/* ─── Privault 官网 · token 与 App theme.dart 同源（见 DESIGN.md）─── */

:root {
  --ink: #0b0d12;
  --slate: #161a23;
  --slate2: #20262f;
  --line: #2a313c;
  --text: #eceff6;
  --mist: #8a93a6;
  --steel: #aeb8c9;
  --brass: #f6c84f;
  --brass-12: rgba(246, 200, 79, 0.12);
  --brass-30: rgba(246, 200, 79, 0.3);
  --danger: #ff7676;
  --radius: 14px;
  /* Web 字体只覆盖拉丁字符；CJK/西里尔回退到各系统字体（顺序：中 → 日 → 韩） */
  --cjk: "PingFang SC", "Hiragino Sans", "Yu Gothic", "Apple SD Gothic Neo",
    "Malgun Gothic", "Noto Sans SC", "Noto Sans JP", "Noto Sans KR";
  --display: "Bricolage Grotesque", var(--cjk), system-ui, sans-serif;
  --body: "Geist", var(--cjk), system-ui, sans-serif;
  --mono: "Geist Mono", "Menlo", "SFMono-Regular", var(--cjk), monospace;
  --pad: clamp(20px, 5vw, 48px);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  /* 与 <meta name="color-scheme"> 双保险：UA 控件、滚动条、过滚动区一律暗色 */
  color-scheme: dark;
  background: var(--ink);
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--text);
  font-family: var(--body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.mono { font-family: var(--mono); }

a { color: var(--brass); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

:focus-visible {
  outline: 2px solid var(--brass);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ─── 顶栏（毛玻璃，与 App 浮层同材质）─── */

.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px var(--pad);
  background: rgba(11, 13, 18, 0.68);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-bottom: 1px solid rgba(42, 49, 60, 0.6);
  transition: background 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}
/* 离开顶部后顶栏微微加重：更密的毛玻璃 + 克制阴影，读作浮在内容之上 */
.nav.scrolled {
  background: rgba(11, 13, 18, 0.82);
  border-bottom-color: var(--line);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.28);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand-name {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: 0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(14px, 3vw, 28px);
}
.nav-links a { color: var(--mist); font-size: 0.9375rem; transition: color 0.2s ease; }
.nav-links a:hover { color: var(--text); text-decoration: none; }
/* 滚动高亮：当前所在节 */
.nav-links a.active { color: var(--brass); }

/* ─── 语言切换：自绘下拉（触发钮 = mono 胶囊；浮层 = 毛玻璃，与 App 同材质）─── */

.lang { position: relative; }

.lang-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px 6px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(11, 13, 18, 0.6);
  color: var(--mist);
  font-family: var(--mono);
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.lang-btn:hover,
.lang-btn[aria-expanded="true"] { border-color: var(--steel); color: var(--text); }

.lang-globe,
.lang-caret { flex: 0 0 auto; }
.lang-caret {
  color: var(--mist);
  transition: transform 0.18s ease;
}
.lang-btn[aria-expanded="true"] .lang-caret { transform: rotate(180deg); }

.lang-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 20;
  margin: 0;
  padding: 6px;
  min-width: 176px;
  list-style: none;
  background: rgba(22, 26, 35, 0.82);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid rgba(42, 49, 60, 0.6);
  border-radius: var(--radius);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.35);
}
.lang-menu[hidden] { display: none; }

.lang-menu li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 0.875rem;
  color: var(--steel);
  cursor: pointer;
}
.lang-menu li:hover,
.lang-menu li:focus-visible {
  background: var(--slate2);
  color: var(--text);
  outline: none;
}
/* 当前语言：黄铜文字 + 钥匙点。一屏内唯一的黄铜高亮（浮层打开时） */
.lang-menu li[aria-selected="true"] { color: var(--brass); }
.lang-menu li[aria-selected="true"]::after {
  content: "◆";
  font-size: 0.5625rem;
  opacity: 0.9;
}

