:root {
      --richon-orange: #f47920;
      --hero-ink: #191919;
      --sub-ink: #5f5a55;
      --hero-progress: 0;
      --reveal-size: 150vmax;
      --switch-x: 59.5%;
      --switch-y: 46%;
    }

    .hero-scroll {
      position: relative;
      height: 195vh;
      min-height: 1150px;
      background: #fff;
    }

    .hero-sticky {
      position: sticky;
      top: 0;
      width: 100%;
      height: 100svh;
      min-height: 620px;
      overflow: hidden;
      isolation: isolate;
      background: #171717;
    }

    .hero-layer {
      position: absolute;
      inset: 0;
      background-image: url("richon-hero-desktop.webp");
      background-size: cover;
      background-position: center center;
      background-repeat: no-repeat;
      transform: scale(1.012);
      will-change: filter, transform, opacity;
    }

    /* 같은 밝은 원본을 어둡게 만든 OFF 배경 */
    .hero-bg-dark {
      z-index: 0;
      filter: brightness(.27) saturate(.52) contrast(1.04);
    }

    /* 같은 구도의 밝은 원본을 화면 전체에 겹쳐 노출을 올리듯 보여준다. */
    .hero-bg-light {
      z-index: 1;
      opacity: 1;
    }

    .hero-js .hero-bg-light {
      opacity: 0;
    }

    /* OFF 시 따뜻한 검정 계열. 녹색 tint 사용 안 함 */
    .hero-dim {
      position: absolute;
      inset: 0;
      z-index: 2;
      pointer-events: none;
      background:
        linear-gradient(90deg,
          rgba(10, 9, 8, .66) 0%,
          rgba(13, 12, 11, .55) 34%,
          rgba(16, 14, 13, .31) 58%,
          rgba(18, 16, 14, .20) 100%);
      opacity: .88;
      will-change: opacity;
    }

    /* 스위치 주변에 경계가 보이지 않는 넓은 온기만 먼저 생긴다. */
    .switch-glow {
      position: absolute;
      z-index: 3;
      left: var(--switch-x);
      top: var(--switch-y);
      width: clamp(360px, 38vw, 720px);
      aspect-ratio: 1.28;
      border-radius: 50%;
      transform: translate(-50%, -50%) scale(.72);
      pointer-events: none;
      opacity: 0;
      background: radial-gradient(ellipse at center,
        rgba(255, 225, 176, .24) 0%,
        rgba(255, 231, 196, .12) 28%,
        rgba(244, 121, 32, .045) 48%,
        rgba(244, 121, 32, 0) 74%);
      filter: blur(46px);
      mix-blend-mode: screen;
      will-change: opacity, transform;
    }

    .copy-wrap {
      position: absolute;
      z-index: 6;
      left: clamp(28px, 8vw, 150px);
      top: 50%;
      width: min(800px, 51vw);
      transform: translateY(-54%);
    }

    .copy {
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      margin: 0;
      will-change: opacity, transform;
    }

    .copy h1 {
      margin: 0;
      font-size: clamp(38px, 4vw, 72px);
      line-height: 1.16;
      letter-spacing: -.045em;
      font-weight: 800;
      text-wrap: balance;
    }

    .copy-off {
      color: #fff;
      opacity: 0;
      transform: translateY(0);
      text-shadow: 0 2px 28px rgba(0,0,0,.22);
    }

    .hero-js .copy-off { opacity: 1; }

    .copy-on {
      color: var(--hero-ink);
      opacity: 1;
      transform: translateY(0);
    }

    .hero-js .copy-on {
      opacity: 0;
      transform: translateY(22px);
    }

    .copy-on h1 {
      font-size: clamp(36px, 3.35vw, 62px);
    }

    .copy-on .line {
      display: block;
      white-space: nowrap;
    }

    .copy-on .accent {
      color: var(--richon-orange);
      white-space: nowrap;
    }

    .subcopy {
      margin: 26px 0 0;
      font-size: clamp(16px, 1.28vw, 22px);
      line-height: 1.65;
      letter-spacing: -.02em;
      color: var(--sub-ink);
      font-weight: 500;
    }

    .subcopy strong {
      color: #2b2927;
      font-weight: 750;
    }

    /* 첫 화면에서만 보이는 아주 조용한 스크롤 힌트 */
    .scroll-guide {
      position: absolute;
      z-index: 8;
      left: 50%;
      bottom: clamp(26px, 4vh, 46px);
      transform: translateX(-50%);
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 9px;
      color: rgba(255,255,255,.72);
      font-size: 11px;
      font-weight: 650;
      letter-spacing: .24em;
      line-height: 1;
      text-shadow: 0 2px 18px rgba(0,0,0,.34);
      pointer-events: none;
      will-change: opacity, transform;
    }

    .scroll-guide .chevron {
      width: 9px;
      height: 9px;
      border-right: 1.5px solid currentColor;
      border-bottom: 1.5px solid currentColor;
      transform: rotate(45deg);
      animation: scrollNudge 1.7s ease-in-out infinite;
    }

