/* ═══════════════════════════════════════════════════════════
   Otto Engineering — Shared Design System
   ═══════════════════════════════════════════════════════════ */

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

:root {
  /* Surfaces & background */
  --bg:             #06080f;
  --surface:        #0c0e15;
  --surface-raised: #11131c;
  --surface2:       #12141c;
  --border:         #1c1e28;
  --border-strong:  #2a2d3a;
  --border-focus:   #6ea8dc;

  /* Text — tuned for WCAG AA against --bg */
  --text-strong:   #eef0f5;   /* hero text, marquee numbers */
  --text-heading:  #d4d6dc;   /* h1–h4 */
  --text-body:     #a8aab3;   /* paragraphs, nav */
  --text:          #969aa3;   /* secondary text (AA on --bg) */
  --text-dim:      #7a7c87;   /* metadata, captions (AA on --bg) */

  /* Brand accents (preserved) */
  --accent:        #4a90d1;
  --accent-glow:   rgba(74, 144, 209, 0.28);
  --accent-soft:   rgba(74, 144, 209, 0.10);
  --teal:          #1a9e9e;
  --teal-glow:     rgba(26, 158, 158, 0.22);
  --warm:          #c8864a;
  --warm-glow:     rgba(200, 134, 74, 0.18);
  --amber:         #b89040;
  --amber-glow:    rgba(184, 144, 64, 0.18);
  --red:           #c84646;
  --red-glow:      rgba(200, 70, 70, 0.18);

  /* Per-app accents (consumed by pages) */
  --streams:       #4a90d1;
  --streams-dim:   rgba(74, 144, 209, 0.30);
  --streams-soft:  rgba(74, 144, 209, 0.10);
  --habitat:       #40e0a0;
  --habitat-dim:   rgba(64, 224, 160, 0.30);
  --habitat-soft:  rgba(64, 224, 160, 0.10);
  --ottoverb:      #b89040;
  --ottoverb-dim:  rgba(184, 144, 64, 0.30);
  --ottoverb-soft: rgba(184, 144, 64, 0.10);

  /* Spacing scale */
  --space-1:   4px;
  --space-2:   8px;
  --space-3:  12px;
  --space-4:  16px;
  --space-5:  20px;
  --space-6:  24px;
  --space-8:  32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
  --space-20: 80px;
  --space-24: 96px;
  --space-32: 128px;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 20px;
  --radius-pill: 999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 12px 36px rgba(0, 0, 0, 0.55);

  /* Motion */
  --ease-standard: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring:   cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-out:      cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in-out:   cubic-bezier(0.65, 0, 0.35, 1);
  --dur-fast:   180ms;
  --dur-med:    320ms;
  --dur-slow:   560ms;

  /* Typography scale */
  --fs-xs:   clamp(0.72rem, 0.70rem + 0.1vw, 0.78rem);
  --fs-sm:   clamp(0.82rem, 0.78rem + 0.2vw, 0.92rem);
  --fs-base: clamp(0.95rem, 0.90rem + 0.25vw, 1.05rem);
  --fs-2xl:  clamp(1.6rem, 1.30rem + 1.5vw, 2.4rem);
  --fs-4xl:  clamp(3rem, 2.20rem + 4vw, 6rem);

  /* Layout */
  --container-max: 1240px;
}

html {
  color-scheme: dark;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-feature-settings: "ss01", "cv11", "tnum";
  background: var(--bg);
  color: var(--text-body);
  line-height: 1.6;
  font-weight: 300;
  overflow-x: hidden;
  min-height: 100vh;
}

/* Subtle texture — faint grid of dots that sits beneath content,
   adds just enough surface texture to avoid feeling flat. */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image: radial-gradient(circle at 1px 1px, rgba(255, 255, 255, 0.015) 1px, transparent 0);
  background-size: 32px 32px;
  pointer-events: none;
  z-index: 0;
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-standard);
}
@media (hover: hover) {
  a:hover { text-decoration: underline; }
}

:focus:not(:focus-visible) { outline: none; }
:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 3px;
  border-radius: 4px;
}

img, svg { display: block; max-width: 100%; }

button {
  appearance: none;
  -webkit-appearance: none;
  background: none;
  border: 0;
  color: inherit;
  font: inherit;
  padding: 0;
  cursor: pointer;
}

