/* MainVac 官网。左文右图的产品页骨架 + 自己的氛围层：品牌蓝/青双色光斑背景、
   噪点纸面、截图垫渐变底板浮起。零卡片原则不变——修饰只给截图和图标，不给容器。 */
:root {
  color-scheme: light dark;
  --bg: #fcfcfd; --fg: #17171a; --muted: #6d6d76;
  --line: #e6e6ea; --accent: #1f6feb; --accent-2: #0ea5e9; --accent-fg: #fff;
  --glow-a: rgba(31,111,235,.14); --glow-b: rgba(14,165,233,.12);
  --pad-a: #dbeafe; --pad-b: #cffafe;           /* 截图底板渐变 */
  --mark: rgba(56,189,248,.32);                  /* 荧光笔 */
  --chip: rgba(31,111,235,.09);
  --bezel: #1c1c22;                              /* 手机边框 */
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #101014; --fg: #f0f0f3; --muted: #9a9aa2; --line: #2a2a31;
          --accent: #4c8dff; --accent-2: #38bdf8;
          --glow-a: rgba(59,130,246,.16); --glow-b: rgba(14,165,233,.10);
          --pad-a: #16233f; --pad-b: #0e2a38;
          --mark: rgba(56,189,248,.24); --chip: rgba(76,141,255,.13); --bezel: #33333c; }
}
* { box-sizing: border-box; }
h1, h2, h3 { text-wrap: balance; }
p, li { text-wrap: pretty; }
body { margin: 0; background: var(--bg); color: var(--fg);
       font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
             "PingFang TC", "Noto Sans CJK SC", sans-serif;
       -webkit-font-smoothing: antialiased; }
/* 氛围层：两团柔光 + 细噪点。fixed 让长页滚动时纸面稳定。 */
body::before { content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(560px 420px at 12% -4%, var(--glow-a), transparent 68%),
    radial-gradient(640px 480px at 96% 14%, var(--glow-b), transparent 70%),
    radial-gradient(700px 520px at 50% 108%, var(--glow-a), transparent 74%); }
body::after { content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none;
  opacity: .05; mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E"); }
@media (prefers-color-scheme: dark) { body::after { mix-blend-mode: screen; opacity: .04; } }

main, header.site .bar, footer.site { max-width: 680px; margin: 0 auto; padding: 0 24px; }
main.home, header.site .bar, footer.site { max-width: 1080px; }
a { color: var(--accent); }
html { scroll-padding-top: 76px; }

/* 页头：通栏吸顶、半透明磨砂；内容仍对齐 680 窄栏 */
header.site { position: sticky; top: 0; z-index: 10;
              background: color-mix(in srgb, var(--bg) 78%, transparent);
              -webkit-backdrop-filter: saturate(1.6) blur(14px); backdrop-filter: saturate(1.6) blur(14px);
              border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent); }
header.site .bar { display: flex; align-items: center; gap: 18px; min-height: 60px; }
.brand { display: inline-flex; align-items: center; gap: 8px; margin-left: -4px;
         font-weight: 700; font-size: 17px; letter-spacing: -0.01em; color: var(--fg); text-decoration: none; }
.brand img { width: 36px; height: 36px; display: block; }
nav.primary { display: flex; gap: 20px; margin-left: auto; font-size: 14px; }
nav.primary a { color: var(--muted); text-decoration: none; white-space: nowrap; }
nav.primary a:hover { color: var(--fg); }

.lang-menu { position: relative; }
.lang-menu button { display: inline-flex; align-items: center; gap: 2px; height: 32px; padding: 0 6px 0 7px;
                    border: 1px solid transparent; border-radius: 8px; background: none;
                    color: var(--muted); cursor: pointer; font: inherit; }
.lang-menu button:hover, .lang-menu button[aria-expanded="true"] { color: var(--fg); background: var(--chip); }
.lang-menu button svg { width: 18px; height: 18px; }
.lang-menu button .chev { width: 11px; height: 11px; }
.lang-menu .menu { position: absolute; right: 0; top: calc(100% + 6px); min-width: 132px; padding: 5px;
                   background: var(--bg); border: 1px solid var(--line); border-radius: 10px;
                   box-shadow: 0 14px 32px -12px rgba(9,30,66,.35); }
.lang-menu .menu[hidden] { display: none; }
.lang-menu .menu a { display: block; padding: 6px 10px; border-radius: 6px; font-size: 13.5px;
                     color: var(--fg); text-decoration: none; }
.lang-menu .menu a:hover { background: var(--chip); }
.lang-menu .menu a.on { color: var(--accent); font-weight: 600; }

