:root {
  --bg: #ffffff;
  --fg: #0d0d0d;
  --muted: #6e6e6e;
  --line: #e8e8e8;
  --hair: rgba(0, 0, 0, .08);
  --soft: #f3f3f3;
  --soft-hover: #e9e9e9;
  --solid-bg: #0d0d0d;
  --solid-fg: #ffffff;
  --focus: #0d0d0d;
  --prompt-shadow: 0 1px 2px rgba(0, 0, 0, .04), 0 10px 30px rgba(0, 0, 0, .07);
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --gutter: 32px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --fg: #f5f5f5;
    --muted: #9a9a9a;
    --line: #232323;
    --hair: rgba(255, 255, 255, .08);
    --soft: #161616;
    --soft-hover: #202020;
    --solid-bg: #ffffff;
    --solid-fg: #000000;
    --focus: #f5f5f5;
    --prompt-shadow: none;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 400 16px/1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: inherit; text-decoration: none; }
h1, h2, h3, p, dl, dd, ul { margin: 0; }
ul { padding: 0; list-style: none; }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 3px; border-radius: 6px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.muted { color: var(--muted); }
.wrap { max-width: 1280px; margin: 0 auto; padding: 0 var(--gutter); }

@keyframes hop {
  0% { transform: translateY(0) scale(1, 1); }
  30% { transform: translateY(-8px) scale(.94, 1.06); }
  62% { transform: translateY(0) scale(1.1, .9); }
  100% { transform: none; }
}

/* ---------- header ---------- */
.top {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  backdrop-filter: saturate(1.4) blur(14px);
}
.top-in { height: 64px; display: flex; align-items: center; gap: 36px; }
.wordmark { font-size: 20px; font-weight: 600; letter-spacing: -0.03em; }
.nav { display: flex; gap: 26px; font-size: 14px; }
.nav a { opacity: .75; transition: opacity .15s; }
.nav a:hover { opacity: 1; }
.top .pill { margin-left: auto; }

/* ---------- pills ---------- */
.pill {
  display: inline-flex; align-items: center; gap: 6px;
  height: 38px; padding: 0 16px; border-radius: 999px;
  font: 500 14px/1 var(--sans); white-space: nowrap;
  border: 0; cursor: pointer; transition: background-color .15s, opacity .15s;
}
.pill .arrow { font-size: 13px; }
.pill-solid { background: var(--solid-bg); color: var(--solid-fg); }
.pill-solid:hover { opacity: .86; }
.pill-white { background: #fff; color: #000; height: 42px; padding: 0 20px; }
.pill-white:hover { background: #e8e8e8; }
.pill-ghost { background: #1e1e1e; color: #f2f2f2; }
.pill-ghost:hover { background: #2a2a2a; }

/* ---------- 主动画：我们在搓什么？ ---------- */
.main-hero { padding: clamp(64px, 12vh, 140px) 0 clamp(56px, 9vh, 96px); text-align: center; overflow: hidden; }
.mh-title { font-size: clamp(32px, 4.4vw, 52px); font-weight: 500; line-height: 1.15; letter-spacing: -0.03em; }
.prompt {
  display: flex; align-items: center; gap: 12px;
  width: min(720px, 100%); min-height: 62px; margin: 32px auto 0;
  padding: 10px 10px 10px 12px; border-radius: 31px;
  background: var(--bg); border: 1px solid var(--line); box-shadow: var(--prompt-shadow);
  text-align: left; transition: border-color .2s;
}
@media (prefers-color-scheme: dark) { .prompt { background: var(--soft); } }
.prompt:hover { border-color: var(--muted); }
.prompt-ava { width: 38px; height: 38px; flex: none; }
.prompt-ava svg { display: block; width: 100%; height: 100%; }
.prompt-ava.hop { animation: hop .55s cubic-bezier(.3, 1.5, .5, 1); }
.prompt-text { flex: 1; min-width: 0; font-size: 17px; line-height: 1.5; }
.caret { display: inline-block; width: 2px; height: 1.1em; margin-left: 2px; vertical-align: -3px; background: var(--fg); animation: blink 1.05s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.prompt-send { width: 40px; height: 40px; flex: none; display: grid; place-items: center; border-radius: 50%; background: var(--solid-bg); color: var(--solid-fg); }
.prompt-send svg { width: 18px; height: 18px; }
.main-hero.sent .prompt-send { animation: send .45s ease; }
@keyframes send { 40% { transform: scale(.84); } }
.prompt-meta { margin-top: 12px; font-size: 13px; color: var(--muted); }

