/* =========================================================
   薪火助手 · xinghuocai.cn  —  主样式表
   品牌色取自 Logo：珊瑚粉 #f76c6c + 青绿 #3fc7bd
   ========================================================= */

/* ---------- 变量 ---------- */
:root {
  --coral: #f76c6c;
  --coral-dark: #e8505a;
  --teal: #3fc7bd;
  --teal-dark: #22a89e;
  --ink: #1f2430;
  --ink-soft: #4b5563;
  --muted: #8a94a6;
  --line: #eceff5;
  --bg: #ffffff;
  --bg-soft: #f6f8fb;
  --grad: linear-gradient(135deg, var(--coral) 0%, #ff8e7a 45%, var(--teal) 100%);
  --grad-btn: linear-gradient(135deg, var(--coral) 0%, var(--coral-dark) 100%);
  --shadow-sm: 0 2px 10px rgba(31, 36, 48, .06);
  --shadow-md: 0 12px 30px rgba(31, 36, 48, .10);
  --shadow-lg: 0 24px 60px rgba(31, 36, 48, .16);
  --shadow-coral: 0 14px 34px rgba(247, 108, 108, .35);
  --radius: 18px;
  --radius-lg: 26px;
  --container: 1180px;
  --header-h: 68px;
  --font: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* ---------- 基础重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 12px); -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { margin: 0 0 .5em; line-height: 1.25; font-weight: 800; letter-spacing: -.01em; }
p { margin: 0 0 1em; }
ul { margin: 0; padding: 0; list-style: none; }
code { background: #f1f3f8; padding: .12em .45em; border-radius: 6px; font-size: .9em; color: var(--coral-dark); }

.container { width: 100%; max-width: var(--container); margin-inline: auto; padding-inline: 22px; }
.container-narrow { max-width: 820px; }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 200;
  background: var(--ink); color: #fff; padding: 10px 16px; border-radius: 0 0 10px 0;
}
.skip-link:focus { left: 0; }

/* ---------- 按钮 ---------- */
.btn {
  --btn-py: 12px;
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: var(--btn-py) 22px;
  border: 0; border-radius: 999px;
  font-family: inherit; font-size: 15px; font-weight: 700; line-height: 1;
  cursor: pointer; white-space: nowrap;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease, color .18s ease;
  will-change: transform;
}
.btn:active { transform: translateY(1px) scale(.99); }
.btn-primary { background: var(--grad-btn); color: #fff; box-shadow: var(--shadow-coral); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 18px 40px rgba(247, 108, 108, .45); }
.btn-dark { background: var(--ink); color: #fff; box-shadow: var(--shadow-md); }
.btn-dark:hover { transform: translateY(-2px); background: #000; }
.btn-ghost { background: rgba(255, 255, 255, .14); color: #fff; border: 1.5px solid rgba(255, 255, 255, .55); backdrop-filter: blur(6px); }
.btn-ghost:hover { background: rgba(255, 255, 255, .26); transform: translateY(-2px); }
.btn-lg { --btn-py: 16px; font-size: 16px; padding-inline: 30px; }
.btn-sm { --btn-py: 9px; font-size: 14px; padding-inline: 16px; }
.btn-block { width: 100%; }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  height: var(--header-h);
  display: flex; align-items: center;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: box-shadow .25s ease, border-color .25s ease;
}
.site-header.scrolled { box-shadow: var(--shadow-sm); border-color: var(--line); }
.nav-wrap { display: flex; align-items: center; gap: 18px; }
.brand { display: inline-flex; align-items: center; gap: 10px; }
.brand-logo { border-radius: 10px; box-shadow: var(--shadow-sm); }
.brand-text { font-size: 20px; font-weight: 900; letter-spacing: -.02em; }
.brand-text em { font-style: normal; color: var(--coral); }
.main-nav { display: flex; gap: 4px; margin-left: auto; }
.main-nav a {
  position: relative; padding: 8px 14px; border-radius: 10px;
  font-size: 15px; font-weight: 600; color: var(--ink-soft);
  transition: color .2s ease, background .2s ease;
}
.main-nav a:hover { color: var(--coral); background: #fff5f5; }
.nav-cta { margin-left: 8px; }
.nav-toggle { display: none; }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 56px 0 120px;
  color: #fff;
  overflow: hidden;
  isolation: isolate;
}
.hero-bg {
  position: absolute; inset: 0; z-index: -2;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(63, 199, 189, .55), transparent 60%),
    radial-gradient(1000px 700px at 0% 10%, rgba(247, 108, 108, .75), transparent 55%),
    linear-gradient(135deg, #ff7a6b 0%, #f76c6c 35%, #d76a9a 70%, #3fc7bd 130%);
}
.hero-bg::after {
  content: ""; position: absolute; inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, .18) 1px, transparent 1px);
  background-size: 26px 26px; opacity: .5;
  -webkit-mask-image: linear-gradient(180deg, #000, transparent 70%);
          mask-image: linear-gradient(180deg, #000, transparent 70%);
}
.hero-grid { display: grid; grid-template-columns: 1.05fr .95fr; align-items: center; gap: 40px; }
.hero-copy { max-width: 560px; }
.badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 7px 14px; border-radius: 999px;
  background: rgba(255, 255, 255, .16); border: 1px solid rgba(255, 255, 255, .35);
  font-size: 13px; font-weight: 700; backdrop-filter: blur(6px);
}
.badge-live .dot { width: 8px; height: 8px; border-radius: 50%; background: #7dffd4; box-shadow: 0 0 0 0 rgba(125, 255, 212, .7); animation: pulse 1.8s infinite; }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 rgba(125, 255, 212, .6); } 70% { box-shadow: 0 0 0 10px rgba(125, 255, 212, 0); } 100% { box-shadow: 0 0 0 0 rgba(125, 255, 212, 0); } }
.hero-title { font-size: clamp(38px, 6vw, 60px); margin: 18px 0 6px; text-shadow: 0 6px 24px rgba(0, 0, 0, .12); }
.hero-title .grad { background: linear-gradient(90deg, #fff, #d7fff6); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-sub { font-size: clamp(18px, 2.6vw, 23px); font-weight: 800; margin: 0 0 12px; opacity: .98; }
.hero-desc { font-size: 16px; line-height: 1.8; opacity: .92; max-width: 500px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin: 26px 0 22px; }
.hero-actions .btn-primary { background: #fff; color: var(--coral-dark); box-shadow: 0 16px 36px rgba(0, 0, 0, .18); }
.hero-actions .btn-primary:hover { box-shadow: 0 22px 46px rgba(0, 0, 0, .24); }
.hero-trust { display: flex; flex-wrap: wrap; gap: 18px; font-size: 14px; font-weight: 600; opacity: .95; }
.hero-trust li { display: inline-flex; align-items: center; gap: 6px; }

