@font-face {
  font-family: "Cormorant Infant";
  font-weight: 300;
  font-style: normal;
  src: url("../fonts/CormorantInfant-Light.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 300;
  font-style: italic;
  src: url("../fonts/CormorantInfant-LightItalic.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 400;
  font-style: normal;
  src: url("../fonts/CormorantInfant-Regular.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 400;
  font-style: italic;
  src: url("../fonts/CormorantInfant-Italic.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 500;
  font-style: normal;
  src: url("../fonts/CormorantInfant-Medium.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 500;
  font-style: italic;
  src: url("../fonts/CormorantInfant-MediumItalic.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 500;
  font-style: normal;
  src: url("../fonts/CormorantInfant-SemiBold.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 500;
  font-style: italic;
  src: url("../fonts/CormorantInfant-SemiBoldItalic.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 700;
  font-style: normal;
  src: url("../fonts/CormorantInfant-Bold.ttf") format("truetype");
}
@font-face {
  font-family: "Cormorant Infant";
  font-weight: 700;
  font-style: italic;
  src: url("../fonts/CormorantInfant-BoldItalic.ttf") format("truetype");
}

@font-face {
  font-family: "ChillHuoKai";
  font-weight: 400;
  font-style: normal;
  src: url("../fonts/ChillHuoKai_Regular.otf") format("opentype");
}
@font-face {
  font-family: "ChillHuoKai";
  font-weight: 500;
  font-style: normal;
  src: url("../fonts/ChillHuoKai_ConRegular.otf") format("opentype");
}
@font-face {
  font-family: "ChillHuoKai";
  font-weight: 700;
  font-style: normal;
  src: url("../fonts/ChillHuoKai_ConBold.otf") format("opentype");
}

:root {
  --ink: #124b54;
  --muted: #527579;
  --paper: #f6f1e6;
  --line: rgba(29, 82, 82, 0.14);
  font-family:
    "Cormorant Infant", "Iowan Old Style", "Songti SC", "Noto Serif SC",
    Georgia, serif;
  color: var(--ink);
  background: #eaf2ee;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0 auto;
  min-width: 320px;
  max-width: 1920px;
  background:
    radial-gradient(
      circle at 16% 8%,
      rgba(255, 250, 236, 0.72),
      transparent 34%
    ),
    radial-gradient(
      circle at 82% 72%,
      rgba(225, 239, 234, 0.34),
      transparent 38%
    ),
    linear-gradient(180deg, #f6f1e6 0%, #f5f0e5 100%);
  -webkit-font-smoothing: antialiased;
}

@media (min-width: 769px) {
  body {
    min-width: 1448px;
  }
}

button {
  font: inherit;
  cursor: pointer;
}

.page {
  width: 1400px;
  margin: 0px auto 0;
  /* overflow: hidden; */
  position: relative;
  z-index: 2;
  /* border-radius: 24px; */
  /* background: linear-gradient(180deg, #f6f1e6 0%, #f5f0e5 100%); */
  /* box-shadow: 0 24px 80px rgba(34, 77, 71, 0.12); */
}

.hero {
  position: relative;
  width: 100%;
  overflow: hidden;
}

.lang-switch {
  position: absolute;
  top: 30px;
  right: 40px;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.76);
  border: 1px solid rgba(24, 78, 75, 0.15);
  padding: 6px 14px;
  border-radius: 999px;
  box-shadow: 0 4px 16px rgba(45, 94, 82, 0.08);
  backdrop-filter: blur(8px);
  font-size: 16px;
}

.hero-bg-wap {
  display: none;
  width: 100%;
  height: auto;
}

.lang-switch a,
.lang-switch button {
  border: 0;
  background: transparent;
  padding: 0;
  font-weight: 500;
  color: var(--muted);
  transition: color 150ms ease;
  text-decoration: none;
  cursor: pointer;
}

.lang-switch a.is-active,
.lang-switch button.is-active {
  color: var(--ink);
  font-weight: 700;
}

.lang-switch span {
  color: rgba(29, 82, 82, 0.3);
}

.hero-bg {
  position: relative;
  width: 100%;
}

.hero-logo {
  display: block;
  max-width: 180px;
  width: 100%;
  height: auto;
  margin: 20px auto 0;
}

.hero-bg-pc {
  display: block;
  width: 100%;
  height: auto;
}

.footer-visual > img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1;
  height: 150px;
  background: linear-gradient(
    180deg,
    rgba(246, 241, 230, 0),
    rgba(246, 241, 230, 0.72) 62%,
    #f6f1e6
  );
  pointer-events: none;
}

.hero-copy,
.songs,
.experience,
.footer-visual > div {
  position: relative;
  z-index: 2;
}

.footer-visual button {
  border: 1px solid rgba(24, 78, 75, 0.18);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.76);
  box-shadow: 0 10px 28px rgba(45, 94, 82, 0.13);
  backdrop-filter: blur(8px);
}

.hero-copy {
  position: absolute;
  top: 16%;
  left: 7%;
  width: 46.5%;
  max-width: 900px;
  margin: 0;
}

.hero-copy-en {
  max-width: 1350px;
  top: 30%;
  left: 7%;
  width: 60.5%;
}

.hero-title-img {
  width: 100%;
  height: auto;
  display: block;
}

.hero-copy h1 {
  margin: 0;
  color: #1c6670;
  font-size: clamp(56px, 6.4vw, 92px);
  font-style: italic;
  font-weight: 500;
  line-height: 0.95;
}

.subtitle {
  margin: 16px 0 20px;
  color: #1f636b;
  font-size: clamp(30px, 3.2vw, 48px);
  font-style: italic;
}

.cn {
  margin: 0 0 32px 70px;
  color: #224b50;
  font-size: 22px;
  letter-spacing: 3px;
}

