:root {
  --blue: #1268f3;
  --blue-deep: #073fbb;
  --cyan: #21c7ee;
  --ink: #10213a;
  --muted: #64748b;
  --line: #e7edf6;
  --surface: #f5f8fe;
  --white: #fff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
.section-shell { width: min(1180px, calc(100% - 48px)); margin-inline: auto; }

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  height: 76px;
  padding: 0 max(32px, calc((100vw - 1180px) / 2));
  border-bottom: 1px solid rgb(223 233 247 / 76%);
  background: rgb(255 255 255 / 88%);
  backdrop-filter: blur(18px);
}
.brand { display: inline-flex; align-items: center; gap: 12px; width: max-content; }
.brand img { width: 42px; height: 42px; border-radius: 12px; box-shadow: 0 8px 20px rgb(18 104 243 / 24%); }
.brand span { display: grid; }
.brand strong { font-size: 19px; letter-spacing: .04em; }
.brand small { margin-top: 1px; color: #8290a5; font-size: 9px; letter-spacing: .16em; }
.site-header nav { display: flex; gap: 38px; color: #42516a; font-size: 14px; }
.site-header nav a { position: relative; padding: 28px 0; }
.site-header nav a::after { position: absolute; right: 50%; bottom: 19px; left: 50%; height: 2px; border-radius: 2px; background: var(--blue); content: ""; transition: .2s; }
.site-header nav a:hover { color: var(--blue); }
.site-header nav a:hover::after { right: 0; left: 0; }
.header-action { justify-self: end; padding: 10px 18px; border: 1px solid #cbdcff; border-radius: 9px; color: var(--blue); font-size: 13px; font-weight: 600; }

.hero {
  display: grid;
  grid-template-columns: .88fr 1.12fr;
  align-items: center;
  min-height: 680px;
  padding-top: 58px;
  padding-bottom: 76px;
}
.hero::before {
  position: absolute;
  z-index: -1;
  top: 76px;
  right: 0;
  left: 0;
  height: 680px;
  background: radial-gradient(circle at 83% 24%, rgb(51 151 255 / 17%), transparent 28%), radial-gradient(circle at 8% 10%, rgb(33 199 238 / 10%), transparent 25%), linear-gradient(180deg, #f6faff 0, #fff 88%);
  content: "";
}
.eyebrow, .section-tag { color: var(--blue); font-size: 13px; font-weight: 700; letter-spacing: .08em; }
.eyebrow { display: inline-flex; align-items: center; gap: 9px; padding: 8px 13px; border: 1px solid #d9e7ff; border-radius: 999px; background: rgb(255 255 255 / 78%); }
.eyebrow i { width: 7px; height: 7px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 0 5px rgb(33 199 238 / 13%); }
.hero h1 { margin: 25px 0 22px; font-size: clamp(44px, 4.1vw, 66px); line-height: 1.16; letter-spacing: -.045em; }
.hero h1 em { color: transparent; background: linear-gradient(90deg, #0b5dea, #20bfe7); background-clip: text; font-style: normal; }
.hero-copy > p { max-width: 505px; margin: 0; color: var(--muted); font-size: 17px; line-height: 1.9; }
.hero-actions { display: flex; gap: 14px; margin-top: 34px; }
.primary-button, .ghost-button { display: inline-flex; align-items: center; justify-content: center; min-width: 150px; height: 48px; border-radius: 10px; font-size: 14px; font-weight: 700; }
.primary-button { color: #fff; background: linear-gradient(135deg, var(--blue), #2e93fa); box-shadow: 0 13px 28px rgb(18 104 243 / 27%); }
.ghost-button { border: 1px solid #d7e2f2; background: #fff; }
.hero-points { display: flex; gap: 22px; margin: 28px 0 0; padding: 0; color: #66758b; font-size: 12px; list-style: none; }
.hero-points b { display: inline-grid; place-items: center; width: 18px; height: 18px; margin-right: 4px; border-radius: 50%; color: var(--blue); background: #e8f2ff; }

.hero-visual { position: relative; min-height: 500px; }
.glow { position: absolute; border-radius: 50%; filter: blur(2px); }
