/* ============================================================
   BBATTL — Bulletin of Bubble Battle Tutorials
   Swiss precision dipped in dark water.
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  --tank-black: #06080C;
  --deep-pond: #0F1A22;
  --glass-edge: #1B2A33;
  --lab-paper: #E8EFE5;
  --mint: #39FF8C;
  --cyan: #3DE2FF;
  --magenta: #FF4FB1;
  --sage: #7FA38E;

  --font-display: 'Fraunces', Georgia, serif;
  --font-body: 'Source Serif 4', 'Source Serif Pro', Georgia, serif;
  --font-ui: 'Inter Tight', 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  --baseline: 8px;
  --gutter: 24px;
  --rail-w: 96px;
  --max-w: 1320px;

  --ease-lift: cubic-bezier(0.22, 0.61, 0.36, 1);
}

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

html, body {
  background: var(--tank-black);
  color: var(--lab-paper);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 28px;
  -webkit-font-smoothing: antialiased;
  text-rendering: geometricPrecision;
  overflow-x: hidden;
}

body {
  position: relative;
  min-height: 100vh;
  cursor: crosshair;
}

/* Custom crosshair effect overlay via a 1px tracker */
body::after {
  content: '';
  position: fixed;
  pointer-events: none;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan);
  opacity: 0;
  transform: translate(-50%, -50%);
  transition: opacity 140ms linear;
  z-index: 200;
  box-shadow: 0 0 6px var(--cyan);
  left: var(--cursor-x, -100px);
  top: var(--cursor-y, -100px);
}

body.is-hovering-i::after {
  opacity: 1;
}

a, button {
  color: var(--mint);
  text-decoration: none;
}

.mono {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 22px;
  color: var(--cyan);
  letter-spacing: 0;
}

/* ============================================================
   Top Nav Strip
   ============================================================ */
.navstrip {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 32px 14px calc(var(--rail-w) + 32px);
  background: rgba(6, 8, 12, 0.78);
  backdrop-filter: blur(2px);
  border-bottom: 1px solid var(--glass-edge);
  font-family: var(--font-ui);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--sage);
}

.nav-item {
  color: var(--lab-paper);
  font-weight: 500;
}

.nav-dot {
  color: var(--glass-edge);
}

.nav-item:last-of-type,
.navstrip .nav-item:last-child {
  margin-left: auto;
  color: var(--sage);
}

/* ============================================================
   Spine Rail (column 1, fixed left)
   ============================================================ */
.spine {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--rail-w);
  border-right: 1px solid var(--glass-edge);
  background: var(--tank-black);
  z-index: 90;
  padding: 16px 12px 16px 16px;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  font-family: var(--font-ui);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.spine-mark {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 500;
  color: var(--lab-paper);
  letter-spacing: 0.04em;
  text-transform: none;
  margin-bottom: 32px;
}

.spine-section {
  margin-bottom: 24px;
}

.spine-num {
  color: var(--mint);
  font-weight: 500;
  margin-bottom: 8px;
}

.spine-title {
  color: var(--lab-paper);
  font-weight: 500;
  letter-spacing: 0.16em;
}

.spine-track {
  width: 1px;
  flex: 1 1 auto;
  margin: 24px 0 24px 4px;
  background-image: linear-gradient(to bottom, var(--glass-edge) 50%, transparent 50%);
  background-size: 1px 6px;
  position: relative;
}

.spine-progress {
  position: absolute;
  top: 0;
  left: 0;
  width: 1px;
  height: 0%;
  background: var(--mint);
  box-shadow: 0 0 12px rgba(57, 255, 140, 0.55);
  transition: height 120ms linear;
}

.spine-icon {
  margin-left: -2px;
  margin-bottom: 16px;
}

.spine-foot {
  margin-top: auto;
  font-size: 10px;
  color: var(--sage);
  letter-spacing: 0.18em;
}

/* ============================================================
   Bubble Field
   ============================================================ */
.bubble-field {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 5;
  overflow: hidden;
}

.bubble {
  position: absolute;
  border-radius: 50%;
  border: 1px solid rgba(61, 226, 255, 0.55);
  background: rgba(57, 255, 140, 0.025);
  box-shadow: 0 0 16px rgba(57, 255, 140, 0.18);
  will-change: transform, opacity;
  pointer-events: none;
}

.bubble.burst {
  border-color: rgba(61, 226, 255, 0.8);
  animation: burst-ring 220ms ease-out forwards;
}

