/* ASTELAYA — Bright Tech / Motion-Driven Design System */

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

:root {
  --bg: #F8FAFC;
  --bg-alt: #EFF6FF;
  --surface: #FFFFFF;
  --text: #09090B;
  --text-muted: #475569;
  --primary: #2563EB;
  --cyan: #06B6D4;
  --violet: #8B5CF6;
  --accent: #3B82F6;
  --border: #E2E8F0;
  --border-glow: rgba(37, 99, 235, 0.25);
  --shadow: 0 4px 24px rgba(37, 99, 235, 0.08);
  --shadow-lg: 0 12px 48px rgba(37, 99, 235, 0.12);
  --radius: 16px;
  --nav-h: 72px;
  --max-w: 1140px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-soft: cubic-bezier(0.33, 0, 0.2, 1);
  --ease-out: cubic-bezier(0.33, 1, 0.68, 1);
  --font-head: 'Space Grotesk', system-ui, sans-serif;
  --font-body: 'DM Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SFMono-Regular', monospace;
  --glass-bg: rgba(255, 255, 255, 0.28);
  --glass-bg-md: rgba(255, 255, 255, 0.32);
  --glass-bg-strong: rgba(255, 255, 255, 0.42);
  --glass-blur: blur(20px) saturate(170%);
  --glass-border: rgba(255, 255, 255, 0.45);
  --glass-highlight: rgba(255, 255, 255, 0.72);
  --glass-shadow: 0 4px 24px rgba(37, 99, 235, 0.1);
  --glass-shadow-lg: 0 8px 32px rgba(37, 99, 235, 0.14);
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
}

a { text-decoration: none; transition: color 0.2s, opacity 0.2s; }
img { vertical-align: middle; }

/* ── Scroll progress ── */
.scroll-progress {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 3px;
  z-index: 200;
  background: transparent;
}

.scroll-progress__bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--cyan), var(--primary));
  transition: width 0.1s linear;
  box-shadow: 0 0 12px rgba(6, 182, 212, 0.5);
}

/* ── Background layers ── */
.bg-aurora {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.bg-aurora__blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.32;
  will-change: transform;
}

.bg-aurora__blob--1 {
  width: 55vw;
  height: 55vw;
  max-width: 680px;
  max-height: 680px;
  top: -12%;
  left: -8%;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.45) 0%, rgba(6, 182, 212, 0) 70%);
  animation: auroraDrift1 22s ease-in-out infinite alternate;
}

.bg-aurora__blob--2 {
  width: 48vw;
  height: 48vw;
  max-width: 620px;
  max-height: 620px;
  top: 35%;
  right: -12%;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.4) 0%, rgba(37, 99, 235, 0) 70%);
  animation: auroraDrift2 28s ease-in-out infinite alternate;
}

.bg-aurora__blob--3 {
  width: 40vw;
  height: 40vw;
  max-width: 520px;
  max-height: 520px;
  bottom: -8%;
  left: 30%;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.28) 0%, rgba(139, 92, 246, 0) 70%);
  animation: auroraDrift3 25s ease-in-out infinite alternate;
}

.bg-mesh {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 90% 70% at 15% 15%, rgba(6, 182, 212, 0.07), transparent 60%),
    radial-gradient(ellipse 80% 60% at 85% 35%, rgba(37, 99, 235, 0.06), transparent 60%),
    radial-gradient(ellipse 70% 55% at 50% 85%, rgba(59, 130, 246, 0.06), transparent 60%);
  animation: meshShift 18s ease-in-out infinite alternate;
}

.bg-code-rain {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
}

.bg-code-rain__track {
  position: absolute;
  top: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.48rem;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.04em;
  color: rgba(6, 182, 212, 0.5);
  animation: bgCodeRainFall var(--rain-dur, 10s) linear infinite;
  animation-delay: var(--rain-delay, 0s);
  will-change: transform;
}

.bg-code-rain__track span {
  display: block;
  opacity: 0.58;
}

.bg-code-rain__track span:first-child {
  color: #06B6D4;
  opacity: 0.9;
  font-size: 0.9rem;
  text-shadow: 0 0 10px rgba(6, 182, 212, 0.55);
}

@keyframes bgCodeRainFall {
  0% { transform: translateY(-100%); }
  100% { transform: translateY(100vh); }
}

/* ── Glass surfaces (site-wide) ── */
.hero__badge,
.hero__board-panel,
.flow-chip:not(.active),
.algo-step,
.hero__step-detail,
.quote-card,
.tech-card,
.hobby-card,
.dive-card,
.dive-card__block--case,
.pitfall-card,
.practice-card,
.pill,
.scene-card,
.footer,
.step-rail__num,
.practice-card__tip {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow), inset 0 1px 0 var(--glass-highlight);
}

.cursor-glow {
  position: fixed;
  width: 480px;
  height: 480px;
  margin: -240px 0 0 -240px;
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.12) 0%, rgba(37, 99, 235, 0.06) 35%, transparent 70%);
  opacity: 0;
  transition: opacity 0.5s ease;
  will-change: transform;
}

@media (hover: hover) and (pointer: fine) {
  body.is-interactive .cursor-glow {
    opacity: 1;
  }
}

@keyframes auroraDrift1 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(8vw, 6vh) scale(1.12); }
}

@keyframes auroraDrift2 {
  0% { transform: translate(0, 0) scale(1.05); }
  100% { transform: translate(-6vw, -5vh) scale(0.92); }
}

@keyframes auroraDrift3 {
  0% { transform: translate(0, 0) scale(0.95); }
  100% { transform: translate(5vw, -4vh) scale(1.08); }
}

@keyframes meshShift {
  0% { filter: hue-rotate(0deg) brightness(1); transform: scale(1); }
  100% { filter: hue-rotate(18deg) brightness(1.05); transform: scale(1.03); }
}

/* ── Ticker marquee ── */
.ticker {
  position: relative;
  z-index: 1;
  margin-top: calc(var(--nav-h) + 12px);
  overflow: hidden;
  background: linear-gradient(90deg, var(--primary), var(--cyan));
  padding: 0.45rem 0;
}

.ticker__track {
  display: flex;
  width: max-content;
  animation: ticker 25s linear infinite;
}

.ticker__track span {
  flex-shrink: 0;
  padding-right: 2rem;
  font-family: var(--font-head);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  color: rgba(255, 255, 255, 0.9);
  white-space: nowrap;
}

@keyframes ticker {
  to { transform: translateX(-50%); }
}

/* ── Floating nav — glassmorphism ── */
.nav {
  position: fixed;
  top: 12px;
  left: clamp(12px, 2vw, 24px);
  right: clamp(12px, 2vw, 24px);
  z-index: 100;
  height: 56px;
  width: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(1rem, 3vw, 2rem);
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: 999px;
  box-shadow: var(--glass-shadow), inset 0 1px 0 var(--glass-highlight);
  transition: background 0.35s var(--ease-soft), box-shadow 0.35s var(--ease-soft), border-color 0.35s var(--ease-soft), transform 0.3s var(--ease);
}

.nav.scrolled {
  background: var(--glass-bg-strong);
  border-color: rgba(255, 255, 255, 0.58);
  box-shadow: var(--glass-shadow-lg), inset 0 1px 0 rgba(255, 255, 255, 0.85);
  transform: translateY(-2px);
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.06em;
  color: var(--primary);
  cursor: pointer;
}

.nav__logo-img {
  width: 28px;
  height: 28px;
  object-fit: contain;
  flex-shrink: 0;
}

.nav__logo-icon { color: var(--cyan); }

.nav__links {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  background: transparent;
  border: none;
  box-shadow: none;
}

