/* ===== 02. Intro Page ===== */
.intro-main {
  --pointer-x: 0px;
  --pointer-y: 0px;


  position: relative;
  width: 100%;
  min-height: 100vh;
  min-height: 100dvh;
  overflow: hidden;
  isolation: isolate;
  perspective: 2200px;
  background:
    radial-gradient(circle at 15% 18%, rgba(255, 255, 255, 0.18), transparent 34%),
    radial-gradient(circle at 82% 24%, rgba(96, 140, 255, 0.22), transparent 36%),
    linear-gradient(145deg, #081120 0%, #0b1628 48%, #0f1b30 100%);
}


/* ===== 03. Header ===== */
.intro-header {
  position: absolute;
  top: 22px;
  left: 28px;
  right: 28px;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;

  .brand {
    display: inline-flex;
    align-items: center;

    .brand-mark {
      display: inline-flex;
      align-items: center;
      justify-content: center;

      &>img {
        display: block;
        width: 180px;
        height: auto;
        filter: var(--filter-white);
        transition: filter 0.06s ease;
      }
    }
  }

  & .brand-copy {
    margin: 0;
    font-family: "Montserrat", sans-serif;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.32em;
    text-transform: uppercase;
    color: var(--gray-500);
    transition: color 0.06s ease;
  }
}

.intro-main.is-mobile-panel-left {
  & .intro-header .brand img {
    filter: var(--filter-white);

  }

  & .intro-header .brand-copy {
    color: rgba(233, 241, 255, 0.75);
  }
}

.intro-main.is-mobile-panel-right {
  & .intro-header .brand img {
    filter: var(--filter-black);

  }

  & .intro-header .brand-copy {
    color: rgba(31, 42, 58, 0.82);
  }
}


/* ===== 04. Split Section ===== */
.split-layout {
  position: relative;
  display: grid;
  width: 100%;
  grid-template-columns: 1fr 1fr;
  min-height: 100vh;
  min-height: 100dvh;

  & .setion-split-panel {
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    min-height: 100vh;
    transition: transform 0.3s ease;

    &::before,
    &::after {
      content: "";
      position: absolute;
      border-radius: 999px;
      pointer-events: none;
    }

    /* Left Section */
    &.setion-split-panel-left {
      background: linear-gradient(158deg, #040404 0%, #0a0a0b 52%, #15171b 100%);

      &::before {
        width: 42vw;
        height: 42vw;
        top: -12vw;
        left: -11vw;
        background: radial-gradient(circle, rgba(255, 255, 255, 0.16), transparent 60%);
      }

      &::after {
        width: 280px;
        height: 280px;
        bottom: 8%;
        right: 8%;
        background: radial-gradient(circle, rgba(164, 176, 196, 0.2), transparent 68%);
        transform-origin: center;
        will-change: transform, opacity;
        animation: left-orb-breathe 6.8s ease-in-out infinite;
      }
    }

    /* Right Section */
    &.setion-split-panel-right {
      justify-content: flex-end;
      background: linear-gradient(162deg, #f5f6f8 0%, #eceff3 52%, #e5e9ef 100%);

      &::before {
        width: 42vw;
        height: 42vw;
        bottom: -12vw;
        right: -12vw;
        background: radial-gradient(circle, rgba(255, 255, 255, 0.58), transparent 62%);
      }

      &::after {
        width: 250px;
        height: 250px;
        top: 10%;
        left: 10%;
        background: radial-gradient(circle, rgba(164, 176, 196, 0.26), transparent 70%);
      }
    }
  }

  /* Shared Section Content */
  & .panel-inner {
    position: relative;
    z-index: 2;
    width: min(100%, 760px);
    padding: 130px 5vw 82px;
  }

  & .setion-split-panel-right .panel-inner {
    padding-left: min(13vw, 110px);
    padding-right: 5vw;
  }

  & .panel-kicker,
  & .panel-title,
  & .panel-summary,
  & .menu-card {
    opacity: 0;
    transform: translate3d(0, 30px, 0);
  }

  & .panel-kicker {
    margin: 0 0 16px;
    font-family: "Montserrat", sans-serif;
    font-weight: 700;
    font-size: 0.82rem;
    letter-spacing: 0.35em;
    text-transform: uppercase;
    color: rgba(230, 236, 248, 0.78);
  }