.glow-one { top: 0; right: 6%; width: 320px; height: 320px; background: rgb(43 154 255 / 13%); }
.glow-two { bottom: 0; left: 8%; width: 220px; height: 220px; background: rgb(40 220 229 / 11%); }
.stage-card { position: absolute; top: 56px; right: 0; width: min(620px, 92%); overflow: hidden; border: 1px solid rgb(194 218 250 / 74%); border-radius: 22px; background: #fff; box-shadow: 0 32px 70px rgb(35 88 164 / 19%); transform: perspective(1200px) rotateY(-2deg) rotateX(1deg); }
.stage-topbar { display: flex; align-items: center; height: 48px; padding: 0 17px; color: #dce9ff; background: #142846; font-size: 12px; }
.stage-topbar > span { display: flex; gap: 5px; }
.stage-topbar > span i { width: 7px; height: 7px; border-radius: 50%; background: #517198; }
.stage-topbar strong { margin: auto; font-size: 12px; }
.stage-topbar em { padding: 4px 8px; border-radius: 5px; color: #fff; background: #ff5667; font-size: 9px; font-style: normal; letter-spacing: .08em; }
.stage-content { display: grid; grid-template-columns: 1.75fr .85fr; min-height: 330px; }
.teacher-illustration { position: relative; overflow: hidden; background: linear-gradient(140deg, #0b5ce1, #153e99 62%, #102f73); }
.teacher-illustration::before { position: absolute; inset: 0; background: linear-gradient(90deg, transparent 49.6%, rgb(255 255 255 / 9%) 50%, transparent 50.4%), linear-gradient(0deg, transparent 49.6%, rgb(255 255 255 / 9%) 50%, transparent 50.4%); background-size: 46px 46px; content: ""; opacity: .35; }
.orbit { position: absolute; border: 1px solid rgb(102 229 255 / 38%); border-radius: 50%; }
.orbit-one { top: 42px; left: 44px; width: 250px; height: 250px; }
.orbit-two { top: 86px; left: 90px; width: 160px; height: 160px; }
.screen-lines { position: absolute; top: 44px; right: 28px; display: grid; gap: 10px; width: 105px; }
.screen-lines i { height: 8px; border-radius: 5px; background: rgb(114 225 255 / 35%); }
.screen-lines i:nth-child(2) { width: 72%; }
.screen-lines i:nth-child(3) { width: 86%; }
.person { position: absolute; bottom: 0; left: 118px; width: 164px; height: 254px; }
.person .head { position: absolute; top: 5px; left: 54px; width: 58px; height: 70px; border: 9px solid #17223d; border-radius: 50% 50% 44% 44%; background: #ffd7bd; box-shadow: inset 0 12px #1b2846; }
.person .body { position: absolute; bottom: -15px; width: 164px; height: 205px; border-radius: 70px 70px 18px 18px; background: linear-gradient(105deg, #f0f5ff, #cbdcf9); box-shadow: inset 22px 0 #1a6ce7, inset -20px 0 #164faa; }
.play { position: absolute; z-index: 3; top: 140px; left: 190px; display: grid; place-items: center; width: 56px; height: 56px; padding-left: 4px; border: 1px solid rgb(255 255 255 / 48%); border-radius: 50%; color: #fff; background: rgb(7 31 76 / 48%); backdrop-filter: blur(8px); }
.chat-panel { padding: 18px 14px; background: #f8faff; }
.chat-tabs { display: flex; gap: 20px; padding: 0 4px 13px; border-bottom: 1px solid #e4ebf5; color: #8290a4; font-size: 11px; }
.chat-tabs b { color: var(--blue); }
.message { display: flex; gap: 9px; margin-top: 17px; }
.avatar { flex: 0 0 auto; width: 25px; height: 25px; border-radius: 50%; }
.avatar.blue { background: linear-gradient(135deg, #5296ff, #174ec2); }
.avatar.cyan { background: linear-gradient(135deg, #52dfeb, #119cac); }
.message p { display: grid; gap: 5px; margin: 0; font-size: 9px; }
.message p b { color: #59708e; font-weight: 500; }
.message p span { padding: 7px 8px; border-radius: 2px 8px 8px; color: #56667c; background: #fff; box-shadow: 0 3px 10px rgb(24 58 101 / 7%); }