@keyframes burst-ring {
  0%   { transform: scale(1);   opacity: 0.9; }
  100% { transform: scale(2.4); opacity: 0; border-color: rgba(57,255,140,0.0); }
}

/* ============================================================
   Crossbars: Masthead & Procedure
   ============================================================ */
.crossbar {
  position: relative;
  margin-left: var(--rail-w);
  padding: 0 32px;
  background: var(--tank-black);
  z-index: 10;
}

.masthead {
  padding-top: 88px;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--glass-edge);
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--gutter);
  max-width: var(--max-w);
}

.masthead-rule {
  grid-column: 1 / 13;
  height: 1px;
  background: var(--glass-edge);
  margin-bottom: 16px;
}

.masthead-row {
  grid-column: 1 / 13;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--sage);
  margin-bottom: 56px;
}

.mast-label { color: var(--mint); }
.mast-meta { color: var(--sage); }

.masthead-headline {
  grid-column: 1 / 10;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(40px, 6.4vw, 88px);
  line-height: 1.04;
  letter-spacing: -0.01em;
  color: var(--lab-paper);
  margin-bottom: 32px;
  text-wrap: balance;
  font-variation-settings: "opsz" 144, "SOFT" 50;
}

.masthead-headline em {
  font-style: italic;
  color: var(--lab-paper);
}

.masthead-abstract {
  grid-column: 1 / 7;
  font-style: italic;
  font-size: 17px;
  line-height: 28px;
  color: var(--lab-paper);
  opacity: 0.86;
  max-width: 56ch;
  margin-bottom: 40px;
}

.masthead-byline {
  grid-column: 5 / 10;
  display: flex;
  gap: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--glass-edge);
  font-family: var(--font-body);
}

.byline-num {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--magenta);
  white-space: nowrap;
  padding-top: 2px;
}

.byline-cap {
  font-style: italic;
  font-size: 13px;
  line-height: 20px;
  color: var(--lab-paper);
  opacity: 0.78;
}

/* ============================================================
   Zones (body sections)
   ============================================================ */
.zone {
  position: relative;
  margin-left: var(--rail-w);
  padding: 88px 32px 64px;
  max-width: var(--max-w);
  z-index: 10;
}

.axiom {
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 400;
  font-size: 28px;
  line-height: 38px;
  color: var(--lab-paper);
  margin-bottom: 48px;
  max-width: 28ch;
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--gutter);
}

.axiom::before {
  content: '';
  grid-column: 1 / 5;
}

.axiom {
  /* Drop axiom into column 5 */
}

.axiom > * {
  grid-column: 5 / 11;
}

/* But .axiom has no children — fallback positioning via padding */
.axiom {
  padding-left: 33.33%;
  display: block;
  position: relative;
}

.axiom::after {
  content: '';
  position: absolute;
  left: calc(33.33% - 18px);
  top: 14px;
  width: 8px;
  height: 8px;
  background: var(--magenta);
  border-radius: 50%;
  box-shadow: 0 0 10px rgba(255, 79, 177, 0.6);
}

.body-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--gutter);
}

.bodycol {
  grid-column: 1 / 5;
}

.section-head {
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--glass-edge);
  display: flex;
  align-items: baseline;
  gap: 16px;
  font-family: var(--font-ui);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.section-num {
  font-size: 11px;
  color: var(--mint);
}

.section-title {
  font-size: 13px;
  color: var(--lab-paper);
}

.bodycol p {
  margin-bottom: 20px;
  font-size: 17px;
  line-height: 28px;
  color: var(--lab-paper);
}

.link {
  color: var(--mint);
  border-bottom: 1px solid rgba(57, 255, 140, 0.5);
  text-shadow: 0 0 16px rgba(57, 255, 140, 0.35);
  padding-bottom: 1px;
}

.link:hover {
  border-bottom-color: var(--mint);
}

.fn-marker {
  color: var(--magenta);
  font-size: 11px;
  padding-left: 2px;
  font-family: var(--font-ui);
  font-weight: 500;
}

/* Margin notes (col 11–12) */
.margin-note {
  grid-column: 11 / 13;
  position: relative;
  padding-left: 16px;
  font-family: var(--font-body);
  font-size: 13px;
  line-height: 20px;
  font-style: italic;
  color: var(--sage);
  align-self: start;
  margin-top: 64px;
}

.margin-note .mn-num {
  display: block;
  font-family: var(--font-ui);
  font-style: normal;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--magenta);
  margin-bottom: 6px;
}