/* Hero 客服条（紧邻下载按钮，醒目） */
.hero-service {
  margin-top: 24px; display: inline-flex; align-items: center; gap: 14px; flex-wrap: wrap;
  padding: 12px 16px 12px 18px; border-radius: 16px;
  background: rgba(255, 255, 255, .16); border: 1px solid rgba(255, 255, 255, .42);
  box-shadow: 0 10px 30px rgba(0, 0, 0, .12); backdrop-filter: blur(8px);
}
.hs-label { font-size: 13px; font-weight: 800; opacity: .98; }
.hs-ids { display: flex; gap: 10px; flex-wrap: wrap; }
.hs-chip {
  font-family: inherit; cursor: pointer; padding: 8px 16px; border: 0; border-radius: 999px;
  background: #fff; color: var(--coral-dark); font-size: 15px; font-weight: 900; letter-spacing: .02em;
  box-shadow: 0 6px 16px rgba(0, 0, 0, .16); transition: transform .15s ease, box-shadow .15s ease, background .2s ease, color .2s ease;
}
.hs-chip:hover { transform: translateY(-2px); box-shadow: 0 10px 22px rgba(0, 0, 0, .22); }
.hs-chip.copied { background: linear-gradient(135deg, var(--teal-dark), #16b98a); color: #fff; }

/* Hero 手机模型 */
.hero-visual { position: relative; height: 560px; display: flex; align-items: center; justify-content: center; }
.phone {
  position: absolute; width: 290px; border-radius: 38px; overflow: hidden;
  border: 9px solid #0f1218; background: #0f1218;
  box-shadow: var(--shadow-lg);
}
.phone img { border-radius: 30px; width: 100%; height: auto; }
.phone-back { transform: translate(-92px, 8px) rotate(-7deg) scale(.9); z-index: 1; opacity: .96; }
.phone-front { transform: translate(70px, -4px) rotate(5deg); z-index: 2; }
.float-chip {
  position: absolute; z-index: 3;
  padding: 9px 14px; border-radius: 14px;
  background: rgba(255, 255, 255, .95); color: var(--ink);
  font-size: 13px; font-weight: 800; box-shadow: var(--shadow-md);
  animation: float 4.5s ease-in-out infinite;
}
.chip-1 { top: 8%; left: -2%; animation-delay: 0s; }
.chip-2 { top: 46%; right: -4%; animation-delay: 1.2s; }
.chip-3 { bottom: 6%; left: 4%; animation-delay: 2.1s; }
@keyframes float { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-12px); } }

