/* ============================================================
   XIAOJUNAI / 小俊AI · 品牌落地页样式（Apple × Xiaomi 融合 v3）
   玻璃分层 · 苹果字阶/留白 · 单强调色纪律 · 滚动叙事 · Alive 极光
   ============================================================ */

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 16px);
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: var(--leading-body);
  font-size: var(--fs-base);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background var(--t-base), color var(--t-base);
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; padding: 0; }
button { font: inherit; cursor: pointer; border: none; background: none; color: inherit; }
b, strong { font-weight: 700; color: var(--text); }

/* ---------- 布局工具 ---------- */
.container {
  width: 100%; max-width: var(--maxw);
  margin-inline: auto; padding-inline: var(--sp-6);
}
.container--narrow { max-width: var(--maxw-narrow); }
.section { padding-block: var(--section-y); }
.section--tint { background: var(--bg-elev); }
.grid { display: grid; gap: var(--sp-6); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.visually-hidden {
  position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* 玻璃表面（Apple Liquid Glass 复用基类） */
.surface {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  box-shadow: inset 0 1px 0 var(--glass-hi);
}

/* ---------- 按钮（唯一强调色 = 品牌紫） ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: var(--sp-2);
  padding: 0 var(--sp-6); height: 48px; border-radius: var(--r-pill);
  font-weight: 600; font-size: var(--fs-base); letter-spacing: 0.2px;
  transition: transform var(--t-fast), box-shadow var(--t-fast),
              background var(--t-fast), border-color var(--t-fast);
  white-space: nowrap; will-change: transform;
}
.btn--lg { height: 56px; padding-inline: var(--sp-8); font-size: var(--fs-md); }
.btn--block { width: 100%; }
.btn--primary { background: var(--brand-purple); color: #fff; box-shadow: 0 8px 24px var(--glow); }
.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 14px 36px var(--glow); background: var(--brand-purple-hi); }
.btn--ghost { background: var(--surface); color: var(--text); border: 1px solid var(--border); }
.btn--ghost:hover { border-color: var(--border-strong); background: var(--surface-2); transform: translateY(-2px); }
.btn:focus-visible { outline: 3px solid var(--brand-purple); outline-offset: 3px; }

/* ---------- 字标（真实 outline 矢量，按主题切换） ---------- */
.wordmark { width: 176px; height: auto; }
.wordmark--light { display: none; }
[data-theme="light"] .wordmark--dark { display: none; }
[data-theme="light"] .wordmark--light { display: block; }

/* ============================ 滚动进度条 ============================ */
.scroll-progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: linear-gradient(90deg, var(--brand-purple), var(--brand-cyan));
  z-index: 60; box-shadow: 0 0 10px var(--glow);
  transition: width 80ms linear;
}

/* ============================ 导航（分层玻璃） ============================ */
.nav {
  position: sticky; top: 0; z-index: 50; height: var(--nav-h);
  background: var(--nav-bg);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid transparent;
  box-shadow: inset 0 1px 0 var(--glass-hi); /* 顶部内高光 = Apple 玻璃 */
  transition: background var(--t-base), border-color var(--t-base), box-shadow var(--t-base);
}
.nav.is-scrolled { border-bottom-color: var(--border); box-shadow: inset 0 1px 0 var(--glass-hi), 0 8px 30px rgba(0,0,0,0.12); }
.nav__inner { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: var(--sp-6); }
.nav__links { display: flex; gap: var(--sp-8); }
.nav__links a {
  display: inline-flex; align-items: center; min-height: 44px;
  font-size: var(--fs-sm); color: var(--text-sub); font-weight: 500;
  position: relative; transition: color var(--t-fast);
}
.nav__links a::after {
  content: ""; position: absolute; left: 0; bottom: 8px; height: 2px; width: 0;
  background: var(--brand-purple); border-radius: 2px; transition: width var(--t-base);
}
.nav__links a:hover, .nav__links a.is-active { color: var(--text); }
.nav__links a:hover::after, .nav__links a.is-active::after { width: 100%; }
.nav__actions { display: flex; align-items: center; gap: var(--sp-3); }