.nav__links a {
  font-family: var(--font-head);
  font-size: clamp(0.76rem, 1vw, 0.84rem);
  font-weight: 600;
  letter-spacing: 0.045em;
  color: #475569;
  position: relative;
  cursor: pointer;
  padding: 0.42rem 0.82rem;
  border-radius: 999px;
  white-space: nowrap;
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.45);
  transition:
    color 0.22s var(--ease-soft),
    background 0.22s var(--ease-soft),
    box-shadow 0.22s var(--ease-soft);
}

.nav__links a::after {
  content: "";
  position: absolute;
  bottom: 0.28rem;
  left: 50%;
  width: 0;
  height: 1.5px;
  background: linear-gradient(90deg, var(--cyan), var(--primary));
  transition: width 0.28s var(--ease), left 0.28s var(--ease);
  border-radius: 2px;
  opacity: 0.9;
}

.nav__links a:hover {
  color: #1d4ed8;
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.14), rgba(37, 99, 235, 0.1));
  box-shadow: inset 0 0 0 1px rgba(37, 99, 235, 0.14);
}

.nav__links a:hover::after {
  width: calc(100% - 1.4rem);
  left: 0.7rem;
}

.nav__links a:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
  color: var(--primary);
}

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav__toggle span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text);
  transition: transform 0.3s;
  border-radius: 2px;
}

.nav__toggle[aria-expanded="true"] span:first-child {
  transform: translateY(7px) rotate(45deg);
}
.nav__toggle[aria-expanded="true"] span:last-child {
  transform: translateY(-7px) rotate(-45deg);
}

.nav__backdrop {
  display: none;
}

/* ── Main ── */
main { position: relative; z-index: 1; background: transparent; }

.section {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: clamp(4rem, 10vw, 6rem) clamp(1.25rem, 4vw, 2rem);
}

main > .section:last-of-type {
  padding-bottom: clamp(2rem, 5vw, 3rem);
}

.section--alt {
  background: transparent;
  max-width: none;
}

.section--alt > * {
  max-width: var(--max-w);
  margin-left: auto;
  margin-right: auto;
}

.section__head { margin-bottom: 2.5rem; }

.section__tag {
  display: inline-block;
  font-family: var(--font-head);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--cyan);
  margin-bottom: 0.6rem;
}

.section__head h2 {
  font-family: var(--font-head);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.4rem;
}

.section__head p {
  color: var(--text-muted);
  max-width: 520px;
}

/* ── Hero ── */
.hero {
  min-height: calc(100vh - var(--nav-h));
  display: flex;
  flex-direction: column;
  gap: clamp(1.5rem, 3vw, 2.5rem);
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 1.5rem clamp(1.25rem, 4vw, 2rem) 3.5rem;
  position: relative;
}

.hero__masthead {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  align-items: center;
  gap: clamp(1rem, 3vw, 2rem);
}

.hero__board {
  position: relative;
}

.hero__board-panel {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  padding: 1.25rem 1.5rem 1.5rem;
  border-radius: 20px;
  position: relative;
  overflow: hidden;
}

.hero__board-panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.04), transparent 40%, rgba(139, 92, 246, 0.04));
  pointer-events: none;
}

.hero__intro {
  position: relative;
  z-index: 1;
}

.hero__orbs { display: none; }

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border-radius: 999px;
  font-family: var(--font-head);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--primary);
  margin-bottom: 1.25rem;
  animation: fadeUp 0.7s var(--ease) both;
}

.hero__badge-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--cyan);
  animation: pulse 2s ease-in-out infinite;
  box-shadow: 0 0 8px var(--cyan);
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(0.85); }
}

.hero__title {
  font-family: var(--font-head);
  font-size: clamp(2rem, 5.5vw, 3.2rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
}

.hero__title-line {
  display: block;
  animation: fadeUp 0.7s var(--ease) both;
}
.hero__title-line:nth-child(2) { animation-delay: 0.08s; }

.hero__title-line--gradient {
  position: relative;
  background: linear-gradient(135deg, var(--primary) 0%, var(--cyan) 40%, var(--violet) 70%, var(--accent) 100%);
  background-size: 300% auto;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: fadeUp 0.7s var(--ease) 0.08s both, gradientFlow 5s ease infinite;
  filter: drop-shadow(0 0 30px rgba(6, 182, 212, 0.15));
}

@keyframes gradientFlow {
  0%, 100% { background-position: 0% center; }
  50% { background-position: 100% center; }
}

.hero__desc {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  max-width: 540px;
  animation: fadeUp 0.7s var(--ease) 0.16s both;
}

.hero__flow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 0.15rem;
}

.flow-chip {
  font-family: var(--font-head);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.4rem 0.85rem;
  border-radius: 999px;
  color: var(--text-muted);
  cursor: pointer;
  transition: color 0.45s var(--ease-soft), border-color 0.45s var(--ease-soft), box-shadow 0.45s var(--ease-soft), transform 0.35s var(--ease-soft);
  position: relative;
  overflow: hidden;
  isolation: isolate;
}

.flow-chip::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, var(--primary), var(--cyan));
  opacity: 0;
  transform: scale(0.92);
  transition: opacity 0.45s var(--ease-soft), transform 0.5s var(--ease-out);
  z-index: -1;
}

.flow-chip:hover {
  color: var(--primary);
  border-color: rgba(37, 99, 235, 0.3);
  transform: translateY(-2px);
}

.flow-chip.active {
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.28);
}

.flow-chip.active::before {
  opacity: 1;
  transform: scale(1);
}

.flow-chip.active:hover {
  color: #fff;
}

.flow-chip.active + .flow-connector {
  opacity: 0.85;
  transform: scaleX(1.15);
}

.flow-chip:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.flow-connector {
  display: inline-block;
  width: 18px;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--primary));
  border-radius: 2px;
  opacity: 0.45;
  position: relative;
  overflow: hidden;
  transform: scaleX(1);
  transform-origin: left center;
  transition: opacity 0.5s var(--ease-soft), transform 0.5s var(--ease-out);
}

.flow-connector::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.9), transparent);
  animation: connectorSweep 2s ease-in-out infinite;
}

@keyframes connectorSweep {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.hero__desc-note {
  font-size: clamp(0.88rem, 2vw, 0.95rem);
  color: var(--text-muted);
  line-height: 1.65;
}

.hero__highlight {
  font-weight: 600;
  background: linear-gradient(135deg, var(--primary), var(--cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Step rail — horizontal segmented navigator */
.step-rail {
  position: relative;
  width: 100%;
  padding: 0 0.25rem;
  z-index: 1;
}

.step-rail__track {
  position: absolute;
  top: 18px;
  left: 10%;
  right: 10%;
  height: 3px;
  border-radius: 3px;
  background: rgba(37, 99, 235, 0.1);
  overflow: hidden;
}

.step-rail__fill {
  height: 100%;
  width: 0%;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--cyan), var(--primary), var(--violet), rgba(139, 92, 246, 0.45));
  transition: width 0.9s var(--ease-out);
  box-shadow: 0 0 14px rgba(6, 182, 212, 0.3);
  position: relative;
  -webkit-mask-image: linear-gradient(90deg, #000 0%, #000 72%, transparent 100%);
  mask-image: linear-gradient(90deg, #000 0%, #000 72%, transparent 100%);
}

.step-rail__fill::after {
  content: "";
  position: absolute;
  right: 0;
  top: 50%;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 12px var(--cyan), 0 0 20px rgba(6, 182, 212, 0.5);
  transform: translate(50%, -50%);
  opacity: 0.9;
  transition: opacity 0.4s var(--ease-soft);
}

.step-rail__items {
  display: flex;
  justify-content: space-between;
  position: relative;
  z-index: 1;
}

.step-rail__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
  flex: 1;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.2rem 0.1rem;
  transition: transform 0.25s var(--ease);
}

.step-rail__item:hover { transform: translateY(-2px); }

.step-rail__item:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 8px;
}

.step-rail__num {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-head);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-muted);
  border: 2px solid var(--glass-border);
  border-radius: 50%;
  transition: background 0.55s var(--ease-soft), border-color 0.55s var(--ease-soft), color 0.45s var(--ease-soft), transform 0.55s var(--ease-out), box-shadow 0.55s var(--ease-soft);
}

