/* ==========================================================================
   Pendulum — project site
   Palette: cool blue-biased slate grounds; brass carries the stable quantity
   (the period), rose the unstable one (the count), signal-blue the trace.
   Type: an old-style serif for prose, a monospace for every measured quantity.
   ========================================================================== */

:root {
  --bg:        #f4f6f8;
  --bg-alt:    #eaeef2;
  --panel:     #ffffff;
  --panel-2:   #f8fafb;
  --line:      #d5dce3;
  --line-soft: #e4e9ee;
  --text:      #121920;
  --muted:     #556270;
  --faint:     #7b8794;

  --brass:     #8a6114;
  --brass-dim: #b08a3d;
  --brass-wash:#f3ead8;
  --blue:      #2f5f94;
  --blue-dim:  #6d93bd;
  --blue-wash: #e4ecf5;
  --rose:      #9c3b4a;
  --rose-dim:  #c07f89;
  --rose-wash: #f6e6e8;

  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", "URW Palladio L", Georgia, serif;
  --sans:  system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono:  ui-monospace, "SF Mono", SFMono-Regular, "Cascadia Mono", "Segoe UI Mono", Consolas, "Liberation Mono", monospace;

  --measure: 66ch;
  --wrap: 74rem;
  --r: 3px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:        #0e1319;
    --bg-alt:    #121921;
    --panel:     #161d26;
    --panel-2:   #1b232d;
    --line:      #29343f;
    --line-soft: #212a34;
    --text:      #e2e8ee;
    --muted:     #97a3af;
    --faint:     #78848f;

    --brass:     #e0ac52;
    --brass-dim: #a67f3d;
    --brass-wash:#241d10;
    --blue:      #86b4ec;
    --blue-dim:  #5e7fa5;
    --blue-wash: #131e2b;
    --rose:      #ee9aa3;
    --rose-dim:  #a86b72;
    --rose-wash: #251519;
  }
}

:root[data-theme="dark"] {
  --bg:        #0e1319;
  --bg-alt:    #121921;
  --panel:     #161d26;
  --panel-2:   #1b232d;
  --line:      #29343f;
  --line-soft: #212a34;
  --text:      #e2e8ee;
  --muted:     #97a3af;
  --faint:     #78848f;
  --brass:     #e0ac52;
  --brass-dim: #a67f3d;
  --brass-wash:#241d10;
  --blue:      #86b4ec;
  --blue-dim:  #5e7fa5;
  --blue-wash: #131e2b;
  --rose:      #ee9aa3;
  --rose-dim:  #a86b72;
  --rose-wash: #251519;
}

:root[data-theme="light"] {
  --bg:        #f4f6f8;
  --bg-alt:    #eaeef2;
  --panel:     #ffffff;
  --panel-2:   #f8fafb;
  --line:      #d5dce3;
  --line-soft: #e4e9ee;
  --text:      #121920;
  --muted:     #556270;
  --faint:     #7b8794;
  --brass:     #8a6114;
  --brass-dim: #b08a3d;
  --brass-wash:#f3ead8;
  --blue:      #2f5f94;
  --blue-dim:  #6d93bd;
  --blue-wash: #e4ecf5;
  --rose:      #9c3b4a;
  --rose-dim:  #c07f89;
  --rose-wash: #f6e6e8;
}

/* ── base ──────────────────────────────────────────────────────────────── */

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.62;
  -webkit-text-size-adjust: 100%;
}

p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }
strong { font-weight: 650; }
em { font-style: italic; }

a { color: var(--blue); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--text); }

:focus-visible {
  outline: 2px solid var(--brass);
  outline-offset: 3px;
}

.mono {
  font-family: var(--mono);
  font-size: 0.92em;
  font-variant-numeric: tabular-nums;
}