.margin-note::before {
  content: '';
  position: absolute;
  top: 14px;
  left: -64px;
  width: 64px;
  height: 1px;
  background-image: linear-gradient(to right, var(--glass-edge) 50%, transparent 50%);
  background-size: 4px 1px;
  opacity: 0;
  transform-origin: right center;
  transform: scaleX(0);
  transition: transform 600ms var(--ease-lift), opacity 300ms linear;
}

.margin-note.is-in::before {
  opacity: 1;
  transform: scaleX(1);
}

/* ============================================================
   Featured Procedure Crossbar
   ============================================================ */
.procedure {
  padding-top: 88px;
  padding-bottom: 88px;
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--gutter);
}

.proc-head {
  grid-column: 1 / 10;
  margin-bottom: 32px;
}

.proc-tag {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--magenta);
  display: inline-block;
  margin-bottom: 16px;
}

.proc-title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(28px, 3.4vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--lab-paper);
  max-width: 22ch;
}

.proc-card {
  grid-column: 1 / 11;
  position: relative;
  background: var(--deep-pond);
  border: 1px solid var(--glass-edge);
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 0;
  transition: transform 220ms var(--ease-lift), box-shadow 220ms var(--ease-lift), border-color 220ms var(--ease-lift);
  will-change: transform;
}

.proc-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 24px 24px -8px rgba(57, 255, 140, 0.28);
  border-color: rgba(57, 255, 140, 0.4);
}

.proc-card-rule {
  position: absolute;
  top: 0;
  left: 50%;
  bottom: 0;
  width: 1px;
  background: var(--glass-edge);
}

.proc-diagram {
  padding: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-right: 1px solid var(--glass-edge);
  position: relative;
}

.proc-svg {
  width: 100%;
  height: auto;
  max-width: 360px;
}

.diag-label {
  font-family: var(--font-ui);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.film {
  transition: fill-opacity 220ms var(--ease-lift), stroke-width 220ms var(--ease-lift), stroke 220ms var(--ease-lift);
}

.film.is-active {
  fill: var(--cyan);
  fill-opacity: 0.18;
  stroke: var(--cyan);
  stroke-width: 1.2;
}

.plateau-pt {
  transition: r 220ms var(--ease-lift), fill 220ms var(--ease-lift);
}

.plateau-pt.is-active {
  r: 6;
  fill: var(--cyan);
  filter: drop-shadow(0 0 8px rgba(61, 226, 255, 0.9));
}

.proc-steps {
  list-style: none;
  padding: 40px;
  counter-reset: step;
}

.proc-step {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--glass-edge);
  cursor: crosshair;
  transition: color 180ms linear;
}

.proc-step:last-child {
  border-bottom: 0;
}

.proc-step:hover {
  color: var(--cyan);
}

.proc-step:hover .step-num {
  color: var(--cyan);
  text-shadow: 0 0 12px rgba(61, 226, 255, 0.55);
}

.step-num {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--sage);
  padding-top: 4px;
  transition: color 180ms linear, text-shadow 180ms linear;
}

.step-body {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 24px;
  color: var(--lab-paper);
}

/* ============================================================
   Figure Units (Lower Body)
   ============================================================ */
.figures .fig-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px var(--gutter);
}

.fig-unit {
  display: flex;
  flex-direction: column;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 600ms var(--ease-lift), transform 600ms var(--ease-lift);
}

.fig-unit.is-in {
  opacity: 1;
  transform: translateY(0);
}

.fig-rule {
  height: 1px;
  background: var(--glass-edge);
  margin-bottom: 16px;
}

.fig-art {
  background: var(--deep-pond);
  border: 1px solid var(--glass-edge);
  padding: 16px;
  margin-bottom: 12px;
}

.fig-svg {
  width: 100%;
  height: auto;
  display: block;
}

.fig-cap {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 16px;
  padding-top: 8px;
  border-top: 1px solid var(--glass-edge);
}

.fig-num {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--magenta);
  padding-top: 2px;
  white-space: nowrap;
}

.fig-text {
  font-family: var(--font-body);
  font-style: italic;
  font-size: 13px;
  line-height: 20px;
  color: var(--lab-paper);
  opacity: 0.86;
}

/* ============================================================
   Footnotes § 05
   ============================================================ */
.fn-list {
  list-style: none;
}

.fn-item {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--glass-edge);
  transition: transform 220ms var(--ease-lift), box-shadow 220ms var(--ease-lift);
  will-change: transform;
}