/* 打开动画：浮层聚焦成型（同解密之雾的方向感，幅度更小） */
@keyframes lang-in {
  from { opacity: 0; transform: translateY(-4px); filter: blur(6px); }
  to { opacity: 1; transform: none; filter: blur(0); }
}
.lang-menu:not([hidden]) { animation: lang-in 0.16s ease both; }

/* ─── 按钮 ─── */

.btn {
  display: inline-flex;
  align-items: center;
  padding: 10px 22px;
  border-radius: 999px;
  font-size: 0.9375rem;
  font-weight: 500;
  border: 1px solid transparent;
  transition: transform 0.15s ease, background 0.15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:active { transform: translateY(0) scale(0.98); }

.btn-brass {
  background: var(--brass);
  color: #14171d;
}
.btn-brass:hover { background: #f9d36a; color: #14171d; }

.btn-ghost {
  border-color: var(--line);
  color: var(--text) !important;
}
.btn-ghost:hover { border-color: var(--steel); }

/* ─── Hero：解密之雾 + App 样机 ─── */

.hero {
  position: relative;
  min-height: 88vh;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(32px, 5vw, 72px);
  padding: 48px var(--pad);
  max-width: 1120px;
  margin: 0 auto;
}

/* 顶部黄铜微光：与 App 解锁页 AuroraBackground 同一意象（随强调色） */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(
    ellipse 90% 55% at 50% -8%,
    var(--brass-12),
    transparent 65%
  );
}

.eyebrow {
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--mist);
  margin: 0 0 22px;
  min-height: 1.2em; /* 乱序滚动期间高度稳定 */
}

.hero h1 {
  font-family: var(--display);
  font-weight: 750;
  font-size: clamp(2.6rem, 7vw, 4.6rem);
  line-height: 1.08;
  letter-spacing: -0.015em;
  margin: 0 0 26px;
}

.lede {
  max-width: 34em;
  color: var(--mist);
  font-size: clamp(1rem, 1.6vw, 1.1875rem);
  margin: 0 0 34px;
}

.cta-row { display: flex; flex-wrap: wrap; gap: 14px; }

.stat-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 46px;
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  color: var(--steel);
}
.stat-strip span[aria-hidden] { color: var(--line); }

/* ─── App 样机：纯 CSS 复刻「保险库之夜」主题（色值与 theme.dart 同源） ─── */

.hero-visual {
  position: relative;
  transform: rotate(-2.5deg);
  transition: transform 0.35s ease;
}
.hero-visual:hover { transform: rotate(0deg); }
/* 机身后的黄铜辉光 */
.hero-visual::before {
  content: "";
  position: absolute;
  inset: -12% -18%;
  background: radial-gradient(ellipse 60% 55% at 50% 45%, var(--brass-12), transparent 68%);
  pointer-events: none;
}

.device {
  position: relative;
  width: 284px;
  height: 584px;
  padding: 10px;
  border-radius: 44px;
  background: #05070b;
  border: 1px solid #313a48;
  box-shadow:
    inset 0 0 0 2px #10141c,
    0 24px 60px rgba(0, 0, 0, 0.55);
}
.device-notch {
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: 82px;
  height: 22px;
  border-radius: 999px;
  background: #000;
  border: 1px solid #1a202b;
  z-index: 2;
}
.screen {
  height: 100%;
  border-radius: 34px;
  background: var(--ink);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.app-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 52px 16px 10px;
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--text);
}
.app-bar svg { color: var(--brass); }