.skip {
  position: absolute; left: -9999px; top: 0;
  background: var(--panel); color: var(--text);
  padding: 0.7rem 1rem; z-index: 20; border: 1px solid var(--line);
}
.skip:focus { left: 0.5rem; top: 0.5rem; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1.15rem, 4vw, 3rem);
}

.measure { max-width: var(--measure); }

/* ── headings ──────────────────────────────────────────────────────────── */

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 400;
  text-wrap: balance;
  letter-spacing: -0.012em;
  margin: 0;
}

h2 {
  font-size: clamp(1.6rem, 3.4vw, 2.35rem);
  line-height: 1.16;
  margin: 0 0 1.1rem;
  max-width: 20ch;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--brass);
  margin: 0 0 0.85rem;
}

.cite {
  display: block;
  font-family: var(--mono);
  font-size: 0.74rem;
  line-height: 1.5;
  color: var(--faint);
  margin-top: 0.4rem;
}

.note {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--muted);
  border-left: 2px solid var(--line);
  padding-left: 1rem;
  margin-top: 2rem;
}

/* ── top bar ───────────────────────────────────────────────────────────── */

.topbar {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line-soft);
}
.topbar-in {
  width: 100%; max-width: var(--wrap); margin-inline: auto;
  padding: 0.55rem clamp(1.15rem, 4vw, 3rem);
  display: flex; align-items: center; gap: 1.5rem;
  flex-wrap: wrap;
}
.wordmark {
  font-family: var(--serif);
  font-size: 1.08rem;
  letter-spacing: 0.01em;
}
.wordmark::before {
  content: "";
  display: inline-block;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--brass);
  margin-right: 0.5rem;
  vertical-align: 0.08em;
}
.topnav {
  display: flex; gap: 1.15rem; flex-wrap: wrap;
  margin-left: auto;
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.02em;
}
.topnav a { color: var(--muted); text-decoration: none; }
.topnav a:hover { color: var(--text); text-decoration: underline; }
.topnav-repo { color: var(--brass) !important; }
@media (max-width: 720px) { .topnav { display: none; } }

/* ── hero ──────────────────────────────────────────────────────────────── */

.hero { padding: clamp(2.2rem, 5vw, 3.6rem) 0 clamp(2.5rem, 5vw, 4rem); }

.hero-h1 {
  font-size: clamp(2.15rem, 6.6vw, 4.1rem);
  line-height: 1.04;
  letter-spacing: -0.022em;
  max-width: 15ch;
  margin: 0 0 1.1rem;
}
.hero-em { color: var(--brass); font-style: italic; }

.hero-lede {
  max-width: 56ch;
  font-size: clamp(1.02rem, 1.9vw, 1.17rem);
  line-height: 1.55;
  color: var(--muted);
  margin-bottom: 2rem;
}

.swing { margin: 0 0 2.2rem; }
.swing-canvas {
  display: block;
  width: 100%;
  height: 132px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.swing-cap {
  font-size: 0.83rem;
  line-height: 1.55;
  color: var(--faint);
  max-width: 62ch;
  margin-top: 0.7rem;
}

.isnot {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 21rem), 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r);
  overflow: hidden;
}
.isnot-card { background: var(--panel); padding: 1.35rem 1.5rem; }
.isnot-is   { border-top: 3px solid var(--brass); }
.isnot-not  { border-top: 3px solid var(--rose); }
.isnot-tag {
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  margin: 0 0 0.6rem;
}
.isnot-is  .isnot-tag { color: var(--brass); }
.isnot-not .isnot-tag { color: var(--rose); }
.isnot-card p:last-child { font-size: 0.95rem; line-height: 1.6; }

.isnot-so {
  margin: 1.1rem 0 0;
  font-size: 0.97rem;
  max-width: var(--measure);
}
.so-tag {
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--text);
  border: 1px solid var(--line);
  padding: 0.1rem 0.45rem;
  margin-right: 0.55rem;
  border-radius: 2px;
}