.step-rail__name {
  font-family: var(--font-head);
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  transition: color 0.45s var(--ease-soft), opacity 0.45s var(--ease-soft), font-weight 0.3s;
  white-space: nowrap;
}

.step-rail__item.done .step-rail__num {
  background: color-mix(in srgb, var(--primary) 88%, white);
  border-color: transparent;
  color: #fff;
  box-shadow: 0 2px 10px rgba(37, 99, 235, 0.2);
}

.step-rail__item.done .step-rail__name {
  color: var(--primary);
  opacity: 0.75;
}

.step-rail__item.active .step-rail__num {
  background: linear-gradient(135deg, var(--primary), var(--cyan));
  border-color: transparent;
  color: #fff;
  transform: scale(1.1);
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.35);
}

.step-rail__item.active .step-rail__name {
  color: var(--primary);
  font-weight: 700;
}

.hero__board-body {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
  gap: 1rem;
  align-items: stretch;
  position: relative;
  z-index: 1;
}

.hero__steps {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  min-width: 0;
}

.algo-step {
  display: grid;
  grid-template-columns: 48px 1fr;
  align-items: center;
  gap: 0 0.75rem;
  padding: 0.75rem 0.9rem 0.75rem 0.8rem;
  border-radius: 16px;
  transition: box-shadow 0.55s var(--ease-soft), border-color 0.5s var(--ease-soft), background 0.5s var(--ease-soft), opacity 0.45s var(--ease-soft);
  animation: fadeUp 0.6s var(--ease) both;
  animation-delay: calc(0.3s + var(--i, 0) * 0.08s);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  outline: none;
}

.algo-step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12%;
  bottom: 12%;
  width: 3px;
  border-radius: 0 4px 4px 0;
  background: linear-gradient(180deg, var(--step-accent, var(--primary)), color-mix(in srgb, var(--step-accent, var(--primary)) 30%, transparent));
  transform: scaleY(0);
  transform-origin: center top;
  opacity: 0;
  transition: transform 0.6s var(--ease-out), opacity 0.45s var(--ease-soft);
}

.algo-step:not(.active) {
  opacity: 0.82;
}

.algo-step:hover,
.algo-step:focus-visible {
  opacity: 1;
  border-color: rgba(37, 99, 235, 0.2);
  box-shadow: 0 10px 32px rgba(37, 99, 235, 0.1);
}

.algo-step.active {
  opacity: 1;
  background: var(--glass-bg-strong);
  border-color: color-mix(in srgb, var(--step-accent, var(--primary)) 35%, var(--glass-border));
  box-shadow:
    0 14px 44px color-mix(in srgb, var(--step-accent, var(--primary)) 14%, transparent),
    0 0 0 1px color-mix(in srgb, var(--step-accent, var(--primary)) 8%, transparent);
}

.algo-step.active::before {
  transform: scaleY(1);
  opacity: 1;
}

.algo-step__accent {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--step-accent, var(--primary)), transparent 85%);
  opacity: 0;
  transition: opacity 0.55s var(--ease-soft);
}

.algo-step.active .algo-step__accent { opacity: 1; }

.algo-step__icon {
  grid-column: 1;
  grid-row: 1;
  width: 36px;
  height: 36px;
  justify-self: center;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  background: color-mix(in srgb, var(--step-accent, var(--primary)) 10%, transparent);
  color: var(--step-accent, var(--primary));
  flex-shrink: 0;
  position: relative;
  z-index: 1;
  transition: background 0.5s var(--ease-soft), transform 0.5s var(--ease-out);
}

.algo-step.active .algo-step__icon {
  background: color-mix(in srgb, var(--step-accent, var(--primary)) 18%, transparent);
  transform: scale(1.05);
}

.algo-step__num {
  grid-column: 1;
  grid-row: 2;
  justify-self: center;
  margin-top: 0.35rem;
  flex-shrink: 0;
  width: 28px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-head);
  font-size: 0.68rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--step-accent, var(--primary)), color-mix(in srgb, var(--step-accent, var(--cyan)) 60%, white));
  border-radius: 9px;
  box-shadow: 0 2px 10px color-mix(in srgb, var(--step-accent, var(--primary)) 35%, transparent);
  position: relative;
  z-index: 1;
}

.algo-step__body {
  grid-column: 2;
  grid-row: 1 / -1;
  align-self: center;
  min-width: 0;
  position: relative;
  z-index: 1;
}

.algo-step__head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 0.35rem;
}

.algo-step__title {
  font-family: var(--font-head);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.01em;
}

.algo-step__tag {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  color: var(--step-accent, var(--primary));
  background: color-mix(in srgb, var(--step-accent, var(--primary)) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--step-accent, var(--primary)) 18%, transparent);
}

.algo-step__desc {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* 右侧详情区 — 固定槽位，层级排版 + 装饰动效 */
.hero__step-detail {
  position: relative;
  z-index: 1;
  min-height: 100%;
  padding: 0;
  border-radius: 14px;
  overflow: hidden;
  --detail-accent: var(--cyan);
}

.hero__step-detail::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--detail-accent), color-mix(in srgb, var(--detail-accent) 25%, transparent) 55%, transparent);
  z-index: 2;
  transition: background 0.55s var(--ease-soft);
}

.hero__step-detail__pane {
  position: absolute;
  inset: 0;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.35s var(--ease-soft), visibility 0.35s var(--ease-soft);
}

.hero__step-detail__pane.active {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.hero__step-detail__ambient {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.hero__step-detail__orb {
  position: absolute;
  top: -18%;
  right: -8%;
  width: 58%;
  height: 72%;
  border-radius: 50%;
  background: radial-gradient(circle, color-mix(in srgb, var(--step-accent, var(--cyan)) 22%, transparent) 0%, transparent 68%);
  animation: detailOrbPulse 5s var(--ease-soft) infinite;
}

.hero__step-detail__watermark {
  position: absolute;
  right: 6%;
  bottom: 8%;
  width: clamp(7rem, 32%, 11rem);
  height: clamp(7rem, 32%, 11rem);
  color: var(--step-accent, var(--cyan));
  opacity: 0.1;
  animation: detailWatermarkFloat 7s var(--ease-soft) infinite;
}

.hero__step-detail__watermark svg {
  width: 100%;
  height: 100%;
}

.hero__step-detail__inner {
  position: relative;
  z-index: 1;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1.1rem;
  padding: 1.5rem 1.75rem;
  max-width: 92%;
}

.hero__step-detail__pane.active .hero__step-detail__inner {
  animation: detailInnerIn 0.55s var(--ease-out) both;
}

.hero__step-detail__meta {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin-bottom: 0.75rem;
}

.hero__step-detail__badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.1rem;
  height: 1.65rem;
  padding: 0 0.45rem;
  font-family: var(--font-head);
  font-size: 0.72rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--step-accent, var(--primary)), color-mix(in srgb, var(--step-accent, var(--cyan)) 55%, white));
  border-radius: 8px;
  box-shadow: 0 3px 14px color-mix(in srgb, var(--step-accent, var(--primary)) 32%, transparent);
}

.hero__step-detail__tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--step-accent, var(--primary));
  padding: 0.2rem 0.55rem;
  border-radius: 5px;
  background: color-mix(in srgb, var(--step-accent, var(--primary)) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--step-accent, var(--primary)) 20%, transparent);
}

.hero__step-detail__en {
  font-family: var(--font-mono);
  font-size: clamp(0.88rem, 1.6vw, 1.05rem);
  font-weight: 500;
  color: var(--step-accent, var(--cyan));
  letter-spacing: 0.02em;
  margin-bottom: 0.35rem;
}

