / 1;
}

.plot-box svg {
    display: block;
    width: 100%;
    height: 100%;
}

.plot-box .label {
    position: absolute;
    top: 10px;
    left: 14px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--muted);
    z-index: 2;
    pointer-events: none;
}

.plot-box .label b {
    font-weight: 600;
    letter-spacing: 0.06em;
    color: var(--fg);
}

/* ─── Controls and toolbar ─── */
.toolbar {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    align-items: center;
    padding: 8px;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
}

.toolbar .pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    background: var(--pill-bg);
    border: 1px solid var(--border);
    border-radius: 999px;
    color: var(--text-dim);
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-size: 10px;
    transition: all 0.12s;
    user-select: none;
}
.toolbar .pill:hover { border-color: var(--border-hover); color: var(--fg); }
.toolbar .pill.active {
    background: var(--accent-soft);
    border-color: var(--accent);
    color: var(--accent);
}

.toolbar .divider {
    width: 1px;
    height: 18px;
    background: var(--border);
    margin: 0 4px;
}

.toolbar .hint {
    color: var(--muted);
    font-size: 10px;
    letter-spacing: 0.06em;
    text-transform: none;
    padding-left: 4px;
}

/* ─── Readout breakdown table ─── */
.breakdown {
    margin-top: 14px;
    padding: 14px;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
}

.breakdown table {
    width: 100%;
    border-collapse: collapse;
}

.breakdown th, .breakdown td {
    text-align: left;
    padding: 8px 10px;
    border-bottom: 1px dashed var(--border);
    color: var(--text-dim);
}

.breakdown th {
    color: var(--muted);
    font-weight: 500;
    font-size: 10px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.breakdown tr:last-child td { border-bottom: 0; }
.breakdown tr.r-z1 td.lab { color: var(--z1-color); font-weight: 600; }
.breakdown tr.r-z2 td.lab { color: var(--z2-color); font-weight: 600; }
.breakdown tr.r-out td    { color: var(--result-color); font-weight: 600; background: rgba(123, 224, 137, 0.05); }
[data-theme="light"] .breakdown tr.r-out td { background: rgba(47, 143, 63, 0.06); }

/* ─── D3 plot styling ─── */
svg.argand text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    fill: var(--muted);
}

svg.argand .grid line {
    stroke: var(--grid-line);
    stroke-width: 1;
}

svg.argand .axis-line {
    stroke: var(--grid-zero);
    stroke-width: 1.4;
}

svg.argand .unit-circle {
    fill: none;
    stroke: var(--tick-line);
    stroke-dasharray: 3 3;
    stroke-width: 1;
}

svg.argand .vec {
    fill: none;
    stroke-width: 2.4;
    stroke-linecap: round;
}

svg.argand .vec.z1     { stroke: var(--z1-color); opacity: 0.55; }
svg.argand .vec.z2     { stroke: var(--z2-color); opacity: 0.55; }
svg.argand .vec.result { stroke: var(--result-color); stroke-width: 3; opacity: 1; }
svg.argand .vec.ghost  { stroke: var(--result-color); opacity: 0.4; stroke-dasharray: 4 4; }

svg.argand .vec-arc.a1 { stroke: var(--z1-color); fill: none; opacity: 0.65; stroke-width: 1.4; }
svg.argand .vec-arc.a2 { stroke: var(--z2-color); fill: none; opacity: 0.65; stroke-width: 1.4; }
svg.argand .vec-arc.ar { stroke: var(--result-color); fill: none; opacity: 0.85; stroke-width: 1.8; }

svg.argand .handle {
    cursor: grab;
    stroke: var(--bg);
    stroke-width: 2;
}
svg.argand .handle.dragging { cursor: grabbing; }
svg.argand .handle.z1 { fill: var(--z1-color); opacity: 0.7; }
svg.argand .handle.z2 { fill: var(--z2-color); opacity: 0.7; }
svg.argand .handle.result { fill: var(--result-color); opacity: 1; }

svg.argand foreignObject { overflow: visible; }

svg.argand .lbl {
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
    paint-order: stroke fill;
    stroke: var(--bg-2);
    stroke-width: 4;
    stroke-linejoin: round;
}
svg.argand .lbl.z1     { fill: var(--z1-color); }
svg.argand .lbl.z2     { fill: var(--z2-color); }
svg.argand .lbl.result { fill: var(--result-color); }

svg.argand .axis-tick text {
    fill: var(--muted);
    font-size: 12px;
}

svg.argand .axis-tick line {
    stroke: var(--tick-line);
    stroke-width: 1;
}

/* ─── Grid transformation plot ─── */
svg.transform-argand .source-grid line {
    stroke: rgba(0, 0, 0, 0.35);
    stroke-width: 1.1;
    opacity: 0.5;
}

svg.transform-argand .source-grid line.major {
    opacity: 0.75;
}

svg.transform-argand .mapped-grid line {
    stroke: rgba(0, 0, 0, 0.75);
    stroke-width: 1.15;
    opacity: 0.58;
}

svg.transform-argand .mapped-grid line.major {
    stroke-width: 1.7;
    opacity: 0.82;
}

svg.transform-argand .unit-start {
    fill: var(--bg-2);
    stroke: var(--accent);
    stroke-width: 2;
}

svg.argand .vec.transform {
    stroke: var(--accent);
    stroke-width: 3;
    opacity: 1;
}

svg.argand .handle.transform {
    fill: var(--accent);
    opacity: 1;
}

svg.argand .lbl.transform {
    fill: var(--accent);
}

svg.transform-argand .vec.result.result-z1,
svg.transform-argand .handle.result.result-z1 {
    stroke: var(--z1-color);
    fill: var(--z1-color);
}

svg.transform-argand .vec.result.result-z2,
svg.transform-argand .handle.result.result-z2 {
    stroke: var(--z2-color);
    fill: var(--z2-color);
}

svg.transform-argand .lbl.result.result-z1 {
    fill: var(--z1-color);
}

svg.transform-argand .lbl.result.result-z2 {
    fill: var(--z2-color);
}

svg.argand .mapped-point {
    stroke: var(--bg);
    stroke-width: 2;
}

svg.argand .mapped-point.result-z1 {
    fill: var(--z1-color);
}

svg.argand .mapped-point.result-z2 {
    fill: var(--z2-color);
}

.transform-readout {
    display: grid;
    gap: 8px;
}

.transform-readout .row {
    display: grid;
    grid-template-columns: minmax(80px, 0.8fr) minmax(0, 1.4fr);
    gap: 12px;
    padding-bottom: 8px;
    border-bottom: 1px dashed var(--border);
}

.transform-readout .row:last-child {
    border-bottom: 0;
    padding-bottom: 0;
}

.transform-readout .lab {
    color: var(--muted);
    font-size: 10px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.transform-readout .val {
    color: var(--text-dim);
}

/* ─── Footer ─── */
footer {
    padding: 60px 56px 80px;
    text-align: center;
    color: var(--muted);
    font-size: 13px;
    border-top: 1px solid var(--border);
    font-family: 'JetBrains Mono', monospace;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

@media (max-width: 900px) {
    section.scene {
        grid-template-columns: 1fr;
        padding: 80px 24px 60px;
    }
    h1.hero { font-size: 42px; }
    h2 { font-size: 26px; }
    .brand { top: 16px; left: 16px; }
}