    @keyframes scrollNudge {
      0%, 100% { transform: translateY(0) rotate(45deg); opacity: .55; }
      50% { transform: translateY(6px) rotate(45deg); opacity: 1; }
    }

    /* 공통 헤더 기본 스타일은 frontend/shared/site.css가 소유합니다. */

    @media (max-width: 900px) {
      :root {
        --switch-x: 64%;
        --switch-y: 50%;
      }

      .hero-scroll {
        height: 165vh;
        min-height: 900px;
      }

      .hero-sticky {
        min-height: 560px;
      }

      .hero-layer {
        background-position: 60% center;
        transform: scale(1.02);
      }

      .hero-dim {
        background:
          linear-gradient(180deg,
            rgba(8,8,8,.56) 0%,
            rgba(10,10,10,.38) 48%,
            rgba(12,11,10,.26) 100%);
      }

      .copy-wrap {
        left: 24px;
        right: 24px;
        top: 23%;
        width: auto;
        transform: none;
      }

      .copy h1 {
        font-size: clamp(34px, 9vw, 52px);
        line-height: 1.18;
      }

      .copy-on .line {
        white-space: normal;
      }

      .subcopy {
        margin-top: 20px;
        font-size: 16px;
        line-height: 1.62;
      }
    }

    @media (max-width: 560px) {
      :root {
        --switch-x: 68%;
        --switch-y: 54%;
      }

      .hero-layer {
        background-position: 61% center;
      }

      .copy-wrap {
        top: 17%;
      }

      .copy h1 {
        font-size: clamp(31px, 9.2vw, 44px);
      }

      .subcopy strong {
        display: block;
        margin-bottom: 2px;
      }
    }



    /* ============ 모바일 전용 히어로 ============ */
    @media (max-width: 768px) {
      :root {
        --switch-x: 60.5%;
        --switch-y: 45%;
      }

      .hero-scroll {
        height: 155svh;
        min-height: 760px;
      }

      .hero-sticky {
        height: 100svh;
        min-height: 600px;
      }

      .hero-layer {
        background-image: url("richon-hero-mobile.webp");
        background-size: cover;
        background-position: center center;
        transform: scale(1.006);
      }

      .hero-dim {
        background:
          linear-gradient(180deg,
            rgba(8,8,8,.68) 0%,
            rgba(10,10,10,.48) 32%,
            rgba(12,11,10,.25) 70%,
            rgba(12,11,10,.16) 100%);
      }

      .switch-glow {
        width: clamp(300px, 92vw, 460px);
        aspect-ratio: 1.12;
        filter: blur(52px);
      }

      .copy-wrap {
        left: 24px;
        right: 20px;
        top: clamp(166px, 21svh, 204px);
        width: auto;
        max-width: calc(100vw - 44px);
        transform: none;
      }

      .copy h1 {
        font-size: clamp(31px, 8.4vw, 38px);
        line-height: 1.14;
        letter-spacing: -.04em;
      }

      .copy-on h1 {
        font-size: clamp(30px, 8vw, 36px);
        line-height: 1.14;
      }

      .copy-on .line {
        display: block;
        white-space: nowrap;
      }

      .copy-on .criteria,
      .copy-on .on-phrase {
        display: block;
      }

      .subcopy {
        margin-top: 18px;
        max-width: 330px;
        font-size: 14.5px;
        line-height: 1.55;
      }

      .subcopy strong {
        display: block;
        margin-bottom: 2px;
      }

      .scroll-guide {
        bottom: max(24px, 3.5svh);
        font-size: 10px;
      }
    }

    @media (max-width: 390px) {
      .copy-wrap {
        left: 21px;
        right: 18px;
        top: clamp(154px, 20svh, 188px);
      }

      .copy h1 {
        font-size: clamp(29px, 8.1vw, 33px);
      }

      .copy-on h1 {
        font-size: clamp(28px, 7.8vw, 32px);
      }

      .subcopy {
        font-size: 13.5px;
      }
    }

    @media (prefers-reduced-motion: reduce) {
      .hero-scroll {
        height: 100svh;
        min-height: 620px;
      }

      .hero-bg-dark,
      .hero-dim,
      .copy-off,
      .switch-glow,
      .scroll-guide {
        display: none;
      }

      .hero-bg-light {
        opacity: 1 !important;
      }

      .copy-on {
        opacity: 1 !important;
        transform: none !important;
      }

      .site-nav {
        opacity: 1 !important;
        visibility: visible !important;
        transform: none !important;
        pointer-events: auto !important;
      }
    }
  
/* Production-only integration: no preview interaction disabling. */
.hero-js .site-nav {opacity:0;visibility:hidden;transform:translateY(-16px);pointer-events:none}
html:not(.hero-js) .hero-scroll {height:100svh;min-height:620px}
html:not(.hero-js) .hero-dim {display:none}
html:not(.hero-js) .reveal {opacity:1;transform:none}
#top {display:block;height:0}
#proof,#programs,#instructor {scroll-margin-top:90px}
@media(prefers-reduced-motion:reduce){.hero-js .site-nav {opacity:1;visibility:visible;transform:none;pointer-events:auto}}