.hero__step-detail__title {
  font-family: var(--font-head);
  font-size: clamp(1.15rem, 2.2vw, 1.45rem);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 0.45rem;
}

.hero__step-detail__lead {
  font-size: clamp(0.82rem, 1.4vw, 0.92rem);
  color: var(--text-muted);
  line-height: 1.65;
  max-width: 36ch;
}

.hero__step-detail__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  padding-top: 0.15rem;
  border-top: 1px solid color-mix(in srgb, var(--step-accent, var(--primary)) 14%, var(--glass-border));
}

.hero__step-detail__list li {
  font-size: clamp(0.84rem, 1.35vw, 0.94rem);
  color: var(--text);
  line-height: 1.65;
  padding: 0.45rem 0.65rem 0.45rem 1.35rem;
  position: relative;
  border-radius: 8px;
  background: color-mix(in srgb, var(--step-accent, var(--primary)) 5%, transparent);
  border: 1px solid color-mix(in srgb, var(--step-accent, var(--primary)) 10%, transparent);
}

.hero__step-detail__pane.active .hero__step-detail__list li {
  animation: detailListIn 0.5s var(--ease-out) both;
}

.hero__step-detail__pane.active .hero__step-detail__list li:nth-child(1) { animation-delay: 0.1s; }
.hero__step-detail__pane.active .hero__step-detail__list li:nth-child(2) { animation-delay: 0.18s; }
.hero__step-detail__pane.active .hero__step-detail__list li:nth-child(3) { animation-delay: 0.26s; }

.hero__step-detail__list li::before {
  content: "";
  position: absolute;
  left: 0.55rem;
  top: 0.72em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--step-accent, var(--primary));
  box-shadow: 0 0 8px color-mix(in srgb, var(--step-accent, var(--primary)) 45%, transparent);
}

@keyframes detailInnerIn {
  from { opacity: 0; transform: translateX(10px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes detailListIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes detailOrbPulse {
  0%, 100% { transform: scale(1); opacity: 0.85; }
  50% { transform: scale(1.06); opacity: 1; }
}

@keyframes detailWatermarkFloat {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-6px) rotate(-2deg); }
}

.algo-step__en {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--step-accent, var(--cyan));
  letter-spacing: 0.03em;
  margin-bottom: 0.35rem;
  opacity: 0.85;
}

.algo-step__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.algo-step__list li {
  font-size: 0.74rem;
  color: var(--text-muted);
  line-height: 1.5;
  padding-left: 0.85rem;
  position: relative;
}

.algo-step__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--step-accent, var(--primary));
  opacity: 0.6;
}

.algo-step__hud {
  position: absolute;
  inset: 7px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.55s var(--ease-soft);
}

.algo-step__hud::before,
.algo-step__hud::after {
  content: "";
  position: absolute;
  width: 12px;
  height: 12px;
  border: 1.5px solid var(--step-accent, var(--primary));
  opacity: 0.5;
}

.algo-step__hud::before {
  top: 0;
  left: 0;
  border-right: none;
  border-bottom: none;
}

.algo-step__hud::after {
  bottom: 0;
  right: 0;
  border-left: none;
  border-top: none;
}

.algo-step.active .algo-step__hud { opacity: 1; }

.algo-step__shine {
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(transparent 42%, rgba(255, 255, 255, 0.45) 50%, transparent 58%);
  transform: translateX(-100%) rotate(20deg);
  pointer-events: none;
}

.algo-step.active .algo-step__shine {
  animation: stepShine 4s ease-in-out infinite;
}

@keyframes stepShine {
  0%, 80%, 100% { transform: translateX(-100%) rotate(20deg); }
  40% { transform: translateX(100%) rotate(20deg); }
}

.algo-step:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.hero__pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 2rem;
  animation: fadeUp 0.7s var(--ease) 0.24s both;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: default;
  transition: border-color 0.25s, color 0.25s, box-shadow 0.25s, transform 0.25s var(--ease);
}

.pill--a svg { color: #DC2626; }
.pill--b svg { color: #76B900; }

.hero__stats .stat__num::after { content: none; }

.pill svg { color: var(--primary); flex-shrink: 0; }

/* ── Quote cards ── */
.quote-card {
  position: relative;
  padding: 1.75rem 1.75rem 1.5rem;
  border-radius: var(--radius);
  overflow: hidden;
  cursor: default;
  transition: transform 0.3s var(--ease), box-shadow 0.35s var(--ease-soft), border-color 0.3s;
}

.quote-card::after {
  content: "";
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: linear-gradient(
    transparent 42%,
    rgba(255, 255, 255, 0.5) 50%,
    transparent 58%
  );
  transform: translateX(-100%) rotate(25deg);
  transition: transform 0.7s var(--ease);
  pointer-events: none;
}

.quote-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--card-accent, var(--primary)), transparent);
  opacity: 0;
  transition: opacity 0.3s;
}

.quote-card--a { --card-accent: #DC2626; }
.quote-card--b { --card-accent: #76B900; }

.quote-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--glass-shadow-lg), inset 0 1px 0 var(--glass-highlight);
  border-color: rgba(255, 255, 255, 0.55);
}

.quote-card:hover::before { opacity: 1; box-shadow: 0 0 16px var(--card-accent); }
.quote-card:hover::after { transform: translateX(100%) rotate(25deg); }

.quote-card__mark {
  position: absolute;
  top: 0.5rem; right: 1rem;
  font-family: Georgia, serif;
  font-size: 4rem;
  line-height: 1;
  color: var(--card-accent, var(--primary));
  opacity: 0.08;
  pointer-events: none;
}

.quote-card > p {
  font-size: 1.05rem;
  font-weight: 500;
  line-height: 1.75;
  color: var(--text);
  margin-bottom: 1.25rem;
  position: relative;
  z-index: 1;
}

.quote-card footer {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.quote-card__en {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.5;
  font-style: italic;
}

.pill:hover {
  border-color: var(--border-glow);
  color: var(--primary);
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.1);
  transform: translateY(-2px);
}

.hero__actions {
  display: flex;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
  animation: fadeUp 0.7s var(--ease) 0.32s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.8rem 1.75rem;
  border-radius: 999px;
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.25s var(--ease), box-shadow 0.25s;
}

.btn--primary {
  color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--cyan));
  background-size: 200% auto;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3);
  animation: gradientFlow 4s ease infinite;
}

.btn--primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(37, 99, 235, 0.35);
}

.btn--primary svg {
  animation: bounceDown 1.5s ease-in-out infinite;
}

@keyframes bounceDown {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(3px); }
}

.hero__stats {
  display: flex;
  gap: 1.5rem;
}

.stat { text-align: center; }

.stat__num {
  display: block;
  font-family: var(--font-head);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--primary);
  line-height: 1.2;
}

.stat__label {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

/* ── Hero visual: algo stage (5 unique scenes) ── */
.hero__visual {
  display: flex;
  align-items: center;
  justify-content: center;
  perspective: 900px;
  position: relative;
}

.hero__visual::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 70% at 50% 50%, rgba(6, 182, 212, 0.08), transparent 70%);
  pointer-events: none;
  transition: background 0.9s var(--ease-soft), opacity 0.6s var(--ease-soft);
}

.hero__visual:has(.algo-stage[data-active-step="1"])::before {
  background: radial-gradient(ellipse 80% 70% at 50% 50%, rgba(37, 99, 235, 0.1), transparent 70%);
}
.hero__visual:has(.algo-stage[data-active-step="2"])::before {
  background: radial-gradient(ellipse 80% 70% at 50% 50%, rgba(79, 70, 229, 0.1), transparent 70%);
}
.hero__visual:has(.algo-stage[data-active-step="3"])::before {
  background: radial-gradient(ellipse 80% 70% at 50% 50%, rgba(59, 130, 246, 0.12), transparent 70%);
}
.hero__visual:has(.algo-stage[data-active-step="4"])::before {
  background: radial-gradient(ellipse 80% 70% at 50% 50%, rgba(139, 92, 246, 0.12), transparent 70%);
}

