/* ── Day 07 · Fluid Simulation ── */

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

:root {
  --bg-deep: #030311;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-hover: rgba(255, 255, 255, 0.07);
  --surface-border: rgba(255, 255, 255, 0.08);
  --text-primary: #e8e6f0;
  --text-muted: rgba(255, 255, 255, 0.45);
  --accent: #7b6ff0;
  --accent-soft: rgba(123, 111, 240, 0.15);
  --accent-glow: rgba(123, 111, 240, 0.35);
  --radius: 10px;
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body: 'Instrument Sans', system-ui, sans-serif;
}

html, body {
  height: 100%;
  overflow: hidden;
  background: var(--bg-deep);
  color: var(--text-primary);
  font-family: var(--font-body);
}

/* ── Canvas ── */

.fluid-page {
  position: relative;
  width: 100%;
  height: 100%;
}

canvas[data-fluid-canvas] {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
}

/* ── Overlay ── */

.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  pointer-events: none;
  z-index: 10;
}

/* ── Hero Copy ── */

.hero-copy {
  padding: 2.5rem 3rem;
  transition: opacity 0.8s ease;
}

.hero-copy.hidden {
  opacity: 0;
  pointer-events: none;
}

.eyebrow {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.6rem;
}

.hero-copy h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3.8rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.tagline {
  margin-top: 0.5rem;
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* ── Control Bar ── */

.control-bar {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 1rem 2rem;
  margin: 0 1.5rem 1.5rem;
  background: rgba(8, 8, 30, 0.55);
  backdrop-filter: blur(28px) saturate(160%);
  -webkit-backdrop-filter: blur(28px) saturate(160%);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius);
  pointer-events: auto;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 120px;
}

.control-group--buttons {
  flex-direction: row;
  gap: 0.5rem;
  margin-left: auto;
  min-width: unset;
}

.slider-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.slider-label output {
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
}

/* ── Range Slider ── */

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 2px;
  background: var(--surface-border);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg-deep);
  box-shadow: 0 0 6px var(--accent-glow);
  cursor: pointer;
  transition: transform 0.15s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg-deep);
  box-shadow: 0 0 6px var(--accent-glow);
  cursor: pointer;
}

/* ── Buttons ── */

.btn {
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 0.55rem 1.1rem;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text-primary);
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease;
  white-space: nowrap;
}

.btn:hover {
  background: var(--surface-hover);
  border-color: rgba(255, 255, 255, 0.14);
}

.btn--accent {
  background: var(--accent-soft);
  border-color: rgba(123, 111, 240, 0.25);
  color: #c4beff;
}

.btn--accent:hover {
  background: rgba(123, 111, 240, 0.25);
  border-color: rgba(123, 111, 240, 0.4);
}

/* ── Responsive ── */

@media (max-width: 720px) {
  .hero-copy {
    padding: 1.5rem 1.5rem;
  }

  .hero-copy h1 {
    font-size: 2rem;
  }

  .control-bar {
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 0 0.75rem 0.75rem;
    padding: 0.85rem 1.2rem;
    padding-bottom: calc(0.85rem + env(safe-area-inset-bottom, 0px));
  }

  .control-group {
    min-width: 0;
    flex: 1 1 calc(50% - 0.75rem);
  }

  .control-group--buttons {
    flex: 1 1 100%;
    justify-content: stretch;
    margin-left: 0;
  }

  .btn {
    flex: 1;
    text-align: center;
  }
}

@media (max-width: 420px) {
  .hero-copy h1 {
    font-size: 1.6rem;
  }

  .tagline {
    font-size: 0.82rem;
  }

  .control-bar {
    margin: 0 0.5rem 0.5rem;
    padding: 0.75rem 1rem;
  }
}