/* ── Skip link ───────────────────────────────────────────── */

.skip-link {
  position: fixed;
  top: -100px;
  left: 16px;
  z-index: 200;
  padding: 10px 18px;
  background: var(--surface-raised);
  color: var(--text-strong);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  font-size: var(--fs-sm);
  transition: top var(--dur-fast) var(--ease-standard);
  text-decoration: none;
}
.skip-link:focus-visible {
  top: 12px;
  text-decoration: none;
}

/* ── Site Nav ────────────────────────────────────────────── */

.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 56px;
  z-index: 100;
  background: rgba(6, 8, 15, 0.72);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid transparent;
  padding: 0 max(24px, env(safe-area-inset-right)) 0 max(24px, env(safe-area-inset-left));
  display: flex;
  align-items: center;
  gap: 24px;
  transition: background var(--dur-med) var(--ease-standard),
              border-color var(--dur-med) var(--ease-standard);
}

.site-nav.scrolled {
  background: rgba(6, 8, 15, 0.88);
  border-bottom-color: var(--border);
}

.site-nav .logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  text-decoration: none;
  transition: filter var(--dur-med) var(--ease-standard),
              transform var(--dur-med) var(--ease-spring);
}

.site-nav .logo img {
  height: 28px;
  width: auto;
  max-width: none;
  flex-shrink: 0;
}

.site-nav .logo:hover {
  filter: drop-shadow(0 0 14px var(--accent-glow));
  transform: scale(1.04);
}

.site-nav .nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav .nav-links a,
.site-nav .nav-right a {
  font-size: 13px;
  font-weight: 400;
  color: var(--text-body);
  text-decoration: none;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  position: relative;
  transition: color var(--dur-fast) var(--ease-standard),
              background var(--dur-fast) var(--ease-standard);
}

.site-nav .nav-links a:hover,
.site-nav .nav-right a:hover {
  color: var(--text-strong);
  background: rgba(255, 255, 255, 0.03);
  text-decoration: none;
}

.site-nav .nav-links a.active,
.site-nav .nav-right a.active {
  color: var(--text-strong);
}

.site-nav .nav-links a.active::after,
.site-nav .nav-right a.active::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 2px;
  height: 1px;
  background: currentColor;
  opacity: 0.4;
}

.site-nav a[aria-disabled="true"] {
  color: var(--text-dim);
  pointer-events: none;
  cursor: default;
}

.site-nav .nav-right {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: auto;
}

/* ── App sub-nav (per-app contextual links, mobile-only) ── */
/* Hidden by default; revealed at <=768px. The site-nav .subnav-link
   items shown on desktop are mirrored here for mobile. */

.app-subnav {
  display: none;
  position: fixed;
  top: 52px;
  left: 0;
  right: 0;
  height: 40px;
  z-index: 99;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 0 12px;
  background: rgba(6, 8, 15, 0.72);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid transparent;
  transition: background var(--dur-med) var(--ease-standard),
              border-color var(--dur-med) var(--ease-standard);
  --subnav-accent: var(--accent);
}

.site-nav.scrolled ~ .app-subnav {
  background: rgba(6, 8, 15, 0.88);
  border-bottom-color: var(--border);
}

.app-subnav.streams  { --subnav-accent: var(--streams); }
.app-subnav.habitat  { --subnav-accent: var(--habitat); }
.app-subnav.ottoverb { --subnav-accent: var(--ottoverb); }

.app-subnav a {
  position: relative;
  font-size: 12px;
  font-weight: 400;
  color: var(--text-body);
  text-decoration: none;
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  transition: color var(--dur-fast) var(--ease-standard),
              background var(--dur-fast) var(--ease-standard);
}

.app-subnav a:hover {
  color: var(--text-strong);
  background: rgba(255, 255, 255, 0.03);
  text-decoration: none;
}

.app-subnav a.active { color: var(--subnav-accent); }

.app-subnav a.active::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 1px;
  height: 1px;
  background: currentColor;
  opacity: 0.5;
}

/* ── Section Layout ──────────────────────────────────────── */

section {
  padding: var(--space-24) var(--space-6);
  max-width: var(--container-max);
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.section-title {
  font-size: var(--fs-2xl);
  font-weight: 300;
  color: var(--text-heading);
  letter-spacing: -0.01em;
  margin-bottom: var(--space-4);
  line-height: 1.12;
}

.section-desc {
  font-size: var(--fs-base);
  color: var(--text-body);
  max-width: 640px;
  line-height: 1.7;
  font-weight: 300;
}

/* Eyebrow / kicker above section titles */
.eyebrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: var(--space-3);
  display: inline-block;
}