.algo-stage {
  width: min(300px, 78vw);
  height: min(360px, 88vw);
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s var(--ease);
}

.algo-scene {
  position: absolute;
  inset: 0;
  opacity: 0;
  transform: scale(0.96) translateY(10px);
  filter: blur(5px);
  pointer-events: none;
  transition:
    opacity 0.55s var(--ease-soft),
    transform 0.6s var(--ease-out),
    filter 0.5s var(--ease-soft);
  transition-delay: 0s;
}

.algo-scene.active {
  opacity: 1;
  transform: scale(1) translateY(0);
  filter: blur(0);
  pointer-events: auto;
  z-index: 1;
  transition-delay: 0.14s;
}

.algo-scene.is-leaving {
  opacity: 0;
  transform: scale(1.02) translateY(-8px);
  filter: blur(4px);
  z-index: 2;
  transition-delay: 0s;
}

.scene-card {
  width: 100%;
  height: 100%;
  border-radius: 22px;
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: box-shadow 0.6s var(--ease-soft), border-color 0.6s var(--ease-soft);
}

.scene-body {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  text-align: center;
}

.scene-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  margin-bottom: 0.35rem;
}

.scene-num {
  font-family: var(--font-head);
  font-size: clamp(3rem, 9vw, 3.8rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
}

.scene-word {
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: 0.18em;
}

.scene-en {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  opacity: 0.7;
}

/* ── Scene 01: Question — brain thinking ── */
.scene-card--cyan {
  border-color: rgba(6, 182, 212, 0.28);
  box-shadow: 0 20px 50px rgba(6, 182, 212, 0.12), inset 0 1px 0 var(--glass-highlight);
}

.scene-brain {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  pointer-events: none;
  z-index: 1;
}

.scene-brain__svg {
  width: 78%;
  max-width: 220px;
  opacity: 0.85;
  transform: translateY(6%);
}

.scene-brain__glow {
  position: absolute;
  width: 140px;
  height: 140px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.18), transparent 70%);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -48%);
}

.algo-scene--question.active .scene-brain__glow {
  animation: brainGlow 3s ease-in-out infinite;
}

.scene-brain__thought {
  position: absolute;
  font-family: var(--font-head);
  font-size: 0.85rem;
  font-weight: 700;
  color: rgba(6, 182, 212, 0.35);
  border: 1.5px solid rgba(6, 182, 212, 0.25);
  border-radius: 50%;
  width: 22px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
}

.scene-brain__thought--1 { top: 14%; right: 18%; }
.scene-brain__thought--2 { top: 22%; left: 16%; font-size: 0.7rem; width: 18px; height: 18px; }

.algo-scene--question.active .scene-brain__thought--1 {
  animation: thoughtFloat 4s ease-in-out infinite;
}

.algo-scene--question.active .scene-brain__thought--2 {
  animation: thoughtFloat 4s ease-in-out infinite 1.8s;
}

.algo-scene--question.active .scene-brain__node {
  animation: nodeFire 2.4s ease-in-out infinite;
}

.algo-scene--question.active .scene-brain__node:nth-of-type(2) { animation-delay: 0.3s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(3) { animation-delay: 0.6s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(4) { animation-delay: 0.9s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(5) { animation-delay: 0.15s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(6) { animation-delay: 0.45s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(7) { animation-delay: 0.75s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(8) { animation-delay: 1.05s; }
.algo-scene--question.active .scene-brain__node:nth-of-type(9) { animation-delay: 1.35s; }

.algo-scene--question.active .scene-brain__spark {
  animation: sparkTravel 2.8s linear infinite;
}

.algo-scene--question.active .scene-brain__spark:nth-of-type(2) {
  animation-name: sparkTravelCenter;
  animation-delay: 0.9s;
}

.algo-scene--question.active .scene-brain__spark:nth-of-type(3) {
  animation-name: sparkTravelRight;
  animation-delay: 1.6s;
}

.algo-scene--question.active .scene-brain__link {
  stroke-dasharray: 40;
  animation: linkPulse 2.4s ease-in-out infinite;
}

.algo-scene--question.active .scene-brain__link:nth-of-type(2) { animation-delay: 0.2s; }
.algo-scene--question.active .scene-brain__link:nth-of-type(3) { animation-delay: 0.4s; }
.algo-scene--question.active .scene-brain__link:nth-of-type(4) { animation-delay: 0.6s; }
.algo-scene--question.active .scene-brain__link:nth-of-type(5) { animation-delay: 0.8s; }

.algo-scene--question.active .scene-brain__fold {
  animation: foldShimmer 3.5s ease-in-out infinite;
}

.algo-scene--question.active .scene-brain__fold:nth-of-type(2) { animation-delay: 0.4s; }
.algo-scene--question.active .scene-brain__fold:nth-of-type(3) { animation-delay: 0.8s; }
.algo-scene--question.active .scene-brain__fold:nth-of-type(4) { animation-delay: 1.2s; }

@keyframes brainGlow {
  0%, 100% { opacity: 0.5; transform: translate(-50%, -48%) scale(0.95); }
  50% { opacity: 1; transform: translate(-50%, -48%) scale(1.08); }
}

@keyframes thoughtFloat {
  0%, 100% { opacity: 0; transform: translateY(6px) scale(0.85); }
  30%, 70% { opacity: 0.7; transform: translateY(-4px) scale(1); }
}

@keyframes nodeFire {
  0%, 100% { opacity: 0.35; filter: drop-shadow(0 0 0 transparent); }
  50% { opacity: 1; filter: drop-shadow(0 0 6px rgba(6, 182, 212, 0.7)); }
}

@keyframes linkPulse {
  0%, 100% { stroke-dashoffset: 40; opacity: 0.3; }
  50% { stroke-dashoffset: 0; opacity: 0.8; }
}

@keyframes foldShimmer {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

.scene-brain__spark {
  transform-box: fill-box;
  transform-origin: center;
}

@keyframes sparkTravel {
  0% { transform: translate(0, 0); opacity: 0; }
  15% { opacity: 1; }
  50% { transform: translate(32px, -14px); opacity: 1; }
  85% { opacity: 0; }
  100% { transform: translate(64px, 0); opacity: 0; }
}

@keyframes sparkTravelCenter {
  0% { transform: translate(0, 0); opacity: 0; }
  15% { opacity: 1; }
  50% { transform: translate(40px, -8px); opacity: 1; }
  85% { opacity: 0; }
  100% { transform: translate(80px, 0); opacity: 0; }
}

@keyframes sparkTravelRight {
  0% { transform: translate(0, 0); opacity: 0; }
  15% { opacity: 1; }
  50% { transform: translate(0, 32px); opacity: 1; }
  85% { opacity: 0; }
  100% { transform: translate(0, 80px); opacity: 0; }
}

.scene-card--cyan .scene-icon {
  background: rgba(6, 182, 212, 0.12);
  color: #06B6D4;
}

.scene-card--cyan .scene-num {
  background: linear-gradient(180deg, #2563EB, #06B6D4);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.scene-card--cyan .scene-en { color: #06B6D4; }

.scene-ripple {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
}

.scene-ripple__ring {
  position: absolute;
  width: 50px;
  height: 50px;
  border: 2px solid rgba(6, 182, 212, 0.45);
  border-radius: 50%;
  opacity: 0;
}

.algo-scene--question.active .scene-ripple__ring {
  animation: rippleOut 3.5s ease-out infinite;
}

.algo-scene--question.active .scene-ripple__ring:nth-child(2) { animation-delay: 1.15s; }
.algo-scene--question.active .scene-ripple__ring:nth-child(3) { animation-delay: 2.3s; }

.algo-scene--question.active .scene-icon--pulse {
  animation: iconPulse 2s ease-in-out infinite;
}

