/* ---------------------------------------------------------------------------
   ADAPTIVE SCREEN · product site
   Aesthetic: photometric journal / instrument panel
   Palette: tungsten black, bone cream, amber, cool cyan
   Type:    Fraunces (display) · Geist (body) · Geist Mono (data)
   --------------------------------------------------------------------------- */

:root {
  --bg:         #0E0C08;   /* warm near-black */
  --bg-raised:  #15110B;
  --panel:      #1A150E;
  --hairline:   #2B241B;
  --hairline-2: #3A3126;

  --fg:         #EFE7D5;   /* bone */
  --fg-muted:   #9C9181;
  --fg-dim:     #5E5648;

  --amber:      #F4B942;   /* tungsten accent */
  --amber-dim:  #B88638;
  --amber-deep: #6F4F1E;
  --cyan:       #6EC6D3;   /* camera/luma accent */
  --cyan-dim:   #44909C;
  --red:        #DF6E5F;   /* manual override dot */

  --warmth:     0;         /* driven by the instrument slider (range -1 … +1) */

  --serif:      'Fraunces', 'Cormorant Garamond', Georgia, serif;
  --sans:       'Geist', 'Söhne', 'Inter', system-ui, sans-serif;
  --mono:       'Geist Mono', 'JetBrains Mono', ui-monospace, 'SF Mono', monospace;
}

/* Warmth-slider demo retints the page subtly. -1 cools (blue shift),
   +1 warms (orange shift). Expressed as an additive hue overlay. */
body {
  background:
    /* warmth overlay */
    radial-gradient(1200px 800px at 50% -10%,
      color-mix(in oklab, var(--amber) calc(var(--warmth, 0) * 6%), transparent),
      transparent 60%),
    radial-gradient(1200px 800px at 100% 120%,
      color-mix(in oklab, var(--cyan) calc(var(--warmth, 0) * -6%), transparent),
      transparent 60%),
    var(--bg);
  transition: background 400ms cubic-bezier(.25,.8,.3,1);
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.55;
  color: var(--fg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
a:hover { color: var(--amber); }

strong { font-weight: 600; color: #F8F1E0; }
em { font-style: italic; }

.mono { font-family: var(--mono); font-size: 0.92em; letter-spacing: -0.01em; }

.sep { display: inline-block; margin: 0 0.4em; opacity: 0.35; }

/* ---------- overlays ---------- */
.grain {
  position: fixed; inset: 0; pointer-events: none; z-index: 100;
  mix-blend-mode: overlay; opacity: 0.14;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 240 240' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 1 0 0 0 0 0.95 0 0 0 0 0.85 0 0 0 0.65 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* Very subtle 24 px graticule in the background (engineering paper) */
.graticule {
  position: fixed; inset: 0; pointer-events: none; z-index: 0;
  background-image:
    linear-gradient(to right,  rgba(239,231,213,.022) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(239,231,213,.022) 1px, transparent 1px);
  background-size: 96px 96px, 96px 96px;
  mask-image: radial-gradient(ellipse at 50% 30%, black, transparent 85%);
}

/* ---------- containers ---------- */
.masthead, .hero, .chapter, .colophon {
  max-width: 1240px;
  margin: 0 auto;
  padding-inline: 48px;
  position: relative; z-index: 1;
}

/* ---------- masthead ---------- */
.masthead { padding-top: 36px; padding-bottom: 40px; }

.issue-bar {
  display: flex;
  gap: 22px;
  align-items: baseline;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--fg-muted);
  text-transform: uppercase;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--hairline);
  flex-wrap: wrap;
}
.issue-bar .issue-mark {
  color: var(--amber);
  font-size: 14px;
}
.issue-bar .kv .k { color: var(--fg-dim); margin-right: 6px; }
.issue-bar .kv .v { color: var(--fg); }
.top-nav { margin-left: auto; display: flex; gap: 22px; }
.top-nav a {
  color: var(--fg-muted);
  transition: color 180ms;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
}
.top-nav a:hover { color: var(--amber); border-bottom-color: var(--amber); }

