/* 超级助手官网。和应用同一套视觉：蓝紫（问答）、橙（操作）、光点；跟随系统深浅色。 */

:root {
  --ask-a: #5B8CFF;
  --ask-b: #9B6BFF;
  --act-a: #FFB547;
  --act-b: #FF7A45;
  --ok: #3CCB7F;
  --font: "Segoe UI Variable Display", "Segoe UI Variable Text", "Segoe UI", -apple-system, BlinkMacSystemFont,
    "SF Pro Display", "Helvetica Neue", "PingFang SC", "Microsoft YaHei UI", "Noto Sans SC", sans-serif;
  --max: 1160px;
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);

  color-scheme: light;
  --bg: #FBFBFD;
  --bg-soft: #F3F4F8;
  --card: #FFFFFF;
  --text: #0B0C10;
  --text-2: rgba(11, 12, 16, 0.66);
  --text-3: rgba(11, 12, 16, 0.44);
  --stroke: rgba(11, 12, 16, 0.08);
  --stroke-strong: rgba(11, 12, 16, 0.14);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 14px 40px rgba(20, 24, 40, 0.09);
  --shot-shadow: drop-shadow(0 26px 50px rgba(20, 24, 40, 0.22));
  --nav-bg: rgba(251, 251, 253, 0.74);
  --glow-1: rgba(91, 140, 255, 0.20);
  --glow-2: rgba(155, 107, 255, 0.16);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #07080B;
    --bg-soft: #0D0F14;
    --card: #101218;
    --text: #F4F5F7;
    --text-2: rgba(244, 245, 247, 0.66);
    --text-3: rgba(244, 245, 247, 0.42);
    --stroke: rgba(255, 255, 255, 0.08);
    --stroke-strong: rgba(255, 255, 255, 0.14);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 14px 40px rgba(0, 0, 0, 0.35);
    --shot-shadow: drop-shadow(0 30px 70px rgba(0, 0, 0, 0.6));
    --nav-bg: rgba(7, 8, 11, 0.68);
    --glow-1: rgba(91, 140, 255, 0.24);
    --glow-2: rgba(155, 107, 255, 0.20);
  }
}

/* 只显示当前语言 */
html[data-lang="en"] [lang="zh-CN"],
html[data-lang="zh"] [lang="en"] { display: none !important; }

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; scroll-padding-top: 72px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img, video { display: block; max-width: 100%; height: auto; }
button { font: inherit; color: inherit; }

.skip {
  position: absolute;
  left: 16px;
  top: -60px;
  z-index: 100;
  padding: 8px 14px;
  border-radius: 10px;
  background: var(--card);
  box-shadow: var(--shadow);
}
.skip:focus { top: 12px; }

:focus-visible { outline: 2px solid var(--ask-a); outline-offset: 3px; border-radius: 8px; }

.orb {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--ask-a), var(--ask-b));
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--ask-a) 16%, transparent), 0 0 18px color-mix(in srgb, var(--ask-b) 55%, transparent);
}

/* ---------- 导航 ---------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: saturate(1.6) blur(18px);
  -webkit-backdrop-filter: saturate(1.6) blur(18px);
  border-bottom: 1px solid var(--stroke);
}

.nav-inner {
  max-width: var(--max);
  height: 64px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 28px;
}

.brand { display: inline-flex; align-items: center; gap: 12px; font-weight: 650; font-size: 17px; letter-spacing: -0.01em; }

.links { display: flex; gap: 26px; font-size: 15px; color: var(--text-2); }
.links a:hover { color: var(--text); }

.nav-actions { margin-left: auto; display: flex; align-items: center; gap: 8px; }

.icon-btn {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  color: var(--text-2);
}
.icon-btn:hover { color: var(--text); background: var(--stroke); }
.icon-btn svg { width: 20px; height: 20px; fill: currentColor; }