.photo-grid {
  flex: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-auto-rows: 1fr;
  gap: 5px;
  padding: 6px 10px;
  min-height: 0;
}
.tile {
  position: relative;
  border-radius: 7px;
  overflow: hidden;
  min-height: 0;
}
/* 缩略图：色板内的场景渐变（克制、偏暗，像真实相册而非霓虹demo） */
.t1 { background: radial-gradient(ellipse 80% 50% at 50% 62%, rgba(246, 200, 79, 0.5), transparent 72%),
      linear-gradient(to bottom, #101623, #1b2436 48%, #6b4a33 88%); }
.t2 { background: linear-gradient(165deg, #0e1b2b, #14324a 55%, #1b5a6e); }
.t3 { background: linear-gradient(180deg, #0f1a14, #1c3325 55%, #2e5940); }
.t4 { background: linear-gradient(150deg, #241a1d, #4a2f35 55%, #8a5a52); }
.t5 { background: linear-gradient(180deg, #0d1120, #1c2440 60%, #3a3161); }
.t6 { background: linear-gradient(160deg, #23201a, #4d4030 60%, #8a734f); }
.t7 { background: linear-gradient(175deg, #121826, #233246 55%, #4a5d78); }
.t8 { background: linear-gradient(145deg, #1d1420, #3a2140 55%, #6e3a5e); }
.t9 { background: radial-gradient(ellipse 70% 55% at 40% 30%, rgba(174, 184, 201, 0.28), transparent 70%),
      linear-gradient(180deg, #161d2b, #242f42); }
.t10 { background: linear-gradient(200deg, #101623, #29354a 60%, #506480); }
.tile.dim { filter: brightness(0.75); }
/* 锁定项：静默的冷钢面 + 黄铜锁 */
.tlock {
  background: var(--slate2);
  display: grid;
  place-items: center;
  color: var(--brass);
  border: 1px solid var(--line);
}
.tbadge {
  position: absolute;
  top: 5px;
  left: 5px;
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.5rem;
  letter-spacing: 0.05em;
  color: #fff;
  background: rgba(11, 13, 18, 0.65);
  backdrop-filter: blur(6px);
}
.tbadge-br { top: auto; left: auto; right: 5px; bottom: 5px; }

.tab-bar {
  display: flex;
  align-items: center;
  justify-content: space-around;
  padding: 12px 26px 26px;
  color: var(--mist);
}
.tab-bar svg.on { color: var(--brass); }

/* 浮动徽标：机身边缘的两枚 mono chip */
.float-chip {
  position: absolute;
  padding: 6px 12px;
  font-size: 0.6875rem;
  background: rgba(22, 26, 35, 0.85);
  backdrop-filter: blur(12px);
  border-color: var(--brass-30);
  color: var(--brass);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}
.fc1 { top: 64px; right: -34px; }
.fc2 { bottom: 92px; left: -46px; color: var(--steel); border-color: var(--line); }

/* 解密之雾：模糊聚焦成型（与 App 的 DecryptReveal 同源） */
.fog-reveal,
.fog-reveal-late {
  animation: fog 0.9s cubic-bezier(0.2, 0.7, 0.2, 1) both;
}
.fog-reveal-late { animation-delay: 0.35s; }

@keyframes fog {
  from {
    opacity: 0;
    filter: blur(18px);
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    filter: blur(0);
    transform: none;
  }
}

/* ─── 通用节 ─── */

.section {
  max-width: 1080px;
  margin: 0 auto;
  padding: clamp(96px, 14vh, 160px) var(--pad) 0;
  /* 锚点跳转时给 sticky 顶栏留出高度 */
  scroll-margin-top: 72px;
}

.section h2 {
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  letter-spacing: -0.01em;
  line-height: 1.15;
  margin: 0 0 14px;
}

.section-sub {
  color: var(--mist);
  max-width: 36em;
  margin: 0 0 48px;
}

/* 滚动显现 */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  /* 与解密之雾同一缓动曲线，全站显现动作统一减速手感 */
  transition: opacity 0.6s cubic-bezier(0.2, 0.7, 0.2, 1),
    transform 0.6s cubic-bezier(0.2, 0.7, 0.2, 1);
}
.reveal.in { opacity: 1; transform: none; }