.title {
  font-family: var(--serif);
  font-variation-settings: "opsz" 144, "wght" 560, "SOFT" 30, "WONK" 1;
  font-weight: 500;
  font-size: clamp(64px, 13vw, 200px);
  line-height: 0.88;
  letter-spacing: -0.035em;
  margin: 40px 0 0;
  color: var(--fg);
  display: grid;
  grid-template-columns: auto auto;
  column-gap: 0.12em;
  align-items: end;
}
.title .t1 { display: inline-block; transform-origin: top left; }
.title .t2 {
  display: inline-block;
  font-style: italic;
  font-variation-settings: "opsz" 144, "wght" 420, "SOFT" 60, "WONK" 1;
  color: var(--amber);
  transform: translateY(-0.02em);
}

.epigraph {
  margin: 20px 0 0;
  font-family: var(--serif);
  font-size: 18px;
  color: var(--fg-dim);
  font-variation-settings: "opsz" 36, "wght" 380;
  letter-spacing: 0.02em;
}

/* ---------- hero ---------- */
.hero {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 60px;
  padding-top: 36px;
  padding-bottom: 100px;
  align-items: start;
}

.lede .dek {
  font-family: var(--serif);
  font-variation-settings: "opsz" 60, "wght" 420, "SOFT" 20;
  font-size: clamp(22px, 2.3vw, 28px);
  line-height: 1.28;
  letter-spacing: -0.015em;
  color: var(--fg);
  margin: 0 0 28px;
  max-width: 32ch;
}

.lede-body {
  font-size: 15.5px;
  line-height: 1.65;
  color: var(--fg);
  margin: 0 0 18px;
  max-width: 52ch;
}
.lede-body.muted { color: var(--fg-muted); }

.drop {
  float: left;
  font-family: var(--serif);
  font-variation-settings: "opsz" 144, "wght" 600, "SOFT" 20, "WONK" 1;
  font-size: 68px;
  line-height: 0.82;
  margin: 6px 10px 0 -2px;
  color: var(--amber);
}

/* ---------- CTA ---------- */
.cta { margin-top: 36px; }
.btn-primary {
  display: inline-grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  column-gap: 18px;
  padding: 18px 24px 18px 22px;
  background: var(--amber);
  color: #0A0805;
  border-radius: 3px;
  font-weight: 600;
  transition: transform 180ms, box-shadow 180ms, filter 180ms;
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.25),
    0 10px 30px -8px rgba(244,185,66,0.35),
    0 0 0 1px rgba(244,185,66,0.35);
  position: relative;
}
.btn-primary::before {
  content: "↓";
  font-family: var(--serif);
  font-size: 28px;
  font-weight: 400;
  margin-right: -4px;
}
.btn-primary .btn-label {
  font-family: var(--sans);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.01em;
}
.btn-primary .btn-sub {
  font-family: var(--mono);
  font-size: 11px;
  color: rgba(10,8,5,0.72);
  letter-spacing: 0.02em;
  justify-self: start;
  white-space: nowrap;
}
.btn-primary:hover {
  color: #0A0805;
  transform: translateY(-1px);
  filter: brightness(1.04);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.3),
    0 14px 36px -8px rgba(244,185,66,0.45),
    0 0 0 1px rgba(244,185,66,0.5);
}

.cta-meta {
  margin-top: 14px;
  display: flex; flex-wrap: wrap; gap: 14px;
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--fg-dim);
  letter-spacing: 0.02em;
}
.cta-meta .mono { color: var(--fg-muted); }