.marquee {
  display: grid; gap: 12px; margin-top: clamp(40px, 7vh, 64px);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 9%, #000 91%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 9%, #000 91%, transparent);
}
.mq-row { overflow: hidden; }
.mq-track { display: flex; width: max-content; animation: mq 60s linear infinite; }
.mq-row[data-dir="right"] .mq-track { animation-direction: reverse; }
.mq-row:hover .mq-track { animation-play-state: paused; }
.mq-set { display: flex; }
@keyframes mq { to { transform: translateX(-50%); } }
.pp {
  display: inline-flex; align-items: center; gap: 9px;
  height: 46px; padding: 0 18px 0 9px; margin-right: 10px; border-radius: 999px;
  background: var(--soft); font-size: 15px; white-space: nowrap;
  transition: background-color .3s, color .3s;
}
.pp:hover { background: var(--soft-hover); }
.pp-ball { width: 28px; height: 28px; flex: none; }
.pp-ball svg { display: block; width: 100%; height: 100%; }
.pp-tag { font-size: 12px; color: var(--muted); }
.pp.is-hot { background: var(--fg); color: var(--bg); }
.pp.is-hot .pp-tag { color: inherit; opacity: .65; }
.pp.is-hot .pp-ball { animation: hop .6s cubic-bezier(.3, 1.5, .5, 1); }

/* ---------- 钢琴机器人 takeover ---------- */
.hero {
  position: relative;
  height: clamp(620px, 84vh, 780px);
  background: #000;
  border-radius: 18px;
  overflow: hidden;
  color: #fff;
  isolation: isolate;
}
@media (prefers-color-scheme: dark) { .hero { box-shadow: inset 0 0 0 1px #1a1a1a; } }
.hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; z-index: 0; }
.hero-copy {
  position: absolute; left: 50%; top: 13%;
  transform: translateX(-50%);
  width: min(880px, calc(100% - 40px));
  text-align: center;
  z-index: 1;
  pointer-events: none;
}
.hero-copy .pill { pointer-events: auto; margin-top: 26px; }
.hero-title { font-size: clamp(32px, 4.8vw, 58px); font-weight: 500; line-height: 1.1; letter-spacing: -0.03em; }
.hero-title .nowrap { white-space: nowrap; }
.hero-title .dim { color: #8a8a8a; font-weight: 400; }
.hero-sub { margin: 18px auto 0; max-width: 34em; font-size: clamp(15px, 1.5vw, 17px); line-height: 1.65; color: #cfcfcf; }
.sound { position: absolute; top: 20px; right: 20px; z-index: 2; height: 36px; padding: 0 14px 0 12px; }
.sound svg { width: 18px; height: 18px; }
.sound .wave { display: none; }
.sound[aria-pressed="true"] .wave { display: inline; }
.sound[aria-pressed="true"] .mute { display: none; }

/* ---------- sections ---------- */
.h2 { font-size: clamp(26px, 2.6vw, 32px); font-weight: 500; letter-spacing: -0.02em; line-height: 1.2; }
.sec-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; margin-bottom: 28px; }
.more { font-size: 14px; color: var(--muted); }
.more:hover { color: var(--fg); }

