@font-face {
  font-family: "Roboto Condensed";
  src: url("../assets/fonts/roboto-condensed-regular.ttf") format("truetype");
  font-style: normal;
  font-weight: 400;
  font-display: swap;
}
:root {
  color-scheme: dark;
  --ambient-ink: #f8f1fa;
  --ambient-accent: #e62b1e;
}
* { box-sizing: border-box; }
/* 隐藏页面滚动条，保留触控、滚轮和键盘滚动。 */
html, body { scrollbar-width: none; }
html::-webkit-scrollbar,
body::-webkit-scrollbar { display: none; }
body {
  margin: 0;
  background: #000;
  color: var(--ambient-ink);
  font-family: "Roboto Condensed", "Arial Narrow", sans-serif;
  -webkit-font-smoothing: antialiased;
}
/* 两侧柔光落在黑底上，中间保持纯黑，呼应参考图的暗色层次。 */
.ambient-page { position: relative; isolation: isolate; min-height: 100svh; overflow: clip; }
.ambient-light { position: absolute; inset: 0 0 auto; height: 100svh; z-index: -1; overflow: hidden; pointer-events: none; }
.ambient-light::before,
.ambient-light::after {
  content: "";
  position: absolute;
  inset: -15%;
  background-repeat: no-repeat;
}
.ambient-light::before {
  background-image: radial-gradient(ellipse 48% 55% at 8% 10%, rgb(103 34 7 / 34%), transparent 78%);
  animation: amber-drift 28s ease-in-out infinite alternate;
}
.ambient-light::after {
  background-image: radial-gradient(ellipse 44% 62% at 98% 12%, rgb(30 13 89 / 29%), transparent 80%);
  animation: violet-drift 32s ease-in-out infinite alternate;
}
/* 顶栏独立于标题区，入口放在右上角，保持首屏主体的原有位置。 */
/* 固定顶栏，滚动后用深色背景保持文字可读。 */
.site-header { position: fixed; inset: 0 0 auto; z-index: 10; background: rgb(0 0 0 / 96%); transition: background-color 180ms ease; }
.site-header--at-top { background: transparent; }
.site-nav { display: flex; align-items: center; justify-content: flex-end; gap: 24px; padding: 20px clamp(24px, 4vw, 64px); }
.ambient-intro { text-align: center; padding: clamp(96px, 18svh, 180px) 24px 0; }
.ambient-brand, .app-store-button { font-family: inherit; font-size: 15px; letter-spacing: 0.07em; font-weight: 400; line-height: normal; }
.ambient-brand { margin: 0; color: inherit; text-decoration: none; }
.site-nav .ambient-brand { display: inline-flex; align-items: center; gap: 10px; margin-right: auto; color: inherit; text-decoration: none; }
.site-nav .ambient-brand:hover { opacity: 0.8; }
.ambient-topics {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px 28px;
  margin: 32px 0 0;
  color: #d2c9df;
  font-size: 12px;
  letter-spacing: 0.12em;
}
.ambient-title {
  margin: 48px 0 0;
  font-size: clamp(32px, 3.3vw, 52px);
  font-weight: 400;
  letter-spacing: 0.01em;
  line-height: 1.15;
  text-transform: uppercase;
}
.ambient-accent { width: 44px; height: 3px; border-radius: 2px; margin: 24px auto 0; background: var(--ambient-accent); }
.app-store-button {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  min-height: 44px; margin: 0; padding: 6px 0;
  border: 0; border-radius: 0; background: transparent; color: var(--ambient-ink);
  text-decoration: none; cursor: pointer; transition: opacity 160ms ease;
}
.app-store-button__arrow { display: block; flex: none; }
.app-store-button:hover { opacity: 0.75; }
.app-store-button:active { opacity: 0.6; }
.app-store-button:focus-visible { outline: 2px solid var(--ambient-accent); outline-offset: 5px; }
/* 将底部隐私政策和返回顶部链接保持为同一行。 */
.review-footer__links { display: flex; align-items: center; gap: 24px; white-space: nowrap; }
@media (max-width: 480px) {
  .review-footer { flex-wrap: wrap; }
  .review-footer__links { margin-left: auto; gap: 18px; }
}
/* 按钮移至顶栏后补回留白，保持图表与图例在首屏的位置。 */
.ambient-product { display: flex; justify-content: center; margin: max(80px, calc(82svh - 520px)) 0 0; padding: 0 24px 96px; }
.ambient-product .device-mockup { width: min(300px, 68vw); }
@keyframes amber-drift { to { transform: translate(4%, 3%) scale(1.06); opacity: 0.7; } }
@keyframes violet-drift { to { transform: translate(-3%, 5%) scale(1.08); opacity: 0.72; } }
@media (max-width: 600px) {
  .site-nav { gap: 16px; padding: 18px 24px; }
  .ambient-intro { padding-top: 112px; }
  .ambient-brand, .app-store-button { font-size: 13px; }
  .ambient-topics { gap: 12px 20px; font-size: 10px; margin-top: 28px; }
  .ambient-title { font-size: clamp(30px, 7.7vw, 40px); margin-top: 40px; }
  .ambient-product { margin-top: max(80px, calc(100svh - 564px)); padding-bottom: 64px; }
}
@media (prefers-reduced-motion: reduce) {
  .ambient-light::before, .ambient-light::after { animation: none; }
  .app-store-button, .site-header { transition: none; }
}