/* ---------- instrument panel ---------- */
.instrument {
  position: relative;
  padding: 28px 28px 24px;
  background:
    linear-gradient(180deg, rgba(244,185,66,0.03), transparent 25%),
    var(--panel);
  border: 1px solid var(--hairline);
  border-radius: 4px;
  box-shadow:
    0 30px 80px -30px rgba(0,0,0,0.6),
    inset 0 1px 0 rgba(244,185,66,0.05);
}
.inst-head {
  display: flex; justify-content: space-between; align-items: baseline;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding-bottom: 14px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--hairline);
}
.inst-title { color: var(--fg-muted); }
.inst-stat  { color: var(--amber); }
.inst-stat.active { color: var(--cyan); }

.inst-crosshair {
  position: absolute; width: 10px; height: 10px;
  border-color: var(--amber-deep);
  border-style: solid;
  border-width: 0;
}
.inst-crosshair.top-left     { top: 6px; left: 6px;     border-top-width: 1px; border-left-width: 1px; }
.inst-crosshair.top-right    { top: 6px; right: 6px;    border-top-width: 1px; border-right-width: 1px; }
.inst-crosshair.bottom-left  { bottom: 6px; left: 6px;  border-bottom-width: 1px; border-left-width: 1px; }
.inst-crosshair.bottom-right { bottom: 6px; right: 6px; border-bottom-width: 1px; border-right-width: 1px; }

/* Gauge */
.gauge {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 24px;
  align-items: center;
  margin-bottom: 28px;
}
.gauge svg { width: 100%; height: auto; color: var(--hairline-2); overflow: visible; }
.gauge-label {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  fill: var(--fg-dim);
}
.gauge-readout {
  font-family: var(--serif);
  font-variation-settings: "opsz" 144, "wght" 500, "SOFT" 40, "WONK" 0;
  line-height: 1;
  display: flex; align-items: baseline; gap: 6px;
}
.gauge-readout .readout-val {
  font-size: 72px;
  color: var(--amber);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  transition: color 200ms;
}
.gauge-readout .readout-den {
  font-size: 18px;
  color: var(--fg-dim);
  font-style: italic;
}

/* Sparkline */
.spark { margin: 0 0 24px; }
.spark figcaption {
  display: flex; justify-content: space-between;
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--fg-dim);
  margin-bottom: 4px;
}
.spark figcaption .v { color: var(--fg-muted); }
.spark svg { display: block; width: 100%; height: 60px; background: rgba(244,185,66,0.015); border-top: 1px solid var(--hairline); border-bottom: 1px solid var(--hairline); }

/* Bars */
.bars { margin: 0 0 24px; display: grid; gap: 10px; }
.bar-row {
  display: grid;
  grid-template-columns: 96px 1fr;
  align-items: center;
  gap: 14px;
  font-size: 12.5px;
  color: var(--fg-muted);
}
.bar-row dt {
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 10px;
  color: var(--fg-dim);
}
.bar-row dd { margin: 0; display: grid; grid-template-columns: 1fr 32px; align-items: center; gap: 10px; }
.bar {
  height: 4px;
  background: var(--hairline);
  border-radius: 1px;
  overflow: hidden;
  position: relative;
}
.bar span {
  display: block;
  height: 100%;
  width: var(--v, 50%);
  background: linear-gradient(90deg, var(--amber-dim), var(--amber));
  box-shadow: 0 0 12px -2px var(--amber);
  transition: width 300ms;
}
.bar-row .num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg);
  text-align: right;
  font-variant-numeric: tabular-nums;
}
.bar-row .hint {
  font-family: var(--serif);
  font-style: italic;
  text-transform: none;
  letter-spacing: 0;
  color: var(--cyan-dim);
  font-size: 10px;
  margin-left: 4px;
}
/* Native range styling */
.warmth-row input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 1px;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--fg-dim) 50%, var(--amber) 100%);
  outline: none;
  cursor: ew-resize;
}
.warmth-row input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px; height: 14px;
  background: var(--fg);
  border: 1px solid var(--hairline-2);
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(239,231,213,0.08);
  cursor: grab;
}
.warmth-row input[type="range"]::-moz-range-thumb {
  width: 14px; height: 14px;
  background: var(--fg);
  border: 1px solid var(--hairline-2);
  border-radius: 50%;
  cursor: grab;
}

