/* ==========================================================================
   Fish Finder — scrollytelling presentation (Stage E polish)
   ========================================================================== */

:root {
  --color-bg: #0c1a24;
  --color-bg-panel: #122636;
  --color-surface: #1a3344;
  --color-text: #e8f0f4;
  --color-muted: #8fa8b8;
  --color-accent: #3db8c4;
  --color-accent-soft: rgba(61, 184, 196, 0.15);
  --color-border: rgba(255, 255, 255, 0.08);
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: ui-monospace, 'Cascadia Code', 'Source Code Pro', monospace;
  --sticky-height: 100vh;
  --header-height: 3.5rem;
  --sidebar-width: 10.5rem;
  --step-min-height: 85vh;
  --transition-visual: opacity 0.45s ease;
  --transition-step: opacity 0.35s ease;
}

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

html {
  scroll-behavior: smooth;
  /* Match the layout density of ~90% browser zoom so sidebar labels and
     scrolly panels fit comfortably at 100% zoom. */
  zoom: 0.9;
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: var(--color-accent-soft);
  color: var(--color-text);
}

/* ----- Header & progress ----- */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.25rem;
  background: rgba(12, 26, 36, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.site-title {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.site-title span {
  color: var(--color-accent);
}

.section-indicator {
  display: none;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-muted);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.scroll-progress-track {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  height: 3px;
  z-index: 99;
  background: var(--color-border);
}

.scroll-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--color-accent), #5dd4de);
  transition: width 0.08s ease-out;
  will-change: width;
}

@media (prefers-reduced-motion: reduce) {
  .scroll-progress-bar {
    transition: none;
  }
}

/* ----- Left sidebar section nav ----- */

.section-nav {
  position: fixed;
  top: calc(var(--header-height) + 1.25rem);
  left: max(0.75rem, calc((100vw - 1400px) / 2 - var(--sidebar-width) - 0.5rem));
  z-index: 90;
  width: var(--sidebar-width);
  max-height: calc(100vh - var(--header-height) - 2rem);
  overflow-y: auto;
  overscroll-behavior: contain;
}

.section-nav__heading {
  margin: 0 0 0.5rem;
  padding: 0 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.section-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.section-nav__item {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  width: 100%;
  padding: 0.4rem 0.5rem;
  border: none;
  border-radius: 6px;
  background: transparent;
  color: var(--color-muted);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 500;
  line-height: 1.3;
  text-align: left;
  cursor: pointer;
  transition: color var(--transition-step), background var(--transition-step);
}

.section-nav__item:hover {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.04);
}

.section-nav__item.is-active {
  color: var(--color-text);
  background: var(--color-accent-soft);
}

.section-nav__item:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.section-nav__dot {
  flex-shrink: 0;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-muted);
  opacity: 0.45;
  transition: opacity var(--transition-step), background var(--transition-step), transform var(--transition-step), box-shadow var(--transition-step);
}

.section-nav__item:hover .section-nav__dot {
  opacity: 0.75;
}

.section-nav__item.is-active .section-nav__dot {
  opacity: 1;
  background: var(--color-accent);
  transform: scale(1.2);
  box-shadow: 0 0 0 2px var(--color-bg), 0 0 0 3px var(--color-accent);
}

.section-nav__label {
  flex: 1;
  min-width: 0;
}

/* ----- Scrolly layout ----- */

.scrolly-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  max-width: 1400px;
  margin: 0 auto;
  padding-top: calc(var(--header-height) + 3px);
}

.sticky-visual {
  position: sticky;
  top: var(--header-height);
  height: calc(var(--sticky-height) - var(--header-height));
  align-self: start;
  background:
    radial-gradient(ellipse at 30% 20%, rgba(61, 184, 196, 0.06), transparent 55%),
    var(--color-bg-panel);
  border-right: 1px solid var(--color-border);
  overflow: hidden;
}

.visual-state {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.75rem;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition-visual);
  pointer-events: none;
  overflow-y: auto;
  overscroll-behavior: contain;
}

.visual-state.is-active {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

@media (prefers-reduced-motion: reduce) {
  .visual-state {
    transition: none;
  }
}

/* Placeholder visual cards */

.visual-card {
  width: 100%;
  max-width: 420px;
  padding: 1.75rem;
  border-radius: 12px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.18);
  text-align: center;
  flex-shrink: 0;
}

.visual-card__label {
  display: inline-block;
  margin-bottom: 0.75rem;
  padding: 0.25rem 0.75rem;
  font-size: 1rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  background: var(--color-accent-soft);
  border-radius: 999px;
}

.visual-card__title {
  margin: 0 0 0.5rem;
  font-size: 1.35rem;
}

.visual-card__stat {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-accent);
  margin: 0.5rem 0;
}

.visual-card__hint {
  margin: 0;
  font-size: 1rem;
  color: var(--color-muted);
}