.songs-container {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  margin-bottom: 0;
  visibility: hidden;
  width: 100%;
  transition:
    max-height 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    opacity 0.6s ease,
    margin-bottom 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    visibility 0.8s step-end;
}

.songs-container.is-open {
  max-height: 1200px;
  opacity: 1;
  margin-bottom: 20px;
  /* margin-top: 20px; */
  visibility: visible;
  width: calc(100% + 24px);
  margin-left: -12px;
  margin-right: -12px;
  padding: 8px;
  box-sizing: border-box;
  transition:
    max-height 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    opacity 0.8s ease,
    margin-bottom 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    visibility 0.8s step-start;
}

.songs {
  display: grid;
  grid-template-columns: 200px repeat(4, minmax(0, 1fr));
  gap: 20px;
  padding: 24px 28px 18px;
  background: rgba(250, 248, 240, 0.94);
  border-radius: 24px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.15);
  min-height: 0;
}

/* Staggered entrance animation for song cards */
.songs .section-intro,
.songs .song-card {
  opacity: 0;
  transform: translateY(24px);
  transition:
    transform 0.6s cubic-bezier(0.16, 1, 0.3, 1),
    opacity 0.6s ease;
}

.songs-container.is-open .section-intro {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.1s;
}

.songs-container.is-open .song-list-scroll .song-card:nth-child(1) {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.2s;
}

.songs-container.is-open .song-list-scroll .song-card:nth-child(2) {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.3s;
}

.songs-container.is-open .song-list-scroll .song-card:nth-child(3) {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.4s;
}

.songs-container.is-open .song-list-scroll .song-card:nth-child(4) {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.5s;
}

.section-intro {
  position: relative;
  padding: 30px 16px;
  border-radius: 18px;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  box-sizing: border-box;
  overflow: hidden;
}

.section-intro .cloud-tr {
  position: absolute;
  top: 0px;
  right: 4px;
  width: 50px;
  height: auto;
  pointer-events: none;
}

.section-intro .cloud-bl {
  position: absolute;
  bottom: 4px;
  left: 4px;
  width: 50px;
  height: auto;
  pointer-events: none;
}

.section-intro .intro-icon {
  width: 88px;
  height: auto;
  margin-bottom: 16px;
  display: block;
}

.section-intro h3 {
  margin: 0 0 16px;
  font-size: 20px;
  letter-spacing: 2px;
  word-wrap: break-word;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1.3;
}

.section-intro h3 .sub-title {
  font-size: 15px;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 2px;
  margin-bottom: 4px;
}

.section-intro h3 .main-title {
  font-size: 30px;
  font-weight: 700;
  font-style: italic;
  color: var(--ink);
  letter-spacing: 4px;
  margin-bottom: 4px;
}

.section-intro h3 .desc-title {
  font-size: 17px;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: 3px;
}

.section-intro p {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

.song-list-scroll {
  display: contents;
}

.song-card-img-wap {
  display: none !important;
}

.song-card {
  position: relative;
  min-height: 220px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 16px;
  color: var(--ink);
  text-align: left;
  background: #fff;
  box-shadow: 0 12px 28px rgba(44, 76, 70, 0.12);
  transition:
    transform 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    border-color 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    background-color 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.song-card img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.song-card::after {
  display: none;
}

.song-card strong,
.song-card small,
.song-card span {
  position: relative;
  z-index: 1;
  display: block;
}

.song-card strong {
  margin: -60px 0 8px 8px;
  font-size: 20px;
  letter-spacing: 2px;
}

.song-card small {
  margin-left: 24px;
  font-size: 16px;
}

.song-card span {
  position: absolute;
  left: 24px;
  bottom: 22px;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  color: #1b7378;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 6px 18px rgba(32, 72, 69, 0.15);
  font-size: 22px;
  transition:
    transform 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    background-color 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    color 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.song-card span .play-icon {
  margin-left: 2px;
}

.song-card:hover {
  transform: translateY(-6px);
  border-color: rgba(38, 121, 111, 0.46);
  box-shadow: 0 18px 34px rgba(45, 90, 84, 0.2);
}

.song-card:hover span {
  transform: scale(1.08);
}

.song-card.is-active {
  transform: translateY(-4px);
  border-color: var(--ink);
  background-color: #f2f7f5;
  box-shadow:
    0 12px 28px rgba(18, 75, 84, 0.16),
    inset 0 0 0 1px var(--ink);
}

.song-card.is-active span {
  background-color: var(--ink);
  color: #ffffff;
  box-shadow: 0 6px 14px rgba(18, 75, 84, 0.3);
}

.song-card.is-active:hover {
  transform: translateY(-6px);
  box-shadow:
    0 18px 34px rgba(18, 75, 84, 0.22),
    inset 0 0 0 1px var(--ink);
}

.song-card.is-active:hover span {
  transform: scale(1.08);
  box-shadow: 0 8px 18px rgba(18, 75, 84, 0.4);
}

.song-card:active {
  transform: scale(0.96) translateY(-2px);
  transition: transform 0.1s ease;
}

.experience {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0;
  padding: 0;
  transition: gap 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.experience.has-player {
  gap: 20px;
}

.interactive-panel {
  display: grid;
  grid-template-columns: 1fr 450px;
  gap: 30px;
  /* padding: 36px; */
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 12px 28px rgba(44, 76, 70, 0.11);
  background: url("../images/panel-bg.png") center / cover;
  min-height: 520px;
}

.player-card {
  position: relative;
  box-sizing: border-box;
  border-radius: 18px;
  background: url("../images/play-card-bg.png") center bottom / cover;
  box-shadow: 0 12px 28px rgba(44, 76, 70, 0.11);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;