@keyframes rippleOut {
  0% { transform: scale(0.4); opacity: 0.9; }
  100% { transform: scale(5); opacity: 0; }
}

@keyframes iconPulse {
  0%, 100% { transform: scale(1); box-shadow: 0 0 0 rgba(6, 182, 212, 0); }
  50% { transform: scale(1.06); box-shadow: 0 0 20px rgba(6, 182, 212, 0.35); }
}

/* ── Scene 02: Delete — dissolve ── */
.scene-card--blue {
  border-color: rgba(37, 99, 235, 0.28);
  box-shadow: 0 20px 50px rgba(37, 99, 235, 0.1), inset 0 1px 0 var(--glass-highlight);
}

.scene-card--blue .scene-icon {
  background: rgba(239, 68, 68, 0.08);
  color: #EF4444;
}

.scene-card--blue .scene-num {
  color: #2563EB;
  opacity: 0.35;
  text-decoration: line-through;
  text-decoration-color: #EF4444;
  text-decoration-thickness: 3px;
}

.scene-card--blue .scene-word { color: var(--text); }
.scene-card--blue .scene-en { color: #2563EB; }

.scene-dissolve {
  position: absolute;
  inset: 0;
}

.scene-dissolve__block {
  position: absolute;
  width: 28px;
  height: 28px;
  border-radius: 6px;
  background: rgba(37, 99, 235, 0.12);
  border: 1px solid rgba(37, 99, 235, 0.15);
}

.scene-dissolve__block:nth-child(1) { top: 18%; left: 15%; }
.scene-dissolve__block:nth-child(2) { top: 22%; right: 18%; }
.scene-dissolve__block:nth-child(3) { bottom: 28%; left: 20%; }
.scene-dissolve__block:nth-child(4) { bottom: 22%; right: 14%; }

.algo-scene--delete.active .scene-dissolve__block {
  animation: dissolveFade 2.8s ease-in-out infinite;
}

.algo-scene--delete.active .scene-dissolve__block:nth-child(2) { animation-delay: 0.4s; }
.algo-scene--delete.active .scene-dissolve__block:nth-child(3) { animation-delay: 0.8s; }
.algo-scene--delete.active .scene-dissolve__block:nth-child(4) { animation-delay: 1.2s; }

.scene-dissolve__slash {
  position: absolute;
  top: 50%;
  left: -10%;
  width: 120%;
  height: 2px;
  background: linear-gradient(90deg, transparent, #EF4444, transparent);
  transform: rotate(-32deg);
  opacity: 0;
}

.algo-scene--delete.active .scene-dissolve__slash {
  animation: slashSweep 2.5s ease-in-out infinite;
}

@keyframes dissolveFade {
  0%, 70%, 100% { opacity: 1; transform: scale(1); }
  85% { opacity: 0; transform: scale(0.6) rotate(8deg); }
}

@keyframes slashSweep {
  0%, 100% { opacity: 0; transform: rotate(-32deg) scaleX(0.5); }
  50% { opacity: 0.85; transform: rotate(-32deg) scaleX(1); }
}

/* ── Scene 03: Simplify — layer merge ── */
.scene-card--indigo {
  border-color: rgba(79, 70, 229, 0.28);
  box-shadow: 0 20px 50px rgba(79, 70, 229, 0.1), inset 0 1px 0 var(--glass-highlight);
}

.scene-card--indigo .scene-icon {
  background: rgba(79, 70, 229, 0.1);
  color: #4F46E5;
}

.scene-card--indigo .scene-num {
  background: linear-gradient(135deg, #4F46E5, #818CF8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.scene-card--indigo .scene-en { color: #4F46E5; }

.scene-layers {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.scene-layers__layer {
  position: absolute;
  border-radius: 10px;
  border: 2px solid rgba(79, 70, 229, 0.25);
  background: rgba(79, 70, 229, 0.04);
}

.scene-layers__layer--3 { width: 72%; height: 58%; }
.scene-layers__layer--2 { width: 58%; height: 46%; }
.scene-layers__layer--1 { width: 44%; height: 34%; background: rgba(79, 70, 229, 0.08); }

.algo-scene--simplify.active .scene-layers__layer--3 {
  animation: layerFadeOuter 3s ease-in-out infinite;
}

.algo-scene--simplify.active .scene-layers__layer--2 {
  animation: layerFadeMid 3s ease-in-out infinite;
}

.algo-scene--simplify.active .scene-layers__layer--1 {
  animation: layerSolid 3s ease-in-out infinite;
}

@keyframes layerFadeOuter {
  0%, 100% { opacity: 0.5; transform: scale(1); }
  50% { opacity: 0; transform: scale(1.08); }
}

@keyframes layerFadeMid {
  0%, 100% { opacity: 0.7; transform: scale(1); }
  50% { opacity: 0.15; transform: scale(0.96); }
}

@keyframes layerSolid {
  0%, 100% { opacity: 0.8; transform: scale(1); box-shadow: none; }
  50% { opacity: 1; transform: scale(1.05); box-shadow: 0 0 30px rgba(79, 70, 229, 0.25); }
}

/* ── Scene 04: Accelerate — speed streaks ── */
.scene-card--speed {
  border-color: rgba(59, 130, 246, 0.3);
  box-shadow: 0 20px 50px rgba(59, 130, 246, 0.12), inset 0 1px 0 var(--glass-highlight);
}

.scene-card--speed .scene-num {
  background: linear-gradient(90deg, #1D4ED8, #3B82F6, #93C5FD, #3B82F6, #1D4ED8);
  background-size: 200% auto;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.scene-card--speed .scene-en { color: #3B82F6; }

.scene-body--speed { margin-top: 1rem; }

.scene-num--blur {
  position: relative;
}

.algo-scene--accelerate.active .scene-num--blur {
  animation: speedBlur 1.5s ease-in-out infinite, gradientFlow 2s linear infinite;
}

.scene-speed {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.scene-speed__line {
  position: absolute;
  left: -100%;
  width: 60%;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.6), transparent);
  opacity: 0;
}

.algo-scene--accelerate.active .scene-speed__line {
  animation: speedStreak 1.4s linear infinite;
}

.scene-speed__line:nth-child(1) { top: 22%; animation-delay: 0s; }
.scene-speed__line:nth-child(2) { top: 38%; animation-delay: 0.25s; height: 3px; }
.scene-speed__line:nth-child(3) { top: 55%; animation-delay: 0.5s; }
.scene-speed__line:nth-child(4) { top: 72%; animation-delay: 0.75s; height: 1px; }

.scene-speed__bolt {
  position: absolute;
  top: 12%;
  right: 14%;
  color: #3B82F6;
  opacity: 0.25;
}

.algo-scene--accelerate.active .scene-speed__bolt {
  animation: boltFlash 2s ease-in-out infinite;
}

@keyframes speedStreak {
  0% { left: -60%; opacity: 0; }
  20% { opacity: 1; }
  100% { left: 120%; opacity: 0; }
}

@keyframes speedBlur {
  0%, 100% { letter-spacing: -0.04em; filter: blur(0); }
  50% { letter-spacing: 0.02em; filter: blur(0.5px); }
}

@keyframes boltFlash {
  0%, 100% { opacity: 0.2; transform: scale(1); }
  50% { opacity: 0.7; transform: scale(1.15); }
}

/* ── Scene 05: Automate — circuit grid ── */
.scene-card--violet {
  border-color: rgba(139, 92, 246, 0.3);
  box-shadow: 0 20px 50px rgba(139, 92, 246, 0.12), inset 0 1px 0 var(--glass-highlight);
  background-image:
    linear-gradient(rgba(139, 92, 246, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(139, 92, 246, 0.04) 1px, transparent 1px);
  background-size: 16px 16px;
}

.scene-card--violet .scene-icon {
  background: rgba(139, 92, 246, 0.12);
  color: #8B5CF6;
}

