/* ==========================================================================
   SMART CLEAN-AIR — Peak Animation System
   GPU-accelerated · Scroll-driven · Reduced-motion aware
   ========================================================================== */

/* ---------- Custom easing curves ---------- */
:root {
  --ease-out-quint: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1);
  --ease-in-out-circ: cubic-bezier(0.85, 0, 0.15, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-elastic: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* ---------- Scroll Progress Indicator ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent-blue), var(--color-accent-green));
  z-index: 10000;
  transition: none;
  will-change: width;
}

/* ---------- Base Reveal System ---------- */

/* All reveal elements start hidden */
.reveal-up,
.reveal-down,
.reveal-left,
.reveal-right,
.reveal-fade,
.reveal-scale,
.reveal-clip-up,
.reveal-clip-left,
.reveal-rotate {
  will-change: transform, opacity;
}

.reveal-up {
  opacity: 0;
  transform: translateY(60px);
  transition: opacity 0.9s var(--ease-out-quint),
              transform 1s var(--ease-out-quint);
}

.reveal-down {
  opacity: 0;
  transform: translateY(-60px);
  transition: opacity 0.9s var(--ease-out-quint),
              transform 1s var(--ease-out-quint);
}

.reveal-fade {
  opacity: 0;
  transition: opacity 1s var(--ease-out-quint);
}

.reveal-left {
  opacity: 0;
  transform: translateX(-80px);
  transition: opacity 0.9s var(--ease-out-quint),
              transform 1s var(--ease-out-quint);
}

.reveal-right {
  opacity: 0;
  transform: translateX(80px);
  transition: opacity 0.9s var(--ease-out-quint),
              transform 1s var(--ease-out-quint);
}

.reveal-scale {
  opacity: 0;
  transform: scale(0.85);
  transition: opacity 0.8s var(--ease-out-quint),
              transform 1s var(--ease-spring);
}

/* Clip-path reveals: content wipes in from edge */
.reveal-clip-up {
  clip-path: inset(100% 0 0 0);
  transition: clip-path 1s var(--ease-in-out-circ);
}

.reveal-clip-left {
  clip-path: inset(0 100% 0 0);
  transition: clip-path 1s var(--ease-in-out-circ);
}

.reveal-rotate {
  opacity: 0;
  transform: translateY(40px) rotate(3deg);
  transform-origin: left bottom;
  transition: opacity 0.7s var(--ease-out-quint),
              transform 1s var(--ease-out-quint);
}

/* ---------- Visible State ---------- */
.is-visible {
  opacity: 1 !important;
  transform: translate(0, 0) scale(1) rotate(0deg) !important;
  clip-path: inset(0 0 0 0) !important;
}

/* ---------- Stagger Delays (more granular) ---------- */
.delay-1 { transition-delay: 0.08s; }
.delay-2 { transition-delay: 0.16s; }
.delay-3 { transition-delay: 0.24s; }
.delay-4 { transition-delay: 0.32s; }
.delay-5 { transition-delay: 0.40s; }
.delay-6 { transition-delay: 0.48s; }
.delay-7 { transition-delay: 0.56s; }
.delay-8 { transition-delay: 0.64s; }

/* ---------- Stagger Children ---------- */
.reveal-stagger > * {
  opacity: 0;
  transform: translateY(30px) scale(0.97);
  transition: opacity 0.6s var(--ease-out-quint),
              transform 0.8s var(--ease-spring);
}
.is-visible.reveal-stagger > * {
  opacity: 1;
  transform: translateY(0) scale(1);
}
.is-visible.reveal-stagger > *:nth-child(1) { transition-delay: 0.05s; }
.is-visible.reveal-stagger > *:nth-child(2) { transition-delay: 0.12s; }
.is-visible.reveal-stagger > *:nth-child(3) { transition-delay: 0.19s; }
.is-visible.reveal-stagger > *:nth-child(4) { transition-delay: 0.26s; }
.is-visible.reveal-stagger > *:nth-child(5) { transition-delay: 0.33s; }
.is-visible.reveal-stagger > *:nth-child(6) { transition-delay: 0.40s; }
.is-visible.reveal-stagger > *:nth-child(7) { transition-delay: 0.47s; }
.is-visible.reveal-stagger > *:nth-child(8) { transition-delay: 0.54s; }