.product-chip { display: flex; gap: 9px; align-items: center; margin-top: 21px; padding: 9px; border: 1px solid #dce9fc; border-radius: 9px; background: #fff; }
.product-chip > i { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 7px; color: #fff; background: linear-gradient(135deg, #176cf1, #21c6e8); font-size: 12px; font-style: normal; }
.product-chip span { display: grid; gap: 3px; font-size: 9px; }
.product-chip small { color: #8c99aa; }
.stage-footer { display: flex; justify-content: space-between; padding: 14px 20px; color: #75849a; font-size: 10px; }
.stage-footer span i { display: inline-block; width: 7px; height: 7px; margin-right: 5px; border-radius: 50%; background: #2bd18a; box-shadow: 0 0 0 4px rgb(43 209 138 / 12%); }
.float-card { position: absolute; display: flex; align-items: center; border: 1px solid rgb(205 220 243 / 72%); border-radius: 12px; background: rgb(255 255 255 / 91%); box-shadow: 0 15px 34px rgb(49 85 140 / 14%); backdrop-filter: blur(10px); }
.viewers { right: -8px; bottom: 22px; display: grid; padding: 15px 24px; }
.viewers b { color: var(--blue); font-size: 20px; }
.viewers span { margin-top: 2px; color: #7e8da2; font-size: 9px; }
.signal { top: 27px; left: 3px; gap: 9px; padding: 11px 16px; color: #52657e; font-size: 10px; }
.signal i { width: 9px; height: 9px; border-radius: 50%; background: #2bd18a; box-shadow: 0 0 0 5px rgb(43 209 138 / 13%); }

.trust-strip { display: flex; align-items: center; justify-content: center; gap: 28px; min-height: 86px; border-block: 1px solid #edf2f8; color: #8592a5; background: #fbfcfe; font-size: 13px; }
.trust-strip span { color: #a2adbc; font-size: 12px; }
.trust-strip b { color: #526176; font-weight: 600; }
.trust-strip i { width: 3px; height: 3px; border-radius: 50%; background: #c3cbd7; }

.content-section { padding-top: 108px; padding-bottom: 112px; }
.section-heading { max-width: 680px; margin: 0 auto 48px; text-align: center; }
.section-heading > span { color: var(--blue); font-size: 11px; font-weight: 800; letter-spacing: .18em; }
.section-heading h2, .scene-copy h2, .about-card h2, .contact-card h2, .legal-section h2 { margin: 13px 0 14px; font-size: 35px; letter-spacing: -.035em; }
.section-heading p, .scene-copy > p, .about-card p, .contact-card p, .legal-section p { margin: 0; color: var(--muted); line-height: 1.9; }
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.feature-card { position: relative; min-height: 290px; overflow: hidden; padding: 28px 25px; border: 1px solid var(--line); border-radius: 18px; background: #fff; box-shadow: 0 12px 30px rgb(34 70 118 / 5%); transition: .25s; }
.feature-card:hover { transform: translateY(-6px); box-shadow: 0 20px 45px rgb(34 70 118 / 11%); }
.feature-card > span { position: absolute; top: 22px; right: 22px; color: #dce4ef; font-size: 12px; font-weight: 700; }
.feature-card h3 { margin: 25px 0 12px; font-size: 18px; }
.feature-card p { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.85; }
.feature-primary { color: #fff; border-color: transparent; background: linear-gradient(145deg, #135fd9, #073da9); box-shadow: 0 18px 38px rgb(18 94 211 / 24%); }
.feature-primary::after { position: absolute; right: -70px; bottom: -80px; width: 210px; height: 210px; border: 1px solid rgb(255 255 255 / 12%); border-radius: 50%; content: ""; box-shadow: 0 0 0 34px rgb(255 255 255 / 4%), 0 0 0 68px rgb(255 255 255 / 3%); }
.feature-primary p, .feature-primary > span { color: #bdd6ff; }
.feature-icon { position: relative; display: grid; place-items: center; width: 50px; height: 50px; border-radius: 14px; background: #eaf3ff; }