  /* Collapsed state by default */
  width: 0;
  max-height: 0;
  min-height: 0;
  opacity: 0;
  padding: 0;
  border: 0px solid var(--line);
  overflow: hidden;
  transform: translateX(-30px) scale(0.95);
  visibility: hidden;

  transition:
    width 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    max-height 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    padding 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    opacity 0.6s ease,
    transform 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    border-width 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    visibility 0.8s step-end;
}

.experience.has-player .player-card {
  width: 355px;
  max-height: 918px;
  min-height: 420px;
  padding: 32px 28px;
  border: 1px solid var(--line);
  opacity: 1;
  transform: translateX(0) scale(1);
  visibility: visible;
  transition:
    width 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    max-height 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    padding 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    opacity 0.8s ease 0.1s,
    transform 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    border-width 0.8s cubic-bezier(0.16, 1, 0.3, 1),
    visibility 0.8s step-start;
}

.player-card h3 {
  margin: 0 0 8px;
  font-size: 24px;
  /* letter-spacing: 3px; */
  margin-top: 60px;
  margin-bottom: 20px;
}

.player-card p {
  margin: 0;
}

.player-cd-wrap {
  display: none;
}

.playing-line {
  display: flex;
  flex-direction: column;
  align-items: center;
  align-self: stretch;
  margin: 30px 0 30px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.7);
  box-sizing: border-box;
  position: absolute;
  bottom: 38%;
  left: 50%;
  width: 85%;
  transform: translateX(-50%);
}

.playing-info-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
  font-size: 14px;
}

.playing-info-wrap img {
  width: 16px;
  height: 16px;
  display: block;
}

.player-slider-container {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
}

.slider-time {
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  min-width: 38px;
  text-align: center;
}

.player-slider-container input[type="range"] {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  border-radius: 999px;
  background: rgba(29, 82, 82, 0.12);
  outline: none;
  cursor: pointer;
  transition: background 0.2s ease;
  margin: 0;
}

.player-slider-container input[type="range"]:hover {
  background: rgba(29, 82, 82, 0.2);
}

.player-slider-container input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--ink);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.15);
  cursor: pointer;
  transition:
    transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275),
    background-color 0.2s ease;
}

.player-slider-container input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.3);
  background: #1e5e67;
}

.player-slider-container input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border: none;
  border-radius: 50%;
  background: var(--ink);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.15);
  cursor: pointer;
  transition:
    transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275),
    background-color 0.2s ease;
}

.player-slider-container input[type="range"]::-moz-range-thumb:hover {
  transform: scale(1.3);
  background: #1e5e67;
}

.lyrics {
  color: #234f54;
  font-size: 17px;
  line-height: 1.8;
  height: 96px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.player-actions {
  position: absolute;
  bottom: 30%;
  left: 9.3%;
  right: 9.3%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  margin: 0;
}

.player-actions button {
  display: grid;
  place-items: center;
  border: 1.5px solid rgba(23, 76, 76, 0.3);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.85);
  width: 52px;
  height: 52px;
  transition: all 0.2s ease;
  box-shadow: 0 4px 10px rgba(29, 82, 82, 0.08);
}

.player-actions button[data-action="toggle"] {
  width: 60px;
  height: 60px;
  border-width: 2px;
  box-shadow: 0 6px 14px rgba(29, 82, 82, 0.12);
}

.player-actions button:hover {
  transform: scale(1.06);
  border-color: var(--ink);
  background: #ffffff;
  color: #1a7378;
}

.player-actions button:active {
  transform: scale(0.96);
}

.player-hints {
  position: absolute;
  bottom: 26.5%;
  left: 9.3%;
  right: 9.3%;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  justify-content: center;
  margin: 0;
  font-size: 13px;
  color: #000;
}

.player-hints span {
  white-space: nowrap;
}

.music-source {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  color: #7a9b97;
}

.assembly-card {
  padding: 36px;
  position: relative;
  text-align: center;
  display: flex;
  flex-direction: column;
}

.header-icon {
  width: 120px;
  height: auto;
  object-fit: contain;
  margin: 0 auto;
}

.assembly-card h3 {
  margin: 0 0 12px;
  font-size: 28px;
  letter-spacing: 5px;
  color: #0d4d58;
}

.assembly-subtitle {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 500;
  color: #0d4d58;
}

.assembly-prompt {
  margin: 0 0 10px;
  font-size: 16px;
  color: #6d8f8a;
  line-height: 1.5;
}

.erhu-guide {
  position: relative;
  flex: 1;
  min-height: 450px;
  /* background: url("../images/hero-wuxi-erhu.png") center bottom / contain
    no-repeat; */
  margin-top: 10px;
}

/* When erhu is completely assembled: hide loose parts/masks/dots and show a single unified image */
.assembly-card.is-assembled .part1,
.assembly-card.is-assembled .part2,
.assembly-card.is-assembled .part3,
.assembly-card.is-assembled .part4,
.assembly-card.is-assembled .part5,
.assembly-card.is-assembled .mask,
.assembly-card.is-assembled .dot {
  display: none !important;
}

.assembly-card.is-assembled .erhu-guide {
  background: url("../images/erhu.png") no-repeat center bottom / contain !important;
  min-height: 450px;
}

/* PC Reset Button Styling */
.reset-btn-pc {
  display: none;
  position: absolute;
  bottom: 24px;
  right: 24px;
  padding: 10px 24px;
  border: 1px solid rgba(24, 78, 75, 0.25);
  border-radius: 999px;
  font-size: 16px;
  font-weight: 500;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.85);
  box-shadow: 0 4px 12px rgba(45, 94, 82, 0.1);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition:
    transform 0.2s ease,
    background-color 0.2s ease,
    border-color 0.2s ease,
    box-shadow 0.2s ease;
  z-index: 10;
  cursor: pointer;
  letter-spacing: 1px;
}