.lang-btn, .link-btn {
  height: 36px;
  padding: 0 12px;
  border-radius: 10px;
  border: 0;
  background: transparent;
  color: var(--text-2);
  font-size: 14.5px;
  cursor: pointer;
}
.lang-btn:hover, .link-btn:hover { color: var(--text); background: var(--stroke); }

/* ---------- 按钮 ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 44px;
  padding: 0 20px;
  border-radius: 999px;
  border: 1px solid var(--stroke-strong);
  background: var(--card);
  color: var(--text);
  font-weight: 600;
  font-size: 15px;
  white-space: nowrap;
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease), background 0.2s;
}
.btn svg { width: 19px; height: 19px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.btn:hover { transform: translateY(-1px); }
.btn .muted { color: var(--text-3); font-weight: 500; }

.btn-primary {
  border: 0;
  color: #fff;
  background: linear-gradient(135deg, var(--ask-a), var(--ask-b));
  box-shadow: 0 12px 30px -10px rgba(110, 110, 255, 0.7), inset 0 1px 0 rgba(255, 255, 255, 0.25);
}
.btn-primary:hover { box-shadow: 0 16px 38px -10px rgba(110, 110, 255, 0.85), inset 0 1px 0 rgba(255, 255, 255, 0.25); }

.btn-ghost { background: transparent; }
.btn-ghost svg path { fill: currentColor; stroke: none; }
.btn-ghost:hover { background: var(--stroke); }

.btn-lg { height: 54px; padding: 0 28px; font-size: 16.5px; }
.btn-sm { height: 36px; padding: 0 16px; font-size: 14px; }

/* ---------- 首屏 ---------- */

.hero {
  position: relative;
  max-width: var(--max);
  margin: 0 auto;
  padding: 76px 20px 24px;
  text-align: center;
}

.hero .glow {
  position: absolute;
  left: 50%;
  top: -140px;
  width: 1400px;
  height: 860px;
  transform: translateX(-50%);
  background:
    radial-gradient(520px 340px at 32% 34%, var(--glow-1), transparent 70%),
    radial-gradient(560px 380px at 68% 42%, var(--glow-2), transparent 70%);
  pointer-events: none;
  z-index: -1;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid var(--stroke-strong);
  background: color-mix(in srgb, var(--card) 65%, transparent);
  font-size: 13.5px;
  color: var(--text-2);
}
.badge:hover { color: var(--text); }
.badge .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ok); box-shadow: 0 0 0 3px color-mix(in srgb, var(--ok) 25%, transparent); }
.sep { color: var(--text-3); }

h1 {
  margin: 24px auto 0;
  font-size: clamp(42px, 7.2vw, 88px);
  line-height: 1.04;
  letter-spacing: -0.035em;
  font-weight: 700;
}
html[data-lang="zh"] h1 { letter-spacing: 0; line-height: 1.12; }
h1 .ph { display: inline-block; white-space: nowrap; } /* 窄屏时只在短语之间换行 */

.grad {
  font-style: normal;
  background: linear-gradient(90deg, var(--ask-a), var(--ask-b) 55%, var(--act-b));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.lead {
  max-width: 660px;
  margin: 24px auto 0;
  font-size: clamp(17px, 2vw, 20.5px);
  line-height: 1.55;
  color: var(--text-2);
}

.cta { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-top: 34px; }

.fine { margin: 16px 0 0; font-size: 13.5px; color: var(--text-3); }
.fine a { color: var(--text-2); }
.fine a:hover { color: var(--text); }

.stage {
  position: relative;
  max-width: 1100px;
  margin: 56px auto 0;
  aspect-ratio: 16 / 9;
  border-radius: 22px;
  overflow: hidden;
  background: #07080B;
  border: 1px solid var(--stroke-strong);
  box-shadow: 0 40px 100px -30px rgba(40, 40, 120, 0.45), var(--shadow);
}
.stage video { width: 100%; height: 100%; object-fit: cover; cursor: pointer; }