/* ─── 按住解密卡 ─── */

.vault-demo { display: flex; flex-direction: column; align-items: center; }

.vault-card {
  position: relative;
  width: min(520px, 100%);
  aspect-ratio: 4 / 3;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--slate);
  padding: 0;
  cursor: pointer;
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
}

.layer {
  position: absolute;
  inset: 0;
  transition: opacity 0.18s ease, filter 0.18s ease;
}

.cipher-layer {
  padding: 18px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: flex-start;
}
.cipher-layer pre {
  margin: 0;
  font-size: clamp(0.6rem, 1.6vw, 0.75rem);
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--steel);
  opacity: 0.85;
  overflow: hidden;
}

.plain-layer {
  opacity: 0;
  filter: blur(14px);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
}
/* “照片”：色板内的黄昏场景（墨蓝天际 + 黄铜地平线） */
.plain-layer .photo {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 42% at 50% 66%, rgba(246, 200, 79, 0.55), transparent 70%),
    linear-gradient(to bottom, #101623 0%, #1b2436 45%, #3a3143 66%, #6b4a33 82%, #14171d 100%);
}
.plain-meta {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  background: linear-gradient(to top, rgba(11, 13, 18, 0.9), transparent);
  color: #fff;
  font-size: 0.8125rem;
}

.vault-card { transition: box-shadow 0.25s ease; }
.vault-card.decrypted .cipher-layer { opacity: 0; filter: blur(10px); }
.vault-card.decrypted .plain-layer { opacity: 1; filter: blur(0); }
/* 按住时的黄铜辉光：解密是"发生了什么"的那一刻 */
.vault-card.decrypted {
  box-shadow: 0 0 0 1px var(--brass-30), 0 10px 44px rgba(246, 200, 79, 0.14);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 9px;
  border-radius: 8px;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  background: rgba(11, 13, 18, 0.6);
  border: 1px solid rgba(42, 49, 60, 0.8);
  color: var(--steel);
}
.chip-live { color: #fff; }

.hold-hint {
  margin-top: 16px;
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ─── 一张照片的旅程：四幕舞台（data-scene 驱动） ─── */

.j-stage {
  display: grid;
  grid-template-columns: auto 1fr auto 1fr auto;
  align-items: center;
  gap: clamp(8px, 2vw, 18px);
  padding: clamp(28px, 4.5vw, 48px) clamp(16px, 3vw, 36px) clamp(20px, 3vw, 32px);
  background: var(--slate);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.j-node {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.j-label {
  display: block;
  margin-top: 12px;
  font-size: 0.625rem;
  letter-spacing: 0.12em;
  color: var(--mist);
  text-align: center;
}

/* 设备外框 */
.j-phone {
  width: 78px;
  height: 132px;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--slate2);
  transition: box-shadow 0.4s ease;
}
.j-mac {
  position: relative;
  width: 150px;
  height: 96px;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--slate2);
}
.j-macbase {
  width: 172px;
  height: 5px;
  background: var(--slate2);
  border: 1px solid var(--line);
  border-top: none;
  border-radius: 0 0 6px 6px;
}
.j-media {
  position: relative;
  width: 100%;
  height: 100%;
  border-radius: 8px;
  overflow: hidden;
  background: var(--ink);
}
.j-photo,
.j-cipher {
  position: absolute;
  inset: 0;
}
.j-photo {
  background:
    radial-gradient(ellipse 80% 50% at 50% 62%, rgba(246, 200, 79, 0.5), transparent 72%),
    linear-gradient(to bottom, #101623, #1b2436 48%, #6b4a33 88%);
  transition: opacity 0.55s ease, filter 0.55s ease;
}
.j-cipher {
  padding: 5px;
  font-size: 7px;
  line-height: 1.95;
  letter-spacing: 0.08em;
  color: var(--steel);
  opacity: 0;
  overflow: hidden;
  transition: opacity 0.55s ease;
}