/* ---------- Hero Cinematic Entrance ---------- */
.hero-section .hero-background {
  opacity: 0;
  transform: scale(1.08);
  transition: opacity 1.5s ease-out, transform 2.5s var(--ease-out-quint);
}
.hero-loaded .hero-background {
  opacity: 1;
  transform: scale(1);
}

/* Hero title split-line reveal */
.hero-section h1 {
  opacity: 0;
  clip-path: inset(0 100% 0 0);
  transition: clip-path 1s var(--ease-in-out-circ) 0.5s,
              opacity 0.01s linear 0.5s;
}
.hero-loaded h1 {
  opacity: 1;
  clip-path: inset(0 0 0 0);
}

.hero-section .hero-subtitle {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s var(--ease-out-quint) 0.9s,
              transform 1s var(--ease-out-quint) 0.9s;
}
.hero-loaded .hero-subtitle {
  opacity: 1;
  transform: translateY(0);
}

.hero-section .hero-description {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.8s var(--ease-out-quint) 1.1s,
              transform 1s var(--ease-out-quint) 1.1s;
}
.hero-loaded .hero-description {
  opacity: 1;
  transform: translateY(0);
}

.hero-section .hero-ctas {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--ease-out-quint) 1.4s,
              transform 0.8s var(--ease-out-quint) 1.4s;
}
.hero-loaded .hero-ctas {
  opacity: 1;
  transform: translateY(0);
}

.hero-section .hero-sensors {
  opacity: 0;
  transform: translateY(15px);
  transition: opacity 0.6s var(--ease-out-quint) 1.7s,
              transform 0.8s var(--ease-out-quint) 1.7s;
}
.hero-loaded .hero-sensors {
  opacity: 1;
  transform: translateY(0);
}

.hero-section .sensor-badge {
  opacity: 0;
  transform: scale(0.8);
  transition: opacity 0.5s var(--ease-out-quint),
              transform 0.6s var(--ease-spring);
}
.hero-loaded .sensor-badge:nth-child(1) { opacity: 1; transform: scale(1); transition-delay: 1.8s; }
.hero-loaded .sensor-badge:nth-child(2) { opacity: 1; transform: scale(1); transition-delay: 1.95s; }
.hero-loaded .sensor-badge:nth-child(3) { opacity: 1; transform: scale(1); transition-delay: 2.1s; }

.hero-section .scroll-indicator {
  opacity: 0;
  transition: opacity 0.6s ease 2.4s;
}
.hero-loaded .scroll-indicator {
  opacity: 1;
}

/* ---------- Hero Parallax on Scroll ---------- */
.hero-section[data-scroll] .hero-background {
  /* JS sets --scroll-y custom property */
  transform: translateY(calc(var(--scroll-y, 0) * 0.3px)) scale(1.02);
}
.hero-section[data-scroll] h1 {
  transform: translateY(calc(var(--scroll-y, 0) * -0.15px));
}

/* ---------- Section Divider Lines ---------- */
.section-divider {
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-accent-blue), transparent);
  margin: 0 auto;
  transition: width 1.2s var(--ease-out-quint);
}
.section-divider.is-visible {
  width: 120px;
}

/* ---------- Card Hover Micro-interactions ---------- */
.card {
  transition: transform 0.5s var(--ease-out-quint),
              box-shadow 0.5s var(--ease-out-quint),
              border-color 0.4s ease;
}

.card:hover {
  transform: translateY(-6px) scale(1.01);
  box-shadow: 0 20px 50px rgba(0,0,0,0.08);
}

.card-dark:hover {
  box-shadow: 0 20px 50px rgba(0,0,0,0.3);
  border-color: rgba(255,255,255,0.15);
}

/* ---------- Button Hover Effects ---------- */
.btn {
  position: relative;
  overflow: hidden;
  transition: transform 0.4s var(--ease-out-quint),
              box-shadow 0.4s var(--ease-out-quint),
              color 0.3s ease;
}

.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,0.15);
  transform: translateX(-101%);
  transition: transform 0.5s var(--ease-out-quint);
}

.btn:hover::after {
  transform: translateX(0);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.btn:active {
  transform: translateY(0) scale(0.98);
  transition-duration: 0.1s;
}

/* ---------- Missing System Section Styling ---------- */
.traditional-purifier {
  transition: opacity 0.6s var(--ease-out-quint), transform 0.6s var(--ease-out-quint);
}