/* 主题切换 */
.theme-toggle {
  width: 44px; height: 44px; border-radius: var(--r-pill);
  display: grid; place-items: center;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text-sub); transition: color var(--t-fast), border-color var(--t-fast), transform var(--t-fast);
}
.theme-toggle:hover { color: var(--text); border-color: var(--border-strong); transform: rotate(15deg); }
.theme-toggle__icon { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; }
.theme-toggle__icon circle { fill: currentColor; stroke: none; }
[data-theme="light"] .theme-toggle__rays { opacity: 0; }
.theme-toggle:focus-visible { outline: 3px solid var(--brand-purple); outline-offset: 3px; }

/* 汉堡 */
.nav__burger {
  display: none; width: 44px; height: 44px; border-radius: var(--r-sm);
  flex-direction: column; gap: 5px; align-items: center; justify-content: center;
}
.nav__burger span { width: 20px; height: 2px; background: var(--text); border-radius: 2px; transition: transform var(--t-fast), opacity var(--t-fast); }
.nav__burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav__burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================ HERO ============================ */
.hero { position: relative; padding-block: clamp(64px, 9vw, 128px) var(--sp-20); overflow: hidden; }
.hero__stars { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; pointer-events: none; }
.hero__mesh {
  position: absolute; inset: 0; z-index: 0; pointer-events: none;
  background:
    radial-gradient(42% 52% at 80% 28%, var(--mesh-1), transparent 70%),
    radial-gradient(38% 46% at 18% 76%, var(--mesh-2), transparent 70%);
  filter: blur(8px); opacity: 0.95;
}
.hero__glow {
  position: absolute; z-index: 0; inset: -20% 30% auto -10%; height: 640px;
  background: radial-gradient(closest-side, var(--glow), transparent 70%);
  filter: blur(20px); opacity: 0.9; pointer-events: none;
  will-change: transform;
}
.hero__inner { position: relative; z-index: 1; display: grid; grid-template-columns: 1.15fr 0.85fr; gap: var(--sp-12); align-items: center; }

.eyebrow {
  display: inline-flex; align-items: center; gap: var(--sp-2);
  font-size: var(--fs-sm); font-weight: 600; color: var(--text-sub);
  padding: 6px 14px; border: 1px solid var(--border); border-radius: var(--r-pill);
  background: var(--surface);
}
.eyebrow::before {
  content: ""; flex: none; width: 8px; height: 8px; border-radius: 50%;
  background: var(--brand-purple); box-shadow: 0 0 10px var(--brand-purple);
}

.hero__title {
  margin-top: var(--sp-6);
  /* CJK 标题排版优化：Apple×小米品牌融合，单行排版「星承大海 · 梦载星河」*/
  font-size: clamp(2.25rem, 5.8vw, 4.5rem);     /* 略缩，单行 4·4 字符 */
  font-weight: 700;                              /* 800→700：CJK 在 800 像粗黑宋；700 现代精致 */
  line-height: 1.25;                             /* 1.06→1.25：CJK 大字号需要垂直呼吸 */
  letter-spacing: 0.08em;                        /* -0.03em→+0.08em：拉丁负字距对 CJK 是灾难 */
  text-align: center;
  white-space: nowrap;                           /* 强制单行，禁止 balance 错位断行 */
  /* 优先现代无衬线 CJK */
  font-family: "HarmonyOS Sans SC", "PingFang SC", "Microsoft YaHei",
               -apple-system, BlinkMacSystemFont, "SF Pro Display",
               "Noto Sans CJK SC", system-ui, sans-serif;
  font-feature-settings: "palt" 1.05;            /* CJK 标点挤压，让"·"更紧凑 */
}
/* 单行排版：星承大海 · 梦载星河（同行内联）*/
.hero__sep {
  color: var(--brand-purple);
  display: inline-block;
  font-weight: 400;
  opacity: 0.85;
  /* 圆点（•）视觉居中：升到 0.52em，vertical-align 0.5em 让点与字肩齐 */
  font-size: 0.52em;
  vertical-align: 0.5em;
  margin: 0 0.6em;
  letter-spacing: 0;
  line-height: 1;
  /* 确保所有浏览器统一渲染成「实心圆点」*/
  font-family: "Apple Color Emoji", "Segoe UI Emoji", "Noto Color Emoji",
               "Helvetica Neue", Arial, sans-serif;
}
/* 备用：3 行竖排修饰类（启用后 = 4字 / 点居中 / 4字），默认不启用 */
.hero__sep--block { display: none; }
.hero__lead { margin-top: var(--sp-6); font-size: var(--fs-lg); color: var(--text-sub); max-width: 40ch; }
.hero__lead b { color: var(--brand-purple); font-weight: 700; }
.hero__cta { margin-top: var(--sp-8); display: flex; flex-wrap: wrap; gap: var(--sp-4); }