.feature-primary .feature-icon { background: rgb(255 255 255 / 15%); }
.feature-icon::before, .feature-icon::after, .feature-icon i::before, .feature-icon i::after { position: absolute; content: ""; }
.camera::before { width: 23px; height: 16px; border: 2px solid currentColor; border-radius: 4px; color: #fff; }
.camera::after { right: 8px; width: 8px; height: 10px; border: 2px solid #fff; border-left: 0; border-radius: 0 4px 4px 0; }
.chat { color: var(--blue); }
.chat::before { width: 24px; height: 17px; border: 2px solid currentColor; border-radius: 6px; }
.chat::after { bottom: 11px; left: 14px; width: 7px; height: 7px; border-bottom: 2px solid currentColor; transform: skew(-28deg); }
.devices { color: var(--blue); }
.devices::before { width: 25px; height: 17px; border: 2px solid currentColor; border-radius: 3px; transform: translate(-3px, -2px); }
.devices::after { right: 10px; bottom: 10px; width: 9px; height: 16px; border: 2px solid currentColor; border-radius: 2px; background: #eaf3ff; }
.bag { color: var(--blue); }
.bag::before { width: 22px; height: 20px; border: 2px solid currentColor; border-radius: 4px; transform: translateY(3px); }
.bag::after { top: 12px; width: 10px; height: 7px; border: 2px solid currentColor; border-bottom: 0; border-radius: 7px 7px 0 0; }
.mini-wave { position: absolute; right: 25px; bottom: 24px; left: 25px; display: flex; align-items: end; gap: 5px; height: 34px; opacity: .45; }
.mini-wave i { flex: 1; height: 30%; border-radius: 2px; background: #7cafff; }
.mini-wave i:nth-child(2), .mini-wave i:nth-child(5) { height: 75%; }
.mini-wave i:nth-child(3) { height: 45%; }.mini-wave i:nth-child(4) { height: 100%; }.mini-wave i:nth-child(6) { height: 58%; }

.scene-section { padding: 100px 0; background: #0e2445; color: #fff; }
.scene-layout { display: grid; grid-template-columns: .82fr 1.18fr; align-items: center; gap: 80px; }
.scene-copy h2 { font-size: 37px; }
.scene-copy > p { color: #aebed5; }
.scene-list { display: grid; gap: 12px; margin-top: 30px; }
.scene-list > div { display: flex; gap: 14px; align-items: center; padding: 14px 16px; border: 1px solid rgb(255 255 255 / 9%); border-radius: 11px; background: rgb(255 255 255 / 4%); }
.scene-list i { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 9px; color: #6bd9f2; background: rgb(33 199 238 / 10%); font-size: 10px; font-style: normal; }
.scene-list span { display: grid; gap: 4px; }
.scene-list b { font-size: 14px; }.scene-list small { color: #94a8c5; font-size: 11px; }
.device-showcase { position: relative; min-height: 420px; }
.desktop-device { position: absolute; top: 10px; left: 0; width: 82%; padding: 10px; border: 1px solid #466184; border-radius: 15px; background: #1a3559; box-shadow: 0 28px 60px rgb(0 0 0 / 30%); }
.device-bar { display: flex; gap: 5px; height: 23px; padding-left: 4px; }
.device-bar i { width: 6px; height: 6px; border-radius: 50%; background: #607a9e; }
.device-video { position: relative; display: grid; place-items: center; height: 270px; overflow: hidden; border-radius: 8px; background: radial-gradient(circle at 42% 45%, #257be9 0 3%, transparent 3.5%), linear-gradient(135deg, #0c59cc, #092e72); }
.device-video::before { position: absolute; inset: 0; background: linear-gradient(90deg, transparent 49%, rgb(255 255 255 / 8%) 50%, transparent 51%); background-size: 45px; content: ""; }
.device-video span { position: relative; z-index: 1; display: grid; place-items: center; width: 54px; height: 54px; padding-left: 4px; border: 1px solid rgb(255 255 255 / 35%); border-radius: 50%; background: rgb(4 28 69 / 43%); }
