/* 3D Point Distance Measure — 官网共享样式
   配色沿用应用内 Graphite & Champagne 主题（石墨暗底 + 香槟金 + 射线青） */

:root {
  color-scheme: dark;
  --ink: #0d0c0b;        /* 页面底色 */
  --surface: #161412;    /* 抬升面板 */
  --line: #2a2620;       /* 分隔线/描边 */
  --text: #f3f1ea;       /* 主文本（暖白） */
  --text2: #a8a196;      /* 次级文本 */
  --gold: #e4c68c;       /* 香槟金强调 */
  --cyan: #9bc2e6;       /* 射线青 */
  --pad: max(20px, env(safe-area-inset-left, 0px));
  --maxw: 1060px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  padding: 0 var(--pad);
  background: var(--ink);
  color: var(--text);
  font: 400 17px/1.65 -apple-system, "Segoe UI", Roboto, "Noto Sans", "PingFang SC", "Hiragino Sans GB", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }

a { color: var(--gold); text-underline-offset: 3px; }
a:focus-visible { outline: 2px solid var(--cyan); outline-offset: 2px; }

.wrap { max-width: var(--maxw); margin: 0 auto; }

/* ---------- 顶栏 ---------- */
.nav {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding: 26px 0 0;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--text);
  text-decoration: none;
}
.brand svg { width: 26px; height: 26px; }
.nav-links { display: flex; gap: 22px; font-size: 15px; }
.nav-links a { color: var(--text2); text-decoration: none; }
.nav-links a:hover { color: var(--text); }

/* ---------- 首屏 ---------- */
.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
  gap: 48px;
  align-items: center;
  padding: 72px 0 88px;
}
.hero h1 {
  margin: 0 0 18px;
  font-size: clamp(34px, 5.2vw, 54px);
  line-height: 1.12;
  letter-spacing: -0.025em;
  font-weight: 700;
}
.hero h1 em { font-style: normal; color: var(--gold); }
.lede { margin: 0 0 30px; color: var(--text2); font-size: 19px; max-width: 34em; }

.cta-row { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.btn-play {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 13px 26px;
  border-radius: 10px;
  background: var(--gold);
  color: #241d0e;
  font-weight: 700;
  font-size: 17px;
  text-decoration: none;
  letter-spacing: -0.01em;
}
.btn-play:hover { background: #f0d49c; }
.btn-play svg { width: 22px; height: 22px; }
.cta-note { color: var(--text2); font-size: 14px; max-width: 20em; }

/* 首屏右侧：射线交会示意（与应用图标同一构图） */
.diagram { width: 100%; max-width: 400px; margin: 0 auto; }
.diagram .ray {
  stroke: var(--cyan);
  stroke-width: 2.2;
  stroke-linecap: round;
  fill: none;
  stroke-dasharray: 90;
  stroke-dashoffset: 90;
  animation: draw 1s ease-out .35s forwards;
}
.diagram .ray.r2 { animation-delay: .55s; }
.diagram .vp { fill: var(--cyan); opacity: 0; animation: pop .4s ease-out .25s forwards; }
.diagram .vp.v2 { animation-delay: .45s; }
.diagram .ring {
  stroke: var(--gold); stroke-width: 2.4; fill: none;
  opacity: 0; animation: pop .5s ease-out 1.15s forwards;
}
.diagram .core { fill: var(--text); opacity: 0; animation: pop .5s ease-out 1.25s forwards; }
.diagram .base {
  stroke: var(--gold); stroke-width: 2; stroke-linecap: round; fill: none;
  opacity: 0; animation: fadein .8s ease-out 1.5s forwards;
}
.diagram .plabel {
  fill: var(--cyan);
  font-size: 10px; font-weight: 700; letter-spacing: .04em;
  opacity: 0; animation: fadein .8s ease-out 1.5s forwards;
}
.diagram .plabel.gold { fill: var(--gold); font-size: 9px; font-weight: 600; letter-spacing: .12em; }
@keyframes draw { to { stroke-dashoffset: 0; } }
@keyframes pop { from { opacity: 0; } to { opacity: 1; } }
@keyframes fadein { to { opacity: 1; } }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .diagram .ray { stroke-dashoffset: 0; animation: none; }
  .diagram .vp, .diagram .ring, .diagram .core,
  .diagram .base, .diagram .plabel { opacity: 1; animation: none; }
}

