:root {
  --bg: #07090f; --bg2: #0c1019; --card: #111623; --line: #1f2737; --text: #e7ecf5; --dim: #8d97ab; --mute: #5d6779;
  --cyan: #35d6e8; --cyan2: #22b8d6; --red: #ff4d4f; --amber: #ffb547; --green: #3ddc84; --violet: #a78bfa;
  --r: 18px; --max: 1180px;
  font-family: "HarmonyOS Sans SC", "PingFang SC", "Microsoft YaHei UI", "Microsoft YaHei", system-ui, sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text); line-height: 1.7; font-size: 16px; -webkit-font-smoothing: antialiased; overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
code, kbd { font-family: "JetBrains Mono", Consolas, monospace; font-size: .9em; }
kbd { border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 6px; padding: 0 6px; background: var(--bg2); }
.wrap { width: min(var(--max), calc(100% - 40px)); margin: 0 auto; }

/* 顶栏 */
.nav { position: fixed; inset: 0 0 auto; z-index: 50; transition: background .3s, border-color .3s; border-bottom: 1px solid transparent; }
.nav.solid { background: rgba(7, 9, 15, .82); backdrop-filter: blur(14px); border-color: var(--line); }
.nav .wrap { display: flex; align-items: center; gap: 28px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: .02em; }
.brand img { width: 30px; height: 30px; border-radius: 8px; }
.nav-links { display: flex; gap: 22px; margin-left: auto; font-size: 15px; color: var(--dim); }
.nav-links a:hover { color: var(--text); }
.nav .btn { padding: 8px 18px; font-size: 14px; }
@media (max-width: 860px) { .nav-links { display: none; } .nav .btn { margin-left: auto; } }

/* 按钮 */
.btn { display: inline-flex; align-items: center; gap: 10px; padding: 14px 26px; border-radius: 999px; font-weight: 700; border: 1px solid var(--line); background: var(--card); color: var(--text); cursor: pointer; transition: transform .2s, box-shadow .2s, background .2s; font-size: 16px; font-family: inherit; }
.btn:hover { transform: translateY(-2px); }
.btn.primary { background: linear-gradient(135deg, #46e3f2, #1fb2d4); color: #04131a; border: 0; box-shadow: 0 10px 40px -10px rgba(53, 214, 232, .65); }
.btn.primary:hover { box-shadow: 0 16px 50px -10px rgba(53, 214, 232, .85); }
.btn.ghost { background: transparent; }
.btn svg { width: 20px; height: 20px; flex: none; }
.btn small { font-weight: 500; opacity: .75; font-size: 13px; }

/* 首屏 */
.hero { position: relative; padding: 140px 0 60px; text-align: center; overflow: hidden; }
.hero canvas { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; opacity: .9; }
.hero::before { content: ""; position: absolute; inset: -20% -10% auto; height: 900px; background: radial-gradient(ellipse 50% 45% at 50% 30%, rgba(53, 214, 232, .18), transparent 70%), radial-gradient(ellipse 30% 30% at 80% 20%, rgba(255, 77, 79, .12), transparent 70%), radial-gradient(ellipse 30% 30% at 15% 35%, rgba(167, 139, 250, .12), transparent 70%); pointer-events: none; }
.hero > .wrap { position: relative; }
.pill { display: inline-flex; align-items: center; gap: 8px; padding: 6px 14px; border-radius: 999px; border: 1px solid rgba(53, 214, 232, .35); background: rgba(53, 214, 232, .08); color: var(--cyan); font-size: 13px; font-weight: 600; }
.pill i { width: 7px; height: 7px; border-radius: 50%; background: var(--red); box-shadow: 0 0 0 4px rgba(255, 77, 79, .25); animation: pulse 1.6s infinite; }
@keyframes pulse { 50% { box-shadow: 0 0 0 8px rgba(255, 77, 79, 0); } }
.hero h1 { font-size: clamp(40px, 7vw, 84px); line-height: 1.08; margin: 22px 0 14px; letter-spacing: -.01em; font-weight: 900; }
.grad { background: linear-gradient(100deg, #fff 10%, #7deaf5 45%, #35d6e8 60%, #ff8a8b 95%); -webkit-background-clip: text; background-clip: text; color: transparent; background-size: 200% auto; animation: shine 8s linear infinite; }
@keyframes shine { to { background-position: 200% center; } }
.hero .lead { font-size: clamp(17px, 2.1vw, 21px); color: var(--dim); max-width: 860px; margin: 0 auto; text-wrap: balance; }
.sub, h2, h3 { text-wrap: balance; }
.hero .lead b { color: var(--text); font-weight: 600; }
.cta { display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; margin: 36px 0 12px; }
.cta .btn.primary { padding: 18px 34px; font-size: 18px; }
.btn { white-space: nowrap; }
.win .bar span { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
@media (max-width: 600px) {
  .cta .btn.primary { padding: 16px 22px; font-size: 16px; } .cta .btn.primary small { display: none; }
  .hero { padding-top: 110px; } .stage { margin-top: 40px; } .stats { margin-top: 90px; }
  .stat b { font-size: 30px; } section { padding-top: 80px; }
}
.alt-dl { font-size: 14px; color: var(--mute); }
.alt-dl a { color: var(--dim); border-bottom: 1px dashed var(--mute); margin: 0 6px; }
.alt-dl a:hover { color: var(--cyan); }