.status {
  display: flex; align-items: baseline; gap: 0.7rem; flex-wrap: wrap;
  margin-top: 1.6rem;
}
.pill {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--brass);
  border: 1px solid var(--brass-dim);
  border-radius: 999px;
  padding: 0.18rem 0.65rem;
  white-space: nowrap;
}
.status-txt { font-size: 0.87rem; color: var(--faint); max-width: 56ch; }

/* ── bands ─────────────────────────────────────────────────────────────── */

.band { padding: clamp(3rem, 7vw, 5.5rem) 0; border-top: 1px solid var(--line-soft); }
.band-alt { background: var(--bg-alt); }
.band-limits { background: var(--bg-alt); }

/* ── devices ───────────────────────────────────────────────────────────── */

.devices {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 20rem), 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}
.device {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 1.4rem 1.5rem;
}
.device-where {
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--brass);
  margin: 0 0 0.5rem;
}
.device-what {
  font-family: var(--serif);
  font-size: 1.28rem;
  line-height: 1.25;
  margin: 0 0 0.65rem;
}
.device-why { font-size: 0.92rem; line-height: 1.6; color: var(--muted); margin: 0; }

/* ── reasons ───────────────────────────────────────────────────────────── */

.reasons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
  gap: 1.5rem;
  margin: 2.2rem 0 2.8rem;
}
.reason {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
  font-size: 0.93rem;
  line-height: 1.6;
}
.reason-tag {
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--brass);
  margin: 0 0 0.5rem;
}

.varbars { display: grid; gap: 0.5rem; margin-top: 1rem; }
.varbar {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.25rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
}
.varbar-lab { color: var(--muted); }
.varbar-track {
  display: block; height: 7px;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: 1px;
  overflow: hidden;
}
.varbar-fill { display: block; height: 100%; width: var(--w); }
.varbar-rose  { background: var(--rose); }
.varbar-brass { background: var(--brass); }
.varbar-num { color: var(--text); }

/* ── the interactive demonstration ─────────────────────────────────────── */

.demo {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: clamp(1.3rem, 3.2vw, 2.2rem);
}
.panel-tag {
  font-family: var(--mono);
  font-size: 0.69rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--brass);
  margin: 0 0 0.6rem;
}
.demo-h3 {
  font-size: clamp(1.25rem, 2.6vw, 1.6rem);
  line-height: 1.2;
  margin: 0 0 0.8rem;
  max-width: 24ch;
}
.demo-intro { font-size: 0.94rem; line-height: 1.62; color: var(--muted); }

.demo-control { margin: 2rem 0 0.4rem; }
.demo-label {
  display: block;
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.55rem;
}
.demo-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  background: transparent;
  margin: 0;
  cursor: pointer;
}
.demo-slider::-webkit-slider-runnable-track {
  height: 4px;
  background: var(--line);
  border-radius: 2px;
}
.demo-slider::-moz-range-track {
  height: 4px;
  background: var(--line);
  border-radius: 2px;
}
.demo-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px; height: 20px;
  margin-top: -8px;
  border-radius: 50%;
  background: var(--brass);
  border: 2px solid var(--panel);
  box-shadow: 0 0 0 1px var(--brass);
}
.demo-slider::-moz-range-thumb {
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--brass);
  border: 2px solid var(--panel);
  box-shadow: 0 0 0 1px var(--brass);
}
.demo-value {
  display: block;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.05rem;
  color: var(--brass);
  margin-top: 0.9rem;
}
.demo-ticks {
  position: relative;
  height: 1.3rem;
  margin-top: -0.2rem;
}
.demo-tick {
  position: absolute;
  left: var(--at);
  transform: translateX(-50%);
  font-family: var(--mono);
  font-size: 0.66rem;
  color: var(--faint);
  white-space: nowrap;
}
.demo-tick-mark { color: var(--muted); }
.demo-tick-mark::before {
  content: "";
  position: absolute;
  left: 50%; top: -0.75rem;
  width: 1px; height: 0.5rem;
  background: var(--muted);
}

