:root {
  color-scheme: dark;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: #ecf0f5; background: #080f1c; font-synthesis: none;
  text-rendering: optimizeLegibility; -webkit-font-smoothing: antialiased;
}
* { box-sizing: border-box; }
html { min-width: 320px; }
body { min-width: 320px; margin: 0; }
button, a { -webkit-tap-highlight-color: transparent; touch-action: manipulation; }
button { font: inherit; }
::selection { color: #fff; background: #30575f; }
.ambient { position: fixed; inset: 0; overflow: hidden; pointer-events: none; z-index: -1; background: #080f1c; }
.ambient::before { content: ""; position: absolute; inset: 0; background: url('assets/page-lines-v1.png') center / cover no-repeat; opacity: .72; }
.ambient::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, #080f1c08, #080f1c1a); }
.page-shell { width: min(100% - 112px, 1280px); min-height: 100svh; margin: auto; display: flex; flex-direction: column; }
.site-header { display: flex; align-items: center; justify-content: space-between; padding: 35px 0; }
.brand { display: flex; align-items: center; flex-shrink: 0; }
.brand-logo { display: block; width: 190px; max-width: 100%; height: auto; }
.header-note { font-size: 11px; letter-spacing: .16em; color: #8996a8; }
main { flex: 1; padding: clamp(38px, 6.5vh, 80px) 0 32px; }
.intro { margin: 0 0 35px; }
.eyebrow { display: flex; align-items: center; gap: 10px; font-size: 10px; font-weight: 550; letter-spacing: .2em; color: #8aa6b2; margin: 0 0 23px; }
.eyebrow > span { width: 23px; height: 1px; background: #7fbabb; }
h1 { margin: 0; font-size: clamp(36px, 4vw, 59px); font-weight: 580; letter-spacing: -.035em; line-height: 1.35; }
.title-accent { color: #a5bfc8; }
.intro-bottom { display: flex; align-items: flex-end; justify-content: space-between; gap: 24px; margin-top: 23px; }
.intro-copy { margin: 0; font-size: 13px; line-height: 1.85; color: #9ba7b7; letter-spacing: .045em; }
.mobile-break { display: none; }
.directory-label { display: inline-flex; align-items: center; gap: 20px; font-size: 11px; letter-spacing: .1em; color: #99a8ba; white-space: nowrap; }
.directory-label > span { font-size: 21px; color: #afbecb; }
.platform-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 26px; }
.card-stage { min-width: 0; perspective: 1100px; }
.platform-card {
  --light-x: 50%; --light-y: 50%; --light-opacity: 0; --accent: 119, 218, 210;
  min-width: 0; min-height: 356px; height: 100%; padding: 30px 32px;
  position: relative; display: flex; flex-direction: column; align-items: flex-start; isolation: isolate;
  overflow: hidden; border: 1px solid #ffffff17; border-radius: 22px;
  background: radial-gradient(ellipse at 94% 2%, rgba(var(--accent), .075), transparent 58%), linear-gradient(135deg, #142331ee, #0f1928f5 70%);
  box-shadow: inset 0 1px 0 #ffffff05, 0 20px 50px -26px #0008;
  transform-origin: center; transition: border-color .3s;
}
.platform-card::before { content: ""; position: absolute; inset: 0; z-index: -1; pointer-events: none; opacity: var(--light-opacity); background: radial-gradient(380px circle at var(--light-x) var(--light-y), rgba(var(--accent), .12), transparent 74%); }
.platform-card::after {
  content: ""; position: absolute; inset: 0; border-radius: inherit; padding: 1px; pointer-events: none; z-index: 5; opacity: var(--light-opacity);
  background: radial-gradient(230px circle at var(--light-x) var(--light-y), rgba(var(--accent), .85), rgba(var(--accent), .12) 55%, transparent 75%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude;
}
.teachecho-card { --accent: 235, 193, 145; background: radial-gradient(ellipse at 94% 2%, #d8ab7d12, transparent 58%), linear-gradient(135deg, #202631ee, #151b29f5 70%); }
.card-top { width: 100%; display: flex; align-items: flex-start; justify-content: space-between; }
.logo-frame { width: 62px; height: 62px; display: grid; place-items: center; overflow: hidden; border-radius: 16px; box-shadow: 0 5px 20px #0003; border: 1px solid #ffffff1f; }
.logo-frame img { width: 100%; height: 100%; display: block; object-fit: contain; }
.sonopath-logo { background: #020a19; }
.teachecho-logo { background: #fff; }
.platform-tag { display: inline-flex; gap: 7px; align-items: center; padding: 7px 10px; font-size: 10px; letter-spacing: .12em; color: #abc2c8; border: 1px solid #82baba21; border-radius: 20px; background: #213b461c; }
.platform-tag i { width: 4px; height: 4px; border-radius: 50%; background: #80c3b9; }
.teachecho-card .platform-tag { color: #d0bba7; border-color: #d7b88f21; background: #d7b88f05; }
.teachecho-card .platform-tag i { background: #d7b88f; }
