/* ══════════════════════════════════════════════════════════
   cascading_filters.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 */
    --c-ideal: #58a6ff;
    --c-real:  #ff5c7a;
    --c-stage: #7be089;
    --c-mark:  #22c55e;
    --c-buffered: #58a6ff;
    --c-passive:  #ff5c7a;
    --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);
    --slider-track: rgba(255, 255, 255, 0.12);
    --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);

    --c-ideal: #1d4ed8;
    --c-real:  #dc2626;
    --c-stage: #2f8f3f;
    --c-mark:  #15803d;
    --c-buffered: #1d4ed8;
    --c-passive:  #dc2626;

    --grid-line: rgba(0, 0, 0, 0.07);
    --grid-zero: rgba(0, 0, 0, 0.32);
    --tick-line: rgba(0, 0, 0, 0.22);
    --slider-track: rgba(0, 0, 0, 0.12);
    --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(--c-ideal), var(--c-stage), var(--c-real), var(--c-ideal));
}

.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 auto 24px; max-width: 22ch;
}
h1.hero em {
    font-style: normal;
    background: linear-gradient(135deg, var(--c-ideal), var(--c-real));
    -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.ideal { color: var(--c-ideal); }
h2 em.real  { color: var(--c-real); }

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: 760px;
}

.plot-box {
    position: relative;
    border: 1px solid var(--border);
    border-radius: 12px; background: var(--bg-2);
    overflow: hidden; width: 100%;
}
.plot-box.bode-pair { aspect-ratio: 1 / 1.05; }
.plot-box.bode-side { aspect-ratio: 2 / 1; }
.plot-box.splane    { aspect-ratio: 1 / 1; max-width: 540px; margin: 0 auto; }
.plot-box.single    { aspect-ratio: 1.6 / 1; }

/* Section-specific override: the loaded-cascade section gives the plots
   more horizontal room than the default scene layout, but still scales
   with the viewport (clamped between 640 px and 1000 px). The s-plane
   keeps its own 540 px cap so it stays the same size as before. */
#sec-loaded-cascade .plot-stack {
    max-width: clamp(640px, 78vw, 1000px);
    margin-left: 0;
    margin-right: auto;
}
#sec-loaded-cascade .plot-box.bode-side { aspect-ratio: 2 / 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: 10px 14px; flex-wrap: wrap; align-items: center;
    padding: 10px 12px;
    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;
}
.toolbar .slider-group {
    display: inline-flex; align-items: center; gap: 10px;
    padding: 4px 8px;
}
.toolbar .slider-group .lab {
    color: var(--muted); font-size: 10px;
    letter-spacing: 0.1em; text-transform: uppercase;
}
.toolbar .slider-group .val {
    color: var(--fg); min-width: 5ch; text-align: right;
}
.toolbar input[type="range"] {
    -webkit-appearance: none; appearance: none;
    width: 130px; height: 4px;
    background: var(--slider-track); border-radius: 999px;
    outline: none;
}
.toolbar input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none; appearance: none;
    width: 14px; height: 14px; border-radius: 50%;
    background: var(--accent); cursor: pointer;
    border: 2px solid var(--bg-2);
}
.toolbar input[type="range"]::-moz-range-thumb {
    width: 14px; height: 14px; border-radius: 50%;
    background: var(--accent); cursor: pointer;
    border: 2px solid var(--bg-2);
}

/* ─── Readout breakdown ─── */
.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-ideal td.lab { color: var(--c-ideal); font-weight: 600; }
.breakdown tr.r-real  td.lab { color: var(--c-real);  font-weight: 600; }