/* ---------- 通用小节 ---------- */
section { padding: 72px 0; border-top: 1px solid var(--line); }
.kicker {
  margin: 0 0 10px;
  color: var(--cyan);
  font-size: 14px;
  font-weight: 600;
}
h2 {
  margin: 0 0 14px;
  font-size: clamp(26px, 3.4vw, 36px);
  letter-spacing: -0.02em;
  line-height: 1.2;
}
.sec-lede { margin: 0 0 44px; color: var(--text2); max-width: 42em; }

/* ---------- 使用步骤（测量流程本身是三步序列） ---------- */
.steps { list-style: none; margin: 0; padding: 0; counter-reset: step; }
.steps li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 18px;
  padding: 26px 0;
}
.steps li + li { border-top: 1px solid var(--line); }
.steps li::before {
  content: counter(step);
  font-size: 15px;
  font-weight: 700;
  color: var(--gold);
  border: 1px solid var(--line);
  border-radius: 8px;
  width: 40px; height: 40px;
  display: grid; place-items: center;
  margin-top: 2px;
}
.steps h3 { margin: 0 0 6px; font-size: 20px; letter-spacing: -0.01em; }
.steps p { margin: 0; color: var(--text2); }
.steps code {
  font: 500 15px/1 ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  color: var(--cyan); background: none;
}

/* ---------- 截图画廊 ---------- */
.shots {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(14px, 2.6vw, 28px);
}
.shot { margin: 0; }
.shot figure { margin: 0; }
.phone {
  aspect-ratio: 9 / 19.2;
  border-radius: 22px;
  border: 1px solid var(--line);
  background: var(--surface);
  overflow: hidden;
  box-shadow: 0 18px 50px rgba(0, 0, 0, .55);
}
.phone img { width: 100%; height: 100%; object-fit: cover; }
.shot figcaption {
  padding-top: 12px;
  font-size: 14px;
  color: var(--text2);
  text-align: center;
}
.shot figcaption strong { color: var(--text); font-weight: 600; }

/* ---------- 功能清单（两列定义列表，不做卡片墙） ---------- */
.feat {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(28px, 5vw, 64px);
  margin: 0;
}
.feat > div { padding: 22px 0; border-top: 1px solid var(--line); }
.feat dt { font-weight: 600; font-size: 18px; margin-bottom: 4px; letter-spacing: -0.01em; }
.feat dd { margin: 0; color: var(--text2); font-size: 16px; }

/* ---------- 隐私要点条 ---------- */
.privacy-band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  padding: 30px 32px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
}
.privacy-band p { margin: 0; max-width: 46em; color: var(--text2); }
.privacy-band p strong { color: var(--text); }
.btn-ghost {
  padding: 11px 22px;
  border: 1px solid var(--gold);
  border-radius: 10px;
  color: var(--gold);
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
  white-space: nowrap;
}
.btn-ghost:hover { background: rgba(228, 198, 140, .08); }

/* ---------- 页脚 ---------- */
footer {
  border-top: 1px solid var(--line);
  padding: 34px 0 44px;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
  color: var(--text2);
  font-size: 14px;
}
footer nav { display: flex; gap: 20px; }
footer nav a { color: var(--text2); text-decoration: none; }
footer nav a:hover { color: var(--text); }

/* ---------- 响应式：900 以下画廊两列、首屏单列 ---------- */
@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; gap: 40px; padding: 48px 0 64px; }
  .diagram { max-width: 320px; }
  .shots { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .feat { grid-template-columns: 1fr; }
  section { padding: 56px 0; }
}
@media (max-width: 460px) {
  .phone { border-radius: 16px; }
  .steps li { grid-template-columns: 40px minmax(0, 1fr); gap: 12px; }
}