/* Footer of the instrument */
.inst-foot {
  padding-top: 14px;
  border-top: 1px solid var(--hairline);
  display: grid; gap: 4px;
  font-family: var(--mono);
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--fg-dim);
}
.inst-foot .row { display: flex; gap: 12px; }
.inst-foot .row .k { min-width: 104px; }
.inst-foot .row .v { color: var(--fg-muted); }

/* ---------- generic chapter ---------- */
.chapter { padding-block: 80px; }
.chapter-head {
  display: grid;
  grid-template-columns: auto auto 1fr auto;
  align-items: baseline;
  gap: 20px;
  margin-bottom: 48px;
}
.chapter-head .chap-num {
  font-family: var(--mono);
  color: var(--amber);
  font-size: 11px;
  letter-spacing: 0.1em;
  padding: 4px 8px;
  border: 1px solid var(--amber-deep);
  border-radius: 2px;
}
.chapter-head h2 {
  margin: 0;
  font-family: var(--serif);
  font-variation-settings: "opsz" 60, "wght" 520, "SOFT" 40;
  font-size: clamp(32px, 4vw, 52px);
  letter-spacing: -0.02em;
  line-height: 1;
}
.chapter-head .chap-rule {
  height: 1px;
  background: repeating-linear-gradient(
    to right,
    var(--hairline) 0, var(--hairline) 3px,
    transparent 3px, transparent 8px
  );
  align-self: center;
}
.chapter-head .chap-meta {
  font-family: var(--mono);
  color: var(--fg-dim);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ---------- method flow ---------- */
.method-flow {
  display: grid;
  grid-template-columns: repeat(4, 1fr) ;
  gap: 0;
  align-items: stretch;
  position: relative;
}
.method-flow .flow-step {
  margin: 0;
  padding: 24px;
  border: 1px solid var(--hairline);
  border-right: 0;
  background: linear-gradient(180deg, rgba(244,185,66,0.02), transparent 70%);
}
.method-flow .flow-step:last-of-type { border-right: 1px solid var(--hairline); }
.method-flow .step-n {
  font-family: var(--serif);
  font-style: italic;
  font-variation-settings: "opsz" 60, "wght" 400;
  font-size: 22px;
  color: var(--amber);
  display: block;
  margin-bottom: 14px;
}
.method-flow .flow-step h3 {
  margin: 0 0 10px;
  font-family: var(--serif);
  font-variation-settings: "opsz" 60, "wght" 500;
  font-size: 22px;
  letter-spacing: -0.01em;
}
.method-flow .flow-step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--fg-muted);
}
.method-flow .arrow { display: none; }

/* ---------- calibration ---------- */
.two-col-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}
.body-text .lead {
  font-family: var(--serif);
  font-variation-settings: "opsz" 60, "wght" 420, "SOFT" 20;
  font-size: 20px;
  line-height: 1.45;
  letter-spacing: -0.005em;
  color: var(--fg);
  margin-top: 0;
}
.body-text p {
  font-size: 15px;
  line-height: 1.65;
  color: var(--fg-muted);
  max-width: 46ch;
}
.curve-card {
  margin: 0;
  padding: 20px;
  background: var(--panel);
  border: 1px solid var(--hairline);
  border-radius: 3px;
  box-shadow: 0 20px 60px -20px rgba(0,0,0,0.5);
}
.curve-card svg { width: 100%; height: auto; display: block; }
.curve-card .axis-lbl,
.curve-card .marker-label {
  font-family: var(--mono);
  font-size: 10px;
  fill: var(--fg-dim);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.curve-card .marker-label { fill: var(--cyan); text-transform: none; letter-spacing: 0; }