  & .panel-title {
    font-family: "Montserrat", sans-serif;
    font-weight: 900;
    font-size: clamp(30px, 3.250vw + 19.600px, 82px);
    line-height: 0.92;
    letter-spacing: -0.045em;
    color: #ffffff;
    text-shadow: 0 20px 34px rgba(0, 0, 0, 0.35);
    transform-style: preserve-3d;
    perspective: 1200px;
  }

  & .title-line {
    font-family: "Montserrat", sans-serif;
    font-weight: 900;
    display: block;
    will-change: transform, text-shadow, filter;

    &+.title-line {
      margin-top: 0.04em;
    }

    &::after {
      content: "";
      display: block;
      width: 100%;
      height: 2px;
      margin-top: 0.12em;
      opacity: 0;
      transform: scaleX(0);
      transform-origin: left;
    }
  }

  & .setion-split-panel-left .title-line::after {
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.88), rgba(179, 191, 212, 0.42));
  }

  & .setion-split-panel-right .title-line::after {
    background: linear-gradient(90deg, rgba(69, 82, 101, 0.88), rgba(136, 152, 173, 0.35));
  }

  & .panel-summary {
    max-width: 560px;
    margin: 24px 0 0;
    font-size: 1rem;
    line-height: 1.4;
    color: rgba(219, 227, 241, 0.84);
  }

  /* Section Menu Cards */
  & .menu-list {
    display: grid;
    gap: 10px;
    margin-top: 36px;
  }

  & .menu-card {
    position: relative;
    overflow: hidden;
    display: grid;
    gap: 6px;
    padding: 20px 60px 20px 24px;
    border-radius: 8px;
    backdrop-filter: blur(14px);
    transition: transform 0.32s ease, border-color 0.32s ease, box-shadow 0.32s ease, background-color 0.32s ease;

    &::before {
      content: "";
      position: absolute;
      inset: 0;
      background: linear-gradient(120deg, transparent 15%, rgba(255, 255, 255, 0.5) 50%, transparent 85%);
      transform: translateX(-130%);
      transition: transform 0.66s ease;
    }

    &::after {
      content: "";
      position: absolute;
      top: 50%;
      right: 24px;
      width: 6px;
      height: 6px;
      border-top: 1px solid rgba(241, 246, 255, 0.92);
      border-right: 1px solid rgba(241, 246, 255, 0.92);
      transform: translateY(-50%) rotate(45deg);
      transition: transform 0.28s ease, border-color 0.28s ease;
      z-index: 2;
    }

    & strong,
    & span {
      position: relative;
      z-index: 1;
    }

    & strong {
      font-size: 1.24rem;
      font-weight: 700;
      color: #ffffff;
    }

    & span {
      font-size: 0.93rem;
      line-height: 1.58;
      color: rgba(218, 228, 246, 0.82);
    }

    &:hover,
    &:focus-visible {
      transform: translate3d(0, -8px, 0) scale(1.015);
      border-color: rgba(255, 255, 255, 0.56);
      box-shadow: 0 20px 45px rgba(4, 11, 24, 0.35);
    }

    &:hover::before,
    &:focus-visible::before {
      transform: translateX(130%);
    }

    &:hover::after,
    &:focus-visible::after {
      transform: translate3d(4px, -50%, 0) rotate(45deg);
    }
  }

  & .setion-split-panel-left .menu-card {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1), rgba(72, 76, 88, 0.24));
  }

  & .setion-split-panel-right .menu-card {
    border-color: rgba(84, 97, 118, 0.26);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.9), rgba(236, 241, 247, 0.94));

    & strong {
      color: #1f2735;
    }

    & span {
      color: rgba(57, 68, 85, 0.8);
    }

    &::after {
      border-top-color: rgba(39, 49, 63, 0.84);
      border-right-color: rgba(39, 49, 63, 0.84);
    }

    &:hover,
    &:focus-visible {
      border-color: rgba(62, 75, 94, 0.5);
      box-shadow: 0 18px 36px rgba(119, 132, 151, 0.22);
    }
  }

  & .setion-split-panel-right .panel-kicker {
    color: rgba(63, 74, 90, 0.72);
  }

  & .setion-split-panel-right .panel-title {
    color: #202734;
    text-shadow: 0 14px 22px rgba(120, 133, 154, 0.2);
  }

  & .setion-split-panel-right .panel-summary {
    color: rgba(53, 63, 78, 0.86);
  }

  & .center-line {
    position: absolute;
    top: 0;
    left: 50%;
    width: 1px;
    height: 100%;
    transform: translateX(-50%);
    z-index: 10;