.reset-btn-pc:hover {
  background: #ffffff;
  border-color: var(--ink);
  transform: scale(1.04);
  box-shadow: 0 6px 16px rgba(45, 94, 82, 0.15);
}

.reset-btn-pc:active {
  transform: scale(0.96);
}

.assembly-card.is-assembled .reset-btn-pc {
  display: block;
}

.parts-card {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: 12px;
  padding: 12px;
  position: relative;
}

.drag-tip.is-hidden {
  display: none;
}

.parts-title {
  margin: 0 0 8px;
  font-size: 15px;
  font-weight: 500;
  color: #0d4d58;
}

.part {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 18px;
  background: #eaf2ee url("../images/part-bg.jpg") center / cover;
  border: 1px solid rgba(29, 82, 82, 0.12);
  border-radius: 16px;
  min-height: 84px;
  box-shadow: 0 4px 12px rgba(44, 76, 70, 0.04);
  transition: all 180ms ease;
  color: var(--ink);
  text-align: left;
}

.part-info {
  flex: 1;
}

.part strong {
  margin-bottom: 4px;
  font-size: 17px;
  display: block;
}

.part small {
  color: var(--ink);
  line-height: 1.4;
  font-size: 16px;
  font-weight: 400;
  display: block;
}

.part-thumb {
  width: 115px;
  height: 115px;
  padding: 5px;
  margin-right: 5px;
  object-fit: contain;
  flex-shrink: 0;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.part:not(.is-placed) .part-thumb {
  cursor: grab;
}

.part:not(.is-placed):hover .part-thumb {
  transform: scale(1.06);
}

.part.is-dragging .part-thumb {
  cursor: grabbing;
}

.part.is-placed {
  border-color: rgba(38, 121, 111, 0.34);
  box-shadow: 0 8px 20px rgba(43, 83, 76, 0.08);
}

.footer-visual {
  position: relative;
  display: grid;
  place-items: center;
  width: 100%;
  min-height: 320px;
  margin-top: -74px;
  padding-top: 74px;
  overflow: hidden;
  text-align: center;
}

@media (min-width: 769px) {
  .footer-visual {
    display: block;
    min-height: auto;
    padding-top: 0;
  }
  .footer-visual > img {
    position: relative;
    height: auto;
    display: block;
  }
  .footer-visual > div {
    position: absolute;
    top: 65%;
    left: 50%;
    transform: translate(-50%, -30%);
    width: auto;
  }
}

.footer-visual::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(
      180deg,
      #f5f0e5 0%,
      rgba(245, 240, 229, 0.9) 18%,
      rgba(245, 240, 229, 0.34) 42%,
      rgba(237, 245, 240, 0.24) 100%
    ),
    rgba(255, 252, 244, 0.12);
}

.footer-visual::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  z-index: 1;
  height: 130px;
  background: linear-gradient(
    180deg,
    #f5f0e5,
    rgba(245, 240, 229, 0.66) 55%,
    rgba(245, 240, 229, 0)
  );
  pointer-events: none;
}

.footer-visual > div {
  width: 80%;
}

.footer-visual h3 {
  margin: 0 0 10px;
  font-size: 30px;
  letter-spacing: 0px;
}

.footer-visual .footer-subtitle {
  margin: 0 0 10px;
  font-size: 16px;
  font-weight: 500;
  color: #2d6d6b;
}

.footer-visual p {
  margin: 0 0 0px;
  font-size: 18px;
  line-height: 1.6;
}

.footer-visual button {
  padding: 10px 24px;
  color: var(--ink);
}

.status {
  position: fixed;
  left: 50%;
  bottom: 28px;
  z-index: 10;
  max-width: min(86vw, 520px);
  padding: 10px 16px;
  border: 1px solid rgba(28, 85, 82, 0.18);
  border-radius: 999px;
  color: #164c53;
  background: rgba(255, 255, 255, 0.84);
  box-shadow: 0 12px 28px rgba(49, 72, 67, 0.13);
  opacity: 0;
  transform: translate(-50%, 10px);
  transition:
    opacity 180ms ease,
    transform 180ms ease;
  pointer-events: none;
  backdrop-filter: blur(8px);
}

.status.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

.part1 {
  position: absolute;
  top: 42%;
  left: 43%;
  width: 48px;
  height: 255px;
  transform: translateY(-7px);
  background-color: transparent;
  z-index: 5;
}

.part1.placed {
  background: url("../images/erhu-neck.png") no-repeat center / contain !important;
  background-color: transparent !important;
  opacity: 1 !important;
  top: 45.5%;
  left: 42.2%;
  width: 57px;
  height: 255px;
}

.part2 {
  position: absolute;
  top: 17%;
  left: 40.4%;
  width: 141px;
  height: 249px;
  transform: translateY(-7px);
  background-color: transparent;
  z-index: 5;
}

.part2.placed {
  background: url("../images/erhu-pegs.png") no-repeat center / contain !important;
  background-color: transparent !important;
  opacity: 1 !important;
}

.part3 {
  position: absolute;
  top: 34.6%;
  left: 39%;
  width: 50px;
  height: 361px;
  transform: translateY(-7px);
  background-color: transparent;
}

.part3.placed {
  background: url("../images/erhu-strings.png") no-repeat center / contain !important;
  background-color: transparent !important;
  opacity: 1 !important;
  left: 39.5%;
}

.part4 {
  position: absolute;
  top: 80%;
  left: 37%;
  width: 165px;
  height: 130px;
  transform: translateY(-7px);
  background-color: transparent;
}

.part4.placed {
  background: url("../images/erhu-body.png") no-repeat center / contain !important;
  background-color: transparent !important;
  opacity: 1 !important;
  left: 36.95%;
}