/* 传输轨道与数据包 */
.j-track {
  position: relative;
  height: 0;
  border-top: 1px dashed var(--line);
  align-self: center;
}
.j-packet {
  position: absolute;
  top: -3.5px;
  left: -8px;
  width: 6px;
  height: 6px;
  border-radius: 2px;
  background: var(--steel);
  opacity: 0;
}
@keyframes j-flow {
  0% { left: -6px; opacity: 0; }
  12% { opacity: 1; }
  86% { opacity: 1; }
  100% { left: calc(100% + 2px); opacity: 0; }
}

/* 云 */
.j-cloudwrap { position: relative; }
.j-cloud {
  position: relative;
  width: 150px;
  height: 94px;
  display: grid;
  place-items: center;
  color: var(--steel);
}
.j-cloud-shape {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.7;
}
.j-cipher-mini {
  position: relative;
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 8px;
  line-height: 1.7;
  letter-spacing: 0.08em;
  color: var(--steel);
  text-align: center;
  opacity: 0;
  transition: opacity 0.45s ease, box-shadow 0.35s ease;
}

/* 窥探者：云商与黑客 */
.j-peeker {
  position: absolute;
  z-index: 2;
  gap: 6px;
  font-size: 0.625rem;
  background: rgba(22, 26, 35, 0.9);
  opacity: 0;
  transition: opacity 0.4s ease, transform 0.4s ease;
}
.j-peek1 { top: -16px; right: -36px; transform: translateY(-8px); }
.j-peek2 { bottom: 30px; left: -44px; transform: translateY(8px); }
.j-x { color: var(--danger); font-style: normal; font-weight: 700; }

/* 解锁钥匙徽章 */
.j-key {
  position: absolute;
  right: -9px;
  bottom: -9px;
  display: grid;
  place-items: center;
  padding: 5px;
  border-radius: 9px;
  background: var(--brass);
  color: #14171d;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.4);
  opacity: 0;
  transform: scale(0.5);
  transition: opacity 0.35s ease, transform 0.35s ease;
}

/* ── 幕次状态 ── */

/* 幕 1+：手机里照片 → 密文 */
:is([data-scene="1"], [data-scene="2"], [data-scene="3"], [data-scene="4"]) .j-phone .j-photo {
  opacity: 0;
  filter: blur(10px);
}
:is([data-scene="1"], [data-scene="2"], [data-scene="3"], [data-scene="4"]) .j-phone .j-cipher {
  opacity: 1;
}
[data-scene="1"] .j-phone { box-shadow: 0 0 0 1px var(--brass-30), 0 0 28px rgba(246, 200, 79, 0.1); }

/* 幕 2+：密文上行，云端出现密文 */
[data-scene="2"] .j-track1 .j-packet { animation: j-flow 1.4s linear forwards; }
[data-scene="2"] .j-track1 .j-packet:nth-child(2) { animation-delay: 0.3s; }
[data-scene="2"] .j-track1 .j-packet:nth-child(3) { animation-delay: 0.6s; }
:is([data-scene="2"], [data-scene="3"], [data-scene="4"]) .j-cipher-mini { opacity: 1; }
[data-scene="2"] .j-cipher-mini { transition-delay: 1.15s; }

/* 幕 3：窥探失败（danger 只在这一幕点亮） */
[data-scene="3"] .j-cipher-mini { box-shadow: 0 0 0 1px rgba(255, 118, 118, 0.55); }
[data-scene="3"] .j-peeker { opacity: 1; transform: none; }
[data-scene="4"] .j-peeker { opacity: 0.35; transform: none; }