    & .center-line-core {
      position: absolute;
      inset: 0;
      width: 1px;
      background: linear-gradient(to bottom, transparent, rgba(255, 255, 255, 0.45), transparent);
      transform: scaleY(0);
      transform-origin: center;
    }

    & .center-line-orb {
      position: absolute;
      top: 50%;
      left: 50%;
      width: 16px;
      height: 16px;
      border-radius: 50%;
      background: rgba(235, 243, 255, 0.25);
      transform: translate(-50%, -50%) scale(0.2);
    }
  }
}


/* ===== 04-1. Center Shortcut ===== */
.center-shortcut {
  position: absolute;
  top: 50%;
  left: 50%;
  z-index: 16;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  min-width: 130px;
  height: 130px;
  padding: 0 20px;
  border-radius: 999px;
  background: rgb(var(--rgb-white), 50%);
  backdrop-filter: blur(14px);
  box-shadow: 0 16px 30px rgba(10, 17, 28, 0.18);
  font-size: 20px;
  font-weight: 600;
  color: var(--black);
  transform: translate(-50%, -50%);
  transition: transform 0.2s ease, background-color 0.2s ease,
    border-color 0.2s ease, color 0.2s ease;

  &::after {
    content: "";
    display: block;
    width: 16px;
    height: 16px;
    background: url("../images/arrow-right.svg") no-repeat center center;
    background-size: 100% auto;
    filter: var(--filter-black);
  }

  &:hover,
  &:focus-visible {
    background: rgba(255, 255, 255, 0.24);
    border-color: rgba(255, 255, 255, 0.7);
    transform: translate(-50%, -50%) scale(1.03);
  }
}

@media all and (max-width: 1024px) {
  .center-shortcut {
    min-width: auto;
    height: 60px;
    padding: 0 32px;
    font-size: 20px;
  }
}



/* ===== 05. Floating Copy ===== */
.floating-copy {
  position: absolute;
  bottom: 24px;
  z-index: 8;
  font-family: "Montserrat", sans-serif;
  font-size: clamp(2.4rem, 7.2vw, 7rem);
  font-weight: 900;
  letter-spacing: -0.06em;
  pointer-events: none;
  user-select: none;
  opacity: 0;

  &.floating-copy-left {
    left: 24px;
    color: rgba(233, 241, 255, 0.16);
  }

  &.floating-copy-right {
    right: 24px;
    color: rgba(30, 38, 49, 0.14);
  }
}


/* ===== 06. Particles ===== */
.particles {

  &::before,
  &::after {
    content: "";
    position: absolute;
    width: 2px;
    height: 2px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.56);
    animation: particle-float 10s linear infinite;
  }

  &::before {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
  }

  &::after {
    top: 68%;
    right: 12%;
    animation-delay: 5s;
  }

  &.particles-1 {
    &::before {
      top: 36%;
      left: 78%;
      animation-delay: 2.2s;
    }

    &::after {
      top: 82%;
      left: 20%;
      animation-delay: 7s;
    }
  }

  &.particles-2 {
    &::before {
      top: 14%;
      right: 28%;
      animation-delay: 1.2s;
    }

    &::after {
      top: 58%;
      left: 52%;
      animation-delay: 6s;
    }
  }
}


/* ===== 07. Slider Arrow ===== */
.slider-arrow {
  display: none;
  position: absolute;
  top: 50%;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 999px;
  color: rgb(var(--rgb-black), 10%);
  color: #ffffff;
  font-size: 0;
  line-height: 1;
  transform: translateY(-50%);
  z-index: 40;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  backdrop-filter: blur(8px);
  transition: opacity 0.24s ease, background-color 0.24s ease,
    border-color 0.24s ease;

  &::before {
    content: "";
    display: block;
    width: 8px;
    height: 8px;
    border-top: 1px solid currentColor;
    border-right: 1px solid currentColor;
  }

  &:hover {
    background: rgba(18, 33, 62, 0.78);
    border-color: rgba(255, 255, 255, 0.58);
  }

  &:disabled {
    opacity: 0.3;
    cursor: not-allowed;
  }

  &.slider-arrow-prev {
    left: 10px;

    &::before {
      transform: rotate(-135deg);
      margin-left: 4px;
    }
  }

  &.slider-arrow-next {
    right: 10px;

