.demo-section {
  background: linear-gradient(180deg, #ffffffa3, #ffffff00 28%, #ffffff52),
    linear-gradient(115deg, #eaf4fa 0%, #f3f8fc 40%, #ffffff 76%, #f6faff 100%);
  padding: 64px 0 72px;
  scroll-margin-top: 0;
  font-family: "Microsoft YaHei", "Segoe UI", sans-serif;
}
.demo-inner { width: min(1080px, calc(100% - 96px)); margin: 0 auto; }
.demo-heading { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-bottom: 28px; }
.demo-heading h2 { margin: 0; color: var(--accent); font: 600 28px/1.4 "Microsoft YaHei", "Segoe UI", sans-serif; }
.demo-language {
  --selected-tab: 0;
  --tab-width: 104px;
  position: relative;
  display: inline-grid;
  grid-template-columns: repeat(2, var(--tab-width));
  flex: none;
  padding: 5px;
  border: 1px solid #ffffffed;
  border-radius: 40px;
  background: linear-gradient(145deg, #ffffffb8, #eaf0f86b);
  box-shadow: 0 5px 16px #526d8a12, inset 0 1px 0 #fff, inset 0 -1px 2px #879ab118;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}
.demo-language::before {
  content: "";
  position: absolute;
  top: 5px;
  bottom: 5px;
  left: 5px;
  width: var(--tab-width);
  border: 1px solid #92a8c099;
  border-radius: 30px;
  background: linear-gradient(170deg, #cad8edbb 0%, #dce6f599 52%, #eaf4ffdd 100%);
  box-shadow: inset 0 2px 1px #ffffffeb, inset 0 -2px 3px #f0f7ff, 0 2px 4px #506d9717;
  transform: translateX(calc(var(--selected-tab) * var(--tab-width)));
  transition: transform 260ms cubic-bezier(.22, .8, .3, 1);
  pointer-events: none;
}
.demo-language button { position: relative; min-height: 42px; padding: 8px 14px; border: 0; border-radius: 30px; background: transparent; color: #546c82; font: 600 14px/1.5 "Microsoft YaHei", "Segoe UI", sans-serif; cursor: pointer; transition: color 180ms ease; }
.demo-language button[aria-selected="true"] { color: var(--accent); text-shadow: 0 1px 0 #ffffff80; }
.demo-language button:hover { color: var(--accent); }
.demo-language button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.demo-shell {
  padding: 12px;
  border: 1px solid #ffffffed;
  border-radius: 28px;
  background: linear-gradient(135deg, #ffffffad, #ffffff45 46%, #f1f8ffa6);
  box-shadow: 0 22px 56px -24px #51778040, 0 6px 18px -8px #66868b26, inset 0 1px 0 #fff;
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}
.demo-screen { position: relative; aspect-ratio: 16 / 9; width: 100%; overflow: hidden; border-radius: 17px; background: #f1f7f8; box-shadow: 0 0 0 1px #718f951f; }
.demo-screen video { display: block; width: 100%; height: 100%; object-fit: contain; background: #f1f7f8; }
.demo-panel { height: 100%; }
.demo-screen [hidden] { display: none !important; }
.demo-play { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); display: grid; place-items: center; width: 64px; height: 64px; padding: 0; border-radius: 50%; border: 1px solid #fff; background: linear-gradient(145deg, #ffffffd9, #e4f3f2ab); color: var(--accent); box-shadow: inset 0 1px 2px #fff, 0 6px 18px #385e6d26; backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); cursor: pointer; }
.demo-play svg { width: 26px; height: 26px; fill: currentColor; margin-left: 3px; }
.demo-play:hover { background: #eff5f7; }
.demo-play:focus-visible { outline: 3px solid #49778c; outline-offset: 4px; }
.demo-error { position: absolute; inset: 0; display: grid; place-content: center; background: #f1f7f8; padding: 24px; text-align: center; color: #36454d; }
.header .nav-row nav { gap: 32px; }
.header .nav-demo[aria-current="location"] { color: #315f74; text-decoration: underline; text-underline-offset: 8px; }
@media (min-width: 1700px) {
  .demo-inner { width: min(1280px, calc(100% - 160px)); }
}
@media (max-width: 1100px) {
  .header .nav-row { gap: 16px; }
  .header .nav-row nav { gap: 20px; }
  .header .nav-cta { display: none; }
}
@media (max-width: 700px) {
  .header .nav-row { height: auto; min-height: 100px; flex-wrap: wrap; gap: 8px 16px; padding-block: 10px; }
  .header .nav-row nav { display: flex; width: 100%; order: 3; justify-content: space-between; gap: 8px; margin: 0; font-size: 13px; }
  .header .nav-row nav a { display: inline-block; white-space: nowrap; padding: 4px 0; }
  .header .locale-link { margin-left: auto; }
  html { scroll-padding-top: 116px; }
  .demo-section { padding: 36px 0 40px; }
  .demo-inner { width: calc(100% - 32px); }
  .demo-heading { gap: 12px; margin-bottom: 20px; }
  .demo-heading h2 { font-size: 22px; }
  .demo-language { --tab-width: 76px; }
  .demo-language button { min-height: 40px; padding: 6px 9px; font-size: 13px; }
  .demo-shell { padding: 7px; border-radius: 20px; }
  .demo-screen { border-radius: 13px; }
  .demo-play { width: 52px; height: 52px; }
}
@media (prefers-reduced-motion: reduce) {
  .demo-language::before, .demo-language button { transition: none; }
}
@media (max-width: 360px) {
  .browser-install-head { flex-wrap: wrap; }
}