/* 首屏截图：教师端 + 学生画面叠放，鼠标视差 */
.stage { position: relative; margin: 64px auto 0; max-width: 1100px; perspective: 1800px; }
.stage .tilt { transform-style: preserve-3d; transform: rotateX(14deg); transition: transform .25s ease-out; }
.win { border-radius: 14px; overflow: hidden; border: 1px solid #263045; background: #0b0e16; box-shadow: 0 40px 120px -30px rgba(0, 0, 0, .9), 0 0 0 1px rgba(255, 255, 255, .02) inset; }
.win .bar { height: 30px; display: flex; align-items: center; gap: 7px; padding: 0 12px; background: #121725; border-bottom: 1px solid #1d2535; font-size: 12px; color: var(--mute); }
.win .bar i { width: 10px; height: 10px; border-radius: 50%; background: #2a3346; }
.win .bar i:nth-child(1) { background: #ff5f57; } .win .bar i:nth-child(2) { background: #febc2e; } .win .bar i:nth-child(3) { background: #28c840; }
.win .bar span { margin-left: 8px; }
.stage .student { position: absolute; width: 44%; right: -5%; bottom: -12%; transform: translateZ(80px); }
.stage .student .bar { background: #2a0f14; color: #ffb3b4; }
.stage .tag { position: absolute; z-index: 2; padding: 6px 12px; border-radius: 10px; background: rgba(10, 14, 22, .88); border: 1px solid var(--line); font-size: 13px; color: var(--dim); backdrop-filter: blur(6px); transform: translateZ(120px); white-space: nowrap; }
.stage .tag b { color: var(--text); }
.stage .t1 { left: -3%; top: 18%; } .stage .t2 { right: 2%; bottom: 33%; } .stage .t3 { left: 6%; bottom: -6%; }
@media (max-width: 760px) { .stage .tag { display: none; } .stage .student { right: -2%; bottom: -16%; width: 52%; } }

/* 数字 */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin: 130px auto 0; }
.stat { text-align: center; padding: 22px 10px; border-radius: var(--r); background: linear-gradient(180deg, rgba(255, 255, 255, .03), transparent); border: 1px solid var(--line); }
.stat b { display: block; font-size: 38px; line-height: 1.1; font-weight: 800; color: #fff; font-variant-numeric: tabular-nums; }
.stat span { color: var(--dim); font-size: 14px; }
@media (max-width: 760px) { .stats { grid-template-columns: repeat(2, 1fr); } }

/* 区块 */
section { padding: 110px 0 40px; position: relative; }
.kicker { color: var(--cyan); font-weight: 700; font-size: 14px; letter-spacing: .14em; }
h2 { font-size: clamp(30px, 4.2vw, 48px); line-height: 1.2; margin: 10px 0 16px; font-weight: 850; }
.sub { color: var(--dim); font-size: 18px; max-width: 720px; }
.center { text-align: center; } .center .sub { margin: 0 auto; }