.list-sec { padding-top: 110px; }
.specs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px 24px; margin-bottom: 36px; }
.specs dt { font-size: 30px; font-weight: 500; letter-spacing: -0.02em; line-height: 1.1; }
.specs dd { margin-top: 6px; font-size: 13px; color: var(--muted); }
.list { border-top: 1px solid var(--line); }
.list li { border-bottom: 1px solid var(--line); }
.list a { display: flex; align-items: baseline; justify-content: space-between; gap: 24px; padding: 20px 0; }
.li-title { font-size: 17px; line-height: 1.5; }
.list a:hover .li-title { text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
.li-meta { flex: none; font-size: 13px; color: var(--muted); }

.statement { padding: 130px 0 20px; max-width: 980px; }
.big { font-size: clamp(26px, 3.4vw, 42px); line-height: 1.28; font-weight: 400; letter-spacing: -0.02em; }
.big + .big { margin-top: 12px; }

/* ---------- 成员与项目 ---------- */
.team-sec { padding-top: 110px; }
.team { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; align-items: start; }
.member { padding: 24px 24px 8px; border-radius: 14px; background: var(--soft); }
.m-head { display: flex; align-items: center; gap: 14px; }
.ava { width: 48px; height: 48px; flex: none; color: var(--fg); transition: transform .3s cubic-bezier(.3, 1.6, .5, 1); }
.m-head:hover .ava { transform: translateY(-3px); }
.m-name { display: block; font-size: 18px; font-weight: 500; letter-spacing: -0.01em; line-height: 1.3; }
.m-link { display: block; font-size: 13px; color: var(--muted); }
.m-head:hover .m-link { color: var(--fg); }
.m-desc { margin-top: 14px; font-size: 14px; line-height: 1.65; color: var(--muted); }
.m-projects { margin-top: 18px; border-top: 1px solid var(--hair); }
.m-projects li + li { border-top: 1px solid var(--hair); }
.m-projects a { display: block; padding: 13px 0; }
.mp-name { display: block; font-size: 15px; font-weight: 500; }
.mp-line { display: block; margin-top: 2px; font-size: 13px; line-height: 1.55; color: var(--muted); }
.m-projects a:hover .mp-name { text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }

.next { padding: 140px 0 120px; }

/* ---------- footer ---------- */
.foot { border-top: 1px solid var(--line); padding: 48px 0 40px; font-size: 14px; }
.foot-cols { display: grid; grid-template-columns: repeat(3, minmax(0, 200px)); gap: 32px; }
.foot-h { color: var(--muted); font-size: 13px; margin-bottom: 12px; }
.foot-cols a { display: block; padding: 3px 0; opacity: .85; }
.foot-cols a:hover { opacity: 1; text-decoration: underline; text-underline-offset: 3px; }
.copy { margin-top: 48px; color: var(--muted); font-size: 13px; }

/* ---------- responsive ---------- */
@media (max-width: 1000px) {
  .team { grid-template-columns: 1fr; }
  .specs { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 720px) {
  :root { --gutter: 16px; }
  .nav { display: none; }
  .top-in { height: 56px; }
  .main-hero { padding-top: 56px; }
  .prompt { min-height: 56px; margin-top: 26px; }
  .prompt-text { font-size: 15px; }
  .prompt-ava { width: 34px; height: 34px; }
  .prompt-send { width: 36px; height: 36px; }
  .pp { height: 40px; font-size: 14px; padding-right: 15px; }
  .pp-ball { width: 24px; height: 24px; }
  .hero { height: 600px; border-radius: 14px; }
  .hero-copy { top: 72px; }
  .sound { top: 14px; right: 14px; padding: 0; width: 36px; justify-content: center; }
  .sound-label { display: none; }
  .statement { padding-top: 96px; }
  .list-sec, .team-sec { padding-top: 80px; }
  .list a { flex-direction: column; gap: 4px; padding: 16px 0; }
  .li-title { font-size: 16px; }
  .foot-cols { grid-template-columns: repeat(2, 1fr); }
  .next { padding: 100px 0 80px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .mq-row { overflow-x: auto; }
}