.part5 {
  position: absolute;
  top: 27%;
  left: 61%;
  width: 35px;
  height: 591px;
  transform: translateY(-7px);
  rotate: 9.5deg;
  background-color: transparent;
}

.part5.placed {
  background: url("../images/erhu-bow.png") no-repeat center / contain !important;
  background-color: transparent !important;
  opacity: 1 !important;
  width: 150px;
  height: 640px;
  rotate: 0deg;
  top: 23%;
  left: 55%;
}

.mask {
  position: absolute;
  background: rgba(255, 255, 255, 0);
  font-size: 11px;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none; /* Crucial so that mouse events (drags) pass through to .part1-.part5 */
  z-index: 5;
}

.mask1 {
  top: 47%;
  left: 43%;
  width: 48px;
  height: 255px;
  transform: translateY(-7px);
}

.mask2 {
  top: 18%;
  left: 40%;
  width: 100px;
  height: 236px;
  transform: translateY(-7px);
}

.mask3 {
  top: 32%;
  left: 38%;
  width: 50px;
  height: 400px;
  transform: translateY(-7px);
}

.mask4 {
  top: 80%;
  left: 37%;
  width: 165px;
  height: 130px;
  transform: translateY(-7px);
}

.mask5 {
  top: 27%;
  left: 61%;
  width: 35px;
  height: 591px;
  transform: translateY(-7px);
  rotate: 9.5deg;
}

/* Five small red dot indicators */
.dot {
  position: absolute;
  width: 22px;
  height: 22px;
  background: transparent;
  border: 2.5px solid #e74c3c;
  border-radius: 50%;
  z-index: 6;
  pointer-events: none;
  box-shadow: 0 0 6px rgba(231, 76, 60, 0.4);
  transform: translate(-50%, -50%);
  transition:
    opacity 0.3s ease,
    visibility 0.3s ease,
    transform 0.3s ease;
}

.dot1 {
  top: 57%;
  left: 46%;
}

.dot2 {
  top: 30%;
  left: 46%;
}

.dot3 {
  top: 52%;
  left: 41%;
}

.dot4 {
  top: 86%;
  left: 46%;
}

.dot5 {
  top: 50%;
  left: 65%;
}

/* Hide masks when the parts are placed */
.part1.placed ~ .mask1,
.part2.placed ~ .mask2,
.part3.placed ~ .mask3,
.part4.placed ~ .mask4,
.part5.placed ~ .mask5 {
  opacity: 0;
  visibility: hidden;
  transform: translateY(-7px) scale(0.9);
}

/* Hide red dots when corresponding part is placed */
.part1.placed ~ .dot1,
.part2.placed ~ .dot2,
.part3.placed ~ .dot3,
.part4.placed ~ .dot4,
.part5.placed ~ .dot5 {
  opacity: 0;
  visibility: hidden;
  transform: translate(-50%, -50%) scale(0.5);
}

/* Drag and drop highlight effects */
/* .part1.drag-hover,
.part2.drag-hover,
.part3.drag-hover,
.part4.drag-hover,
.part5.drag-hover {
  background-color: #276a6d !important;
  opacity: 0.8 !important;
  transform: scale(1.1);
  transition:
    transform 150ms ease,
    background-color 150ms ease;
} */

.part1.placed,
.part2.placed,
.part3.placed,
.part4.placed,
.part5.placed {
  opacity: 1 !important;
}
.part4.placed {
  background-size: 180px auto !important;
  height: 230px;
  top: 72%;
}
.is-hidden {
  display: none !important;
}

/* Drag states and placement feedback */
.part.is-dragging {
  opacity: 0.5;
  border-style: dashed;
  border-color: #276a6d;
  background: rgba(234, 242, 238, 0.6);
  transform: scale(0.98);
}

.part.is-placed {
  /* border-color: rgba(93, 155, 135, 0.5) !important;
  background: rgba(246, 250, 248, 0.95) url("../images/part-bg.jpg") center /
    cover !important;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1); */
}

.part.is-placed .part-thumb {
  border-color: #5d9b87;
  filter: grayscale(0.2) opacity(0.85);
}

.footer-btn {
  display: block;
  max-width: 250px;
  margin: 20px auto 0;
  object-fit: contain !important;
  cursor: pointer;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.footer-btn:hover {
  transform: scale(1.05);
}

.footer-btn:active {
  transform: scale(0.96);
}

.footer-visual {
  margin-top: -15%;
}
.footer-visual .footer-content {
  /* padding-bottom: 70px; */
}
/* Hide mobile-only UI on desktop */
@media (min-width: 769px) {
  .mobile-controls,
  .page-start-btn {
    display: none;
  }

  .drag-tip {
    display: block;
    position: absolute;
    bottom: 97%;
    left: 70%;
    margin-bottom: 12px;
    width: 200px;
    background: #0d4d58;
    color: #fff;
    font-size: 14px;
    line-height: 1.5;
    padding: 10px 16px;
    border-radius: 8px;
    text-align: left;
    z-index: 200;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  }

  .drag-tip::after {
    content: "";
    position: absolute;
    bottom: -8px;
    left: 24px;
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-top: 8px solid #0d4d58;
  }
}

@media (max-width: 768px) {
  .drag-tip {
    display: none;
  }
  .interactive-panel {
    background: url("../images/panel-bg.png") 10% center / cover;
  }

  .hero-bg-pc {
    display: none;
  }

  .hero-bg-wap {
    display: block;
  }

  .hero-logo {
    max-width: 120px;
    margin-top: 15px;
  }

  .hero::before {
    height: 8px;
  }
  .songs-container {
    display: none !important;
  }

  .lang-switch {
    top: 15px;
    right: 10px;
  }
  .page {
    width: min(100% - 24px, 1400px);
    margin-top: -20px;
  }