/* 左右图文 */
.split { display: grid; grid-template-columns: 1fr 1.35fr; gap: 56px; align-items: center; margin-top: 56px; }
.split.rev { grid-template-columns: 1.35fr 1fr; } .split.rev .txt { order: 2; }
.split h3 { font-size: 28px; margin: 0 0 12px; line-height: 1.3; }
.split p { color: var(--dim); margin: 0 0 14px; }
.split ul { list-style: none; padding: 0; margin: 18px 0 0; }
.split li { position: relative; padding-left: 26px; margin: 10px 0; color: #c9d1df; }
.split li::before { content: ""; position: absolute; left: 4px; top: .62em; width: 9px; height: 9px; border-radius: 3px; background: var(--cyan); box-shadow: 0 0 12px var(--cyan); }
.shot { border-radius: 14px; overflow: hidden; border: 1px solid #263045; box-shadow: 0 30px 80px -30px rgba(0, 0, 0, .9); background: #0b0e16; cursor: zoom-in; transition: transform .35s; }
.shot:hover { transform: translateY(-4px); }
.shot.pair { position: relative; overflow: visible; border: 0; box-shadow: none; background: none; }
.shot.pair img { border-radius: 14px; border: 1px solid #263045; box-shadow: 0 30px 80px -30px rgba(0, 0, 0, .9); }
.shot.pair img + img { position: absolute; width: 55%; right: -6%; bottom: -14%; }
@media (max-width: 900px) { .split, .split.rev { grid-template-columns: 1fr; gap: 28px; } .split.rev .txt { order: 0; } }

/* 功能卡 */
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 50px; }
.card { position: relative; padding: 26px 24px; border-radius: var(--r); background: var(--card); border: 1px solid var(--line); overflow: hidden; transition: border-color .3s, transform .3s; }
.card::after { content: ""; position: absolute; inset: 0; background: radial-gradient(400px circle at var(--mx, 50%) var(--my, 0%), rgba(53, 214, 232, .10), transparent 40%); opacity: 0; transition: opacity .3s; pointer-events: none; }
.card:hover { border-color: #2c3a52; transform: translateY(-3px); } .card:hover::after { opacity: 1; }
.card .ico { width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; background: rgba(53, 214, 232, .1); color: var(--cyan); margin-bottom: 16px; }
.card .ico svg { width: 22px; height: 22px; }
.card h4 { margin: 0 0 6px; font-size: 18px; }
.card p { margin: 0; color: var(--dim); font-size: 15px; }
.card.red .ico { background: rgba(255, 77, 79, .1); color: var(--red); } .card.amber .ico { background: rgba(255, 181, 71, .1); color: var(--amber); }
.card.green .ico { background: rgba(61, 220, 132, .1); color: var(--green); } .card.violet .ico { background: rgba(167, 139, 250, .12); color: var(--violet); }
@media (max-width: 900px) { .grid { grid-template-columns: repeat(2, 1fr); } } @media (max-width: 600px) { .grid { grid-template-columns: 1fr; } }

/* 演示画廊 */
.tabs { display: inline-flex; gap: 6px; padding: 5px; border-radius: 999px; background: var(--card); border: 1px solid var(--line); margin: 34px 0 26px; }
.tabs button { border: 0; background: none; color: var(--dim); padding: 9px 20px; border-radius: 999px; font: inherit; font-weight: 600; cursor: pointer; }
.tabs button.on { background: var(--cyan); color: #04131a; }
.gallery { display: grid; grid-template-columns: 1.6fr 1fr; gap: 18px; }
.gallery .shot { position: relative; } .gallery .shot figcaption { position: absolute; left: 12px; bottom: 12px; padding: 4px 12px; border-radius: 8px; background: rgba(7, 9, 15, .8); font-size: 13px; color: var(--dim); }
.gallery .side { display: grid; gap: 18px; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 26px; }
.chips span { padding: 5px 12px; border-radius: 999px; border: 1px solid var(--line); color: var(--dim); font-size: 13px; background: var(--bg2); }
@media (max-width: 800px) { .gallery { grid-template-columns: 1fr; } }