/* ── Buttons ─────────────────────────────────────────────── */

.btn-primary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 28px;
  font-weight: 500;
  font-size: 14px;
  letter-spacing: 0.01em;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  text-decoration: none;
  position: relative;
  transition: transform var(--dur-med) var(--ease-spring),
              box-shadow var(--dur-med) var(--ease-standard),
              background-position var(--dur-slow) var(--ease-standard);
  will-change: transform;
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--accent) 0%, var(--teal) 50%, var(--accent) 100%);
  background-size: 200% 100%;
  background-position: 0% 50%;
  box-shadow: 0 6px 24px var(--accent-glow), inset 0 1px 0 rgba(255, 255, 255, 0.12);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 40px var(--accent-glow), inset 0 1px 0 rgba(255, 255, 255, 0.18);
  background-position: 100% 50%;
  text-decoration: none;
}

.btn-primary:active {
  transform: translateY(0) scale(0.98);
  transition-duration: 80ms;
}

.btn-primary svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
  transition: transform var(--dur-fast) var(--ease-spring);
}

.btn-primary:hover svg { transform: translateX(2px); }

.btn-ghost {
  color: var(--text-heading);
  background: transparent;
  border: 1px solid var(--border-strong);
}

.btn-ghost:hover {
  color: var(--text-strong);
  border-color: var(--text-body);
  background: rgba(255, 255, 255, 0.02);
  transform: translateY(-1px);
  text-decoration: none;
}

.btn-ghost:active { transform: translateY(0) scale(0.98); }

/* ── Feature Cards ───────────────────────────────────────── */

.feature-card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: border-color var(--dur-med) var(--ease-standard),
              transform var(--dur-med) var(--ease-spring),
              box-shadow var(--dur-med) var(--ease-standard),
              background var(--dur-med) var(--ease-standard);
}

.feature-card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, var(--accent-soft), transparent 60%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
          mask-composite: exclude;
  opacity: 0;
  transition: opacity var(--dur-med) var(--ease-standard);
  pointer-events: none;
}

@media (hover: hover) {
  .feature-card:hover {
    border-color: var(--border-strong);
    transform: translateY(-6px);
    background: var(--surface-raised);
    box-shadow: var(--shadow-lg);
  }
  .feature-card:hover::before { opacity: 1; }
}

.feature-card h3 {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-heading);
  margin-bottom: 10px;
  letter-spacing: -0.005em;
}

.feature-card p {
  font-size: 0.90rem;
  color: var(--text-body);
  line-height: 1.65;
}

/* ── Platform / metadata tags ────────────────────────────── */

.tag {
  display: inline-flex;
  align-items: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  background: rgba(255, 255, 255, 0.02);
}

/* ── Footer ──────────────────────────────────────────────── */

.site-footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--border);
  padding: var(--space-6) var(--space-6);
  margin-top: var(--space-16);
}

.site-footer .footer-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}

.site-footer .footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  min-width: 0;
}

.site-footer .footer-brand img {
  height: 24px;
  width: auto;
  opacity: 0.8;
  flex-shrink: 0;
}

.site-footer .footer-brand p,
.site-footer .footer-copy {
  font-size: var(--fs-xs);
  color: var(--text-dim);
  line-height: 1.5;
  margin: 0;
}

.site-footer .footer-copy {
  flex-shrink: 0;
  text-align: right;
}

.site-footer .footer-meta {
  display: flex;
  flex-direction: row;
  align-items: baseline;
  gap: var(--space-3);
  flex-shrink: 0;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.site-footer .footer-links {
  display: flex;
  gap: var(--space-3);
}

.site-footer .footer-links a {
  font-size: clamp(0.65rem, 0.63rem + 0.1vw, 0.72rem);
  color: var(--text-dim);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-standard);
}

.site-footer .footer-links a:hover,
.site-footer .footer-links a:focus-visible {
  color: var(--text-strong);
}

/* ── Fade-in Reveal ──────────────────────────────────────── */

.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children on cascading reveals. */
.reveal-stagger > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
}
.reveal-stagger.visible > *:nth-child(1) { transition-delay: 0ms;   }
.reveal-stagger.visible > *:nth-child(2) { transition-delay: 60ms;  }
.reveal-stagger.visible > *:nth-child(3) { transition-delay: 120ms; }
.reveal-stagger.visible > *:nth-child(4) { transition-delay: 180ms; }
.reveal-stagger.visible > *:nth-child(5) { transition-delay: 240ms; }
.reveal-stagger.visible > *:nth-child(6) { transition-delay: 300ms; }
.reveal-stagger.visible > *:nth-child(7) { transition-delay: 360ms; }
.reveal-stagger.visible > *:nth-child(8) { transition-delay: 420ms; }
.reveal-stagger.visible > * {
  opacity: 1;
  transform: translateY(0);
}