.scene-card--violet .scene-num {
  background: linear-gradient(135deg, #7C3AED, #8B5CF6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.scene-card--violet .scene-en { color: #8B5CF6; }

.scene-circuit {
  position: absolute;
  inset: 15%;
}

.scene-circuit__node {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(139, 92, 246, 0.2);
  border: 2px solid rgba(139, 92, 246, 0.3);
}

.scene-circuit__node:nth-child(1) { top: 0; left: 0; }
.scene-circuit__node:nth-child(2) { top: 0; right: 0; }
.scene-circuit__node:nth-child(3) { bottom: 0; left: 0; }
.scene-circuit__node:nth-child(4) { bottom: 0; right: 0; }

.algo-scene--automate.active .scene-circuit__node {
  animation: nodeBlink 2s ease-in-out infinite;
}

.algo-scene--automate.active .scene-circuit__node:nth-child(2) { animation-delay: 0.5s; }
.algo-scene--automate.active .scene-circuit__node:nth-child(3) { animation-delay: 1s; }
.algo-scene--automate.active .scene-circuit__node:nth-child(4) { animation-delay: 1.5s; }

.scene-circuit__line {
  position: absolute;
  background: rgba(139, 92, 246, 0.2);
}

.scene-circuit__line--h {
  top: 4px;
  left: 10px;
  right: 10px;
  height: 2px;
}

.scene-circuit__line--v {
  left: 4px;
  top: 10px;
  bottom: 10px;
  width: 2px;
}

.scene-circuit__pulse {
  position: absolute;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #8B5CF6;
  top: 50%;
  left: 0;
  margin-top: -4px;
  opacity: 0;
  box-shadow: 0 0 12px #8B5CF6;
}

.algo-scene--automate.active .scene-circuit__pulse {
  animation: circuitPulse 2.5s linear infinite;
}

@keyframes nodeBlink {
  0%, 100% { background: rgba(139, 92, 246, 0.2); box-shadow: none; }
  50% { background: #8B5CF6; box-shadow: 0 0 14px rgba(139, 92, 246, 0.6); }
}

@keyframes circuitPulse {
  0% { left: 0; opacity: 0; }
  10% { opacity: 1; }
  45% { left: calc(100% - 8px); opacity: 1; }
  55% { top: 50%; left: calc(100% - 8px); opacity: 1; }
  90% { top: calc(100% - 8px); left: calc(100% - 8px); opacity: 1; }
  100% { top: calc(100% - 8px); left: calc(100% - 8px); opacity: 0; }
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── Tech cards ── */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.card-grid--2 {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.tech-card {
  position: relative;
  padding: 1.75rem;
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.3s var(--ease), box-shadow 0.3s, border-color 0.3s;
}

.tech-card::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: calc(var(--radius) + 1px);
  background: linear-gradient(135deg, var(--cyan), var(--primary), var(--cyan));
  background-size: 300% 300%;
  z-index: -1;
  opacity: 0;
  transition: opacity 0.4s;
  animation: gradientFlow 6s ease infinite;
}

.tech-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.tech-card:hover::before { opacity: 1; }

.tech-card__icon {
  width: 48px; height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.08), rgba(6, 182, 212, 0.08));
  color: var(--primary);
  margin-bottom: 1rem;
  transition: transform 0.3s var(--ease);
}

.tech-card:hover .tech-card__icon { transform: scale(1.1) rotate(-5deg); }

.tech-card h3 {
  font-family: var(--font-head);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.tech-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.65;
}

.tech-card__corner {
  position: absolute;
  top: 0; right: 0;
  width: 40px; height: 40px;
  border-top: 2px solid rgba(37, 99, 235, 0.15);
  border-right: 2px solid rgba(37, 99, 235, 0.15);
  border-radius: 0 var(--radius) 0 0;
  transition: border-color 0.3s;
}

.tech-card:hover .tech-card__corner {
  border-color: var(--cyan);
}

/* ── Hobby cards ── */
.hobby-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1rem;
}

.hobby-card {
  aspect-ratio: 1;
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  font-family: var(--font-head);
  font-size: 1.1rem;
  font-weight: 600;
  position: relative;
  overflow: hidden;
  color: hsl(var(--hue, 210), 70%, 45%);
  cursor: pointer;
  transition: transform 0.35s var(--ease), box-shadow 0.35s;
}

.hobby-card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, hsla(var(--hue, 210), 80%, 60%, 0.12), transparent 60%);
  transition: opacity 0.35s;
}

.hobby-card::after {
  content: "";
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: linear-gradient(transparent 40%, rgba(255,255,255,0.4) 50%, transparent 60%);
  transform: translateX(-100%) rotate(25deg);
  transition: transform 0.6s;
}

.hobby-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: 0 12px 32px hsla(var(--hue, 210), 60%, 50%, 0.15);
}

.hobby-card:hover::after {
  transform: translateX(100%) rotate(25deg);
}

.hobby-card svg, .hobby-card span { position: relative; z-index: 1; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ── Deep dive ── */
.dive-grid {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.dive-card {
  padding: 1.75rem 2rem;
  border-radius: var(--radius);
  border-left: 3px solid var(--step-accent, var(--primary));
  position: relative;
  overflow: hidden;
  transition: box-shadow 0.35s var(--ease-soft), transform 0.3s var(--ease), border-color 0.35s var(--ease-soft);
}

.dive-card:hover {
  box-shadow: var(--glass-shadow-lg), inset 0 1px 0 var(--glass-highlight);
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--step-accent, var(--primary)) 30%, var(--glass-border));
}

.dive-card__head {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.dive-card__num {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-head);
  font-size: 0.9rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--step-accent, var(--primary)), color-mix(in srgb, var(--step-accent, var(--cyan)) 50%, white));
  border-radius: 12px;
  box-shadow: 0 4px 14px color-mix(in srgb, var(--step-accent, var(--primary)) 30%, transparent);
}

.dive-card__head h3 {
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.15rem;
}

.dive-card__en {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--step-accent, var(--primary));
  letter-spacing: 0.04em;
  opacity: 0.8;
}

.dive-card__lead {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 1.25rem;
}

.dive-card__lead strong {
  color: var(--text);
  font-weight: 600;
}

.dive-card__cols {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

.dive-card__block h4 {
  font-family: var(--font-head);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--step-accent, var(--primary));
  margin-bottom: 0.6rem;
}

.dive-card__block ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.dive-card__block li {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
  padding-left: 1rem;
  position: relative;
}

.dive-card__block li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--step-accent, var(--primary));
  font-size: 0.75rem;
}

.dive-card__block--case {
  padding: 0.85rem 1rem;
  border-radius: 10px;
  border-left: 2px solid color-mix(in srgb, var(--step-accent, var(--primary)) 45%, transparent);
}

.dive-card__block--case p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.7;
  background: transparent;
  border: none;
  box-shadow: none;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  padding: 0;
}

/* ── Pitfalls ── */
.pitfall-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.pitfall-card {
  padding: 1.5rem;
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
  transition: transform 0.3s var(--ease), box-shadow 0.35s var(--ease-soft);
}

.pitfall-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, #EF4444, transparent);
  opacity: 0.6;
}

.pitfall-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--glass-shadow-lg), inset 0 1px 0 var(--glass-highlight);
}

.pitfall-card__icon {
  display: inline-flex;
  width: 28px;
  height: 28px;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(239, 68, 68, 0.1);
  color: #EF4444;
  margin-bottom: 0.75rem;
}

.pitfall-card h3 {
  font-family: var(--font-head);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.pitfall-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.65;
}

.pitfall-card p strong {
  color: var(--text);
  font-weight: 600;
}

/* ── Practice ── */
.practice-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}

.practice-card {
  padding: 1.75rem;
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
  transition: transform 0.3s var(--ease), box-shadow 0.35s var(--ease-soft), border-color 0.3s;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.practice-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--glass-shadow-lg), inset 0 1px 0 var(--glass-highlight);
  border-color: rgba(255, 255, 255, 0.55);
}