.card-texture { position: absolute; inset: 0; pointer-events: none; z-index: -2; background-size: cover; background-position: center; opacity: .78; }
.sonopath-card .card-texture { background-image: url('assets/sonopath-texture-v1.png'); }
.teachecho-card .card-texture { background-image: url('assets/teachecho-texture-v1.png'); }
.card-texture::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, #101b2940, transparent 65%), linear-gradient(0deg, #101b2944, transparent 40%); }
.card-copy { margin: 27px 0 26px; position: relative; }
.card-kicker { color: #86aaaf; font-size: 10px; letter-spacing: .22em; margin: 0 0 8px; font-weight: 550; }
.teachecho-card .card-kicker { color: #b9a58f; }
h2 { font-size: 30px; line-height: 1.3; letter-spacing: .025em; font-weight: 570; margin: 0 0 9px; }
.card-description { font-size: 12px; color: #a9b9c9; margin: 0; letter-spacing: .08em; }
.card-detail { color: #8596a8; font-size: 12px; line-height: 1.6; margin: 12px 0 0; letter-spacing: .03em; }
.card-index { position: absolute; bottom: 46px; right: 31px; font: 9px ui-monospace, SFMono-Regular, Consolas, monospace; color: #77879b; letter-spacing: .1em; pointer-events: none; }
.platform-card:focus-within { border-color: #a8cdc9; }
.entry-link:focus-visible, .site-footer a:focus-visible { outline: 2px solid #e6c9a3; outline-offset: 5px; }
.workspace-note { display: flex; align-items: center; justify-content: center; gap: 8px; font-size: 10px; color: #7d8da2; letter-spacing: .05em; margin: 25px 0 0; }
.workspace-note > span { color: #93aaaf; font-size: 14px; }
.site-footer { display: flex; align-items: center; justify-content: space-between; gap: 15px; border-top: 1px solid #b9ced714; padding: 22px 0 27px; color: #78879b; font-size: 10px; letter-spacing: .04em; }
.site-footer a { color: #8e9caf; text-decoration: none; }
.site-footer a:hover { color: #c6d4e1; }
.capsule-layer { position: fixed; inset: 0; z-index: 100; pointer-events: none; overflow: hidden; }
.click-capsule { position: absolute; display: inline-flex; align-items: center; gap: 8px; white-space: nowrap; padding: 11px 16px; border: 1px solid #ead4b842; border-radius: 30px; background: #252c3cf2; color: #f2dfc6; box-shadow: 0 8px 25px #0004, inset 0 1px 0 #fff1; font-size: 12px; letter-spacing: .1em; }
.click-capsule::before { content: ""; width: 4px; height: 4px; border-radius: 50%; background: #dfc09a; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
@media (prefers-reduced-motion: no-preference) {
  .intro { animation: reveal .85s cubic-bezier(.16,1,.3,1) both; }
  .card-stage { animation: reveal 1s .1s cubic-bezier(.16,1,.3,1) both; }
  .card-stage + .card-stage { animation-delay: .2s; }
  @keyframes reveal { from { opacity: 0; transform: translateY(18px); } to { opacity: 1; transform: none; } }
}
@media (min-width: 1800px) {
  .page-shell { width: min(100% - 160px, 1480px); }
  main { display: flex; flex-direction: column; justify-content: center; padding-bottom: 60px; }
  .intro { margin-bottom: 45px; }
  h1 { font-size: 68px; }
  .platform-card { min-height: 410px; padding: 38px; }
  .logo-frame { width: 72px; height: 72px; }
  h2 { font-size: 35px; }
  .card-copy { margin-top: 32px; }
  .card-index { bottom: 54px; right: 38px; }
}
@media (max-width: 1000px) {
  .page-shell { width: calc(100% - 64px); }
  .platform-grid { gap: 18px; }
  .platform-card { padding: 26px; }
  .card-index { display: none; }
  .card-detail { max-width: 200px; }
}
@media (max-width: 680px) {
  .page-shell { width: calc(100% - 40px); max-width: 480px; }
  .site-header { padding: 25px 0; }
  .header-note { font-size: 9px; letter-spacing: .03em; }
  .brand-logo { width: 148px; }
  main { padding: 36px 0 30px; }
  h1 { font-size: clamp(29px, 6.9vw, 43px); line-height: 1.4; letter-spacing: -.045em; }
  .eyebrow { font-size: 8px; letter-spacing: .15em; margin-bottom: 20px; }
  .intro { margin-bottom: 27px; }
  .intro-bottom { margin-top: 19px; }
  .intro-copy { font-size: 11px; }
  .directory-label { display: none; }
  .mobile-break { display: inline; }
  .platform-grid { grid-template-columns: minmax(0, 1fr); gap: 18px; }
  .platform-card { min-height: 333px; padding: 26px; }
  .card-copy { margin: 23px 0; }
  .card-texture { background-position: 62% center; }
  h2 { font-size: 28px; }
  .card-index { display: block; font-size: 8px; right: 25px; bottom: 43px; }
  .entry-link { gap: 18px; }
  .site-footer { flex-wrap: wrap; font-size: 9px; padding: 20px 0; }
}
@media (max-width: 360px) { .header-note { display: none; } .card-index { display: none; } }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .platform-card { transform: none !important; }
  .entry-link, .entry-link:hover, .entry-link:active { transform: none !important; }
}