/* Hero 视觉：方印 + Alive 网点 */
.hero__visual { display: grid; place-items: center; }
.hero__seal { position: relative; width: min(340px, 82%); aspect-ratio: 1; display: grid; place-items: center; }
.seal-svg { width: 100%; height: 100%; filter: drop-shadow(0 22px 56px var(--glow)); animation: float 7s var(--ease) infinite; }
.dot {
  position: absolute; width: 16px; height: 16px; border-radius: 50%;
  box-shadow: var(--dot-shadow); animation: pulse 3s var(--ease) infinite;
}
.dot--cyan { background: var(--brand-cyan); top: 6%; right: 8%; }
.dot--gold { background: var(--brand-gold); bottom: 12%; right: 2%; animation-delay: 0.6s; }
.dot--pink { background: var(--brand-pink); bottom: 4%; left: 10%; animation-delay: 1.2s; }

@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-14px); } }
@keyframes pulse { 0%,100% { transform: scale(1); opacity: 1; } 50% { transform: scale(1.35); opacity: 0.55; } }

/* ============================ 品牌签章（深色横幅） ============================ */
.signature {
  position: relative;
  isolation: isolate;            /* 让光晕圆角不漏到外 */
  overflow: hidden;
  padding-block: clamp(56px, 8vw, 96px);
  text-align: center;
  background: linear-gradient(135deg, #0E0E26 0%, #181835 60%, #23234E 100%);
  color: #fff;
  border-block: 1px solid rgba(255,255,255,0.06);
}
/* 顶部渐变发丝分隔线（与 stats::before 同语言，衔接 Hero → 签章） */
.signature::before {
  content: ""; position: absolute; top: 0; left: 50%; transform: translateX(-50%);
  width: min(640px, 80%); height: 1px; z-index: -1;
  background: linear-gradient(90deg, transparent, var(--brand-purple), var(--brand-cyan), transparent);
  opacity: 0.7;
}
/* 双色光晕：品牌紫 + 品牌青 + 品牌金（呼应文字渐变） */
.signature__glow {
  position: absolute; border-radius: 50%; filter: blur(80px); pointer-events: none;
  z-index: -1; opacity: 0.55;
}
.signature__glow--1 { top: -30%; left: -10%; width: 460px; height: 460px; background: var(--brand-purple); opacity: 0.45; }
.signature__glow--2 { bottom: -40%; right: -10%; width: 520px; height: 520px; background: var(--brand-cyan); opacity: 0.30; }

/* 标题：隽采中秀(品牌粉→金渐变) · 芳华与共(品牌青→紫渐变) ，中间点品牌紫 */
.signature__title {
  font-size: clamp(2rem, 5.8vw, 3.75rem);
  font-weight: 700;
  letter-spacing: 0.18em;          /* 「四字成语 + · + 四字」需要呼吸字距 */
  line-height: 1.25;
  margin: 0;
  font-family: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei",
               "Noto Sans CJK SC", system-ui, sans-serif;
  text-shadow: 0 4px 24px rgba(0,0,0,0.35);
}
/* 品牌色板：紫 #7C5CFF · 青 #22D3EE · 金 #FACC15 · 粉 #F472B6 */
.signature__a {
  background: linear-gradient(90deg, #F472B6 0%, #FACC15 100%);
  -webkit-background-clip: text;
          background-clip: text;
  -webkit-text-fill-color: transparent;
          color: transparent;
  display: inline-block;
  text-shadow: none;            /* 渐变文字不要 text-shadow */
}
.signature__b {
  background: linear-gradient(90deg, #22D3EE 0%, #7C5CFF 100%);
  -webkit-background-clip: text;
          background-clip: text;
  -webkit-text-fill-color: transparent;
          color: transparent;
  display: inline-block;
  text-shadow: none;
}
.signature__sep {
  color: var(--brand-purple);
  display: inline-block;
  vertical-align: 0.22em;
  margin: 0 0.3em;
  font-size: 0.66em;
  font-weight: 400;
  opacity: 0.9;
}
.signature__sub {
  margin: var(--sp-6) auto 0;
  max-width: 38ch;
  font-size: var(--fs-md);
  color: rgba(255,255,255,0.7);
  letter-spacing: 0.04em;
  line-height: 1.7;
}