/* ---------- 隐私政策文档页 ---------- */
.legal { max-width: 760px; margin: 0 auto; padding: 64px 0 24px; }
.legal h1 { font-size: clamp(28px, 4vw, 40px); letter-spacing: -0.02em; margin: 0 0 8px; }
.legal .meta { color: var(--text2); font-size: 15px; margin: 0 0 40px; }
.legal h2 { font-size: 23px; margin: 46px 0 12px; }
.legal h3 { font-size: 17px; margin: 26px 0 8px; }
.legal p { margin: 0 0 14px; }
.legal ul { margin: 0 0 16px; padding-left: 22px; }
.legal li { margin-bottom: 7px; }
.legal table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin: 0 0 22px;
  display: block;
  overflow-x: auto;
}
.legal th, .legal td {
  text-align: left;
  vertical-align: top;
  padding: 10px 14px 10px 0;
  border-bottom: 1px solid var(--line);
}
.legal th { color: var(--gold); font-weight: 600; white-space: nowrap; }
.legal .callout {
  border-left: 2px solid var(--gold);
  background: var(--surface);
  padding: 16px 20px;
  border-radius: 0 10px 10px 0;
  margin: 0 0 24px;
  color: var(--text2);
  font-size: 15.5px;
}
.legal .callout strong { color: var(--text); }

/* ---------- 射线纠偏原理 ---------- */
.principle {
  display: grid;
  grid-template-columns: minmax(0, 300px) minmax(0, 1fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: start;
}
.p-shot { margin: 0; position: sticky; top: 28px; }
.p-shot .phone { border-radius: 26px; }
.p-shot figcaption {
  padding-top: 12px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--text2);
}
.p-shot figcaption strong { color: var(--text); font-weight: 600; }
.p-copy p { margin: 0 0 18px; }
.p-copy p:first-child { margin-top: 0; }
.p-copy em { color: var(--text); font-style: normal; }
.p-list {
  list-style: none;
  margin: 0 0 18px;
  padding: 0;
}
.p-list li {
  position: relative;
  padding: 14px 0 14px 24px;
  color: var(--text2);
}
.p-list li + li { border-top: 1px solid var(--line); }
.p-list li::before {
  content: "";
  position: absolute;
  left: 2px; top: 24px;
  width: 10px; height: 10px;
  border: 2px solid var(--cyan);
  border-radius: 50%;
}
.p-list strong { color: var(--text); }
@media (max-width: 820px) {
  .principle { grid-template-columns: 1fr; }
  .p-shot { position: static; max-width: 300px; margin: 0 auto 8px; }
}

/* ---------- 用户群体与场景 ---------- */
.uses {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(28px, 5vw, 64px);
  margin: 0 0 56px;
}
.uses > div { padding: 20px 0; border-top: 1px solid var(--line); }
.uses dt { font-weight: 600; font-size: 18px; letter-spacing: -0.01em; margin-bottom: 4px; }
.uses dt::before {
  content: "";
  display: inline-block;
  width: 8px; height: 8px;
  margin-right: 10px;
  background: var(--gold);
  border-radius: 2px;
  transform: rotate(45deg);
}
.uses dd { margin: 0; color: var(--text2); font-size: 16px; }
@media (max-width: 820px) { .uses { grid-template-columns: 1fr; } }

/* 对比条：三列并排，手机下堆叠 */
.edge {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3.4vw, 40px);
  border-top: 1px solid var(--line);
  padding-top: 34px;
}
.edge h3 {
  margin: 0 0 8px;
  font-size: 16px;
  color: var(--gold);
  letter-spacing: -0.01em;
}
.edge p { margin: 0; font-size: 15px; color: var(--text2); }
.edge em { color: var(--text); font-style: normal; }
@media (max-width: 820px) { .edge { grid-template-columns: 1fr; } }