/* 窄屏：导航换到第二行，横向排开 */
@media (max-width: 560px) {
  html { scroll-padding-top: 104px; }
  header.site .bar { flex-wrap: wrap; gap: 0 12px; padding-top: 6px; padding-bottom: 4px; min-height: 0; }
  .lang-menu { margin-left: auto; }
  nav.primary { order: 3; flex-basis: 100%; margin-left: 0; gap: 18px; padding: 4px 0 6px;
                overflow-x: auto; }
}

/* 首屏：左文右图，窄屏上下叠 */
.hero { display: grid; grid-template-columns: 1.25fr 1fr; gap: 56px; align-items: center;
        padding: 56px 0 8px; margin: 0; }
.hero h1 { font-size: clamp(30px, 4vw, 44px); line-height: 1.16; letter-spacing: -0.025em;
           font-weight: 750; margin: 0 0 12px; }
mark { background: linear-gradient(transparent 58%, var(--mark) 58%);
       color: inherit; padding: 0 2px; border-radius: 2px; }
.slogan { font-size: 19px; font-weight: 650; color: var(--accent); margin: 0 0 16px; letter-spacing: -0.005em; }
.lede { font-size: 17px; color: var(--muted); margin: 0 0 28px; max-width: 32em; }
.cta { margin: 0; display: flex; align-items: center; flex-wrap: wrap; gap: 12px 18px; }
.button { display: inline-block; color: var(--accent-fg);
          background: linear-gradient(180deg, color-mix(in srgb, var(--accent) 82%, #fff), var(--accent));
          box-shadow: inset 0 1px 0 rgba(255,255,255,.25), 0 6px 18px -8px var(--accent);
          font-weight: 600; font-size: 15px; padding: 11px 22px; border-radius: 10px;
          text-decoration: none; transition: transform .06s ease; }
.button:active { transform: scale(.97); }
.aside-link { font-size: 14.5px; font-weight: 500; text-decoration: none; }
.req { font-size: 13px; color: var(--muted); margin: 16px 0 0; }
.stores { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.store { display: inline-flex; align-items: center; gap: 9px; height: 46px; padding: 0 16px 0 13px;
         border-radius: 10px; background: #000; color: #fff; text-decoration: none;
         border: 1px solid rgba(255,255,255,.18); transition: transform .06s ease; }
.store:active { transform: scale(.97); }
.store svg { width: 22px; height: 22px; flex: 0 0 22px; }
.store span { display: flex; flex-direction: column; line-height: 1.1; }
.store small { font-size: 10.5px; opacity: .85; }
.store b { font-size: 17px; font-weight: 600; letter-spacing: -0.01em; }
.hero-art { max-width: 380px; justify-self: end; width: 100%; }

/* 插画底板：渐变垫底，插画铺满，手被圆角裁掉 */
.pad { border-radius: 22px; overflow: hidden;
       background: linear-gradient(135deg, var(--pad-a), var(--pad-b)); }
.pad img { display: block; width: 100%; height: auto; }

section { margin-top: 104px; }
section h2 { font-size: clamp(24px, 3vw, 30px); font-weight: 720; letter-spacing: -0.018em;
             margin: 0 0 32px; text-align: center; }
section.narrow { max-width: 632px; margin-left: auto; margin-right: auto; }
section.narrow h2 { margin-bottom: 10px; }
.sub { text-align: center; color: var(--muted); margin: 0 0 26px; font-size: 15px; }

