:root {
  color-scheme: light;
  --white: #ffffff;
  --blue: #c7d3db;
  --blue-hover: #b5c6d1;
  --taupe: #a79a8a;
  --cream: #fcf7df;
  --ink: #3e3630;
  --muted: #7c7268;
  font-family: "Helvetica Neue", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--white);
  font-synthesis: none;
  -webkit-font-smoothing: antialiased;
}

* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; }
[hidden] { display: none !important; }
button { font: inherit; -webkit-tap-highlight-color: transparent; }
button:focus-visible { outline: 2px solid var(--ink); outline-offset: 5px; }
button:disabled { cursor: default; }
::selection { background: var(--blue); color: var(--ink); }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.desk-background {
  position: fixed;
  inset: -14px;
  z-index: -1;
  background: url("./img/TINY_ECHO_空桌面_正面视角.png") center / cover no-repeat;
  filter: blur(8px);
}

.sound-toggle {
  position: absolute;
  top: 24px;
  right: 28px;
  z-index: 20;
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid rgba(167, 154, 138, .25);
  border-radius: 50%;
  background: rgba(255, 255, 255, .8);
  color: var(--muted);
  cursor: pointer;
  transition: background .2s;
}
.sound-toggle:hover { background: var(--cream); }
.sound-bars { height: 16px; display: flex; align-items: center; gap: 3px; }
.sound-bars i { width: 1.5px; height: 5px; background: currentColor; border-radius: 1px; }
.sound-bars i:nth-child(2) { height: 12px; animation-delay: -.6s; }
.sound-bars i:nth-child(3) { height: 16px; animation-delay: -.9s; }
.sound-bars i:nth-child(4) { height: 8px; animation-delay: -.3s; }
.sound-toggle[aria-pressed="true"] .sound-bars i { animation-name: sound-wave; animation-duration: 1.3s; animation-timing-function: ease-in-out; animation-iteration-count: infinite; animation-direction: alternate; }

/* PDF composition, with a white surface and the reference blue/taupe palette. */
.entrance {
  min-height: 100vh;
  min-height: 100svh;
  display: grid;
  place-items: center;
  padding: 76px 32px;
  transition: opacity .5s ease, transform .6s ease;
}
.intro-card {
  width: min(100%, 900px);
  min-height: 555px;
  padding: 32px 64px 46px;
  border-radius: 20px;
  border: 1px solid rgba(167, 154, 138, .14);
  background: var(--white);
  box-shadow: 0 16px 54px -22px rgba(62, 54, 48, .1);
}
.project-heading { text-align: center; }
h1 { margin: 0; font-size: 64px; font-weight: 400; line-height: 1.2; }
.english-title { margin: 0; font-size: 48px; font-weight: 400; line-height: 1.2; letter-spacing: .01em; }

.interaction-guide { margin-top: 13px; }
.gestures { margin: 0 0 0 68px; padding: 0; list-style: none; display: grid; gap: 8px; }
.gestures li { display: flex; align-items: center; min-height: 35px; gap: 15px; }
.gestures svg { width: 27px; height: 27px; flex: 0 0 auto; stroke: var(--taupe); stroke-width: 1.35; stroke-linecap: round; stroke-linejoin: round; }
.gesture-detail { opacity: .7; }
.gesture-name { min-width: 116px; font-size: 18px; font-weight: 400; white-space: nowrap; }
.gesture-name span { font-size: 15px; }
.gesture-description { color: var(--muted); font-size: 14px; line-height: 1.5; }

.entry-action { position: relative; margin-top: 76px; text-align: center; }
.enter-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 275px;
  max-width: 100%;
  min-height: 93px;
  padding: 13px 18px;
  border: 0;
  border-radius: 10px;
  background: var(--blue);
  color: var(--ink);
  cursor: pointer;
  transition: background .25s, transform .25s, box-shadow .25s;
}
.button-copy { display: flex; flex-direction: column; align-items: center; gap: 0; }
.button-copy > span:first-child { font-size: 30px; line-height: 1.25; font-weight: 400; }
.button-english { font-size: 23px; line-height: 1.3; }
.enter-button:hover { transform: translateY(-3px); background: var(--blue-hover); box-shadow: 0 8px 18px -10px rgba(62, 54, 48, .24); }
.enter-button:active { transform: translateY(-1px); }
.entry-status { position: absolute; top: calc(100% + 12px); left: 0; right: 0; margin: 0; color: var(--muted); font-size: 12px; line-height: 1.5; }

@keyframes sound-wave { from { transform: scaleY(.4); } to { transform: scaleY(1); } }

@media (max-width: 700px) {
  .entrance { padding: 70px 22px; }
  .intro-card { min-height: 520px; padding: 32px 30px 44px; }
  h1 { font-size: 52px; }
  .english-title { font-size: 38px; }
  .interaction-guide { margin-top: 26px; }
  .gestures { margin-left: 8px; gap: 12px; }
  .gestures li { gap: 12px; }
  .gesture-name { font-size: 16px; min-width: 106px; }
  .gesture-name span { font-size: 13px; }
  .gesture-description { font-size: 12px; }
  .entry-action { margin-top: 50px; }
  .enter-button { width: 250px; min-height: 82px; }
  .button-copy > span:first-child { font-size: 26px; }
  .button-english { font-size: 20px; }
}
@media (max-width: 440px) {
  .entrance { padding: 65px 18px; }
  .intro-card { padding: 30px 22px 44px; min-height: 500px; border-radius: 18px; }
  .sound-toggle { top: 17px; right: 19px; width: 36px; height: 36px; }
  h1 { font-size: 46px; }
  .english-title { font-size: 32px; }
  .gestures { margin-left: 0; gap: 11px; }
  .gestures li { gap: 9px; }
  .gestures svg { width: 23px; height: 23px; }
  .gesture-name { min-width: 93px; font-size: 14px; }
  .gesture-name span { font-size: 12px; }
  .gesture-description { font-size: 11px; }
  .entry-action { margin-top: 46px; }
  .enter-button { width: 230px; min-height: 78px; }
  .button-copy > span:first-child { font-size: 25px; }
  .button-english { font-size: 19px; }
}
@media (max-width: 359px) {
  .intro-card { padding-inline: 17px; }
  .gestures li { gap: 7px; }
  .gesture-name { min-width: 88px; font-size: 13px; }
  .gesture-description { font-size: 10px; }
}
@media (max-height: 650px) and (min-width: 701px) {
  .entrance { padding-block: 36px; }
  .intro-card { min-height: 0; padding-block: 24px 36px; }
  h1 { font-size: 48px; }
  .english-title { font-size: 36px; }
  .interaction-guide { margin-top: 16px; }
  .gestures { gap: 5px; }
  .entry-action { margin-top: 38px; }
  .enter-button { min-height: 76px; }
  .button-copy > span:first-child { font-size: 26px; }
  .button-english { font-size: 20px; }
}
@media (max-height: 650px) and (max-width: 700px) {
  .entrance { padding-block: 62px 20px; }
  .intro-card { min-height: 0; padding-top: 24px; padding-bottom: 38px; }
  .interaction-guide { margin-top: 22px; }
  .gestures { gap: 7px; }
  .entry-action { margin-top: 30px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}