/* ── Scroll indicator (hero bottom chevron) ──────────────── */

.scroll-indicator {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  color: var(--text-dim);
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  z-index: 3;
  pointer-events: none;
  animation: scroll-fade-in 1.6s var(--ease-out) 0.6s both;
}

.scroll-indicator .chevron {
  width: 14px;
  height: 14px;
  border-right: 1px solid currentColor;
  border-bottom: 1px solid currentColor;
  transform: rotate(45deg);
  animation: scroll-bob 2.4s ease-in-out infinite;
}

@keyframes scroll-fade-in {
  from { opacity: 0; transform: translate(-50%, 10px); }
  to   { opacity: 1; transform: translate(-50%, 0); }
}

@keyframes scroll-bob {
  0%, 100% { transform: rotate(45deg) translate(0, 0); opacity: 0.5; }
  50%      { transform: rotate(45deg) translate(3px, 3px); opacity: 1; }
}

/* Opacity is driven by JS (scroll-linked inline style) for a smooth,
   finger-matched fade. See each page's nav-scroll IIFE. */

/* ── Canvas pause control ────────────────────────────────── */

.canvas-pause {
  position: absolute;
  bottom: 16px;
  right: 16px;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: rgba(6, 8, 15, 0.6);
  backdrop-filter: blur(8px);
  color: var(--text-body);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity var(--dur-med) var(--ease-standard),
              visibility 0s linear var(--dur-med),
              color var(--dur-fast) var(--ease-standard),
              transform var(--dur-fast) var(--ease-spring);
  z-index: 3;
}

.hero:hover .canvas-pause,
.canvas-pause:focus-visible {
  opacity: 0.85;
  visibility: visible;
  pointer-events: auto;
  transition-delay: 0s;
}

/* On touch devices we never get :hover, so reveal the pause control
   at lower opacity by default — taps still work, and the control can
   be opted out per-page (e.g. streams tutorial hides #vizPause). */
@media (hover: none) {
  .canvas-pause {
    opacity: 0.7;
    visibility: visible;
    pointer-events: auto;
  }
}

.canvas-pause:hover {
  color: var(--text-strong);
  transform: scale(1.05);
}

.canvas-pause svg { width: 14px; height: 14px; fill: currentColor; }

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

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .reveal,
  .reveal-stagger > * {
    opacity: 1 !important;
    transform: none !important;
  }
  .scroll-indicator { display: none; }
}

/* ── Responsive ──────────────────────────────────────────── */

@media (max-width: 1280px) {
  section { padding: var(--space-20) var(--space-6); }
}

@media (max-width: 1024px) {
  section { padding: var(--space-20) var(--space-5); }
}

@media (max-width: 768px) {
  section { padding: var(--space-16) var(--space-5); }
  .site-nav {
    height: 52px;
    padding: 0 16px;
    gap: 12px;
  }
  .site-nav .logo img { height: 24px; }
  .site-nav .nav-links { gap: 0; }
  .site-nav .nav-links a,
  .site-nav .nav-right a { font-size: 12px; padding: 14px 12px; }
  /* Show app sub-nav, and hide its duplicates in the main nav */
  .app-subnav { display: flex; }
  .site-nav .subnav-link { display: none; }
  body.has-subnav .hero { padding-top: 40px; }
  body.has-subnav main > section:first-of-type { scroll-margin-top: 92px; }
}

/* Narrow phones: footer brand+copy crams horribly on a single row. Stack. */
@media (max-width: 600px) {
  .site-footer .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
  }
  .site-footer .footer-copy { text-align: left; }
  .site-footer .footer-meta { align-items: flex-start; }
}

@media (max-width: 480px) {
  section { padding: var(--space-12) var(--space-4); }
  .site-nav {
    gap: 8px;
    padding: 0 max(12px, env(safe-area-inset-right)) 0 max(12px, env(safe-area-inset-left));
  }
  .site-nav .nav-links {
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
  }
  .site-nav .nav-links::-webkit-scrollbar { display: none; }
  .site-nav .nav-right { gap: 0; }
  .site-nav .nav-right a { padding: 14px 10px; }
  .btn-primary, .btn-ghost { padding: 12px 22px; font-size: 13px; }
  .site-footer { padding: var(--space-6) var(--space-4); }
}