.system-approach {
  transition: opacity 0.6s var(--ease-out-quint), transform 0.6s var(--ease-out-quint);
}

/* ---------- Node Connection Animation ---------- */
.node {
  transition: transform 0.5s var(--ease-spring),
              box-shadow 0.5s var(--ease-out-quint),
              border-color 0.3s ease;
}

.node:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 10px 25px rgba(0,0,0,0.1);
  border-color: var(--color-accent-blue);
}

.is-visible .node-container .node {
  animation: node-pop 0.6s var(--ease-spring) both;
}
.is-visible .node-container .node:nth-child(1) { animation-delay: 0.1s; }
.is-visible .node-container .node:nth-child(2) { animation-delay: 0.2s; }
.is-visible .node-container .node:nth-child(3) { animation-delay: 0.3s; }
.is-visible .node-container .node:nth-child(4) { animation-delay: 0.4s; }
.is-visible .node-container .node:nth-child(5) { animation-delay: 0.5s; }

@keyframes node-pop {
  0% { opacity: 0; transform: translateY(30px) scale(0.7); }
  70% { transform: translateY(-5px) scale(1.05); }
  100% { opacity: 1; transform: translateY(0) scale(1); }
}

.is-visible .node-result {
  animation: result-reveal 0.8s var(--ease-out-quint) 0.8s both;
}

@keyframes result-reveal {
  0% { opacity: 0; transform: translateY(20px); }
  100% { opacity: 1; transform: translateY(0); }
}

/* ---------- Equation Diagram Cascade ---------- */
.equation-diagram .eq-item,
.equation-diagram .eq-operator,
.equation-diagram .eq-equals,
.equation-diagram .eq-result {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s var(--ease-out-quint),
              transform 0.8s var(--ease-spring);
}

.is-visible .equation-diagram .eq-item:nth-child(1) { opacity: 1; transform: none; transition-delay: 0s; }
.is-visible .equation-diagram .eq-operator:nth-child(2) { opacity: 1; transform: none; transition-delay: 0.15s; }
.is-visible .equation-diagram .eq-item:nth-child(3) { opacity: 1; transform: none; transition-delay: 0.3s; }
.is-visible .equation-diagram .eq-operator:nth-child(4) { opacity: 1; transform: none; transition-delay: 0.45s; }
.is-visible .equation-diagram .eq-item:nth-child(5) { opacity: 1; transform: none; transition-delay: 0.6s; }
.is-visible .equation-diagram .eq-equals { opacity: 1; transform: none; transition-delay: 0.8s; }
.is-visible .equation-diagram .eq-result { opacity: 1; transform: none; transition-delay: 1s; }

/* Result box glow pulse */
.is-visible .eq-box.highlighted {
  animation: glow-pulse 2s ease-in-out 1.5s infinite alternate;
}

@keyframes glow-pulse {
  0% { box-shadow: 0 0 20px rgba(59, 125, 216, 0.2); }
  100% { box-shadow: 0 0 40px rgba(59, 125, 216, 0.5), 0 0 80px rgba(59, 125, 216, 0.15); }
}

/* ---------- SVG Stroke Drawing ---------- */
.svg-draw-path {
  stroke-dasharray: var(--path-length, 1000);
  stroke-dashoffset: var(--path-length, 1000);
  transition: stroke-dashoffset 2s var(--ease-out-quint);
}

.is-visible .svg-draw-path {
  stroke-dashoffset: 0;
}

/* ---------- Airflow Particle Animation ---------- */
@keyframes airflow-drift {
  0% {
    transform: translate(0, 0);
    opacity: 0;
  }
  10% { opacity: 0.6; }
  90% { opacity: 0.6; }
  100% {
    transform: translate(var(--drift-x, 200px), var(--drift-y, -50px));
    opacity: 0;
  }
}

.airflow-particle {
  position: absolute;
  width: var(--particle-size, 4px);
  height: var(--particle-size, 4px);
  background: var(--particle-color, rgba(59, 125, 216, 0.4));
  border-radius: 50%;
  animation: airflow-drift var(--particle-duration, 4s) var(--particle-delay, 0s) infinite linear;
  pointer-events: none;
}

/* ---------- Scroll Indicator ---------- */
@keyframes scroll-bounce {
  0%, 100% {
    transform: translateY(0);
    opacity: 0.6;
  }
  50% {
    transform: translateY(8px);
    opacity: 1;
  }
}

