:root {
  --gold: #d7b426;
  --white: #ffffff;
  --soft-white: rgba(255, 255, 255, 0.86);
  --line: rgba(255, 255, 255, 0.38);
  --dark-overlay: rgba(0, 0, 0, 0.44);
  --dark-overlay-hover: rgba(0, 0, 0, 0.28);
  --slide-time: 18s;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  min-height: 100%;
  margin: 0;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  background: #111;
  color: var(--white);
}

.intro-page {
  position: relative;
  min-height: 100vh;
  overflow: hidden;
}

.brand-mark {
  position: fixed;
  z-index: 10;
  top: 22px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 78px;
  height: 170px;
  padding: 10px 12px;
  pointer-events: none;
  background: rgba(255, 255, 255, 0.22);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 18px;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.12);
  backdrop-filter: blur(2px);
}

.brand-mark img {
  display: block;
  width: auto;
  height: 100%;
  object-fit: contain;
  filter: drop-shadow(0 10px 22px rgba(0, 0, 0, 0.38));
}

.split-area {
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 100vh;
}

.panel {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 210px 42px 82px;
  overflow: hidden;
  text-decoration: none;
  isolation: isolate;
  background: #111;
}

.panel-left {
  border-right: 1px solid var(--line);
}

.panel-slider,
.slide {
  position: absolute;
  inset: 0;
  display: block;
}

.panel-slider {
  z-index: 0;
  overflow: hidden;
}

.slide {
  background-position: center;
  background-size: cover;
  opacity: 0;
  transform: scale(1.02);
  animation: slideFade var(--slide-time) infinite;
  transition: transform 0.55s ease, filter 0.55s ease;
}

.panel-left .slide-1 { background-image: url("assets/images/left-1.jpg"); animation-delay: 0s; opacity: 1; }
.panel-left .slide-2 { background-image: url("assets/images/left-2.jpg"); animation-delay: 6s; }
.panel-left .slide-3 { background-image: url("assets/images/left-3.jpg"); animation-delay: 12s; }

.panel-right .slide-1 { background-image: url("assets/images/right-1.jpg"); animation-delay: 0s; opacity: 1; }
.panel-right .slide-2 { background-image: url("assets/images/right-2.jpg"); animation-delay: 6s; }
.panel-right .slide-3 { background-image: url("assets/images/right-3.jpg"); animation-delay: 12s; }

@keyframes slideFade {
  0% { opacity: 0; transform: scale(1.02); }
  5% { opacity: 1; }
  31% { opacity: 1; }
  38% { opacity: 0; transform: scale(1.08); }
  100% { opacity: 0; transform: scale(1.08); }
}

.panel-overlay {
  position: absolute;
  inset: 0;
  z-index: 1;
  background:
    linear-gradient(180deg, rgba(0, 0, 0, 0.08), rgba(0, 0, 0, 0.42)),
    var(--dark-overlay);
  transition: background 0.35s ease;
}

.panel-content {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  width: min(100%, 390px);
  min-height: 330px;
  text-align: center;
}

.panel-title {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  padding: 0 4px;
  color: var(--soft-white);
  font-size: clamp(13px, 1.1vw, 18px);
  font-weight: 600;
  letter-spacing: 0.24em;
  line-height: 1.35;
  text-align: center;
  text-shadow: 0 7px 18px rgba(0, 0, 0, 0.48);
}

.panel-title::after {
  content: "";
  display: block;
  position: absolute;
  width: 46px;
  height: 2px;
  margin-top: 46px;
  border-radius: 999px;
  background: var(--gold);
  opacity: 0.9;
}

.panel-logo {
  display: block;
  width: auto;
  max-width: min(46%, 160px);
  max-height: 168px;
  object-fit: contain;
  filter: drop-shadow(0 18px 30px rgba(0, 0, 0, 0.45));
  transition: transform 0.4s ease, filter 0.4s ease;
}

.panel-logo-right {
  max-width: min(48%, 178px);
  max-height: 184px;
}

.panel:hover .slide {
  transform: scale(1.09);
  filter: saturate(1.08);
}

.panel:hover .panel-overlay {
  background:
    linear-gradient(180deg, rgba(0, 0, 0, 0.03), rgba(0, 0, 0, 0.34)),
    var(--dark-overlay-hover);
}

.panel:hover .panel-logo {
  transform: translateY(-6px) scale(1.02);
  filter: drop-shadow(0 22px 34px rgba(0, 0, 0, 0.55));
}

@media (prefers-reduced-motion: reduce) {
  .slide {
    animation: none;
  }

  .panel-left .slide-1,
  .panel-right .slide-1 {
    opacity: 1;
  }
}

@media (max-width: 900px) {
  .intro-page {
    overflow: auto;
  }

  .brand-mark {
    position: absolute;
    top: 16px;
    width: 62px;
    height: 138px;
    padding: 8px 10px;
    border-radius: 15px;
  }

  .split-area {
    grid-template-columns: 1fr;
  }

  .panel {
    min-height: 50vh;
    padding: 132px 24px 54px;
  }

  .panel-left {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .panel-content {
    gap: 22px;
    min-height: 220px;
  }

  .panel-title {
    font-size: 12px;
    letter-spacing: 0.18em;
  }

  .panel-logo,
  .panel-logo-right {
    max-width: min(52%, 136px);
    max-height: 146px;
  }
}

@media (max-width: 520px) {
  .brand-mark {
    width: 54px;
    height: 116px;
    padding: 7px 9px;
    border-radius: 13px;
  }

  .panel {
    padding: 112px 18px 44px;
  }

  .panel-content {
    gap: 18px;
    min-height: 190px;
  }

  .panel-title {
    font-size: 11px;
    letter-spacing: 0.13em;
  }

  .panel-logo,
  .panel-logo-right {
    max-width: min(58%, 118px);
    max-height: 126px;
  }
}