/* ---------- solar ---------- */
.solar { display: grid; grid-template-columns: 1fr; gap: 32px; }
.solar-lead {
  font-family: var(--serif);
  font-variation-settings: "opsz" 60, "wght" 420, "SOFT" 20;
  font-size: 21px;
  line-height: 1.4;
  max-width: 68ch;
  color: var(--fg);
  margin: 0;
}
.day-bar {
  margin: 0;
  padding: 36px 16px 24px;
  background: var(--panel);
  border: 1px solid var(--hairline);
  border-radius: 3px;
}
.day-bar-track {
  position: relative;
  height: 20px;
  background: linear-gradient(90deg,
    var(--bg-raised) 0%,
    var(--bg-raised) 22%,
    rgba(244,185,66,0.12) 26%,
    rgba(244,185,66,0.08) 34%,
    var(--bg-raised) 50%,
    rgba(244,185,66,0.08) 66%,
    rgba(244,185,66,0.12) 74%,
    var(--bg-raised) 78%,
    var(--bg-raised) 100%
  );
  border: 1px solid var(--hairline);
  border-radius: 3px;
}
.day-bar .band.window {
  position: absolute; top: -3px; bottom: -3px;
  border: 1px solid var(--amber);
  background: transparent;
  border-radius: 2px;
}
.day-bar .band.sun {
  position: absolute; top: -9px; bottom: -9px;
  width: 2px; background: var(--amber);
  box-shadow: 0 0 14px var(--amber);
}
.day-bar .tick {
  position: absolute; top: 26px;
  font-family: var(--mono);
  font-size: 10px;
  color: var(--fg-dim);
  transform: translateX(-50%);
  letter-spacing: 0.06em;
}
.day-bar .tick em { font-style: normal; }
.day-bar figcaption {
  margin-top: 36px;
  display: flex; gap: 24px; flex-wrap: wrap;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-muted);
}
.day-bar .swatch {
  display: inline-block;
  width: 18px; height: 10px;
  margin-right: 6px;
  vertical-align: middle;
  border-radius: 1px;
}
.day-bar .swatch.warm { background: rgba(244,185,66,0.25); border: 1px solid var(--amber); }
.day-bar .swatch.dim  { background: var(--bg-raised); border: 1px solid var(--hairline); }
.day-bar .swatch.sun  { background: var(--amber); box-shadow: 0 0 8px var(--amber); }

/* ---------- instruments list ---------- */
.instruments-list {
  list-style: none;
  padding: 0; margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
  border: 1px solid var(--hairline);
  background: var(--panel);
}
.instruments-list li {
  padding: 28px 28px 32px;
  border-right: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 24px;
  position: relative;
  transition: background 200ms;
}
.instruments-list li:nth-child(2n)   { border-right: 0; }
.instruments-list li:nth-last-child(-n+2) { border-bottom: 0; }
.instruments-list li:hover { background: rgba(244,185,66,0.02); }

.instruments-list .n {
  font-family: var(--serif);
  font-style: italic;
  font-variation-settings: "opsz" 60, "wght" 420, "SOFT" 40;
  font-size: 38px;
  color: var(--amber);
  line-height: 1;
  padding-top: 2px;
}
.instruments-list h3 {
  margin: 0 0 8px;
  font-family: var(--serif);
  font-variation-settings: "opsz" 36, "wght" 500;
  font-size: 20px;
  letter-spacing: -0.008em;
}
.instruments-list p {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--fg-muted);
  max-width: 40ch;
}