    &::before {
      transform: rotate(45deg);
      margin-right: 4px;
    }
  }
}


/* ===== 08. Entrance Motion ===== */
.is-ready {

  & .panel-kicker,
  & .panel-title,
  & .panel-summary,
  & .menu-card {
    animation: rise-in 0.9s cubic-bezier(0.22, 1, 0.36, 1) forwards;
  }

  & .panel-title .title-line {
    animation: title-reveal 0.95s cubic-bezier(0.22, 1, 0.36, 1) forwards,
      title-float3d 4.8s ease-in-out 1.05s infinite;

    &:nth-child(2) {
      animation-delay: 0.12s, 1.22s;
    }

    &:nth-child(3) {
      animation-delay: 0.2s, 1.4s;
    }

    &::after {
      animation: title-underline 0.6s ease forwards, title-sheen 3.6s linear 1.2s infinite;
    }
  }

  & .center-line-core {
    animation: line-grow 0.9s cubic-bezier(0.22, 1, 0.36, 1) forwards;
  }

  & .center-line-orb {
    animation: orb-in 0.8s cubic-bezier(0.22, 1, 0.36, 1) 0.25s forwards,
      orb-pulse 2.4s ease-in-out 1s infinite;
  }

  & .floating-copy {
    animation: fade-up 0.95s ease forwards 0.65s;
  }

  & .setion-split-panel-left {
    & .panel-kicker {
      animation-delay: 0.14s;
    }

    & .panel-title {
      animation-delay: 0.24s;
    }

    & .panel-summary {
      animation-delay: 0.34s;
    }

    & .menu-card:nth-child(1) {
      animation-delay: 0.46s;
    }

    & .menu-card:nth-child(2) {
      animation-delay: 0.58s;
    }

    & .menu-card:nth-child(3) {
      animation-delay: 0.7s;
    }
  }

  & .setion-split-panel-right {
    & .panel-kicker {
      animation-delay: 0.28s;
    }

    & .panel-title {
      animation-delay: 0.38s;
    }

    & .panel-summary {
      animation-delay: 0.48s;
    }

    & .menu-card:nth-child(1) {
      animation-delay: 0.6s;
    }

    & .menu-card:nth-child(2) {
      animation-delay: 0.72s;
    }

    & .menu-card:nth-child(3) {
      animation-delay: 0.84s;
    }
  }
}


/* ===== 09. Responsive ===== */
@media (max-width: 1024px) {
  .intro-header {
    top: 16px;
    left: 16px;
    right: 16px;
  }

  .split-layout {
    grid-template-columns: 1fr;
    grid-template-rows: 1fr 1fr;

    & .setion-split-panel {
      min-height: 50vh;

      &.setion-split-panel-right {
        justify-content: flex-start;
      }
    }

    & .panel-inner {
      padding: 100px 6vw 60px;
    }

    & .setion-split-panel-right .panel-inner {
      padding-left: 6vw;
      padding-right: 6vw;
    }

    & .center-line {
      display: none;
    }
  }
}

@media (max-width: 768px) {
  .intro-main {
    perspective: 1200px;
    min-height: 100dvh;
  }

  .intro-header {
    .brand {
      .brand-mark {
        &>img {
          width: 150px;
        }
      }
    }

    .brand-copy {
      font-size: 0.55rem;
      letter-spacing: 0.26em;
      text-align: right;
    }
  }

  .split-layout {
    display: flex;
    overflow-x: auto;
    overflow-y: hidden;
    min-height: 100vh;
    min-height: 100dvh;
    height: 100dvh;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior-x: none;
    overscroll-behavior-y: none;
    scrollbar-width: none;

    &::-webkit-scrollbar {
      display: none;
    }

    & .setion-split-panel {
      flex: 0 0 100vw;
      width: 100vw;
      min-height: 100dvh;
      scroll-snap-align: start;

      &.setion-split-panel-right {
        justify-content: flex-start;
      }
    }

    & .panel-inner {
      padding: 82px 6vw 46px;
    }

    & .panel-title {
      font-size: clamp(2rem, 9.5vw, 3.9rem);
    }

    & .menu-card {
      padding: 16px 52px 16px 18px;
    }
  }

  .floating-copy {
    font-size: clamp(1.35rem, 9vw, 3.8rem);
  }

  .slider-arrow {
    position: fixed;
    display: flex;
    top: 50%;
    width: 32px;
    height: 32px;
    background: rgba(8, 18, 35, 0.62);
    box-shadow: 0 10px 28px rgba(0, 0, 0, 0.22);

