.line-surface-scroll-shell {
  position: relative;
  height: 180svh;
  min-height: 920px;
  background: #00060c;
}

.hero--line-surface {
  position: sticky;
  top: 0;
  height: 100svh;
  min-height: 560px;
  align-items: flex-end;
  background:
    radial-gradient(ellipse at 58% 38%, rgba(60, 120, 200, .14), transparent 42%),
    radial-gradient(ellipse at 40% 70%, rgba(100, 160, 220, .06), transparent 36%),
    linear-gradient(160deg, #00060c 0%, #000c1a 55%, #00060c 100%);
}

.hero--line-surface .hero-background {
  background:
    linear-gradient(180deg, rgba(80, 140, 220, .06), transparent 28%),
    radial-gradient(ellipse at 60% 46%, rgba(120, 180, 255, .06), transparent 38%);
}

.hero--line-surface .hero-slide {
  opacity: 1;
}

.hero--line-surface .hero-overlay {
  pointer-events: none;
  background:
    linear-gradient(90deg, rgba(0, 4, 12, .68) 0%, rgba(0, 4, 12, .16) 50%, rgba(0, 4, 12, .44) 100%),
    radial-gradient(ellipse at 56% 52%, transparent 0%, rgba(0, 4, 12, .18) 62%, rgba(0, 4, 12, .62) 100%);
}

.hero-slide--line-surface,
.line-surface-stage {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.hero-slide--line-surface {
  background:
    radial-gradient(ellipse at 58% 38%, rgba(60, 120, 200, .14), transparent 42%),
    radial-gradient(ellipse at 40% 70%, rgba(100, 160, 220, .06), transparent 36%),
    linear-gradient(160deg, #00060c 0%, #000c1a 55%, #00060c 100%);
}

.line-surface-stage {
  isolation: isolate;
}

.line-surface-stage::before,
.line-surface-stage::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

/* Cool vignette — pure blue-white, no warm tones */
.line-surface-stage::before {
  background:
    radial-gradient(ellipse at 58% 42%, rgba(140, 200, 255, .14), transparent 32%),
    linear-gradient(118deg, rgba(200, 230, 255, .07) 0%, transparent 20%, transparent 80%, rgba(180, 220, 255, .05) 100%);
  mix-blend-mode: screen;
  opacity: .78;
}

/* Subtle grid overlay — cool white only */
.line-surface-stage::after {
  background-image:
    linear-gradient(rgba(200, 220, 255, .022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(200, 220, 255, .018) 1px, transparent 1px);
  background-size: 80px 80px;
  mask-image: radial-gradient(ellipse at 58% 48%, rgba(0, 0, 0, .68), transparent 68%);
  opacity: .20;
}

.line-surface-canvas {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
}

.line-surface-hero-content {
  pointer-events: none;
  max-width: 1280px;
  padding-bottom: clamp(2.8rem, 8vw, 5rem);
}

.line-surface-kicker {
  font-family: var(--font-head);
  font-size: clamp(.68rem, 1vw, .86rem);
  letter-spacing: .18em;
  text-transform: uppercase;
  color: rgba(180, 215, 255, .80);
  margin-bottom: .7rem;
}

.line-surface-title .hero-title-line {
  max-width: min(920px, 100%);
  font-size: clamp(2rem, 5.2vw, 4.8rem);
  line-height: 1.04;
  letter-spacing: 0;
  white-space: normal;
  text-shadow:
    0 1px 24px rgba(0, 8, 24, .52),
    0 0  48px rgba(140, 200, 255, .14);
}

.hero--line-surface .hero-title,
.hero--line-surface .hero-title-line,
.hero--line-surface .hero-title-chunk {
  white-space: normal;
}

.line-surface-subtitle {
  max-width: 720px;
  color: rgba(210, 230, 252, .72);
  text-shadow: 0 1px 14px rgba(0, 4, 16, .40);
}

.line-surface-note {
  display: flex;
  align-items: center;
  gap: .8rem;
  margin-top: 1.4rem;
  font-family: var(--font-head);
  font-size: clamp(.72rem, 1vw, .86rem);
  letter-spacing: .08em;
  color: rgba(180, 210, 255, .58);
}

.line-surface-note::before {
  content: "";
  width: 42px;
  height: 1px;
  background: linear-gradient(90deg, rgba(140, 200, 255, .90), rgba(200, 230, 255, .20));
}

.line-surface-test-section {
  min-height: 120svh;
}

.line-surface-tuner {
  position: fixed;
  top: 88px;
  right: 18px;
  z-index: 1200;
  width: min(330px, calc(100vw - 24px));
  padding: 14px;
  border: 1px solid rgba(210, 232, 255, .22);
  border-radius: 8px;
  background: rgba(3, 10, 22, .82);
  color: rgba(240, 248, 255, .95);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 12px;
  line-height: 1.35;
  box-shadow: 0 18px 48px rgba(0, 0, 0, .35);
  backdrop-filter: blur(18px) saturate(1.4);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
}

.line-surface-tuner-title {
  margin-bottom: 10px;
  font-weight: 700;
  letter-spacing: .04em;
}

.line-surface-tuner-row {
  display: grid;
  grid-template-columns: 52px 1fr 48px;
  gap: 8px;
  align-items: center;
  margin: 8px 0;
}

.line-surface-tuner-row input {
  width: 100%;
  accent-color: #8fc6ff;
}

.line-surface-tuner-row output {
  text-align: right;
  color: #cfe8ff;
}

.line-surface-tuner-nudge {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  margin-top: 12px;
}

.line-surface-tuner button {
  min-height: 30px;
  border: 1px solid rgba(210, 232, 255, .20);
  border-radius: 6px;
  background: rgba(130, 185, 245, .12);
  color: rgba(244, 250, 255, .96);
  font: inherit;
  cursor: pointer;
}

.line-surface-tuner button:hover {
  background: rgba(130, 185, 245, .22);
}

.line-surface-tuner-reset {
  width: 100%;
  margin-top: 8px;
}

.line-surface-tuner-readout {
  margin: 12px 0 0;
  padding: 10px;
  border-radius: 6px;
  background: rgba(0, 0, 0, .26);
  color: #eaf6ff;
  white-space: pre-wrap;
  user-select: text;
}

@media (max-width: 768px) {
  .line-surface-scroll-shell {
    height: 170svh;
    min-height: 960px;
  }

  .hero--line-surface {
    height: 100svh;
    min-height: 560px;
  }

  .line-surface-hero-content {
    padding: 1.5rem 1.35rem 4.2rem;
  }

  .line-surface-title .hero-title-line {
    max-width: min(92vw, 22rem);
    font-size: clamp(2.1rem, 11vw, 3.35rem);
  }

  .line-surface-subtitle {
    font-size: .9rem;
    line-height: 1.7;
    max-width: 24rem;
  }

  .line-surface-note {
    display: none;
  }

  .line-surface-tuner {
    top: 82px;
    right: 12px;
    left: 12px;
    width: auto;
    max-height: calc(100svh - 96px);
    overflow: auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  .line-surface-stage::after {
    opacity: .10;
  }
}