.sound-btn {
  position: absolute;
  right: 16px;
  bottom: 16px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 16px 0 12px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(16, 16, 20, 0.62);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: #fff;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.2s;
}
.sound-btn:hover { background: rgba(16, 16, 20, 0.82); }
.sound-btn svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.stage .i-on, .stage .label-on, .stage.sound .i-off, .stage.sound .label-off { display: none; }
.stage.sound .i-on, .stage.sound .label-on { display: inline; }

.engines {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 10px;
  margin: 34px 0 0;
  padding: 0;
  font-size: 14px;
  color: var(--text-3);
}
.chip {
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid var(--stroke);
  background: var(--card);
  color: var(--text-2);
  font-weight: 550;
}

/* ---------- 功能 ---------- */

.features {
  max-width: var(--max);
  margin: 0 auto;
  padding: 120px 20px 40px;
  display: grid;
  gap: 128px;
}

/* 每个功能：居中的文字在上，整宽的画面在下（画面里的界面文字要看得清） */
.feature { display: grid; gap: 44px; }
.feature .copy { max-width: 760px; margin: 0 auto; text-align: center; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin: 0 0 14px;
  font-size: 14px;
  font-weight: 650;
  letter-spacing: 0.01em;
}
.eyebrow.ask { color: var(--ask-a); }
.eyebrow.act { color: var(--act-b); }
.eyebrow.duo {
  background: linear-gradient(90deg, var(--ask-a), var(--act-b));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

kbd {
  display: inline-block;
  padding: 1px 7px;
  border-radius: 6px;
  border: 1px solid currentColor;
  font-family: inherit;
  font-size: 12px;
  font-weight: 650;
  line-height: 1.5;
}

h2 {
  margin: 0 0 18px;
  font-size: clamp(30px, 3.7vw, 46px);
  line-height: 1.1;
  letter-spacing: -0.028em;
  font-weight: 700;
}
html[data-lang="zh"] h2 { letter-spacing: 0; line-height: 1.22; }

.copy p { margin: 0 0 14px; color: var(--text-2); font-size: 17.5px; }

.points { list-style: none; margin: 22px 0 0; padding: 0; display: flex; flex-wrap: wrap; justify-content: center; gap: 10px 28px; }
.points li { position: relative; padding-left: 26px; color: var(--text-2); font-size: 15.5px; text-align: left; }
.points li::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 0.55em;
  width: 11px;
  height: 6px;
  border-left: 2px solid var(--ok);
  border-bottom: 2px solid var(--ok);
  transform: rotate(-45deg);
}

.shot { margin: 0; }
.shot img { width: 100%; filter: var(--shot-shadow); }
@media (min-width: 1240px) { .shot { margin: 0 -40px; } }

/* 一个功能配两张图：上下排，窄的那张居中 */
.shots { display: grid; gap: 28px; }
.shot.narrow { width: 100%; max-width: 820px; margin-left: auto; margin-right: auto; }

/* "越用越好"：大标题开头 */
.better { padding-top: 168px; }
.better-head { max-width: 900px; margin: 0 auto; text-align: center; }
.better-head .big { margin: 0; font-size: clamp(40px, 6vw, 76px); line-height: 1.05; letter-spacing: -0.035em; }
html[data-lang="zh"] .better-head .big { letter-spacing: 0; line-height: 1.15; }
.better-head .lead { margin-top: 18px; }

/* ---------- 放心用 ---------- */

.trust, .start, .faq { max-width: var(--max); margin: 0 auto; padding: 120px 20px 0; }

.section-title { text-align: center; margin-bottom: 44px; }

.grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }

.tile {
  padding: 26px 24px;
  border-radius: 20px;
  border: 1px solid var(--stroke);
  background: var(--card);
  box-shadow: var(--shadow);
}
.tile h3 { margin: 0 0 8px; font-size: 18px; letter-spacing: -0.01em; }
.tile p { margin: 0; color: var(--text-2); font-size: 15px; line-height: 1.55; }