/* ---------- privacy ---------- */
.privacy-chapter .privacy-card {
  padding: 48px 56px;
  border: 1px solid var(--amber-deep);
  background:
    radial-gradient(800px 300px at 50% -10%, rgba(244,185,66,0.06), transparent 60%),
    var(--panel);
  border-radius: 4px;
  position: relative;
}
.privacy-card::before {
  content: "※";
  position: absolute;
  top: 22px; right: 32px;
  color: var(--amber);
  font-size: 20px;
}
.privacy-headline {
  font-family: var(--serif);
  font-variation-settings: "opsz" 144, "wght" 500, "SOFT" 30, "WONK" 1;
  font-size: clamp(28px, 3.6vw, 44px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0 0 28px;
  max-width: 22ch;
}
.privacy-headline strong {
  color: var(--amber);
  font-weight: inherit;
  font-style: italic;
}
.privacy-card p {
  font-size: 15.5px;
  line-height: 1.66;
  max-width: 68ch;
  color: var(--fg);
  margin: 0 0 16px;
}
.privacy-card .ypixel {
  margin: 36px 0 0;
  padding: 22px;
  background: var(--bg-raised);
  border: 1px solid var(--hairline);
  border-radius: 3px;
}
.privacy-card .ypixel figcaption {
  margin-top: 14px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-dim);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ---------- specifications ---------- */
.spec {
  width: 100%;
  border-collapse: collapse;
  font-size: 14.5px;
}
.spec tr { border-bottom: 1px solid var(--hairline); }
.spec tr:first-child { border-top: 1px solid var(--hairline); }
.spec th, .spec td { padding: 16px 4px; text-align: left; vertical-align: top; }
.spec th {
  width: 28%;
  font-weight: 400;
  color: var(--fg-muted);
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.spec td { color: var(--fg); }

/* ---------- download ---------- */
.download-wrap {
  margin-bottom: 28px;
}
.dl-card {
  display: flex; flex-direction: column;
  padding: 26px 24px;
  background: var(--panel);
  border: 1px solid var(--hairline);
  border-radius: 4px;
  transition: border-color 180ms, transform 180ms, background 180ms;
  min-height: 180px;
}
.dl-card.solo {
  padding: 40px 44px;
  min-height: 220px;
  max-width: 640px;
}
.dl-card.solo h3 { font-size: 28px; margin-bottom: 10px; }
.dl-card.solo p  { max-width: 48ch; font-size: 14.5px; }
.dl-card.solo footer { font-size: 13px; margin-top: 28px; }
.dl-card:hover {
  border-color: var(--amber);
  transform: translateY(-2px);
  color: var(--fg);
  background: linear-gradient(180deg, rgba(244,185,66,0.05), transparent 60%), var(--panel);
}
.dl-card.primary {
  border-color: var(--amber-deep);
  background:
    linear-gradient(180deg, rgba(244,185,66,0.08), transparent 60%),
    var(--panel);
}
.dl-card header {
  display: flex; justify-content: space-between;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-dim);
  padding-bottom: 18px;
  border-bottom: 1px solid var(--hairline);
  margin-bottom: 18px;
}
.dl-card .dl-format { color: var(--amber); font-weight: 600; }
.dl-card .dl-size   { color: var(--fg-muted); }
.dl-card h3 {
  margin: 0 0 6px;
  font-family: var(--serif);
  font-variation-settings: "opsz" 36, "wght" 500;
  font-size: 20px;
  letter-spacing: -0.01em;
}
.dl-card p {
  margin: 0;
  font-size: 13.5px;
  color: var(--fg-muted);
}
.dl-card footer {
  margin-top: auto;
  padding-top: 20px;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--amber);
  letter-spacing: 0.04em;
  display: flex; justify-content: space-between; align-items: baseline;
}
.dl-card footer .arrow { font-size: 14px; }
.dl-note {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--fg-muted);
  max-width: 72ch;
  line-height: 1.65;
  letter-spacing: 0.01em;
  border-left: 1px solid var(--amber-deep);
  padding: 8px 0 8px 18px;
  margin: 0;
}