.visual-card__hint--small {
  margin-top: 0.75rem;
  font-size: 1rem;
}

.visual-placeholder {
  width: 100%;
  max-width: 420px;
  aspect-ratio: 16 / 10;
  margin-top: 1rem;
  border-radius: 8px;
  background: repeating-linear-gradient(
    -45deg,
    rgba(255, 255, 255, 0.03),
    rgba(255, 255, 255, 0.03) 8px,
    rgba(255, 255, 255, 0.06) 8px,
    rgba(255, 255, 255, 0.06) 16px
  );
  border: 1px dashed rgba(61, 184, 196, 0.35);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 1rem;
  text-align: center;
  flex-shrink: 0;
}

.visual-placeholder__label {
  display: inline-block;
  padding: 0.2rem 0.55rem;
  font-size: 1rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
  background: var(--color-accent-soft);
  border-radius: 999px;
}

.visual-placeholder__name {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
}

.visual-placeholder__path {
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: 0.25rem 0.5rem;
  background: rgba(0, 0, 0, 0.25);
  border-radius: 4px;
  color: var(--color-muted);
  word-break: break-all;
  max-width: 100%;
}

.visual-image {
  width: 100%;
  max-width: 420px;
  margin-top: 1rem;
  border-radius: 8px;
  border: 1px solid var(--color-border);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
  object-fit: contain;
  background: #0a1520;
  flex-shrink: 0;
}

.visual-image--compact {
  max-width: 400px;
  margin-top: 0.75rem;
}

.sticky-visual .code-block {
  width: 100%;
  max-width: 420px;
  margin-top: 0.75rem;
  flex-shrink: 0;
}

/* Pipeline mini-diagram (placeholder) */

.pipeline-viz {
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.pipeline-step {
  padding: 0.65rem 1rem;
  border-radius: 6px;
  font-size: 1rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--color-border);
  opacity: 0.4;
  transition: opacity var(--transition-visual), border-color var(--transition-visual);
}

.pipeline-step.is-highlight {
  opacity: 1;
  border-color: var(--color-accent);
  background: var(--color-accent-soft);
}

/* ----- Steps column ----- */

.steps-column {
  padding: 2rem 2.5rem 4rem;
}

.step {
  min-height: var(--step-min-height);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 2rem 0;
  opacity: 0.4;
  transition: opacity var(--transition-step);
  border-left: 3px solid transparent;
  padding-left: 1.25rem;
  margin-left: -1.25rem;
}

.step.is-visible {
  opacity: 1;
  border-left-color: var(--color-accent);
}

@media (prefers-reduced-motion: reduce) {
  .step {
    transition: none;
    opacity: 1;
    border-left-color: transparent;
  }

  .step.is-visible {
    border-left-color: var(--color-accent);
  }
}

.step__number {
  display: inline-block;
  margin-bottom: 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 0.1em;
}

.step h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.5rem, 3vw, 2rem);
  line-height: 1.25;
  color: var(--color-text);
}

.step p strong {
  color: var(--color-text);
}

.step p {
  margin: 0 0 1rem;
  color: var(--color-muted);
  max-width: 38rem;
}

.step p:last-child {
  margin-bottom: 0;
}

.step code {
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: 0.1em 0.35em;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 4px;
  color: var(--color-text);
  word-break: break-word;
}

.step ul,
.step ol {
  margin: 0 0 1rem;
  padding-left: 1.25rem;
  color: var(--color-muted);
  max-width: 38rem;
}

.step ul li,
.step ol li {
  margin-bottom: 0.35rem;
}

.step__note--coming {
  border-left-color: var(--color-muted);
  background: rgba(255, 255, 255, 0.04);
  color: var(--color-muted);
  font-style: italic;
}

.visual-placeholder--compact {
  max-width: 400px;
  aspect-ratio: 21 / 9;
  margin-top: 0.75rem;
  font-size: 1rem;
}

.feature-list {
  margin: 0.75rem 0 0;
  padding: 0;
  list-style: none;
  font-size: 1rem;
  color: var(--color-text);
}

.feature-list li {
  padding: 0.35rem 0.65rem;
  margin-bottom: 0.25rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
}

.walkthrough-steps {
  counter-reset: walkthrough-step;
  list-style: none;
}

.walkthrough-steps li {
  counter-increment: walkthrough-step;
  position: relative;
  padding-left: 2rem;
}

.walkthrough-steps li::before {
  content: counter(walkthrough-step);
  position: absolute;
  left: 0.65rem;
  font-weight: 700;
  color: var(--color-accent);
}

.outcomes-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.65rem;
  width: 100%;
  max-width: 420px;
  margin-top: 0.75rem;
  flex-shrink: 0;
}

.outcomes-grid__item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.25rem;
  min-height: 5.25rem;
  padding: 0.85rem 0.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
  text-align: center;
}

.outcomes-grid__label {
  font-size: 1rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
}

.outcomes-grid__title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.25;
}

.outcomes-grid__hint {
  font-size: 1rem;
  color: var(--color-muted);
  line-height: 1.3;
}

.visual-card--compact {
  padding: 1.25rem;
}

.visual-card--compact .visual-card__title {
  font-size: 1.15rem;
  margin-bottom: 0.25rem;
}

.metrics-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
  margin-top: 0.75rem;
  font-size: 1rem;
}