/* 装饰星点（动画轻微闪烁） */
.signature__stars {
  position: absolute; inset: 0; pointer-events: none; z-index: -1;
}
.star {
  position: absolute; width: 4px; height: 4px; border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 6px rgba(255,255,255,0.9);
  opacity: 0;
  animation: starTwinkle 3.2s ease-in-out infinite;
}
.star--1 { top: 22%; left: 12%; animation-delay: 0.2s; }
.star--2 { top: 38%; left: 86%; width: 3px; height: 3px; animation-delay: 1.1s; }
.star--3 { top: 70%; left: 22%; width: 2px; height: 2px; animation-delay: 0.7s; }
.star--4 { top: 78%; left: 76%; width: 3px; height: 3px; animation-delay: 1.8s; }
.star--5 { top: 12%; left: 60%; width: 2px; height: 2px; animation-delay: 2.4s; }
.star--6 { top: 56%; left: 50%; width: 5px; height: 5px; animation-delay: 0.0s; }
@keyframes starTwinkle { 0%,100% { opacity: 0; transform: scale(0.6); } 50% { opacity: 0.85; transform: scale(1); } }

/* ============================ 数据条（小米数据前置） ============================ */
.stats { position: relative; padding-block: var(--sp-16); border-block: 1px solid var(--border); background: var(--bg-elev); }
.stats::before {
  content: ""; position: absolute; top: 0; left: 50%; transform: translateX(-50%);
  width: min(640px, 80%); height: 1px;
  background: linear-gradient(90deg, transparent, var(--brand-purple), var(--brand-cyan), transparent);
  opacity: 0.7;
}
.stats__grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-6); }
.stat { display: flex; flex-direction: column; align-items: center; text-align: center; }
.stat__num {
  font-size: clamp(3rem, 6vw, 4rem); font-weight: 800; line-height: 1; letter-spacing: -0.02em;
  background: linear-gradient(120deg, var(--brand-purple), var(--brand-cyan));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  font-variant-numeric: tabular-nums;
}
.stat__label { margin-top: var(--sp-3); font-size: var(--fs-sm); color: var(--text-sub); }

/* ============================ 区块标题 ============================ */
.section__head { max-width: 720px; margin-bottom: var(--sp-12); }
.kicker { font-size: var(--fs-sm); font-weight: 700; letter-spacing: var(--tracking-wide); color: var(--brand-purple); }
.section__title { margin-top: var(--sp-3); font-size: var(--fs-3xl); font-weight: 800; line-height: var(--leading-tight); letter-spacing: var(--tracking-tight); }
.section__sub { margin-top: var(--sp-4); font-size: var(--fs-md); color: var(--text-sub); }

/* ============================ 卡片（玻璃 + 顶部强调线，去三色点噪声） ============================ */
.card {
  position: relative; padding: var(--sp-8);
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--r-lg);
  box-shadow: inset 0 1px 0 var(--glass-hi);
  overflow: hidden;
  transition: transform var(--t-base), border-color var(--t-base), background var(--t-base), box-shadow var(--t-base);
}
.card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, var(--brand-purple), var(--brand-cyan));
  transform: scaleX(0); transform-origin: left; transition: transform var(--t-base) var(--ease-out);
}
.card:hover { transform: translateY(-6px); border-color: var(--border-strong); box-shadow: var(--shadow-float); }
.card:hover::before { transform: scaleX(1); }
.card__title { font-size: var(--fs-lg); font-weight: 700; letter-spacing: -0.01em; }
.card__text { margin-top: var(--sp-3); color: var(--text-sub); font-size: var(--fs-base); }

/* ============================ 意识内核 · 滚动叙事（Apple 招牌） ============================ */
.core__layout { display: grid; grid-template-columns: 0.85fr 1.15fr; gap: var(--sp-16); align-items: start; }
.core__sticky { position: sticky; top: calc(var(--nav-h) + 48px); align-self: start; }
.core__rail { display: flex; flex-direction: column; gap: 14px; margin-bottom: var(--sp-8); }
.rail__tick { width: 26px; height: 3px; border-radius: 3px; background: var(--border-strong); transition: background var(--t-base), width var(--t-base), transform var(--t-base); }
.rail__tick.is-active { background: linear-gradient(90deg, var(--brand-purple), var(--brand-cyan)); width: 44px; }
.core__stage {
  display: block; font-size: clamp(5rem, 11vw, 8.5rem); font-weight: 800; line-height: 0.95;
  letter-spacing: var(--tracking-display);
  background: linear-gradient(120deg, var(--brand-purple), var(--brand-cyan));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  font-variant-numeric: tabular-nums;
}
.core__stagelabel { display: block; margin-top: var(--sp-4); font-size: var(--fs-xl); font-weight: 700; letter-spacing: var(--tracking-tight); }
.core__stephint { margin-top: var(--sp-3); font-size: var(--fs-sm); color: var(--text-mute); }