/* 幕 4：密文下行，你的密码解开 */
[data-scene="4"] .j-track2 .j-packet { animation: j-flow 1.4s linear forwards; }
[data-scene="4"] .j-track2 .j-packet:nth-child(2) { animation-delay: 0.3s; }
[data-scene="4"] .j-track2 .j-packet:nth-child(3) { animation-delay: 0.6s; }
.j-mac .j-photo { opacity: 0; filter: blur(10px); }
[data-scene="4"] .j-mac .j-cipher { opacity: 1; transition-delay: 0.9s; }
[data-scene="4"] .j-key { opacity: 1; transform: scale(1); transition-delay: 1.5s; }
[data-scene="4"] .j-mac .j-photo { opacity: 1; filter: blur(0); transition-delay: 2s; }

/* ── 步骤条 ── */

.j-steps {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}
.j-steps button {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  width: 100%;
  padding: 14px 6px 0 0;
  background: none;
  border: none;
  border-top: 1px solid var(--line);
  border-radius: 0;
  font: inherit;
  font-size: 0.875rem;
  line-height: 1.5;
  text-align: left;
  color: var(--mist);
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease;
}
.j-steps button:hover { color: var(--text); }
.j-step-no {
  flex: 0 0 auto;
  display: inline-grid;
  place-items: center;
  width: 20px;
  height: 20px;
  margin-top: 1px;
  border: 1px solid var(--line);
  border-radius: 50%;
  font-size: 0.6875rem;
  color: var(--mist);
  transition: all 0.2s ease;
}
.j-steps button[aria-current="true"] {
  color: var(--text);
  border-top-color: var(--brass);
}
.j-steps button[aria-current="true"] .j-step-no {
  background: var(--brass);
  border-color: var(--brass);
  color: #14171d;
}

/* ─── 加密设计 ─── */

.key-diagram {
  margin: 0 0 40px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--slate);
  padding: clamp(18px, 4vw, 36px);
  overflow-x: auto;
}
.key-diagram pre {
  margin: 0;
  font-size: clamp(0.72rem, 2.2vw, 0.9375rem);
  line-height: 1.9;
  color: var(--steel);
}
.key-diagram figcaption {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  color: var(--mist);
  font-size: 0.9375rem;
  max-width: 44em;
}

.crypto-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}
.crypto-facts li {
  display: flex;
  align-items: baseline;
  gap: 16px;
  color: var(--mist);
}
.fact-key {
  flex: 0 0 auto;
  min-width: 9.5em;
  color: var(--brass);
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
}

/* ─── 常见问题 ─── */

.faq-list {
  margin: 0 0 44px;
  display: grid;
  gap: 32px;
  max-width: 46em;
}
.faq-item dt {
  font-family: var(--display);
  font-weight: 650;
  font-size: 1.1875rem;
  margin: 0 0 8px;
}
.faq-item dd { margin: 0; color: var(--mist); }

/* 技术细节折叠：主叙事之外，给较真的人 */
.tech {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--slate);
}
.tech summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 20px;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--mist);
}
.tech summary::-webkit-details-marker { display: none; }
.tech summary::before {
  content: "▸";
  color: var(--brass);
  transition: transform 0.15s ease;
}
.tech[open] summary::before { transform: rotate(90deg); }
.tech summary:hover { color: var(--text); }
.tech-body { padding: 2px 20px 22px; }
/* 展开时内容淡入下滑（收起无动画，浏览器默认即时收合） */
.tech[open] .tech-body { animation: tech-in 0.28s ease both; }
@keyframes tech-in {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: none; }
}
.tech .key-diagram {
  border: none;
  background: transparent;
  padding: 0;
  margin: 0 0 22px;
}

/* ─── 功能网格 ─── */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.card {
  background: var(--slate);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px 22px;
}
.card h3 {
  font-family: var(--display);
  font-weight: 650;
  font-size: 1.1875rem;
  margin: 14px 0 8px;
}
.card p { margin: 0; color: var(--mist); font-size: 0.9375rem; }
.card {
  transition: border-color 0.2s ease, transform 0.2s ease;
}
.card:hover { border-color: var(--brass-30); transform: translateY(-2px); }
.card-icon {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 11px;
  background: var(--brass-12);
  border: 1px solid var(--brass-30);
  color: var(--brass);
}