.metrics-grid dt {
  color: var(--color-muted);
  font-weight: 500;
}

.metrics-grid dd {
  margin: 0;
  font-weight: 600;
  color: var(--color-text);
}

.metrics-grid--thresholds dd {
  font-size: 1rem;
}

.rules-mini-table {
  width: 100%;
  margin-top: 0.75rem;
  font-size: 1rem;
  border-collapse: collapse;
}

.rules-mini-table th,
.rules-mini-table td {
  padding: 0.35rem 0.5rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.rules-mini-table th {
  color: var(--color-muted);
  font-weight: 600;
}

.rules-mini-table td:last-child {
  text-align: right;
  font-weight: 600;
  color: var(--color-accent);
}

.test-checklist {
  margin: 0.75rem 0 0;
  padding: 0;
  list-style: none;
  font-size: 1rem;
}

.test-checklist__item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.65rem;
  margin-bottom: 0.35rem;
  border-radius: 4px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.test-checklist__item--pass {
  border-left: 3px solid #2f9e44;
}

.test-checklist__mark {
  color: #2f9e44;
  font-weight: 700;
}

.limitations-card {
  margin-top: 0.75rem;
  padding: 0.85rem 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 1rem;
}

.limitations-card__heading {
  margin: 0.5rem 0 0.25rem;
  font-weight: 600;
  color: var(--color-accent);
}

.limitations-card__heading:first-child {
  margin-top: 0;
}

.limitations-card ul {
  margin: 0 0 0.25rem;
  padding-left: 1.1rem;
}

.code-block {
  margin: 0.75rem 0 1rem;
  padding: 0.85rem 1rem;
  background: #1a2630;
  color: #d4d4d4;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 1rem;
  overflow-x: auto;
  white-space: pre-wrap;
  word-break: break-word;
  max-width: 38rem;
}

.code-block code {
  background: none;
  padding: 0;
}

.step__note--learned {
  border-left-color: #5dd4de;
  background: rgba(93, 212, 222, 0.08);
}

.learnings-card {
  width: 100%;
  max-width: 420px;
  margin-top: 0.75rem;
  padding: 0.85rem 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 1rem;
  flex-shrink: 0;
}

.learnings-card__heading {
  margin: 0.5rem 0 0.25rem;
  font-weight: 600;
  color: #5dd4de;
}

.learnings-card__heading:first-child {
  margin-top: 0;
}

.learnings-card ul {
  margin: 0 0 0.25rem;
  padding-left: 1.1rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.step__note {
  margin-top: 1.25rem;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  border-left: 3px solid var(--color-accent);
  background: var(--color-accent-soft);
  border-radius: 0 6px 6px 0;
  color: var(--color-text);
}

/* Section anchors (for nav) */
.step-anchor {
  scroll-margin-top: calc(var(--header-height) + 1rem);
}

/* ----- Footer ----- */

.site-footer {
  padding: 2.5rem 1.5rem;
  text-align: center;
  background: var(--color-bg-panel);
  border-top: 1px solid var(--color-border);
}

.site-footer__title {
  margin: 0 0 0.35rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
}

.site-footer__meta {
  margin: 0;
  font-size: 1rem;
  color: var(--color-muted);
}

/* Hide sidebar when viewport is too narrow for the left gap */
@media (max-width: 1100px) {
  .section-nav {
    display: none;
  }

  .section-indicator {
    display: block;
  }
}

/* ----- Mobile ----- */

@media (max-width: 768px) {
  :root {
    --sticky-height: 44vh;
    --step-min-height: 50vh;
  }

  .section-nav {
    display: none;
  }

  .scrolly-container {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
  }

  .sticky-visual {
    position: sticky;
    top: var(--header-height);
    height: var(--sticky-height);
    border-right: none;
    border-bottom: 1px solid var(--color-border);
    order: -1;
  }

  .visual-state {
    padding: 1rem;
    justify-content: flex-start;
  }

  .steps-column {
    padding: 1.5rem 1.25rem 3rem;
  }

  .step {
    padding-left: 0.75rem;
    margin-left: 0;
    border-left-width: 2px;
  }

  .section-indicator {
    display: block;
  }

  .site-header {
    padding: 0 1rem;
    gap: 0.75rem;
  }

  .site-title {
    font-size: 1rem;
    flex-shrink: 0;
  }

  .visual-card {
    padding: 1rem;
  }

  .visual-card__stat {
    font-size: 1.75rem;
  }

  .visual-placeholder {
    aspect-ratio: 16 / 9;
    margin-top: 0.65rem;
  }

  .visual-placeholder__path {
    font-size: 1rem;
  }

  .feature-list,
  .outcomes-grid,
  .metrics-grid,
  .rules-mini-table,
  .test-checklist {
    max-width: 100%;
  }

  .outcomes-grid__item {
    min-height: 4.25rem;
    padding: 0.6rem 0.45rem;
  }

  .outcomes-grid__title {
    font-size: 1rem;
  }
}

@media (max-width: 480px) {
  :root {
    --sticky-height: 40vh;
  }

  body {
    font-size: 1rem;
  }

  .step h2 {
    font-size: 1.35rem;
  }
}