.practice-card__icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.08), rgba(6, 182, 212, 0.08));
  color: var(--primary);
}

.practice-card h3 {
  font-family: var(--font-head);
  font-size: 1.1rem;
  font-weight: 600;
}

.practice-card p {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.7;
  flex: 1;
}

.practice-card__tip {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--primary);
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  border-left: 2px solid var(--cyan);
}

/* ── Footer ── */
.footer {
  position: relative;
  z-index: 1;
  margin: 0.5rem clamp(12px, 2vw, 24px) 1rem;
  padding: 0.6rem clamp(1rem, 3vw, 2rem);
  text-align: center;
  border-radius: 999px;
}

.footer__legal {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.footer__legal a {
  color: #5ec4b6;
  cursor: pointer;
}

.footer__legal a:hover { color: #3aa896; }

.footer__legal img {
  margin: 0 4px;
  vertical-align: middle;
  object-fit: contain;
}

/* ── Scroll reveal ── */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
  transition-delay: calc(var(--delay, 0) * 0.08s);
}

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

/* ── Glitch text ── */
.glitch {
  position: relative;
}

.glitch::before,
.glitch::after {
  content: attr(data-text);
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  -webkit-background-clip: text;
  background-clip: text;
  pointer-events: none;
  opacity: 0.85;
}

.glitch::before {
  color: var(--cyan);
  -webkit-text-fill-color: var(--cyan);
  animation: glitchTop 3.2s steps(2, end) infinite;
  clip-path: polygon(0 0, 100% 0, 100% 45%, 0 45%);
}

.glitch::after {
  color: var(--violet);
  -webkit-text-fill-color: var(--violet);
  animation: glitchBottom 2.6s steps(2, end) infinite;
  clip-path: polygon(0 55%, 100% 55%, 100% 100%, 0 100%);
}

@keyframes glitchTop {
  0%, 92%, 100% { transform: translate(0); opacity: 0; }
  93% { transform: translate(-2px, -1px); opacity: 0.9; }
  96% { transform: translate(2px, 1px); opacity: 0.7; }
}

@keyframes glitchBottom {
  0%, 90%, 100% { transform: translate(0); opacity: 0; }
  91% { transform: translate(2px, 1px); opacity: 0.9; }
  94% { transform: translate(-2px, -1px); opacity: 0.7; }
}

/* ── HUD corner brackets ── */
.card-hud {
  position: absolute;
  inset: 8px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.35s;
}

.card-hud::before,
.card-hud::after {
  content: "";
  position: absolute;
  width: 16px; height: 16px;
  border: 2px solid var(--card-accent, var(--primary));
}

.card-hud::before {
  top: 0; left: 0;
  border-right: none; border-bottom: none;
}

.card-hud::after {
  bottom: 0; right: 0;
  border-left: none; border-top: none;
}

.quote-card:hover .card-hud { opacity: 0.9; }

.card-hud--panel {
  inset: 10px;
  opacity: 0.5;
}

.card-hud--panel::before,
.card-hud--panel::after {
  width: 22px; height: 22px;
  border-color: var(--cyan);
}

/* ── 3D tilt ── */
.tilt {
  transform-style: preserve-3d;
  will-change: transform;
}

/* ── Tech ring HUD ── */
.tech-ring__hud {
  position: absolute;
  inset: -6%;
  border-radius: 50%;
  border: 1px solid rgba(139, 92, 246, 0.2);
}

.tech-ring__hud::before,
.tech-ring__hud::after {
  content: "";
  position: absolute;
  width: 14px; height: 14px;
  border: 2px solid var(--violet);
}

.tech-ring__hud::before {
  top: 6%; left: 6%;
  border-right: none; border-bottom: none;
}

.tech-ring__hud::after {
  bottom: 6%; right: 6%;
  border-left: none; border-top: none;
}

/* ── Responsive ── */
@media (max-width: 900px) {
  .hero__masthead {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero__intro {
    display: flex;
    flex-direction: column;
    align-items: center;
  }

  .hero__desc, .hero__flow {
    justify-content: center;
  }

  .hero__visual { order: -1; }
  .algo-stage { width: 240px; height: 300px; }

  .hero__board-panel {
    padding: 1rem;
  }

  .step-rail__num {
    width: 30px;
    height: 30px;
    font-size: 0.62rem;
  }

  .step-rail__name {
    font-size: 0.62rem;
  }

  .step-rail__track {
    top: 15px;
    left: 8%;
    right: 8%;
  }

  .hero__board-body {
    grid-template-columns: 1fr;
    gap: 0.85rem;
  }

  .hero__steps {
    max-width: none;
    text-align: left;
  }

  .algo-step {
    grid-template-columns: auto 1fr;
    padding: 0.85rem 1rem;
    gap: 0.65rem;
  }

  .algo-step__num { display: none; }

  .algo-step__icon {
    grid-row: auto;
    width: 32px;
    height: 32px;
  }

  .algo-step__body { grid-column: 2; }

  .algo-step__title { font-size: 0.88rem; }
  .algo-step__desc { font-size: 0.76rem; }
  .algo-step__tag { font-size: 0.58rem; }

  .flow-chip { font-size: 0.75rem; padding: 0.35rem 0.7rem; }
  .flow-connector { width: 12px; }

  .dive-card__cols { grid-template-columns: 1fr; }
  .dive-card { padding: 1.25rem 1.5rem; }

  .hero__step-detail {
    min-height: 10.5rem;
  }

  .hero__step-detail__inner {
    justify-content: flex-start;
    padding: 1.15rem 1.25rem;
    max-width: 100%;
  }

  .hero__step-detail__watermark {
    width: 5.5rem;
    height: 5.5rem;
    opacity: 0.07;
  }
}

@media (max-width: 768px) {
  .nav {
    top: 8px;
    left: 10px;
    right: 10px;
    padding: 0 1rem;
  }

  .nav__backdrop {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 99;
    background: rgba(15, 23, 42, 0.18);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.3s var(--ease-soft), visibility 0.3s var(--ease-soft);
    cursor: pointer;
  }

  .nav__backdrop.open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .nav__links {
    position: fixed;
    top: 72px;
    left: 10px;
    right: 10px;
    z-index: 101;
    flex-direction: column;
    gap: 0;
    border-radius: var(--radius);
    padding: 0.5rem 0;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
    border: 1px solid rgba(255, 255, 255, 0.72);
    box-shadow: var(--glass-shadow-lg), inset 0 1px 0 rgba(255, 255, 255, 0.9);
    transform: translateY(-120%);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.35s var(--ease), opacity 0.35s, visibility 0.35s;
    pointer-events: none;
  }

  .nav__links.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .nav__links a {
    padding: 0.7rem 1.15rem;
    font-size: 0.8rem;
    letter-spacing: 0.04em;
    text-shadow: none;
  }

  .nav__links a::after { display: none; }

  .nav__links a:hover {
    background: rgba(37, 99, 235, 0.08);
    box-shadow: none;
  }
  .nav__toggle { display: flex; }

  .nav__links { max-height: 70vh; overflow-y: auto; }

  .ticker { margin-top: calc(var(--nav-h) + 4px); }

  .footer {
    margin: 0.35rem 10px 0.75rem;
    padding: 0.55rem 1rem;
  }

  .footer__legal {
    font-size: 0.72rem;
    line-height: 1.55;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .hero__step-detail__pane.active .hero__step-detail__inner,
  .hero__step-detail__pane.active .hero__step-detail__list li {
    animation: none !important;
    opacity: 1 !important;
    transform: none !important;
  }
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
  .bg-aurora, .cursor-glow, .bg-code-rain { display: none; }
  .algo-scene { transition: none; }
  .ticker__track { animation: none; }
}