/* 一节课的流程 */
.flow { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 50px; }
.flow .col { counter-reset: f; padding: 26px; border-radius: var(--r); border: 1px solid var(--line); background: linear-gradient(180deg, var(--card), var(--bg2)); }
.flow h4 { margin: 0 0 4px; font-size: 20px; display: flex; align-items: center; gap: 10px; }
.flow h4 em { font-style: normal; font-size: 12px; padding: 2px 10px; border-radius: 999px; background: rgba(53, 214, 232, .12); color: var(--cyan); }
.flow ol { margin: 14px 0 0; padding: 0; list-style: none; }
.flow li { position: relative; padding: 9px 0 9px 34px; border-top: 1px dashed var(--line); color: #c9d1df; font-size: 15px; }
.flow li::before { counter-increment: f; content: counter(f); position: absolute; left: 0; top: 10px; width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center; font-size: 12px; background: #1a2232; color: var(--cyan); font-weight: 700; }
.flow a { color: var(--cyan); font-size: 13px; }
@media (max-width: 900px) { .flow { grid-template-columns: 1fr; } }

/* 视频 */
.videos { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-top: 46px; }
.video { border-radius: var(--r); overflow: hidden; border: 1px solid var(--line); background: var(--card); }
.video video, .video .poster { width: 100%; aspect-ratio: 16 / 9; display: block; background: #000; object-fit: cover; }
.video div { padding: 16px 20px; } .video h4 { margin: 0 0 4px; font-size: 18px; } .video p { margin: 0; color: var(--dim); font-size: 14px; }
@media (max-width: 800px) { .videos { grid-template-columns: 1fr; } }

/* 下载 */
.dl { display: grid; grid-template-columns: 1.3fr 1fr 1fr; gap: 18px; margin-top: 50px; }
.pkg { padding: 28px 26px; border-radius: var(--r); border: 1px solid var(--line); background: var(--card); display: flex; flex-direction: column; }
.pkg.main { border-color: rgba(53, 214, 232, .5); background: linear-gradient(160deg, rgba(53, 214, 232, .10), var(--card) 50%); box-shadow: 0 30px 80px -40px rgba(53, 214, 232, .5); }
.pkg.me { outline: 2px solid var(--cyan); outline-offset: 3px; }
.pkg .os { display: flex; align-items: center; gap: 12px; } .pkg .os svg { width: 34px; height: 34px; }
.pkg h3 { margin: 0; font-size: 22px; } .pkg .meta { color: var(--mute); font-size: 13px; margin: 8px 0 18px; }
.pkg .btn { justify-content: center; margin-top: auto; } .pkg .btn + .btn { margin-top: 10px; }
.pkg .note { font-size: 13px; color: var(--amber); margin: 0 0 16px; }
.pkg ol { margin: 0 0 18px; padding-left: 20px; color: var(--dim); font-size: 14px; }
.sha { margin-top: 14px; font-size: 11px; color: var(--mute); word-break: break-all; font-family: Consolas, monospace; }
.dl-foot { margin-top: 22px; display: flex; flex-wrap: wrap; gap: 10px 28px; color: var(--dim); font-size: 14px; }
.dl-foot b { color: var(--text); }
@media (max-width: 900px) { .dl { grid-template-columns: 1fr; } }

/* 常见问题 */
.faq { max-width: 860px; margin: 40px auto 0; }
.faq details { border-bottom: 1px solid var(--line); padding: 18px 4px; }
.faq summary { cursor: pointer; font-weight: 600; font-size: 17px; list-style: none; display: flex; justify-content: space-between; gap: 20px; }
.faq summary::after { content: "+"; color: var(--cyan); font-size: 22px; line-height: 1; transition: transform .2s; }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { color: var(--dim); margin: 10px 0 0; }

/* 社区 */
.join { margin-top: 40px; display: grid; grid-template-columns: 1.2fr 1fr; gap: 18px; }
.join .card { padding: 34px; }
.qq { display: flex; align-items: center; gap: 16px; margin-top: 16px; flex-wrap: wrap; }
.qq code { font-size: 30px; font-weight: 800; letter-spacing: .06em; color: #fff; }
.lic li { margin: 6px 0; color: var(--dim); } .lic { padding-left: 20px; margin: 10px 0 0; }
@media (max-width: 800px) { .join { grid-template-columns: 1fr; } }

footer { margin-top: 110px; padding: 40px 0 60px; border-top: 1px solid var(--line); color: var(--mute); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 14px 30px; justify-content: space-between; }
footer a:hover { color: var(--text); }