.demo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr));
  gap: 1.2rem;
  margin-top: 1.6rem;
}
.metric {
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 1rem 1.1rem 1.1rem;
  background: var(--panel-2);
}
.metric-rose  { border-top: 3px solid var(--rose); }
.metric-blue  { border-top: 3px solid var(--blue); }
.metric-brass { border-top: 3px solid var(--brass); }
.metric-tag {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.5rem;
  line-height: 1.45;
}
.metric-fate { color: var(--text); }
.metric-val {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 2rem;
  line-height: 1;
  margin: 0 0 0.7rem;
}
.metric-rose  .metric-val { color: var(--rose); }
.metric-blue  .metric-val { color: var(--blue); }
.metric-brass .metric-val { color: var(--brass); }
.metric-unit { font-size: 0.9rem; color: var(--muted); }
.metric-track {
  display: block; height: 6px;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: 1px;
  overflow: hidden;
}
.metric-fill { display: block; height: 100%; width: 100%; }
.metric-fill-rose  { background: var(--rose); }
.metric-fill-blue  { background: var(--blue); }
.metric-fill-brass { background: var(--brass); }
.metric-foot {
  font-size: 0.78rem;
  line-height: 1.5;
  color: var(--faint);
  margin: 0.7rem 0 0;
}

.hist { margin: 1.8rem 0 0; }
.hist-canvas {
  display: block;
  width: 100%;
  height: 240px;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: var(--panel-2);
}
.hist-cap, .trace-cap {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.3rem;
  margin-top: 0.85rem;
  font-size: 0.76rem;
  line-height: 1.5;
  color: var(--muted);
}
.key { display: inline-flex; align-items: center; gap: 0.45rem; }
.key-swatch { width: 12px; height: 12px; border-radius: 1px; flex: none; }
.key-blue { background: var(--blue); }
.key-line { width: 22px; height: 0; flex: none; border-top-width: 2px; }
.key-line-brass { border-top: 2px solid var(--brass); }
.key-line-rose  { border-top: 2px dashed var(--rose); }
.key-line-dot   { border-top: 2px dotted var(--blue-dim); }
.key-mark { width: 11px; height: 11px; flex: none; }
.key-mark-solid  { background: var(--brass); border-radius: 1px; }
.key-mark-hollow { border: 1.5px solid var(--brass); border-radius: 1px; }
.key-mark-cross  {
  color: var(--muted); font-family: var(--mono); font-size: 0.9rem;
  line-height: 0.8; text-align: center;
}
.key-bar { width: 22px; height: 5px; background: var(--brass-dim); border-radius: 1px; flex: none; }

.demo-note {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line-soft);
  font-size: 0.9rem;
  color: var(--muted);
  min-height: 3.6em;
}

/* ── the night trace ───────────────────────────────────────────────────── */

.trace { margin: 2.4rem 0 0; }
.trace-canvas {
  display: block;
  width: 100%;
  height: 330px;
  background: var(--panel);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.trace-cap { margin-top: 1rem; }

/* ── the processing chain ──────────────────────────────────────────────── */

.chain {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.85rem;
  margin-top: 2.2rem;
}
@media (min-width: 900px) {
  .chain {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    column-gap: 2.5rem;
    align-items: start;
  }
  .stage { grid-column: 1; grid-row: var(--row); }
  .aside { grid-column: var(--col); grid-row: var(--row) / span 2; }
}

.stage {
  position: relative;
  padding: 0 0 0.9rem 3.4rem;
}
.stage::before {
  content: "";
  position: absolute;
  left: 1.05rem; top: 0.3rem; bottom: -0.6rem;
  width: 1px;
  background: var(--line);
}
.stage:last-of-type::before { display: none; }
.stage-n {
  position: absolute;
  left: 0; top: 0;
  width: 2.1rem; height: 2.1rem;
  display: grid; place-items: center;
  font-size: 0.78rem;
  color: var(--brass);
  background: var(--bg-alt);
  border: 1px solid var(--brass-dim);
  border-radius: 50%;
}
.stage-h {
  font-family: var(--serif);
  font-size: 1.17rem;
  line-height: 1.25;
  margin: 0.15rem 0 0.4rem;
}
.stage-b {
  font-size: 0.9rem;
  line-height: 1.58;
  color: var(--muted);
  margin: 0;
  max-width: 54ch;
}