    &.slider-arrow-prev {
      left: 12px;
    }

    &.slider-arrow-next {
      right: 12px;
    }
  }

  .center-shortcut {
    position: fixed;
    top: 85px;
    left: 50%;
    min-width: 108px;
    height: 42px;
    padding: 0 18px;
    font-size: 15px;
    color: var(--black);
    background: rgb(var(--rgb-white), 50%);
    border-color: rgba(255, 255, 255, 0.28);
    transform: translateX(-50%);

    &:hover,
    &:focus-visible {
      transform: translateX(-50%) scale(1.03);
      background: rgba(8, 18, 35, 0.82);
      border-color: rgba(255, 255, 255, 0.42);
    }
  }
}

@media (max-width: 480px) {
  .split-layout {
    & .panel-inner {
      padding: 74px 5vw 34px;
    }

    & .panel-title {
      font-size: clamp(1.55rem, 11vw, 3.1rem);
    }

    & .menu-card {
      & strong {
        font-size: 1.08rem;
      }

      & span {
        font-size: 0.88rem;
      }
    }
  }

  .particles {
    display: none;
  }
}


/* ===== 10. Motion Accessibility ===== */
@media (prefers-reduced-motion: reduce) {

  .intro-main,
  .setion-split-panel,
  .setion-split-panel::before,
  .setion-split-panel::after,
  .title-line,
  .title-line::after,
  .menu-card,
  .particles::before,
  .particles::after {
    animation: none !important;
    transition: none !important;
    transform: none !important;
  }
}


/* ===== 11. Keyframes ===== */
@keyframes rise-in {
  0% {
    opacity: 0;
    transform: translate3d(0, 30px, 0);
  }

  100% {
    opacity: 1;
    transform: translate3d(0, 0, 0);
  }
}

@keyframes title-reveal {
  0% {
    opacity: 0;
    transform: translate3d(0, 38px, 0) scaleY(1.12);
  }

  100% {
    opacity: 1;
    transform: translate3d(0, 0, 0) scaleY(1);
  }
}

@keyframes title-float3d {

  0%,
  100% {
    transform: translate3d(0, 0, 0) rotateX(0deg) rotateY(0deg);
    text-shadow: 0 20px 34px rgba(0, 0, 0, 0.25);
    filter: brightness(1);
  }

  30% {
    transform: translate3d(0, -5px, 0) rotateX(7deg) rotateY(-4deg);
    text-shadow: 0 26px 40px rgba(0, 0, 0, 0.32);
    filter: brightness(1.08);
  }

  60% {
    transform: translate3d(0, 2px, 0) rotateX(-4deg) rotateY(4deg);
    text-shadow: 0 16px 28px rgba(0, 0, 0, 0.22);
    filter: brightness(0.98);
  }
}

@keyframes title-underline {
  0% {
    opacity: 0;
    transform: scaleX(0);
  }

  100% {
    opacity: 1;
    transform: scaleX(1);
  }
}

@keyframes title-sheen {
  0% {
    opacity: 0.18;
    filter: brightness(0.9);
  }

  35% {
    opacity: 0.88;
    filter: brightness(1.2);
  }

  65% {
    opacity: 0.32;
    filter: brightness(1);
  }

  100% {
    opacity: 0.2;
    filter: brightness(0.9);
  }
}

@keyframes line-grow {
  0% {
    transform: scaleY(0);
  }

  100% {
    transform: scaleY(1);
  }
}

@keyframes orb-in {
  0% {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.2);
  }

  100% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
}

@keyframes orb-pulse {

  0%,
  100% {
    box-shadow: 0 0 0 0 rgba(128, 167, 255, 0.3);
  }

  50% {
    box-shadow: 0 0 0 18px rgba(128, 167, 255, 0);
  }
}

@keyframes fade-up {
  0% {
    opacity: 0;
    transform: translateY(18px);
  }

  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes particle-float {
  0% {
    transform: translateY(0) rotate(0deg);
    opacity: 0;
  }

  10% {
    opacity: 1;
  }

  90% {
    opacity: 1;
  }

  100% {
    transform: translateY(-100vh) rotate(360deg);
    opacity: 0;
  }
}

@keyframes left-orb-breathe {

  0%,
  100% {
    transform: translate3d(0, 0, 0) scale(0.92);
    opacity: 0.3;
  }

  35% {
    transform: translate3d(-14px, -10px, 0) scale(1.08);
    opacity: 0.44;
  }

  68% {
    transform: translate3d(12px, 8px, 0) scale(0.86);
    opacity: 0.24;
  }
}