.mouse-icon::after {
  animation: scroll-bounce 2s var(--ease-in-out-circ) infinite;
}

/* ---------- Counter Number Animation ---------- */
.counter-value {
  display: inline-block;
  font-variant-numeric: tabular-nums;
  transition: transform 0.3s var(--ease-out-quint);
}

/* ---------- Table Row Stagger ---------- */
.table-container tbody tr {
  opacity: 0;
  transform: translateX(-20px);
  transition: opacity 0.5s var(--ease-out-quint),
              transform 0.6s var(--ease-out-quint);
}

.table-container.is-visible tbody tr { opacity: 1; transform: none; }
.table-container.is-visible tbody tr:nth-child(1) { transition-delay: 0.05s; }
.table-container.is-visible tbody tr:nth-child(2) { transition-delay: 0.10s; }
.table-container.is-visible tbody tr:nth-child(3) { transition-delay: 0.15s; }
.table-container.is-visible tbody tr:nth-child(4) { transition-delay: 0.20s; }
.table-container.is-visible tbody tr:nth-child(5) { transition-delay: 0.25s; }
.table-container.is-visible tbody tr:nth-child(6) { transition-delay: 0.30s; }

/* ---------- Sensor Badge Hover Float ---------- */
.sensor-badge {
  transition: transform 0.4s var(--ease-out-quint),
              box-shadow 0.4s var(--ease-out-quint);
}
.sensor-badge:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.3);
}

/* ---------- Section Background Transitions ---------- */
.section {
  transition: background-color 0.6s ease;
}

/* ---------- Huge Text Entrance ---------- */
.huge-text {
  opacity: 0;
  transform: translateY(40px) scale(0.95);
  transition: opacity 1s var(--ease-out-quint),
              transform 1.2s var(--ease-out-quint);
}
.is-visible .huge-text,
.huge-text.is-visible {
  opacity: 1;
  transform: translateY(0) scale(1);
}

/* ---------- Decision Cards ---------- */
#decision .card {
  transition: transform 0.6s var(--ease-spring),
              box-shadow 0.6s var(--ease-out-quint),
              border-color 0.3s ease;
}

#decision .card:hover {
  transform: translateY(-10px) scale(1.03);
  box-shadow: 0 25px 60px rgba(0,0,0,0.12);
}

/* ---------- Closing Tagline Sequence ---------- */
#decision .huge-text {
  clip-path: inset(0 100% 0 0);
  opacity: 1;
  transform: none;
  transition: clip-path 1.2s var(--ease-in-out-circ);
}
.is-visible #decision .huge-text,
#decision .is-visible .huge-text {
  clip-path: inset(0 0 0 0);
}

/* ---------- Continuous Ambient Animations ---------- */

/* Floating glow behind engineering principle */
@keyframes ambient-float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  25% { transform: translate(10px, -20px) scale(1.05); }
  50% { transform: translate(-5px, 10px) scale(0.98); }
  75% { transform: translate(15px, 5px) scale(1.02); }
}

#engineering-principle::before {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(59, 125, 216, 0.08) 0%, transparent 70%);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: ambient-float 12s ease-in-out infinite;
  pointer-events: none;
  z-index: 0;
}

/* ---------- Smooth Scroll Behavior ---------- */
html {
  scroll-behavior: smooth;
}

/* ---------- Reduced Motion: Kill everything gracefully ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    animation-delay: 0ms !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }

  .reveal-up, .reveal-down, .reveal-left, .reveal-right,
  .reveal-fade, .reveal-scale, .reveal-clip-up, .reveal-clip-left,
  .reveal-rotate, .reveal-stagger > *, .huge-text,
  .hero-section .hero-background,
  .hero-section h1,
  .hero-section .hero-subtitle,
  .hero-section .hero-description,
  .hero-section .hero-ctas,
  .hero-section .hero-sensors,
  .hero-section .sensor-badge,
  .hero-section .scroll-indicator,
  .traditional-purifier,
  .system-approach,
  .equation-diagram .eq-item,
  .equation-diagram .eq-operator,
  .equation-diagram .eq-equals,
  .equation-diagram .eq-result,
  .table-container tbody tr,
  #decision .huge-text {
    opacity: 1 !important;
    transform: none !important;
    clip-path: none !important;
    filter: none !important;
  }

  .scroll-progress {
    display: none;
  }

  .airflow-particle {
    display: none;
  }
}