.core__steps { display: flex; flex-direction: column; gap: var(--sp-5); }
.core-step {
  display: flex; gap: var(--sp-5); align-items: flex-start;
  padding: var(--sp-8); border-radius: var(--r-lg);
  background: var(--surface); border: 1px solid var(--border);
  box-shadow: inset 0 1px 0 var(--glass-hi);
  transition: transform var(--t-base), border-color var(--t-base), background var(--t-base), box-shadow var(--t-base);
}
.core-step.is-active { border-color: var(--brand-purple); background: var(--surface-2); box-shadow: var(--shadow-card); }
.core-step__no {
  flex: none; display: grid; place-items: center; width: 44px; height: 44px; border-radius: var(--r-sm);
  background: var(--brand-purple); color: #fff; font-weight: 700; font-size: var(--fs-sm);
  font-variant-numeric: tabular-nums;
}
.core-step.is-active .core-step__no { box-shadow: 0 0 0 4px var(--glow-soft); }
.core-step h3 { font-size: var(--fs-lg); font-weight: 700; letter-spacing: -0.01em; }
.core-step p { margin-top: var(--sp-2); color: var(--text-sub); font-size: var(--fs-base); }

/* ============================ 架构图 ============================ */
.arch {
  margin: 0; padding: var(--sp-10);
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-xl);
  box-shadow: inset 0 1px 0 var(--glass-hi);
}
.arch__svg { width: 100%; height: auto; font-family: var(--font-sans); }
.arch__node rect {
  fill: var(--surface-2); stroke: var(--border-strong); stroke-width: 1.5;
  transition: fill var(--t-base), stroke var(--t-base);
}
.arch__node--accent rect { fill: var(--glow-soft); stroke: var(--brand-purple); }
.arch__t { fill: var(--text); font-size: 18px; font-weight: 700; text-anchor: middle; }
.arch__s { fill: var(--text-sub); font-size: 12.5px; text-anchor: middle; }
.arch__links { opacity: 0.85; }
.arch__legend { display: flex; flex-wrap: wrap; gap: var(--sp-6); justify-content: center; margin-top: var(--sp-8); font-size: var(--fs-sm); color: var(--text-sub); }
.arch__legend span { display: inline-flex; align-items: center; gap: 8px; }
.lg { width: 14px; height: 14px; border-radius: 4px; background: var(--surface-2); border: 1.5px solid var(--border-strong); }
.lg--accent { background: var(--glow-soft); border-color: var(--brand-purple); }
.lg--flow { width: 18px; height: 4px; border: none; border-radius: 2px; background: linear-gradient(90deg, var(--brand-purple), var(--brand-cyan)); }

/* ============================ 双集群接入 ============================ */
.tier {
  position: relative; padding: var(--sp-10);
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-xl);
  box-shadow: inset 0 1px 0 var(--glass-hi);
  display: flex; flex-direction: column; gap: var(--sp-6);
  transition: transform var(--t-base), border-color var(--t-base);
}
.tier:hover { transform: translateY(-4px); }
.tier--featured { border-color: var(--brand-purple); background: var(--surface-2); box-shadow: 0 18px 50px var(--glow-soft), inset 0 1px 0 var(--glass-hi); }
.tier__head { display: flex; flex-direction: column; gap: var(--sp-2); }
.tier__tag { align-self: flex-start; font-size: var(--fs-xs); font-weight: 700; letter-spacing: 1px; padding: 4px 12px; border-radius: var(--r-pill); }
.tier__tag--free { background: var(--surface-2); color: var(--text-sub); border: 1px solid var(--border); }
.tier__tag--pro { background: var(--brand-purple); color: #fff; }
.tier__name { font-size: var(--fs-xl); font-weight: 800; }
.tier__price { font-size: var(--fs-md); color: var(--text-sub); }
.tier__price span { font-size: var(--fs-sm); }
.tier__list { display: flex; flex-direction: column; gap: var(--sp-3); margin-block: var(--sp-2); }
.tier__list li { position: relative; padding-left: 26px; color: var(--text-sub); font-size: var(--fs-base); }
.tier__list li::before {
  content: ""; position: absolute; left: 0; top: 7px; width: 16px; height: 16px; border-radius: 50%;
  background: var(--brand-purple); box-shadow: 0 0 0 4px var(--glow-soft);
}
.tier__list li::after {
  content: ""; position: absolute; left: 5px; top: 11px; width: 6px; height: 3px;
  border-left: 2px solid #fff; border-bottom: 2px solid #fff; transform: rotate(-45deg);
}
.tier .btn { margin-top: auto; }