/* ---------- colophon ---------- */
.colophon {
  padding-block: 60px 40px;
  border-top: 1px solid var(--hairline);
  margin-top: 40px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--fg-muted);
}
.colophon-inner {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.colophon .col .k {
  display: block;
  color: var(--fg-dim);
  text-transform: uppercase;
  margin-bottom: 6px;
}
.colophon .col .v { color: var(--fg); }
.colophon-rule {
  height: 1px;
  margin: 40px 0 16px;
  background: repeating-linear-gradient(
    to right,
    var(--hairline) 0, var(--hairline) 2px,
    transparent 2px, transparent 6px
  );
}
.colophon-mark {
  display: flex; justify-content: space-between; align-items: center;
  color: var(--fg-dim);
  font-family: var(--serif);
  font-style: italic;
  font-size: 13px;
}
.colophon-mark span:first-child {
  color: var(--amber);
  font-style: normal;
  font-size: 16px;
}

/* ---------- staggered reveal on load ---------- */
@keyframes rise-in {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}
.masthead, .hero, .chapter, .colophon { animation: rise-in 700ms cubic-bezier(.22,.8,.3,1) both; }
.hero         { animation-delay: 80ms; }
#method       { animation-delay: 0ms; }
#calibration  { animation-delay: 0ms; }
#cadence      { animation-delay: 0ms; }
.instruments-list li { animation: rise-in 600ms cubic-bezier(.22,.8,.3,1) both; }
.instruments-list li:nth-child(2) { animation-delay: 50ms; }
.instruments-list li:nth-child(3) { animation-delay: 100ms; }
.instruments-list li:nth-child(4) { animation-delay: 150ms; }
.instruments-list li:nth-child(5) { animation-delay: 200ms; }
.instruments-list li:nth-child(6) { animation-delay: 250ms; }

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .hero { grid-template-columns: 1fr; gap: 48px; }
  .method-flow { grid-template-columns: repeat(2, 1fr); }
  .method-flow .flow-step:nth-child(2) { border-right: 1px solid var(--hairline); }
  .method-flow .flow-step:nth-child(-n+2) { border-bottom: 0; }
  .method-flow .flow-step:nth-child(n+3) { border-top: 0; }
  .method-flow .flow-step:nth-child(3) { border-left: 1px solid var(--hairline); }
  .two-col-body { grid-template-columns: 1fr; gap: 32px; }
  .colophon-inner { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 720px) {
  .masthead, .hero, .chapter, .colophon { padding-inline: 24px; }
  .chapter { padding-block: 60px; }
  .issue-bar { font-size: 10px; gap: 14px; padding-bottom: 14px; }
  .top-nav { order: 99; width: 100%; margin-left: 0; flex-wrap: wrap; gap: 14px; }
  .title { grid-template-columns: 1fr; row-gap: 0; }
  .title .t2 { transform: none; }
  .hero { padding-bottom: 60px; gap: 36px; }
  .chapter-head { grid-template-columns: auto 1fr; row-gap: 12px; }
  .chapter-head .chap-rule,
  .chapter-head .chap-meta { display: none; }
  .method-flow { grid-template-columns: 1fr; }
  .method-flow .flow-step { border-right: 1px solid var(--hairline) !important; border-top: 0 !important; border-bottom: 0 !important; }
  .method-flow .flow-step:first-child { border-top: 1px solid var(--hairline) !important; }
  .method-flow .flow-step:last-child  { border-bottom: 1px solid var(--hairline) !important; }
  .instruments-list { grid-template-columns: 1fr; }
  .instruments-list li { border-right: 0 !important; border-bottom: 1px solid var(--hairline) !important; }
  .instruments-list li:last-child { border-bottom: 0 !important; }
  .privacy-chapter .privacy-card { padding: 28px 22px; }
  .dl-card.solo { padding: 28px 22px; }
  .colophon-inner { grid-template-columns: 1fr; gap: 20px; }
  .gauge { grid-template-columns: 120px 1fr; gap: 16px; }
  .gauge-readout .readout-val { font-size: 54px; }
  .btn-primary { grid-template-columns: auto auto; row-gap: 2px; padding: 14px 18px 14px 16px; }
  .btn-primary .btn-sub { grid-column: 2; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}