.fn-item:last-child {
  border-bottom: 0;
}

.fn-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px -8px rgba(57, 255, 140, 0.22);
}

.fn-id {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--magenta);
  padding-top: 4px;
}

.fn-body {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 24px;
  color: var(--lab-paper);
}

/* ============================================================
   Colophon § 06
   ============================================================ */
.colophon {
  padding-bottom: 120px;
  border-top: 1px solid var(--glass-edge);
}

.colo-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--gutter);
  margin-bottom: 64px;
}

.colo-block {
  grid-column: span 4;
}

.colo-label {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--mint);
  padding-bottom: 12px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--glass-edge);
}

.colo-spec {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--glass-edge);
  transition: transform 220ms var(--ease-lift), box-shadow 220ms var(--ease-lift);
}

.colo-spec:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px -8px rgba(57, 255, 140, 0.22);
}

.spec-name {
  font-size: 24px;
  line-height: 1.2;
  color: var(--lab-paper);
}

.spec-note {
  font-family: var(--font-ui);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--sage);
}

.palette {
  list-style: none;
}

.palette li {
  display: grid;
  grid-template-columns: 22px 1fr auto;
  gap: 12px;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid var(--glass-edge);
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
}

.sw {
  width: 22px;
  height: 14px;
  display: inline-block;
}

.sw-name {
  color: var(--lab-paper);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 11px;
}

.sw-hex {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--sage);
  letter-spacing: 0;
}

.conditions {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px 16px;
}

.conditions dt {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--sage);
  padding: 6px 0;
  border-bottom: 1px solid var(--glass-edge);
}

.conditions dd {
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--lab-paper);
  padding: 6px 0;
  border-bottom: 1px solid var(--glass-edge);
  text-align: right;
}

.colo-foot {
  display: flex;
  gap: 12px;
  padding-top: 24px;
  border-top: 1px solid var(--glass-edge);
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  align-items: center;
}

.cf-mark { color: var(--mint); }
.cf-sep { color: var(--glass-edge); }
.cf-end {
  color: var(--sage);
  font-family: var(--font-body);
  font-style: italic;
  font-size: 13px;
  letter-spacing: 0;
  text-transform: none;
}

/* ============================================================
   Botanical Plates (floating in negative right columns)
   ============================================================ */
.botanical {
  position: absolute;
  top: 0;
  right: 0;
  width: 240px;
  opacity: 0.18;
  pointer-events: none;
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 980px) {
  :root { --rail-w: 64px; }
  .spine { padding: 12px 8px; }
  .spine-mark { font-size: 14px; margin-bottom: 16px; }
  .spine-section { margin-bottom: 16px; }
  .spine-num, .spine-title { font-size: 10px; }
  .crossbar, .zone { padding-left: 16px; padding-right: 16px; }
  .navstrip { padding-left: calc(var(--rail-w) + 12px); padding-right: 12px; gap: 8px; font-size: 10px; }
  .nav-item { white-space: nowrap; }
  .masthead-headline { grid-column: 1 / 13; }
  .masthead-abstract { grid-column: 1 / 13; }
  .masthead-byline { grid-column: 1 / 13; }
  .proc-head { grid-column: 1 / 13; }
  .proc-card { grid-column: 1 / 13; grid-template-columns: 1fr; }
  .proc-diagram { border-right: 0; border-bottom: 1px solid var(--glass-edge); padding: 24px; }
  .proc-steps { padding: 24px; }
  .figures .fig-row { grid-template-columns: 1fr; }
  .bodycol { grid-column: 1 / 13; }
  .margin-note { grid-column: 1 / 13; margin-top: 24px; }
  .margin-note::before { display: none; }
  .colo-block { grid-column: span 12; }
  .axiom { padding-left: 0; font-size: 22px; line-height: 30px; }
  .axiom::after { display: none; }
}

@media (max-width: 600px) {
  .masthead { padding-top: 64px; padding-bottom: 32px; }
  .masthead-row { flex-direction: column; gap: 4px; margin-bottom: 24px; }
  .zone { padding: 48px 16px; }
  .procedure { padding-top: 48px; padding-bottom: 48px; }
}

/* ============================================================
   Reduced motion
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .bubble {
    opacity: 0.12 !important;
  }
  .proc-card:hover {
    transform: none;
  }
  .fn-item:hover, .colo-spec:hover {
    transform: none;
  }
  .fig-unit {
    opacity: 1;
    transform: none;
  }
}