/* ============================ FAQ ============================ */
.faq { display: flex; flex-direction: column; gap: var(--sp-4); }
.faq__item {
  border: 1px solid var(--border); border-radius: var(--r-md);
  background: var(--surface); overflow: hidden; box-shadow: inset 0 1px 0 var(--glass-hi);
  transition: border-color var(--t-base), background var(--t-base);
}
.faq__item.is-open { border-color: var(--brand-purple); background: var(--surface-2); }
.faq__q {
  width: 100%; display: flex; align-items: center; justify-content: space-between; gap: var(--sp-4);
  padding: var(--sp-5) var(--sp-6); text-align: left; min-height: 56px;
  font-size: var(--fs-md); font-weight: 600; color: var(--text);
}
.faq__icon { position: relative; width: 16px; height: 16px; flex: none; }
.faq__icon::before, .faq__icon::after {
  content: ""; position: absolute; left: 50%; top: 50%; background: var(--brand-purple);
  transform: translate(-50%, -50%); border-radius: 2px;
  transition: transform var(--t-base), opacity var(--t-base);
}
.faq__icon::before { width: 14px; height: 2px; }
.faq__icon::after { width: 2px; height: 14px; }
.faq__item.is-open .faq__icon::after { transform: translate(-50%, -50%) scaleY(0); opacity: 0; }
.faq__a { max-height: 0; overflow: hidden; transition: max-height var(--t-slow) var(--ease); }
.faq__a p { padding: 0 var(--sp-6) var(--sp-5); color: var(--text-sub); font-size: var(--fs-base); }
.faq__q:focus-visible { outline: 3px solid var(--brand-purple); outline-offset: -3px; border-radius: var(--r-md); }

/* ============================ 终章 CTA ============================ */
.cta { position: relative; overflow: hidden; text-align: center; }
.cta__glow {
  position: absolute; left: 50%; top: 40%; transform: translate(-50%, -50%);
  width: 760px; height: 760px; max-width: 130vw;
  background: radial-gradient(closest-side, var(--glow), transparent 70%);
  filter: blur(30px); opacity: 0.85; pointer-events: none;
}
.cta__inner { position: relative; max-width: 680px; margin-inline: auto; }
.cta__kicker { font-size: var(--fs-sm); font-weight: 700; letter-spacing: var(--tracking-wide); color: var(--brand-purple); }
.cta__title { margin-top: var(--sp-3); font-size: var(--fs-4xl); font-weight: 800; line-height: var(--leading-tight); letter-spacing: var(--tracking-display); }
.cta__sub { margin-top: var(--sp-5); font-size: var(--fs-lg); color: var(--text-sub); }
.cta__actions { margin-top: var(--sp-8); display: flex; gap: var(--sp-4); justify-content: center; flex-wrap: wrap; }

/* ============================ 页脚 ============================ */
.footer { border-top: 1px solid var(--border); padding-block: var(--sp-12); background: var(--bg-elev); }
.footer__inner { display: flex; flex-direction: column; align-items: center; gap: var(--sp-6); text-align: center; }
.footer__brand { display: flex; flex-direction: column; align-items: center; gap: var(--sp-3); }
.footer__logo { width: 44px; height: 44px; filter: drop-shadow(0 6px 16px var(--glow)); }
.footer__slogan { color: var(--text-sub); font-size: var(--fs-sm); letter-spacing: 2px; }
.footer__kicker {
  display: inline-flex; align-items: center; gap: var(--sp-2);
  padding: 4px 14px; border: 1px solid var(--border-strong); border-radius: var(--r-pill);
  font-size: var(--fs-xs); font-weight: 500; letter-spacing: 2px; text-transform: uppercase;
  color: var(--text-mute); margin-top: var(--sp-1);
}
.footer__slogan--sub {
  font-size: var(--fs-md); font-weight: 600; letter-spacing: 4px; margin-top: var(--sp-1);
}
.footer__nav { display: flex; gap: var(--sp-6); flex-wrap: wrap; justify-content: center; }
.footer__nav a { color: var(--text-sub); font-size: var(--fs-sm); transition: color var(--t-fast); }
.footer__nav a:hover { color: var(--text); }
.footer__copy { color: var(--text-mute); font-size: var(--fs-xs); }