.hero-wave { position: absolute; left: 0; right: 0; bottom: -1px; z-index: 1; line-height: 0; }
.hero-wave svg { width: 100%; height: 90px; display: block; }

/* ---------- 通用 Section ---------- */
.section { padding: 84px 0; }
.section:nth-of-type(even) { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 52px; }
.eyebrow {
  display: inline-block; font-size: 13px; font-weight: 800; letter-spacing: .14em;
  text-transform: uppercase; color: var(--coral); margin-bottom: 10px;
}
.section-head h2 { font-size: clamp(26px, 4vw, 38px); }
.section-head p { color: var(--muted); font-size: 17px; margin: 0; }

/* ---------- 特性 ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.feature-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg);
  padding: 30px 24px; box-shadow: var(--shadow-sm);
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.feature-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-md); border-color: transparent; }
.feature-icon {
  width: 58px; height: 58px; border-radius: 16px; display: grid; place-items: center;
  font-size: 26px; margin-bottom: 16px;
  background: color-mix(in srgb, var(--c) 16%, #fff);
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--c) 28%, #fff);
}
.feature-card h3 { font-size: 19px; }
.feature-card p { color: var(--ink-soft); font-size: 15px; margin: 0; }

/* ---------- 界面预览 ---------- */
.preview-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 34px; max-width: 760px; margin-inline: auto; }
.preview-item { margin: 0; text-align: center; }
.preview-shot {
  position: relative; border-radius: 30px; overflow: hidden;
  border: 10px solid #0f1218; background: #0f1218; box-shadow: var(--shadow-lg);
  transition: transform .3s ease;
}
.preview-item:hover .preview-shot { transform: translateY(-8px) scale(1.01); }
.preview-shot img { width: 100%; height: auto; }
.preview-item figcaption { margin-top: 18px; color: var(--ink-soft); font-size: 15px; font-weight: 600; }

/* ---------- 下载 ---------- */
.download-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 26px; max-width: 900px; margin-inline: auto; }
.device-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg);
  padding: 34px 30px; box-shadow: var(--shadow-sm);
  transition: transform .25s ease, box-shadow .25s ease;
}
.device-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); }
.device-icon { font-size: 40px; margin-bottom: 10px; }
.device-card h3 { font-size: 22px; }
.device-card p { color: var(--ink-soft); font-size: 15px; min-height: 60px; }
.meta { display: flex; flex-wrap: wrap; gap: 10px 22px; margin: 18px 0 22px; padding: 16px 0; border-top: 1px dashed var(--line); border-bottom: 1px dashed var(--line); }
.meta li { font-size: 14px; color: var(--muted); }
.meta strong { color: var(--ink); font-weight: 800; }
.safety-tip { text-align: center; margin-top: 30px; color: var(--muted); font-size: 14px; }

/* 下载区客服横幅 */
.download-service {
  margin: 26px auto 0; max-width: 900px;
  display: flex; align-items: center; gap: 18px; flex-wrap: wrap;
  padding: 22px 26px; border-radius: var(--radius-lg);
  background: linear-gradient(135deg, #fff5f4, #eefbf9);
  border: 1px solid #ffdfda; box-shadow: var(--shadow-md);
}
.ds-icon { font-size: 34px; line-height: 1; }
.ds-text { display: flex; flex-direction: column; margin-right: auto; min-width: 220px; }
.ds-text strong { font-size: 17px; }
.ds-text span { font-size: 13px; color: var(--muted); margin-top: 3px; }
.ds-btns { display: flex; gap: 12px; flex-wrap: wrap; }
.btn-service {
  background: #fff; color: var(--coral-dark); border: 1.5px solid #ffd0cb;
  font-size: 16px; letter-spacing: .02em; box-shadow: var(--shadow-sm);
}
.btn-service:hover { transform: translateY(-2px); box-shadow: var(--shadow-coral); border-color: transparent; }
.btn-service.copied { background: linear-gradient(135deg, var(--teal-dark), #16b98a); color: #fff; border-color: transparent; box-shadow: 0 14px 34px rgba(34, 168, 158, .4); }