  /* .hero height is determined by .hero-bg image flow */

  .hero-copy {
    position: absolute;
    top: 34%;
    left: 2%;
    width: 98%;
    margin: 0;
    transform: none;
  }

  .hero-zh {
    top: 26%;
    left: 7%;
    width: 64%;
  }

  .cn {
    margin-left: 0;
  }

  .interactive-panel {
    grid-template-columns: 1fr;
  }

  .songs {
    display: flex;
    flex-direction: column;
    gap: 20px;
    padding: 24px 20px;
    background: rgba(250, 248, 240, 0.94);
    border-radius: 24px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.15);
  }

  .song-list-scroll {
    display: flex;
    flex-direction: row;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    gap: 16px;
    scrollbar-width: none;
    padding: 6px 0;
  }

  .song-list-scroll::-webkit-scrollbar {
    display: none;
  }

  .songs .section-intro {
    width: 100%;
    box-sizing: border-box;
    padding: 20px 16px;
  }

  .song-card-img-pc {
    display: none !important;
  }

  .song-card-img-wap {
    display: block !important;
  }

  .song-list-scroll .song-card {
    flex: 0 0 78%;
    scroll-snap-align: start;
    box-sizing: border-box;
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
    min-height: auto !important;
    display: flex !important;
    justify-content: center !important;
    align-items: center !important;
    padding: 35px !important;
    transform: none !important;
  }

  .song-list-scroll .song-card strong,
  .song-list-scroll .song-card span {
    display: none !important;
  }

  .song-list-scroll .song-card img.song-card-img-wap {
    position: static !important;
    width: 220px !important;
    height: 220px !important;
    object-fit: contain !important;
    border-radius: 50% !important;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
    transition: filter 0.3s ease;
    animation: spin 15s linear infinite;
    animation-play-state: paused;
  }

  .song-list-scroll .song-card.is-playing img.song-card-img-wap {
    animation-play-state: running;
  }

  .song-list-scroll .song-card.is-active img.song-card-img-wap {
    box-shadow: 0 12px 32px rgba(18, 75, 84, 0.28);
    filter: drop-shadow(0 0 8px rgba(27, 115, 120, 0.3));
  }

  .song-list-scroll .song-card:active {
    transform: scale(0.96) !important;
    transition: transform 0.1s ease !important;
  }

  .experience {
    grid-template-columns: 1fr;
    grid-template-rows: 0fr 1fr;
    gap: 0;
    transition:
      grid-template-rows 0.8s cubic-bezier(0.16, 1, 0.3, 1),
      gap 0.8s cubic-bezier(0.16, 1, 0.3, 1);
  }

  .experience.has-player {
    grid-template-rows: auto 1fr;
    gap: 20px;
    /* margin-top: 40px; */
  }

  body[data-current-step="4"] .experience.has-player {
    /* margin-top: 60px; */
    padding-top: 40px;
  }

  .player-card {
    width: 100% !important;
    max-height: 0;
    min-height: 0 !important;
    padding: 0 28px;
    transform: translateY(-20px) scale(0.95);
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    text-align: center !important;
    overflow: hidden;
    transition:
      max-height 0.8s cubic-bezier(0.16, 1, 0.3, 1),
      padding 0.8s cubic-bezier(0.16, 1, 0.3, 1),
      opacity 0.6s ease,
      transform 0.8s cubic-bezier(0.16, 1, 0.3, 1),
      border-width 0.8s cubic-bezier(0.16, 1, 0.3, 1),
      visibility 0.8s step-end;
  }

  .experience.has-player .player-card {
    max-height: 700px !important;
    min-height: max(85vh, 800px) !important;
    padding: 24px 28px;
    transform: translateY(0) scale(1);
    overflow: visible !important;
  }

  .player-card h3 {
    margin-top: 0px !important;
    margin-bottom: 4px !important;
    font-size: 24px !important;
  }

  .player-card p#song-en {
    margin-bottom: 8px !important;
    font-size: 15px !important;
  }

  .player-cd-wrap {
    display: flex;
    justify-content: center;
    margin: 8px 0 16px 0 !important;
  }

  #player-cd-img {
    width: 170px !important;
    height: 170px !important;
    object-fit: contain;
    border-radius: 50%;
    box-shadow: 0 8px 24px rgba(18, 75, 84, 0.15);
    border: 1px solid rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: transform 0.3s ease;
    animation: spin 15s linear infinite;
    animation-play-state: paused;
  }

  .player-card.is-playing #player-cd-img {
    animation-play-state: running;
  }

  #player-cd-img:active {
    transform: scale(0.96);
  }

  .playing-line {
    margin: 10px 0 10px !important;
    padding: 6px 12px !important;
    font-size: 14px !important;
  }

  .lyrics {
    font-size: 18px !important;
    line-height: 1.2 !important;
    margin: 8px 0 !important;
    padding: 8px 16px !important;
    border-radius: 8px !important;
    color: #040404;
  }

  .player-hints {
    position: absolute;
    bottom: 29.5%;
    left: 9.3%;
    right: 9.3%;
    width: auto;
    margin: 0;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 6px 12px;
    padding: 6px 12px;
    border-radius: 8px;
    font-size: 12px;
    color: #040404;
    box-shadow: none;
  }

  .player-actions {
    position: absolute;
    bottom: 33.5%;
    left: 9.3%;
    right: 9.3%;
    margin: 0;
  }

  .interactive-panel {
    gap: 20px;
    padding: 20px;
  }

  .song-card {
    min-height: auto;
    padding-bottom: 52px;
    min-height: 220px;
  }
  .footer-content {
    position: absolute !important;
    width: 100%;
    top: 18%;
    left: 0%;
    padding: 10px;
    /* display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    padding: 10px 20px;
    box-sizing: border-box;
    transform: translateY(-30px); */
  }
  .footer-visual {
    margin-top: -10%;
  }
  .footer-visual h3 {
    font-size: 24px;
  }