/* ─── 三步上手 ─── */

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  counter-reset: none;
}
.step {
  padding: 24px 22px 22px;
  border-top: 1px solid var(--line);
}
.step-num {
  display: inline-block;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--brass);
  margin-bottom: 14px;
}
.step h3 {
  font-family: var(--display);
  font-weight: 650;
  font-size: 1.1875rem;
  margin: 0 0 8px;
}
.step p { margin: 0; color: var(--mist); font-size: 0.9375rem; }

/* ─── 信任模型节 / 页脚 ─── */

.section-trust { text-align: center; padding-bottom: 40px; }
.section-trust .section-sub {
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 40px;
}

.platform-strip {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}
.platform-strip .chip { padding: 6px 14px; font-size: 0.75rem; }

.soon {
  margin: 18px 0 0;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brass);
  opacity: 0.85;
}

.footer {
  border-top: 1px solid var(--line);
  margin-top: clamp(96px, 14vh, 160px);
}
.footer-grid {
  max-width: 1080px;
  margin: 0 auto;
  padding: 56px var(--pad) 48px;
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.2fr;
  gap: 36px;
  font-size: 0.8125rem;
  color: var(--mist);
}
.footer-brand .brand-name { font-size: 1rem; }
.footer-tagline { margin: 12px 0 0; letter-spacing: 0.05em; }
.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.footer a { color: var(--mist); font-size: 0.875rem; }
.footer a:hover { color: var(--brass); text-decoration: none; }
.footer-meta {
  display: flex;
  flex-direction: column;
  gap: 10px;
  justify-content: flex-end;
  align-items: flex-end;
  text-align: right;
  letter-spacing: 0.05em;
}

/* ─── 响应式 ─── */

@media (max-width: 1020px) {
  /* 窄屏收起样机：hero 回到纯文字（样机是增强，不是信息） */
  .hero { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
}
@media (max-width: 960px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: 1fr; gap: 0; }
  .step { border-top: 1px solid var(--line); }
}
@media (max-width: 820px) {
  .j-steps { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .feature-grid { grid-template-columns: 1fr; }
  .hero { min-height: 76vh; }
  .nav-links a:not(.btn) { display: none; }
  .fact-key { min-width: 7em; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-meta { align-items: flex-start; text-align: left; }
  /* 旅程舞台：紧凑但完整（E2E 两端都在场） */
  .j-phone { width: 54px; height: 96px; border-radius: 10px; padding: 4px; }
  .j-mac { width: 96px; height: 66px; padding: 4px; }
  .j-macbase { width: 110px; }
  .j-cloud { width: 96px; height: 64px; }
  .j-cipher { font-size: 5px; line-height: 2; padding: 3px; }
  .j-cipher-mini { font-size: 6px; }
  .j-label { font-size: 0.5rem; letter-spacing: 0.08em; }
  .j-peek1 { right: -12px; }
  .j-peek2 { left: -14px; bottom: 24px; }
  .j-steps { grid-template-columns: 1fr; gap: 4px; }
  .j-key { right: -6px; bottom: -6px; padding: 4px; }
}

/* ─── CJK 排版微调：方块字不需要负字距 ─── */

:is(:lang(zh-CN), :lang(ja), :lang(ko)) :is(h1, h2, h3) {
  letter-spacing: 0;
}

/* ─── 减弱动态效果 ─── */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .fog-reveal,
  .fog-reveal-late { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .layer { transition: none; }
  .btn { transition: none; }
  .card { transition: none; }
  .lang-caret { transition: none; }
  .lang-menu:not([hidden]) { animation: none; }
  .hero-visual { transition: none; }
  .nav { transition: none; }
  .vault-card { transition: none; }
  .tech[open] .tech-body { animation: none; }
  .journey *, .journey *::before { transition: none !important; animation: none !important; }
}