/* ---------- 安装教程 Tabs ---------- */
.tabs { max-width: 860px; margin-inline: auto; }
.tab-buttons { display: flex; gap: 10px; justify-content: center; margin-bottom: 30px; flex-wrap: wrap; }
.tab-btn {
  padding: 12px 24px; border-radius: 999px; border: 1.5px solid var(--line);
  background: #fff; color: var(--ink-soft); font-family: inherit; font-size: 15px; font-weight: 700;
  cursor: pointer; transition: all .2s ease;
}
.tab-btn.active { background: var(--ink); color: #fff; border-color: var(--ink); box-shadow: var(--shadow-md); }
.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fadeUp .4s ease; }
.steps { display: grid; gap: 16px; }
.steps li {
  display: grid; grid-template-columns: 48px 1fr; gap: 18px; align-items: start;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px 24px; box-shadow: var(--shadow-sm);
}
.step-no {
  width: 48px; height: 48px; border-radius: 14px; display: grid; place-items: center;
  background: var(--grad); color: #fff; font-weight: 900; font-size: 20px;
}
.steps h4 { font-size: 17px; margin-bottom: 4px; }
.steps p { margin: 0; color: var(--ink-soft); font-size: 15px; }

/* ---------- 联系客服 ---------- */
.support { background: linear-gradient(135deg, #fff5f4 0%, #eefbf9 100%) !important; }
.support-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; max-width: 780px; margin-inline: auto; }
.service-card {
  display: flex; align-items: center; gap: 16px;
  background: #fff; border-radius: var(--radius-lg); padding: 22px 24px;
  box-shadow: var(--shadow-md); border: 1px solid #fff;
}
.service-avatar {
  flex: none; width: 58px; height: 58px; border-radius: 16px; display: grid; place-items: center;
  color: #fff; font-size: 24px; font-weight: 900; background: var(--grad-btn);
}
.service-avatar.alt { background: linear-gradient(135deg, var(--teal), var(--teal-dark)); }
.service-info { display: flex; flex-direction: column; margin-right: auto; min-width: 0; }
.service-label { font-size: 13px; color: var(--muted); font-weight: 600; }
.service-id { font-size: 22px; font-weight: 900; letter-spacing: .02em; color: var(--ink); word-break: break-all; }
.btn-copy { flex: none; }
.btn-copy.copied { background: linear-gradient(135deg, #22a89e, #16b98a); box-shadow: 0 14px 34px rgba(34, 168, 158, .4); }
.support-note { text-align: center; margin-top: 28px; color: var(--ink-soft); font-size: 14px; }

/* ---------- FAQ ---------- */
.faq-list { display: grid; gap: 12px; }
.faq-item {
  background: #fff; border: 1px solid var(--line); border-radius: 16px;
  padding: 0 22px; box-shadow: var(--shadow-sm); overflow: hidden;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.faq-item[open] { border-color: #ffd9d6; box-shadow: var(--shadow-md); }
.faq-item summary {
  list-style: none; cursor: pointer; display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 20px 0; font-weight: 700; font-size: 16px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-ico { position: relative; flex: none; width: 22px; height: 22px; }
.faq-ico::before, .faq-ico::after {
  content: ""; position: absolute; background: var(--coral); border-radius: 2px;
  top: 50%; left: 50%; transform: translate(-50%, -50%);
  transition: transform .25s ease, opacity .25s ease;
}
.faq-ico::before { width: 14px; height: 2.5px; }
.faq-ico::after { width: 2.5px; height: 14px; }
.faq-item[open] .faq-ico::after { transform: translate(-50%, -50%) rotate(90deg); opacity: 0; }
.faq-body { padding: 0 0 20px; color: var(--ink-soft); font-size: 15px; }
.faq-body p { margin: 0; }

.notice {
  margin-top: 34px; padding: 24px 26px; border-radius: var(--radius);
  background: #fff8ee; border: 1px solid #ffe6bf; color: #8a6a2f;
}
.notice h4 { margin-bottom: 8px; color: #b9791f; }
.notice p { margin: 0; font-size: 14px; line-height: 1.8; }