.aside {
  border: 1px dashed var(--line);
  border-left: 2px dashed var(--blue-dim);
  border-radius: var(--r);
  background: var(--panel);
  padding: 1rem 1.15rem;
  margin: 0 0 0.9rem;
}
.aside-tag {
  font-family: var(--mono);
  font-size: 0.67rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue);
  margin: 0 0 0.4rem;
}
.aside-h {
  font-family: var(--serif);
  font-size: 1.08rem;
  margin: 0 0 0.4rem;
}
.aside-b { font-size: 0.86rem; line-height: 1.55; color: var(--muted); margin: 0; }
.aside-edge {
  font-family: var(--mono);
  font-size: 0.71rem;
  color: var(--blue);
  margin: 0.7rem 0 0;
  padding-top: 0.5rem;
  border-top: 1px dashed var(--line);
}

/* ── screenshots ───────────────────────────────────────────────────────── */

.shots {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
  gap: 2.4rem 2rem;
  margin-top: 2.4rem;
}
.shot { margin: 0; }
.shot img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #0b0e12;
}
.shot-watch img {
  width: 62%;
  max-width: 240px;
  border-radius: 50%;
  border: 6px solid var(--line);
}
.shot figcaption {
  font-size: 0.85rem;
  line-height: 1.58;
  color: var(--muted);
  margin-top: 0.9rem;
}
.shot-t {
  display: block;
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--brass);
  margin-bottom: 0.4rem;
}

/* ── limits ────────────────────────────────────────────────────────────── */

.limits {
  list-style: none;
  counter-reset: lim;
  padding: 0;
  margin: 2.2rem 0 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 19rem), 1fr));
  gap: 1.6rem 2.2rem;
}
.limit {
  counter-increment: lim;
  position: relative;
  padding-left: 2.4rem;
  font-size: 0.91rem;
  line-height: 1.58;
  color: var(--muted);
}
.limit::before {
  content: counter(lim, decimal-leading-zero);
  position: absolute;
  left: 0; top: 0.15rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--rose);
}
.limit-h {
  font-family: var(--serif);
  font-size: 1.1rem;
  line-height: 1.3;
  color: var(--text);
  margin: 0 0 0.35rem;
}

/* ── next ──────────────────────────────────────────────────────────────── */

.next {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
  gap: 1.4rem;
  margin-top: 2.2rem;
}
.nextcard {
  display: block;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 1.4rem 1.5rem;
  text-decoration: none;
  color: inherit;
}
.nextcard:hover { border-color: var(--brass); color: inherit; }
.nextcard-h {
  font-family: var(--serif);
  font-size: 1.25rem;
  margin: 0 0 0.55rem;
}
.nextcard-b { font-size: 0.89rem; line-height: 1.58; color: var(--muted); margin: 0 0 0.9rem; }
.nextcard-go { font-size: 0.76rem; color: var(--brass); margin: 0; }

/* ── footer ────────────────────────────────────────────────────────────── */

.foot {
  border-top: 1px solid var(--line);
  background: var(--bg-alt);
  padding: 2.6rem 0 3.4rem;
}
.foot-in { display: grid; gap: 1rem; }
.foot-main { font-size: 0.9rem; line-height: 1.6; max-width: var(--measure); color: var(--muted); }
.foot-meta { font-size: 0.78rem; line-height: 1.6; color: var(--faint); max-width: var(--measure); }

/* ── motion ────────────────────────────────────────────────────────────── */

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}