/* ---------- 开始使用 ---------- */

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.steps li {
  position: relative;
  padding: 28px 26px 26px;
  border-radius: 20px;
  border: 1px solid var(--stroke);
  background: var(--card);
  box-shadow: var(--shadow);
}
.steps .n {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin-bottom: 16px;
  border-radius: 50%;
  color: #fff;
  font-weight: 700;
  font-size: 15px;
  background: linear-gradient(135deg, var(--ask-a), var(--ask-b));
}
.steps h3 { margin: 0 0 8px; font-size: 19px; }
.steps p { margin: 0; color: var(--text-2); font-size: 15.5px; line-height: 1.55; }

.cta.center { margin-top: 40px; }

.note { max-width: 680px; margin: 18px auto 0; text-align: center; font-size: 14px; color: var(--text-3); }
.note b { color: var(--text-2); font-weight: 600; }
.note a { color: var(--ask-a); }
.mirror { display: block; margin-top: 6px; }

/* ---------- 常见问题 ---------- */

.qa { max-width: 820px; margin: 0 auto; border-top: 1px solid var(--stroke); }

details { border-bottom: 1px solid var(--stroke); }

summary {
  position: relative;
  padding: 22px 44px 22px 2px;
  font-size: 18px;
  font-weight: 600;
  list-style: none;
  cursor: pointer;
}
summary::-webkit-details-marker { display: none; }
summary::after {
  content: "";
  position: absolute;
  right: 8px;
  top: 50%;
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--text-3);
  border-bottom: 2px solid var(--text-3);
  transform: translateY(-70%) rotate(45deg);
  transition: transform 0.25s var(--ease);
}
details[open] summary::after { transform: translateY(-30%) rotate(-135deg); }
details p { margin: -6px 0 22px; padding-right: 40px; color: var(--text-2); }

/* ---------- 页脚 ---------- */

.footer { margin-top: 140px; border-top: 1px solid var(--stroke); }
.footer-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 32px 20px 40px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px 28px;
  font-size: 14.5px;
  color: var(--text-2);
}
.footer nav { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 22px; }
.footer nav a:hover { color: var(--text); }
.footer .link-btn { height: auto; padding: 0; }
.footer .link-btn:hover { background: none; }
.copyright { margin: 0 0 0 auto; color: var(--text-3); }

/* ---------- 滚动时浮现 ---------- */

html.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.8s var(--ease), transform 0.8s var(--ease); }
html.js .reveal.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  html.js .reveal { opacity: 1; transform: none; transition: none; }
  .btn:hover { transform: none; }
}

/* ---------- 窄屏 ---------- */

@media (max-width: 960px) {
  .links { display: none; }
  .grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 860px) {
  .hero { padding-top: 56px; }
  .features { padding-top: 88px; gap: 88px; }
  .feature { gap: 28px; }
  .steps { grid-template-columns: 1fr; }
  .trust, .start, .faq { padding-top: 88px; }
  .stage { margin-top: 40px; border-radius: 16px; }
  .sound-btn { right: 10px; bottom: 10px; height: 36px; font-size: 13px; }
}

@media (max-width: 560px) {
  body { font-size: 16px; }
  .nav-inner { gap: 12px; padding: 0 16px; }
  .brand span:not(.orb) { font-size: 16px; }
  .hero, .features, .trust, .start, .faq { padding-left: 16px; padding-right: 16px; }
  .grid { grid-template-columns: 1fr; }
  .cta .btn { width: 100%; }
  .copy p { font-size: 16.5px; }
  .footer-inner { padding-left: 16px; padding-right: 16px; }
  .copyright { margin-left: 0; }
  .sound-btn .label-off, .sound-btn .label-on { display: none !important; }
  .sound-btn { padding: 0 11px; }
}