/* 三栏小节：图标 chip + 标题 + 说明，无卡片 */
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 36px; }
.grid3 h3 { font-size: 16.5px; font-weight: 650; margin: 14px 0 6px; }
.grid3 p { font-size: 14.5px; color: var(--muted); margin: 0; }
.ic { width: 40px; height: 40px; border-radius: 11px; background: var(--chip);
      display: grid; place-items: center; color: var(--accent); }
.ic svg { width: 21px; height: 21px; }

/* 功能行：图文左右交替 */
.rows .row { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.rows .row + .row { margin-top: 56px; }
.rows .row .pad { max-width: 320px; width: 100%; justify-self: end; }
.rows .row:nth-of-type(even) .pad { order: 2; justify-self: start; }
.rows .row.wide { grid-template-columns: 1.5fr 1fr; gap: 48px; }
.rows .row.wide .pad { max-width: none; order: 0; padding: clamp(14px, 3vw, 28px); }
.rows .row.wide .pad img { border-radius: 10px;
  box-shadow: 0 22px 44px -18px rgba(9,30,66,.45), 0 3px 10px rgba(9,30,66,.14); }
.copy { max-width: 440px; }
.copy h3 { font-size: clamp(21px, 2.4vw, 26px); font-weight: 720; letter-spacing: -0.015em; margin: 0 0 12px; }
.copy p { font-size: 16px; color: var(--muted); margin: 0; }
.checks { list-style: none; padding: 0; margin: 18px 0 0; }
.checks li { display: flex; gap: 10px; font-size: 15px; margin-top: 10px; }
.checks svg { flex: 0 0 18px; height: 18px; margin-top: 3px; color: var(--accent); }
.checks b { font-weight: 650; }
kbd { font: 12px ui-monospace, SFMono-Regular, Menlo, monospace;
      border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 5px;
      padding: 1px 5px; color: var(--muted); background: var(--bg); }

@media (max-width: 820px) {
  .hero { grid-template-columns: 1fr; gap: 36px; padding-top: 36px; }
  .hero-art { justify-self: center; max-width: 340px; }
  .grid3 { grid-template-columns: 1fr; gap: 28px; }
  .rows .row, .rows .row.wide { grid-template-columns: 1fr; gap: 24px; }
  .rows .row .pad, .rows .row:nth-of-type(even) .pad { order: 0; justify-self: center; max-width: 280px; }
  .rows .row.wide .pad { max-width: none; }
  .copy { max-width: none; }
  .rows .row + .row { margin-top: 56px; }
  section { margin-top: 80px; }
}

/* 定价：一行三项，中列 accent 数字 */
.plans { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.plan { display: flex; flex-direction: column; align-items: flex-start; gap: 0; padding: 16px 18px 18px;
        font: inherit; text-align: left; color: var(--fg); cursor: pointer;
        background: color-mix(in srgb, var(--bg) 70%, transparent);
        border: 1px solid var(--line); border-radius: 14px;
        transition: border-color .15s ease, box-shadow .15s ease; }
.plan:hover { border-color: color-mix(in srgb, var(--fg) 22%, var(--line)); }
.plan[aria-checked="true"] { border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 16%, transparent); }
.plan:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.plan-top { display: flex; align-items: center; justify-content: space-between; width: 100%; }
.plan .cycle { font-size: 13px; font-weight: 600; color: var(--muted); }
.plan[aria-checked="true"] .cycle { color: var(--accent); }
.plan .radio { width: 16px; height: 16px; border-radius: 50%; border: 1.5px solid var(--line);
               transition: border .15s ease; }
.plan[aria-checked="true"] .radio { border: 5px solid var(--accent); }
.plan .price { font-size: 30px; font-weight: 750; letter-spacing: -0.025em; line-height: 1; margin: 14px 0 8px; }
.plan .note { font-size: 13px; color: var(--muted); }
.plan .cycle { display: inline-flex; align-items: center; gap: 7px; }
.plan .save { font-size: 11px; font-weight: 650; line-height: 1; padding: 3px 6px; border-radius: 999px;
              color: #fff; background: var(--accent); }
.plan .desc { font-size: 12.5px; line-height: 1.45; color: var(--muted); margin-top: 14px; padding-top: 12px;
              border-top: 1px solid var(--line); width: 100%; }
@media (max-width: 560px) { .plans { grid-template-columns: 1fr; } }
.plan-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin: 22px 0 0; }
.button.secondary { color: var(--accent); background: transparent; box-shadow: none;
                    border: 1px solid color-mix(in srgb, var(--accent) 55%, transparent); padding: 10px 21px; }
.button.secondary:hover { background: var(--chip); }
.button[aria-disabled="true"] { opacity: .45; pointer-events: none; box-shadow: none; }