/* ─── Bode plot styling ─── */
svg.bode text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px; fill: var(--muted);
}
svg.bode .grid line { stroke: var(--grid-line); stroke-width: 1; }
svg.bode .grid line.major { stroke: var(--grid-zero); stroke-width: 1.2; }
svg.bode .axis-line { stroke: var(--grid-zero); stroke-width: 1.4; }
svg.bode .axis-tick text { fill: var(--muted); font-size: 12px; }
svg.bode .axis-tick line { stroke: var(--tick-line); stroke-width: 1; }

svg.bode .trace { fill: none; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }
svg.bode .trace.ideal     { stroke: var(--c-ideal); }
svg.bode .trace.real      { stroke: var(--c-real); }
svg.bode .trace.buffered  { stroke: var(--c-buffered); }
svg.bode .trace.passive   { stroke: var(--c-passive); }
svg.bode .trace.faint     { opacity: 0.35; stroke-width: 1.6; stroke-dasharray: 4 4; }
svg.bode .trace.stage     { stroke: var(--c-stage); opacity: 0.5; stroke-width: 1.6; }

svg.bode .marker-line { stroke: var(--c-mark); stroke-width: 1.4; stroke-dasharray: 5 4; }
svg.bode .marker-dot  { fill: var(--c-mark); stroke: var(--bg-2); stroke-width: 2; }
svg.bode .marker-band { fill: var(--c-mark); opacity: 0.08; }
svg.bode .cutoff-single {
    stroke: var(--c-mark);
    stroke-width: 1;
    stroke-dasharray: 3 3;
    opacity: 0.65;
    fill: none;
}

svg.bode foreignObject { overflow: visible; }
svg.bode .legend-pill {
    fill: var(--bg-panel); stroke: var(--border); stroke-width: 1;
}

/* Hover crosshair and value readout */
svg.bode .hover-overlay { fill: transparent; cursor: crosshair; }
svg.bode .hover-vline {
    stroke: var(--fg); stroke-width: 1; stroke-dasharray: 3 3; opacity: 0.55;
}
svg.bode .hover-dot { stroke: var(--bg-2); stroke-width: 1.6; }
svg.bode .hover-dot.ideal     { fill: var(--c-ideal); }
svg.bode .hover-dot.real      { fill: var(--c-real); }
svg.bode .hover-dot.buffered  { fill: var(--c-buffered); }
svg.bode .hover-dot.passive   { fill: var(--c-passive); }
svg.bode .hover-dot.stage     { fill: var(--c-stage); }

svg.bode .readout-bg {
    fill: var(--bg-panel);
    stroke: var(--border); stroke-width: 1;
}
svg.bode .readout-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    fill: var(--text-dim);
}
svg.bode .readout-text.title { fill: var(--fg); }
svg.bode .readout-text.ideal     { fill: var(--c-ideal); }
svg.bode .readout-text.real      { fill: var(--c-real); }
svg.bode .readout-text.buffered  { fill: var(--c-buffered); }
svg.bode .readout-text.passive   { fill: var(--c-passive); }
svg.bode .readout-text.stage     { fill: var(--c-stage); }

/* ─── Circuit diagram ─── */
svg.circuit { display: block; width: 100%; height: 100%; }
svg.circuit .wire   { stroke: var(--fg); stroke-width: 2; fill: none; stroke-linecap: round; }
svg.circuit .resistor { fill: var(--bg-2); stroke: var(--fg); stroke-width: 1.6; }
svg.circuit .cap-plate { stroke: var(--fg); stroke-width: 2; }
svg.circuit .gnd { stroke: var(--fg); stroke-width: 1.6; }
svg.circuit .source { fill: var(--bg-2); stroke: var(--fg); stroke-width: 1.6; }
svg.circuit .node-dot { fill: var(--fg); }
svg.circuit .opamp-body { fill: var(--bg-2); stroke: var(--fg); stroke-width: 1.6; }
svg.circuit text { font-family: 'JetBrains Mono', monospace; font-size: 13px; fill: var(--fg); }

.circuit-box {
    border: 1px solid var(--border); border-radius: 12px;
    background: var(--bg-2); padding: 18px 20px;
    aspect-ratio: 2.4 / 1; width: 100%; max-width: 760px;
}

/* ─── 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; }
}