.device-video b { position: absolute; bottom: 24px; left: 25px; font-size: 18px; }
.device-chat { display: flex; gap: 7px; padding: 11px 3px 2px; }.device-chat i { height: 6px; border-radius: 5px; background: #39597d; }.device-chat i:nth-child(1) { width: 36%; }.device-chat i:nth-child(2) { width: 23%; }.device-chat i:nth-child(3) { width: 13%; }
.mobile-device { position: absolute; z-index: 2; right: 0; bottom: -3px; width: 180px; height: 352px; padding: 12px; border: 5px solid #dbe6f5; border-radius: 30px; color: var(--ink); background: #fff; box-shadow: 0 25px 55px rgb(0 0 0 / 37%); }
.mobile-notch { width: 62px; height: 12px; margin: -12px auto 7px; border-radius: 0 0 9px 9px; background: #dbe6f5; }
.mobile-video { display: grid; place-items: center; height: 178px; border-radius: 16px; color: #fff; background: linear-gradient(145deg, #1681f3, #1245b5); }
.mobile-video span { display: grid; place-items: center; width: 42px; height: 42px; padding-left: 3px; border-radius: 50%; background: rgb(255 255 255 / 19%); }
.mobile-line { height: 8px; margin-top: 16px; border-radius: 5px; background: #e8eef6; }.mobile-line.short { width: 70%; margin-top: 9px; }
.mobile-button { margin-top: 31px; padding: 11px; border-radius: 9px; color: #fff; background: var(--blue); font-size: 11px; text-align: center; }

.section-heading.compact { margin-bottom: 39px; }
.security-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.security-grid article { padding: 30px; border: 1px solid var(--line); border-radius: 16px; background: linear-gradient(150deg, #fff, #f8fbff); }
.security-grid article > i { position: relative; display: grid; place-items: center; width: 44px; height: 44px; border-radius: 12px; color: var(--blue); background: #eaf3ff; font-style: normal; font-weight: 800; }
.security-grid h3 { margin: 20px 0 10px; font-size: 17px; }.security-grid p { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.8; }
.lock::before { width: 15px; height: 13px; border: 2px solid currentColor; border-radius: 3px; content: ""; transform: translateY(4px); }.lock::after { position: absolute; top: 9px; width: 11px; height: 11px; border: 2px solid currentColor; border-bottom: 0; border-radius: 8px 8px 0 0; content: ""; }
.eye::before { width: 23px; height: 14px; border: 2px solid currentColor; border-radius: 70% 15%; content: ""; transform: rotate(45deg); }.eye::after { position: absolute; width: 6px; height: 6px; border-radius: 50%; background: currentColor; content: ""; }

.about-section { padding-bottom: 110px; }
.about-card { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 70px; padding: 48px 55px; border: 1px solid #dbe8fa; border-radius: 22px; background: linear-gradient(120deg, #f1f7ff, #fbfdff); }
.about-card > div { max-width: 760px; }.about-card p + p { margin-top: 8px; }.about-card img { width: 125px; height: 125px; border-radius: 28px; box-shadow: 0 19px 36px rgb(18 104 243 / 22%); }
.contact-section { padding: 80px 0; background: linear-gradient(130deg, #0e5ee0, #073aab); color: #fff; }
.contact-card { display: flex; align-items: center; justify-content: space-between; gap: 60px; }
.contact-card > div { max-width: 720px; }.contact-card span { color: #8fdcf2; font-size: 11px; font-weight: 800; letter-spacing: .18em; }.contact-card h2 { margin-top: 10px; }.contact-card p { color: #c3d8f7; }
.contact-card > a { flex: 0 0 auto; padding: 14px 24px; border-radius: 10px; color: var(--blue-deep); background: #fff; font-size: 13px; font-weight: 700; box-shadow: 0 12px 28px rgb(0 23 77 / 22%); }