/* ---------- 页脚 ---------- */
.site-footer { background: #12151c; color: #c3cad6; padding-top: 60px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1.2fr; gap: 40px; padding-bottom: 44px; }
.footer-brand .brand-text { color: #fff; }
.footer-brand p { margin-top: 16px; font-size: 14px; color: #9aa4b2; max-width: 320px; }
.site-footer h4 { color: #fff; font-size: 15px; margin-bottom: 16px; letter-spacing: .04em; }
.footer-links { display: flex; flex-direction: column; gap: 10px; }
.footer-links a { font-size: 14px; color: #9aa4b2; transition: color .2s ease; }
.footer-links a:hover { color: var(--coral); }
.footer-contact p { font-size: 14px; color: #9aa4b2; margin-bottom: 10px; }
.footer-contact strong { color: #fff; }
.footer-contact .btn { margin-top: 8px; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, .08); padding: 22px 0; text-align: center; }
.footer-bottom p { margin: 0; font-size: 13px; color: #7f8a99; }
.footer-disclaimer { margin-top: 6px !important; color: #64707f !important; }

/* ---------- 移动端悬浮下载条 ---------- */
.mobile-bar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 90;
  display: none; padding: 10px 14px calc(10px + env(safe-area-inset-bottom));
  background: rgba(255, 255, 255, .92); backdrop-filter: blur(14px);
  border-top: 1px solid var(--line);
  transform: translateY(120%); transition: transform .35s ease;
}
.mobile-bar.show { transform: translateY(0); }
.mobile-bar-inner { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.mobile-bar-info { display: flex; align-items: center; gap: 10px; min-width: 0; }
.mobile-bar-info img { border-radius: 9px; }
.mobile-bar-info div { display: flex; flex-direction: column; line-height: 1.2; }
.mobile-bar-info strong { font-size: 15px; }
.mobile-bar-info span { font-size: 12px; color: var(--muted); }

/* ---------- 返回顶部 ---------- */
.back-top {
  position: fixed; right: 22px; bottom: 96px; z-index: 80;
  width: 46px; height: 46px; border-radius: 50%; border: 0; cursor: pointer;
  background: var(--ink); color: #fff; font-size: 20px; font-weight: 700;
  box-shadow: var(--shadow-md); opacity: 0; visibility: hidden; transform: translateY(12px);
  transition: all .3s ease;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { background: var(--coral); }

/* ---------- 悬浮客服 ---------- */
.float-service {
  position: fixed; right: 22px; bottom: 26px; z-index: 86;
  display: flex; flex-direction: column; align-items: flex-end; gap: 12px;
  pointer-events: none; /* 容器不拦截点击，避免关闭态面板遮挡下方元素 */
}
.fs-toggle {
  position: relative; width: 58px; height: 58px; border-radius: 50%; border: 0; cursor: pointer;
  background: var(--grad-btn); color: #fff; display: grid; place-items: center;
  box-shadow: var(--shadow-coral); transition: transform .2s ease; pointer-events: auto;
}
.fs-toggle:hover { transform: scale(1.07); }
.fs-dot { position: absolute; top: 1px; right: 1px; width: 15px; height: 15px; border-radius: 50%; background: #22c55e; border: 2px solid #fff; box-shadow: 0 0 0 0 rgba(34, 197, 94, .6); animation: pulse 1.8s infinite; }
.fs-panel {
  width: 224px; padding: 16px; border-radius: 18px; background: #fff;
  box-shadow: var(--shadow-lg); border: 1px solid var(--line); pointer-events: auto;
  opacity: 0; visibility: hidden; transform: translateY(10px) scale(.96); transform-origin: bottom right;
  transition: opacity .25s ease, transform .25s ease, visibility .25s;
}
.float-service.open .fs-panel { opacity: 1; visibility: visible; transform: translateY(0) scale(1); }
.fs-title { font-size: 13px; font-weight: 700; color: var(--ink-soft); margin: 0 0 12px; }
.fs-item {
  display: block; width: 100%; margin-bottom: 10px; cursor: pointer; font-family: inherit;
  padding: 12px 14px; border-radius: 12px; border: 1.5px solid #ffd0cb; background: #fff6f5;
  color: var(--coral-dark); font-size: 17px; font-weight: 900; letter-spacing: .02em; transition: all .18s ease;
}
.fs-item:last-child { margin-bottom: 0; }
.fs-item:hover { background: var(--grad-btn); color: #fff; border-color: transparent; }
.fs-item.copied { background: linear-gradient(135deg, var(--teal-dark), #16b98a); color: #fff; border-color: transparent; }

/* ---------- Toast ---------- */
.toast {
  position: fixed; left: 50%; bottom: 90px; z-index: 200;
  transform: translate(-50%, 20px);
  background: rgba(18, 21, 28, .94); color: #fff; padding: 12px 22px;
  border-radius: 999px; font-size: 14px; font-weight: 600;
  box-shadow: var(--shadow-lg); opacity: 0; visibility: hidden;
  transition: all .3s ease; pointer-events: none;
}
.toast.show { opacity: 1; visibility: visible; transform: translate(-50%, 0); }