  .footer-visual > div {
    width: auto;
  }

  /* ========== Mobile Step System ========== */

  /* Body padding: only when controls are visible (steps 2-4) */
  body[data-current-step] {
    padding-bottom: 80px;
    min-height: 100vh;
  }

  /* Step 1: full-height flex layout for hero / page / footer */
  body[data-current-step="1"] {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    padding-bottom: 0;
  }

  body[data-current-step="1"] .hero,
  body[data-current-step="1"] .footer-visual {
    flex-shrink: 0;
  }

  body[data-current-step="1"] .page {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    flex: 1 0 auto;
    flex-shrink: 0;
    margin-top: 0;
    text-align: center;
    margin-top: -20%;
  }

  /* Step 1: prevent grid collapsing (0fr row squashes content) */
  body[data-current-step="1"] .experience {
    grid-template-rows: auto;
    display: flex;
    flex-direction: column;
  }

  body[data-current-step="1"] .assembly-card {
    padding: 0px;
  }

  /* Step 1: interactive-panel should not constrain height */
  body[data-current-step="1"] .interactive-panel {
    min-height: 300px;
    min-width: 280px;
    margin: 10px;
  }

  body[data-current-step="1"] .assembly-prompt {
    margin-top: 12px;
  }

  /* Step 2: same grid fix, parts-card needs full height to show all parts */
  body[data-current-step="2"] .experience {
    grid-template-rows: auto;
    display: flex;
    flex-direction: column;
    padding: 0;
    height: 93vh;
  }

  body[data-current-step="2"] .interactive-panel {
    min-height: 0;
    overflow-y: auto;
    padding-top: 0px;
    gap: 5px;
    border-radius: 0;
    height: 93vh;
  }

  body[data-current-step="2"] .assembly-card {
    display: none;
  }

  body[data-current-step="2"] .page {
    margin: 0;
    width: 100%;
    margin-bottom: -8px;
  }

  body[data-current-step="2"] .parts-card {
    justify-content: center;
  }

  body[data-current-step="2"] .part {
    background: url("../images/part-bg-wap.png") center / cover;
  }

  /* Step 3: same grid fix, assembly zone + parts-card need room */
  body[data-current-step="3"] .experience {
    grid-template-rows: auto;
    display: flex;
    flex-direction: column;
  }

  body[data-current-step="3"] .interactive-panel {
    min-height: 0;
    overflow-y: auto;
  }

  body[data-current-step="3"] .page {
    margin-top: 0;
    margin: 0;
    width: 100%;
    margin-bottom: -8px;
  }

  /* Step 3: parts-card → image-only drag source at top */
  body[data-current-step="3"] .parts-card > h3,
  body[data-current-step="3"] .part-info {
    display: none !important;
  }

  body[data-current-step="3"] .interactive-panel {
    display: flex;
    flex-direction: column;
    background: url("../images/panel-bg-wap.jpg") center / cover;
    overflow-y: hidden;
    position: relative;
    width: 100%;
    max-width: 450px;
    margin-left: auto;
    margin-right: auto;
    height: 93vh;
    min-height: 710px;
    margin: 0;
    border-radius: 0;
  }

  body[data-current-step="3"] .assembly-card {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    padding: 0;
    pointer-events: none;
    display: flex;
    flex-direction: column;
  }

  body[data-current-step="3"] .part1,
  body[data-current-step="3"] .part2,
  body[data-current-step="3"] .part3,
  body[data-current-step="3"] .part4,
  body[data-current-step="3"] .part5 {
    pointer-events: auto;
  }

  body[data-current-step="3"] .header-icon {
    display: none;
  }

  .mask1 {
    top: 55%;
    left: 35%;
    width: 18%;
    height: 23%;
  }

  .mask2 {
    top: 33%;
    left: 31%;
    width: 30%;
    height: 23%;
  }

  .mask3 {
    top: 44%;
    left: 31%;
    width: 8%;
    height: 34%;
  }

  .mask4 {
    top: 79%;
    left: 24%;
    width: 36%;
    height: 16%;
  }

  .mask5 {
    top: 40%;
    left: 65%;
    width: 11%;
    height: 55%;
  }

  .dot1 {
    top: 65%;
    left: 44%;
  }

  .dot2 {
    top: 38%;
    left: 46%;
  }

  .dot3 {
    top: 63%;
    left: 36%;
  }

  .dot4 {
    top: 84;
    left: 41%;
  }

  .dot5 {
    top: 60%;
    left: 74%;
  }

  .playing-line {
    bottom: 43%;
  }

  body[data-current-step="3"] .parts-card {
    order: -1;
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px 16px;
    padding: 8px 12px;
    margin-bottom: 12px;
    background: rgba(255, 255, 255, 0);
    border-radius: 14px;
    position: relative;
    z-index: 10;
  }

  body[data-current-step="3"] .part {
    min-height: auto;
    padding: 6px;
    flex: 0 0 calc((100% - 32px) / 3);
    background: transparent;
    border: none;
    box-shadow: none;
    display: flex;
    justify-content: center;
    align-items: center;
  }

  body[data-current-step="3"] .part-thumb {
    width: 56px;
    height: 56px;
    border: 1.5px solid rgba(29, 82, 82, 0.08);
    border-radius: 50%;
  }

  body[data-current-step="3"] .part1 {
    background-size: 100% auto !important;
    width: 10%;
    height: 20%;
    top: 56%;
    left: 38.3%;
  }

  body[data-current-step="3"] .part2 {
    background-size: 100% auto !important;
    width: 24%;
    height: 21%;
    top: 35.2%;
    left: 35.6%;
  }

  body[data-current-step="3"] .part3 {
    background-size: 100% auto !important;
    width: 7% !important;
    height: 37% !important;
    top: 45.9% !important;
    left: 34.6% !important;
  }

  body[data-current-step="3"] .part4 {
    background-size: 100% auto !important;
    width: 30%;
    height: 25%;
    aspect-ratio: 165 / 130;
    top: 72%;
    left: 29.5%;
  }

  body[data-current-step="3"] .part5 {
    background-size: 100% auto !important;
    width: 24%;
    height: 52%;
    top: 41%;
    left: 59%;
  }

  body[data-current-step="3"] .assembly-card.is-assembled .erhu-guide {
    background: url("../images/erhu.png") no-repeat 66% bottom / 62% auto !important;
    min-height: 0 !important;
    height: 100% !important;
    margin-bottom: 6%;
  }