/* ============================ 渐变字工具类（v2 四色板） ============================ */
.text-gradient {
  background: linear-gradient(120deg, var(--brand-purple), var(--brand-cyan));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.text-gradient--alt {
  background: linear-gradient(120deg, var(--brand-pink), var(--brand-gold), var(--brand-cyan));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
/* 亮色模式对比度治理：金/粉/青在浅底上对比度不足（WCAG AA 大字号 3:1 兜底），
   改用加深的品牌紫→深青，保留渐变质感同时保证可读性；暗色模式维持原 vivid 渐变 */
[data-theme="light"] .text-gradient,
[data-theme="light"] .text-gradient--alt {
  background: linear-gradient(120deg, #5B3BE0, #0E7490);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}

/* ============================ 滚动揭示 ============================ */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity var(--t-slow) var(--ease-out), transform var(--t-slow) var(--ease-out); }
.reveal.is-visible { opacity: 1; transform: none; }

/* ============================ 无障碍 ============================ */
.skip-link {
  position: absolute; left: 50%; top: -60px; transform: translateX(-50%);
  background: var(--brand-purple); color: #fff; padding: 10px 18px; border-radius: 0 0 var(--r-sm) var(--r-sm);
  z-index: 100; transition: top var(--t-fast);
}
.skip-link:focus { top: 0; }
:focus-visible { outline: 3px solid var(--brand-purple); outline-offset: 3px; border-radius: 4px; }

/* ============================ 板块自治引擎 · 自动纠错修复类 ============================ */
.is-contrast-fixed { color: var(--text) !important; font-weight: 600; }
img.is-broken { opacity: 0.35; filter: grayscale(1); }

/* ============================ 板块自治引擎 · 自进化面板 ============================ */
.selfheal-toggle {
  position: fixed; left: 16px; bottom: 16px; z-index: 70;
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 14px; border-radius: var(--r-pill);
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text-sub); font-size: var(--fs-sm); font-weight: 600;
  box-shadow: inset 0 1px 0 var(--glass-hi), 0 8px 24px rgba(0,0,0,0.18);
  -webkit-backdrop-filter: blur(16px); backdrop-filter: blur(16px);
  transition: color var(--t-fast), border-color var(--t-fast), transform var(--t-fast);
}
.selfheal-toggle:hover { color: var(--text); border-color: var(--border-strong); transform: translateY(-2px); }
.selfheal-toggle__dot { width: 8px; height: 8px; border-radius: 50%; background: var(--brand-purple); box-shadow: 0 0 10px var(--brand-purple); animation: pulse 2.4s var(--ease) infinite; }
.selfheal {
  position: fixed; left: 16px; bottom: 60px; z-index: 70; width: min(320px, calc(100vw - 32px));
  padding: var(--sp-5); border-radius: var(--r-lg);
  background: var(--surface); border: 1px solid var(--border);
  box-shadow: inset 0 1px 0 var(--glass-hi), 0 18px 50px rgba(0,0,0,0.22);
  -webkit-backdrop-filter: blur(20px) saturate(180%); backdrop-filter: blur(20px) saturate(180%);
}
.selfheal[hidden] { display: none; }
.selfheal__head { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-4); margin-bottom: var(--sp-4); }
.selfheal__head strong { font-size: var(--fs-sm); color: var(--text); letter-spacing: 0.3px; }
.selfheal__meta { font-size: var(--fs-xs); color: var(--text-mute); font-variant-numeric: tabular-nums; }
.selfheal__list { display: flex; flex-direction: column; gap: 4px; max-height: 42vh; overflow: auto; margin: 0; padding: 0; }
.selfheal__row { display: flex; align-items: center; justify-content: space-between; padding: 6px 10px; border-radius: var(--r-sm); background: var(--surface-2); font-size: var(--fs-sm); }
.selfheal__name { color: var(--text-sub); font-weight: 600; }
.selfheal__state { font-size: var(--fs-xs); color: var(--text-mute); }
.selfheal__row.is-ok .selfheal__state { color: #34d399; }
.selfheal__row.is-fixed .selfheal__state { color: var(--brand-cyan); }
.selfheal__row.is-warn .selfheal__state { color: #fbbf24; }
.selfheal__hint { margin-top: var(--sp-4); font-size: var(--fs-xs); color: var(--text-mute); line-height: 1.5; }