/* ---------- 滚动动画 ---------- */
[data-animate] { opacity: 0; transform: translateY(26px); transition: opacity .6s ease, transform .6s ease; }
[data-animate].in { opacity: 1; transform: none; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }

/* =========================================================
   响应式 —— 平板
   ========================================================= */
@media (max-width: 980px) {
  .main-nav { display: none; }
  .hero-grid { grid-template-columns: 1fr; gap: 10px; }
  .hero-copy { max-width: 620px; margin-inline: auto; text-align: center; }
  .hero-actions, .hero-trust { justify-content: center; }
  .hero-desc { margin-inline: auto; }
  .hero-visual { height: 500px; margin-top: 8px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

/* =========================================================
   响应式 —— 手机
   ========================================================= */
@media (max-width: 720px) {
  :root { --header-h: 60px; }
  .section { padding: 60px 0; }
  .nav-cta { display: none; }

  /* 汉堡菜单 */
  .nav-toggle {
    display: inline-flex; flex-direction: column; justify-content: center; gap: 5px;
    width: 44px; height: 44px; margin-left: auto; padding: 0 10px;
    background: transparent; border: 0; cursor: pointer;
  }
  .nav-toggle span { height: 2.5px; width: 100%; background: var(--ink); border-radius: 2px; transition: transform .3s ease, opacity .3s ease; }
  .nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7.5px) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7.5px) rotate(-45deg); }

  .main-nav {
    position: fixed; inset: var(--header-h) 0 auto 0; display: flex; flex-direction: column; gap: 2px;
    background: #fff; padding: 14px 22px 26px; margin: 0;
    box-shadow: var(--shadow-md); border-bottom: 1px solid var(--line);
    transform: translateY(-130%); transition: transform .32s ease; z-index: 99;
  }
  .main-nav.open { transform: translateY(0); display: flex; }
  .main-nav a { padding: 14px 10px; font-size: 16px; border-bottom: 1px solid var(--bg-soft); }
  .main-nav a:last-child { border-bottom: 0; }

  /* Hero */
  .hero { padding: 34px 0 96px; }
  .hero-title { font-size: 40px; }
  .hero-visual { height: 430px; }
  .phone { width: 220px; border-width: 7px; }
  .phone-front { transform: translate(48px, 0) rotate(5deg); }
  .phone-back { transform: translate(-72px, 6px) rotate(-7deg) scale(.9); }
  .float-chip { font-size: 11px; padding: 7px 11px; }
  .chip-1 { left: 2%; } .chip-2 { right: 0; } .chip-3 { left: 8%; }
  .hero-wave svg { height: 60px; }

  /* 网格单列 */
  .feature-grid { grid-template-columns: 1fr; gap: 16px; }
  .preview-grid { grid-template-columns: 1fr; gap: 26px; }
  .download-grid { grid-template-columns: 1fr; }
  .support-grid { grid-template-columns: 1fr; }
  .device-card p { min-height: auto; }
  .steps li { grid-template-columns: 40px 1fr; gap: 14px; padding: 18px; }
  .step-no { width: 40px; height: 40px; font-size: 17px; }

  /* 页脚 */
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  body { padding-bottom: 74px; }
  .mobile-bar { display: block; }
  .back-top { display: none; }
  .float-service { right: 14px; bottom: 86px; }
  .fs-toggle { width: 52px; height: 52px; }
  .fs-panel { width: 200px; }
  .toast { bottom: 160px; }

  /* Hero 客服条堆叠 */
  .hero-service { width: 100%; justify-content: center; text-align: center; }

  /* 下载客服横幅堆叠 */
  .download-service { flex-direction: column; align-items: stretch; text-align: center; gap: 14px; }
  .ds-text { margin-right: 0; align-items: center; }
  .ds-btns { justify-content: center; }
  .btn-service { flex: 1; min-width: 150px; }
}

@media (max-width: 400px) {
  .hero-title { font-size: 34px; }
  .hero-visual { height: 380px; }
  .phone { width: 190px; }
  .phone-front { transform: translate(40px, 0) rotate(5deg); }
  .phone-back { transform: translate(-60px, 6px) rotate(-7deg) scale(.9); }
  .service-id { font-size: 18px; }
}

/* ---------- 无障碍：减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
  [data-animate] { opacity: 1; transform: none; }
}