  /* Step 4: remove negative page margin (hero hidden) */
  body[data-current-step="4"] .page {
    margin-top: 0;
  }

  /* Hide elements not belonging to current step */
  [data-mobile-step].mobile-step-hidden {
    display: none !important;
  }

  /* Prevent elements belonging to other mobile steps from flashing before JS runs */
  body:not([data-current-step]) [data-mobile-step]:not([data-mobile-step~="1"]),
  body[data-current-step="1"] [data-mobile-step]:not([data-mobile-step~="1"]) {
    display: none !important;
  }

  /* Transition animations for mobile steps */
  @keyframes mobileStepFadeSlide {
    from {
      opacity: 0;
      transform: translateY(30px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

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

  body[data-current-step] .hero:not(.mobile-step-hidden),
  body[data-current-step] .songs-container:not(.mobile-step-hidden),
  body[data-current-step] .parts-card:not(.mobile-step-hidden),
  body[data-current-step] .footer-visual:not(.mobile-step-hidden),
  body[data-current-step] .page-start-btn:not(.mobile-step-hidden),
  body[data-current-step] .assembly-card h3:not(.mobile-step-hidden),
  body[data-current-step] .assembly-subtitle:not(.mobile-step-hidden),
  body[data-current-step] .erhu-guide:not(.mobile-step-hidden) {
    animation: mobileStepFadeSlide 0.8s cubic-bezier(0.16, 1, 0.3, 1) both;
  }

  body[data-current-step]
    .assembly-card
    [class^="part"]:not(.mobile-step-hidden),
  body[data-current-step] .assembly-card .mask:not(.mobile-step-hidden),
  body[data-current-step] .assembly-card .dot:not(.mobile-step-hidden) {
    animation: mobileStepFadeOnly 0.6s ease both;
  }

  /* Mobile controls - fixed bottom bar */
  .mobile-controls {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 100;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 16px;
    padding: 14px 20px;
    background: rgba(246, 241, 230, 0.94);
    border-top: 1px solid var(--line);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }

  .mobile-nav-btn {
    display: none;
    min-width: 100px;
    padding: 12px 28px;
    border: 1px solid rgba(24, 78, 75, 0.2);
    border-radius: 999px;
    font-size: 17px;
    font-weight: 500;
    /* font-family: inherit; */
    color: var(--ink);
    background: rgba(255, 255, 255, 0.85);
    box-shadow: 0 4px 12px rgba(45, 94, 82, 0.1);
    transition: all 0.2s ease;
    cursor: pointer;
    letter-spacing: 1px;
  }

  .mobile-nav-btn:active {
    transform: scale(0.96);
  }

  /* Button visibility per step */

  /* Step 1: hide mobile-controls bar, start is inside .page */
  body[data-current-step="1"] .mobile-controls {
    display: none;
  }

  /* Steps 2 & 3: Prev + Next */
  body[data-current-step="2"] #mobile-prev,
  body[data-current-step="2"] #mobile-next,
  body[data-current-step="3"] #mobile-prev,
  body[data-current-step="3"] #mobile-next {
    display: block;
  }

  /* Step 4: Prev + Home + Reset */
  body[data-current-step="4"] #mobile-prev,
  body[data-current-step="4"] #mobile-home,
  body[data-current-step="4"] #mobile-reset-btn {
    display: block;
  }

  /* Force hide PC reset button in mobile viewports */
  .reset-btn-pc {
    display: none !important;
  }

  /* Next button disabled state (Step 3, assembly not complete) */
  #mobile-next.is-disabled {
    opacity: 0.4;
    pointer-events: none;
    cursor: default;
  }

  /* Disable dragging on step 2 (viewing only) */
  body[data-current-step="2"] .part-thumb {
    pointer-events: none;
    cursor: default;
  }

  /* Page Start button (inside .page, Screen 1) */
  .page-start-btn {
    margin-top: 24px;
    margin-bottom: 44px;
    justify-self: center;
    min-width: 140px;
    min-height: 50px;
    padding: 0px 40px;
    border: none;
    border-radius: 999px;
    font-size: 20px;
    font-weight: 700;
    /* font-family: inherit; */
    color: #fff;
    background: var(--ink);
    box-shadow: 0 8px 24px rgba(18, 75, 84, 0.3);
    cursor: pointer;
    letter-spacing: 2px;
    transition: all 0.2s ease;
  }

  .page-start-btn:active {
    transform: scale(0.96);
    background: #0d3d45;
  }

  /* Adjust song-card grid on mobile step 4 */
  body[data-current-step="4"] .songs {
    display: flex;
    flex-direction: column;
  }

  /* Step 4: hide assembly panel (only songs + player visible) */
  body[data-current-step="4"] .interactive-panel {
    display: none !important;
  }
}

@media (max-width: 480px) {
  .hero {
    /* min-height: 200px !important; */
  }
  .footer-visual {
    margin-top: -15%;
  }
  .footer-btn {
    max-width: 180px;
  }
}