/**
 * KALPA Brand Cinematic Loading Animation
 * Faithfully implementing the 4-phase sequence from brand_a.png:
 * 01 FADE IN -> 02 CONSTRUCT -> 03 FORM -> 04 REVEAL -> UNVEIL
 */

#brandLoader {
  position: fixed;
  inset: 0;
  z-index: 10000;
  background-color: #050505;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  user-select: none;
  transition: opacity 0.85s cubic-bezier(0.16, 1, 0.3, 1), 
              visibility 0.85s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.85s cubic-bezier(0.16, 1, 0.3, 1);
}

#brandLoader.loader-hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: scale(1.03);
}

/* Background Atmosphere & Ambient Vignette */
.loader-ambient {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: 
    radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.12) 0%, transparent 65%),
    radial-gradient(circle at 50% 100%, rgba(8, 10, 14, 0.95) 0%, transparent 100%);
  opacity: 0;
  animation: loaderAmbientFadeIn 1.2s ease forwards;
}

@keyframes loaderAmbientFadeIn {
  from { opacity: 0; transform: scale(0.9); }
  to { opacity: 1; transform: scale(1); }
}

/* Background Technical Blueprint Grid */
.loader-grid-lines {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: 
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 40px 40px;
  background-position: center center;
  opacity: 0;
  animation: loaderGridFadeIn 1s ease 0.4s forwards;
}

@keyframes loaderGridFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Top Telemetry Header */
.loader-header {
  position: absolute;
  top: clamp(1.5rem, 4vh, 2.5rem);
  left: 0;
  right: 0;
  padding-inline: clamp(1.5rem, 5vw, 3rem);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-display, 'Space Grotesk', sans-serif);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #88847C;
  z-index: 2;
  opacity: 0;
  animation: loaderHeaderFade 0.8s ease 0.3s forwards;
}

@keyframes loaderHeaderFade {
  to { opacity: 1; }
}

.loader-phases-track {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.phase-step {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  opacity: 0.35;
  transition: opacity 0.3s ease, color 0.3s ease;
}

.phase-step.is-active {
  opacity: 1;
  color: #F4F3EF;
}

.phase-step.is-complete {
  opacity: 0.75;
  color: #C0B9AC;
}

.phase-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background-color: currentColor;
}

/* Center Visual Stage */
.loader-stage {
  position: relative;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 280px;
  width: 100%;
  max-width: 600px;
  padding: 1rem;
}

/* Phase 1 & 2: Construct Wireframe Monogram */
.loader-wireframe-wrap {
  position: absolute;
  width: 110px;
  height: 110px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: scale(0.92);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.loader-wireframe-wrap.active {
  opacity: 1;
  transform: scale(1);
}

.loader-wireframe-wrap.faded {
  opacity: 0;
  transform: scale(1.08);
  pointer-events: none;
}

.loader-svg-wireframe {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.loader-svg-wireframe path,
.loader-svg-wireframe polygon,
.loader-svg-wireframe line {
  stroke: #FFFFFF;
  stroke-width: 1.2;
  fill: none;
  stroke-dasharray: 200;
  stroke-dashoffset: 200;
  animation: drawWireframe 1.2s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

@keyframes drawWireframe {
  to {
    stroke-dashoffset: 0;
  }
}

/* Precision Corner Crosshairs */
.loader-crosshair {
  position: absolute;
  width: 14px;
  height: 14px;
  pointer-events: none;
}

.loader-crosshair::before,
.loader-crosshair::after {
  content: '';
  position: absolute;
  background-color: rgba(255, 255, 255, 0.45);
}

.loader-crosshair::before {
  top: 6px;
  left: 0;
  right: 0;
  height: 1px;
}

.loader-crosshair::after {
  left: 6px;
  top: 0;
  bottom: 0;
  width: 1px;
}

.ch-tl { top: -20px; left: -20px; }
.ch-tr { top: -20px; right: -20px; }
.ch-bl { bottom: -20px; left: -20px; }
.ch-br { bottom: -20px; right: -20px; }

/* Phase 3: Form Solid 3D Metallic Monogram */
.loader-solid-monogram {
  position: absolute;
  width: 110px;
  height: 110px;
  opacity: 0;
  transform: scale(0.95);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1), transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  align-items: center;
  justify-content: center;
}

.loader-solid-monogram.active {
  opacity: 1;
  transform: scale(1);
}

.loader-solid-monogram.faded {
  opacity: 0;
  transform: scale(1.1);
  pointer-events: none;
}

.loader-solid-monogram img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  filter: drop-shadow(0 0 35px rgba(255, 255, 255, 0.5));
}

/* Specular Gleam Sweep */
.loader-solid-monogram::after {
  content: '';
  position: absolute;
  inset: -20px;
  background: linear-gradient(115deg, transparent 35%, rgba(255, 255, 255, 0.85) 50%, transparent 65%);
  transform: translateX(-150%);
  pointer-events: none;
}

.loader-solid-monogram.gleam::after {
  animation: specularGleam 0.75s ease forwards;
}

@keyframes specularGleam {
  to {
    transform: translateX(150%);
  }
}

/* Phase 4: Reveal Concept C Primary Wordmark */
.loader-wordmark-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: translateY(12px) scale(0.96);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1), transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.loader-wordmark-wrap.active {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.loader-primary-logo {
  max-width: clamp(260px, 45vw, 380px);
  height: auto;
  filter: drop-shadow(0 4px 30px rgba(255, 255, 255, 0.35));
}

.loader-tagline {
  font-family: var(--font-display, 'Space Grotesk', sans-serif);
  font-size: clamp(0.72rem, 1.1vw, 0.88rem);
  font-weight: 500;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: #A3A3A3;
  margin-top: 1rem;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity 0.6s ease 0.25s, transform 0.6s ease 0.25s;
}

.loader-wordmark-wrap.active .loader-tagline {
  opacity: 0.9;
  transform: translateY(0);
}

/* Bottom Progress & Skip Controls */
.loader-footer {
  position: absolute;
  bottom: clamp(1.5rem, 4vh, 2.5rem);
  left: 0;
  right: 0;
  padding-inline: clamp(1.5rem, 5vw, 3rem);
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  z-index: 2;
}

.loader-bar-wrap {
  width: 100%;
  height: 2px;
  background-color: rgba(255, 255, 255, 0.08);
  position: relative;
  overflow: hidden;
}

.loader-bar-fill {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 0%;
  background: linear-gradient(90deg, #717885 0%, #FFFFFF 50%, #B8C0CC 100%);
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.7);
  transition: width 0.15s linear;
}

.loader-bottom-info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-display, 'Space Grotesk', sans-serif);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #7A756D;
}

.loader-skip-btn {
  background: none;
  border: none;
  color: #7A756D;
  font-family: inherit;
  font-size: inherit;
  letter-spacing: inherit;
  text-transform: inherit;
  cursor: pointer;
  padding: 4px 8px;
  transition: color 0.2s ease;
}

.loader-skip-btn:hover {
  color: #F4F3EF;
}