/* ============================ Ω-Prime 十六重自循环 ============================ */
.omega-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-5); }
.omega-card { padding: var(--sp-6); display: flex; flex-direction: column; gap: var(--sp-3); }
.omega-card__top { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-3); }
.omega-card__no {
  font-size: var(--fs-xl); font-weight: 800; letter-spacing: var(--tracking-display); line-height: 1;
  background: linear-gradient(120deg, var(--brand-purple), var(--brand-cyan));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  font-variant-numeric: tabular-nums;
}
.omega-card__name { font-size: var(--fs-md); font-weight: 700; letter-spacing: -0.01em; display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px; }
.omega-card__name small { font-size: var(--fs-xs); font-weight: 600; letter-spacing: 0.4px; color: var(--text-mute); text-transform: uppercase; }
.omega-badge {
  flex: none; font-size: var(--fs-xs); font-weight: 700; letter-spacing: 0.3px;
  padding: 3px 10px; border-radius: var(--r-pill); border: 1px solid var(--border); white-space: nowrap;
  transition: color var(--t-fast), background var(--t-fast), border-color var(--t-fast);
}
.omega-badge[data-kind="live"] { color: var(--brand-purple); background: var(--glow-soft); border-color: transparent; }
.omega-badge[data-kind="road"] { color: var(--text-sub); background: var(--surface-2); }
.omega-badge[data-kind="vision"] { color: var(--brand-cyan); background: rgba(34, 211, 238, 0.10); border-color: transparent; }
@media (max-width: 940px) { .omega-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .omega-grid { grid-template-columns: 1fr; } }

/* ============================ 响应式 ============================ */
@media (max-width: 940px) {
  .hero__inner { grid-template-columns: 1fr; gap: var(--sp-10); }
  .hero__visual { order: -1; }
  .hero__seal { width: min(240px, 60%); }
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
  .core__layout { grid-template-columns: 1fr; gap: var(--sp-10); }
  .core__sticky { position: static; }
  .core__rail { flex-direction: row; flex-wrap: wrap; }
  .stats__grid { grid-template-columns: repeat(2, 1fr); gap: var(--sp-8); }
}
@media (max-width: 720px) {
  .nav__links { display: none; }
  .nav__cta { display: none; }
  .nav__burger { display: flex; }
  .nav__links.is-open {
    display: flex; flex-direction: column; gap: var(--sp-4);
    position: absolute; top: var(--nav-h); left: 0; right: 0;
    padding: var(--sp-6); background: var(--nav-bg);
    -webkit-backdrop-filter: blur(20px); backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
  }
  .grid--2, .grid--3 { grid-template-columns: 1fr; }
  .section { padding-block: var(--sp-16); }
  .section__title { font-size: var(--fs-2xl); }
  .cta__title { font-size: var(--fs-3xl); }
  .hero__lead { max-width: none; }
  .arch { padding: var(--sp-6); }
  .arch__svg { font-size: 11px; }
  .theme-toggle { width: 40px; height: 40px; }  /* 触控目标 ≥40px */
}
@media (max-width: 480px) {
  .stats__grid { grid-template-columns: 1fr; }
  /* 小屏：签名区 0.18em 字距会溢出，收紧字距与副文案字号 */
  .signature__title { letter-spacing: 0.06em; }
  .signature__sub { font-size: var(--fs-base); }
  /* 小屏：Hero 标题收紧字距，降低换行/溢出风险（不改变换行行为） */
  .hero__title { letter-spacing: 0.04em; }
}

@media (prefers-reduced-motion: reduce) {
  .seal-svg, .dot { animation: none; }
  .reveal { transition: none; opacity: 1; transform: none; }
  .hero__stars { display: none; }
  .faq__a { transition: none; }
}