.faq details { border-bottom: 1px solid var(--line); padding: 11px 0; }
.faq details:first-of-type { border-top: 1px solid var(--line); }
.faq summary { cursor: pointer; font-weight: 600; font-size: 14.5px; }
.faq p { color: var(--muted); font-size: 14px; margin: 8px 0 2px; }

footer.site { margin-top: 96px; padding-top: 20px; padding-bottom: 44px;
              border-top: 1px solid var(--line); font-size: 12.5px; color: var(--muted); }
footer.site a { color: var(--muted); }
footer.site .links a { margin-right: 14px; }
footer.site p { margin: 10px 0 0; }

article h1 { font-size: 28px; margin: 36px 0 6px; letter-spacing: -0.02em; }
article .updated { color: var(--muted); font-size: 13px; margin-bottom: 26px; }
article h2 { font-size: 17px; margin: 28px 0 6px; }
article p, article li { font-size: 15px; }

/* 推广折扣码：带 ?code= 进站时在定价区提醒并可复制；没有码时一行淡提示 */
.promo { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: 6px 10px;
         margin: 18px auto 0; padding: 10px 14px; border-radius: 12px; font-size: 14px;
         background: var(--chip); color: var(--fg); }
.promo[hidden] { display: none; }
.promo code { font: 600 14px ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: .02em;
              padding: 2px 8px; border-radius: 6px; background: var(--bg); border: 1px dashed var(--accent); }
.promo button { font: inherit; font-size: 13px; font-weight: 600; color: var(--accent); cursor: pointer;
                background: none; border: 0; padding: 2px 4px; }
.promo .promo-how { color: var(--muted); font-size: 13px; flex-basis: 100%; text-align: center; }
.promo-hint { text-align: center; font-size: 13px; color: var(--muted); margin: 14px 0 0; }
.promo-hint[hidden] { display: none; }

/* 开始使用页（/download）：App 内「先在电脑上安装」的落点。页头无导航，语言菜单靠右 */
header.site .brand + .lang-menu { margin-left: auto; }
main.start h1 { font-size: clamp(28px, 4vw, 36px); line-height: 1.2; letter-spacing: -0.022em;
                font-weight: 750; margin: 44px 0 12px; }
main.start .lead { font-size: 16.5px; color: var(--muted); margin: 0 0 8px; }
.steps { list-style: none; padding: 0; margin: 0; counter-reset: step; }
.steps li { counter-increment: step; position: relative; padding: 28px 0 28px 52px;
            border-bottom: 1px solid var(--line); }
.steps li::before { content: counter(step); position: absolute; left: 0; top: 26px;
                    width: 34px; height: 34px; border-radius: 50%; background: var(--chip); color: var(--accent);
                    display: grid; place-items: center; font-weight: 700; font-size: 15px; }
.steps h2 { font-size: 18px; font-weight: 680; margin: 4px 0 10px; letter-spacing: -0.01em; }
.steps p { font-size: 15px; color: var(--muted); margin: 0; }
.steps p b { color: var(--fg); font-weight: 600; }
.steps .cta { margin-top: 14px; }
.steps .req { margin-top: 10px; }
.steps .phone-note { margin-top: 12px; font-size: 14px; }
.steps .stores { margin-top: 18px; }
main.start .store[aria-disabled="true"] { opacity: .45; pointer-events: none; }
main.start .help { font-size: 14px; color: var(--muted); margin: 26px 0 0; }