.legal-section { padding-top: 80px; padding-bottom: 80px; }.legal-section h2 { font-size: 27px; }.legal-section p { font-size: 14px; }.legal-section p + p { margin-top: 9px; }
.site-footer { color: #a6b5ca; background: #091a32; }
.footer-main { display: flex; align-items: center; justify-content: space-between; padding-top: 38px; padding-bottom: 30px; }
.footer-brand strong { color: #fff; }.footer-brand small { color: #7086a4; font-size: 10px; letter-spacing: 0; }.footer-brand img { width: 38px; height: 38px; }
.footer-links { display: flex; gap: 28px; font-size: 12px; }.footer-links a:hover { color: #fff; }
.footer-bottom { display: flex; justify-content: space-between; padding-top: 18px; padding-bottom: 18px; border-top: 1px solid rgb(255 255 255 / 8%); font-size: 11px; }

@media (max-width: 980px) {
  .site-header { grid-template-columns: 1fr auto; padding-inline: 24px; }.site-header nav { display: none; }
  .hero { grid-template-columns: 1fr; padding-top: 72px; }.hero-copy { text-align: center; }.hero-copy > p { margin-inline: auto; }.hero-actions, .hero-points { justify-content: center; }.hero-visual { margin-top: 30px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }.scene-layout { grid-template-columns: 1fr; }.scene-copy { max-width: 680px; }.device-showcase { width: min(720px, 100%); margin-inline: auto; }
}

@media (max-width: 640px) {
  .section-shell { width: min(100% - 30px, 1180px); }.site-header { height: 66px; padding-inline: 15px; }.brand img { width: 36px; height: 36px; }.brand strong { font-size: 16px; }.header-action { padding: 8px 12px; font-size: 11px; }
  .hero { min-height: auto; padding-top: 52px; padding-bottom: 35px; }.hero::before { top: 66px; height: 730px; }.hero h1 { font-size: 38px; }.hero-copy > p { font-size: 15px; }.hero-actions { flex-direction: column; }.hero-points { gap: 10px; flex-wrap: wrap; }
  .hero-visual { min-height: 380px; }.stage-card { top: 42px; width: 100%; transform: none; }.stage-content { grid-template-columns: 1fr; min-height: 250px; }.teacher-illustration { min-height: 250px; }.chat-panel { display: none; }.person { left: calc(50% - 82px); }.play { left: calc(50% - 28px); }.viewers { right: 0; bottom: -5px; }.signal { left: -4px; }
  .trust-strip { gap: 10px; min-height: 70px; padding: 12px 15px; flex-wrap: wrap; }.trust-strip span { width: 100%; text-align: center; }
  .content-section { padding-top: 72px; padding-bottom: 74px; }.section-heading h2, .scene-copy h2, .about-card h2, .contact-card h2 { font-size: 28px; }.feature-grid, .security-grid { grid-template-columns: 1fr; }.feature-card { min-height: 245px; }
  .scene-section { padding: 72px 0; }.scene-layout { gap: 38px; }.device-showcase { min-height: 330px; }.desktop-device { width: 92%; }.device-video { height: 210px; }.mobile-device { right: -2px; width: 132px; height: 270px; border-width: 4px; border-radius: 24px; }.mobile-video { height: 130px; }.mobile-button { margin-top: 22px; padding: 8px; }.mobile-notch { width: 46px; }
  .about-section { padding-bottom: 74px; }.about-card { grid-template-columns: 1fr; gap: 25px; padding: 32px 25px; }.about-card img { grid-row: 1; width: 88px; height: 88px; border-radius: 20px; }
  .contact-section { padding: 58px 0; }.contact-card { align-items: flex-start; flex-direction: column; gap: 28px; }.legal-section { padding-block: 58px; }
  .footer-main, .footer-bottom { align-items: flex-start; flex-direction: column; gap: 22px; }.footer-links { gap: 15px; flex-wrap: wrap; }.footer-bottom { gap: 9px; }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { transition: none !important; } }