/* 进场动画 */
.rv { opacity: 0; transform: translateY(28px); transition: opacity .8s cubic-bezier(.2, .7, .2, 1), transform .8s cubic-bezier(.2, .7, .2, 1); }
.rv.in { opacity: 1; transform: none; }
.rv.d1 { transition-delay: .08s; } .rv.d2 { transition-delay: .16s; } .rv.d3 { transition-delay: .24s; }
@media (prefers-reduced-motion: reduce) { .rv { opacity: 1; transform: none; transition: none; } .grad { animation: none; } }

/* 看大图 */
.lightbox { position: fixed; inset: 0; z-index: 100; background: rgba(3, 5, 9, .92); display: none; place-items: center; padding: 30px; cursor: zoom-out; }
.lightbox.on { display: grid; } .lightbox img { max-height: 92vh; border-radius: 10px; box-shadow: 0 30px 100px rgba(0, 0, 0, .8); }

.toast { position: fixed; left: 50%; bottom: 30px; transform: translate(-50%, 30px); opacity: 0; padding: 10px 20px; border-radius: 10px; background: var(--cyan); color: #04131a; font-weight: 700; transition: .3s; z-index: 120; pointer-events: none; }
.toast.on { opacity: 1; transform: translate(-50%, 0); }

/* 说明书页 */
.manual { display: grid; grid-template-columns: 250px 1fr; gap: 48px; padding-top: 100px; }
.manual aside { position: sticky; top: 84px; align-self: start; max-height: calc(100vh - 100px); overflow: auto; padding-right: 6px; }
.manual aside input { width: 100%; padding: 10px 14px; border-radius: 10px; border: 1px solid var(--line); background: var(--card); color: var(--text); font: inherit; margin-bottom: 14px; }
.manual aside h5 { margin: 16px 0 4px; color: var(--mute); font-size: 12px; letter-spacing: .1em; }
.manual aside a { display: block; padding: 5px 10px; border-radius: 8px; color: var(--dim); font-size: 15px; }
.manual aside a:hover, .manual aside a.on { background: var(--card); color: var(--text); }
.chapter { padding: 10px 0 40px; border-bottom: 1px solid var(--line); margin-bottom: 30px; scroll-margin-top: 90px; }
.chapter .g { color: var(--cyan); font-size: 13px; font-weight: 700; letter-spacing: .1em; }
.chapter h2 { font-size: 32px; margin: 4px 0 14px; }
.chapter .scene { padding: 14px 18px; border-left: 3px solid var(--cyan); background: rgba(53, 214, 232, .06); border-radius: 0 10px 10px 0; color: #cfd6e3; }
.chapter ol.steps { counter-reset: s; list-style: none; padding: 0; margin: 18px 0; }
.chapter ol.steps li { counter-increment: s; position: relative; padding: 6px 0 6px 40px; }
.chapter ol.steps li::before { content: counter(s); position: absolute; left: 0; top: 7px; width: 26px; height: 26px; border-radius: 50%; background: var(--cyan); color: #04131a; font-weight: 800; font-size: 13px; display: grid; place-items: center; }
.chapter ul.tips { padding: 14px 18px 14px 36px; background: var(--card); border-radius: 12px; border: 1px solid var(--line); color: var(--dim); font-size: 15px; }
.chapter table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: 15px; }
.chapter td { border-bottom: 1px solid var(--line); padding: 10px 12px; vertical-align: top; }
.chapter td:first-child { white-space: nowrap; color: var(--text); font-weight: 600; width: 1%; } .chapter td:last-child { color: var(--dim); }
.chapter .shot { margin-top: 20px; }
.manual .hidden { display: none; }
@media (max-width: 860px) { .manual { grid-template-columns: 1fr; } .manual aside { position: static; max-height: none; } .chapter td:first-child { white-space: normal; } }