:root {
  --bg: #ffffff;
  --surface: #f6f6f9;
  --surface-2: #eeeef3;
  --fg: #16171b;
  --fg-2: #5f6068;
  --fg-3: #8b8c95;
  --line: #e5e5ec;
  --line-strong: #d6d6e0;
  --accent: #0b7c94;
  --accent-fg: #ffffff;
  --accent-wash: rgba(11, 124, 148, 0.09);
  --coral: #c1493f;

  --b1: #fe7f3e;
  --b2: #fd81d8;
  --b3: #6f54f8;
  --b4: #53bffd;

  --topbar-bg: rgba(255, 255, 255, 0.78);
  --shadow-sm: 0 1px 2px rgba(16, 18, 26, 0.05);
  --shadow-md: 0 1px 2px rgba(16, 18, 26, 0.04), 0 10px 28px -14px rgba(16, 18, 26, 0.18);
  --shadow-lg: 0 2px 6px rgba(16, 18, 26, 0.05), 0 32px 64px -28px rgba(16, 18, 26, 0.32);

  --r-sm: 11px;
  --r-md: 18px;
  --r-lg: 28px;
  --r-pill: 999px;

  --maxw: 1120px;
  --gutter: clamp(20px, 5vw, 40px);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d0f16;
    --surface: #161923;
    --surface-2: #1e2230;
    --fg: #f2f2f7;
    --fg-2: #a3a6b3;
    --fg-3: #7c8090;
    --line: #242836;
    --line-strong: #343a4c;
    --accent: #57c8e6;
    --accent-fg: #0d0f16;
    --accent-wash: rgba(87, 200, 230, 0.13);
    --coral: #f0908a;

    --b1: #ff945d;
    --b2: #fea0e2;
    --b3: #8872f9;
    --b4: #72cbfe;

    --topbar-bg: rgba(13, 15, 22, 0.76);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 1px 2px rgba(0, 0, 0, 0.4), 0 12px 32px -16px rgba(0, 0, 0, 0.7);
    --shadow-lg: 0 2px 8px rgba(0, 0, 0, 0.45), 0 36px 72px -32px rgba(0, 0, 0, 0.85);
  }
}


*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui,
               "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  content: "";
  position: fixed;
  inset: 0 0 auto 0;
  height: 3px;
  z-index: 60;
  background: linear-gradient(90deg, var(--b1), var(--b2), var(--b3), var(--b4));
}

img { max-width: 100%; height: auto; }

a {
  color: var(--accent);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}
a:hover { text-decoration-thickness: 2px; }

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

p, li { overflow-wrap: break-word; }

strong { font-weight: 650; }

code, kbd {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.9em;
  padding: 1px 5px;
  border-radius: 5px;
  background: var(--surface-2);
}

hr { display: none; }

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
}
.skip:focus {
  left: 12px;
  top: 12px;
  padding: 10px 16px;
  background: var(--bg);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-sm);
  text-decoration: none;
}


html[data-lang="zh"] [lang="en"],
html[data-lang="en"] [lang="zh"] { display: none; }

html[data-lang] .langswitch button { display: inline-block; }


.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding-inline: var(--gutter);
}

.prose { max-width: 760px; }

main { display: block; }


.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--topbar-bg);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}
.topbar.is-scrolled { border-bottom-color: var(--line); }

.topbar__inner {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 60px;
  padding-top: 3px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-weight: 650;
  font-size: 1.06rem;
  letter-spacing: -0.01em;
  color: var(--fg);
  text-decoration: none;
  margin-right: auto;
}
.brand img {
  width: 28px;
  height: 28px;
  border-radius: 7px;
  flex: none;
}

.topnav {
  display: flex;
  align-items: center;
  gap: 4px;
}
.topnav a {
  padding: 7px 12px;
  border-radius: var(--r-sm);
  color: var(--fg-2);
  font-size: 0.94rem;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
}
.topnav a:hover { color: var(--fg); background: var(--surface); }
.topnav a[aria-current="page"] { color: var(--fg); font-weight: 600; }

@media (max-width: 720px) {
  .topnav { display: none; }
}

.langswitch {
  display: inline-flex;
  padding: 3px;
  gap: 2px;
  background: var(--surface-2);
  border-radius: var(--r-pill);
  flex: none;
}
.langswitch button {
  appearance: none;
  border: 0;
  margin: 0;
  padding: 5px 13px;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--fg-2);
  background: transparent;
  border-radius: var(--r-pill);
  cursor: pointer;
  transition: color 0.15s ease, background-color 0.15s ease;
}
.langswitch button:hover { color: var(--fg); }

html[data-lang="zh"] .langswitch [data-set-lang="zh"],
html[data-lang="en"] .langswitch [data-set-lang="en"] {
  color: var(--fg);
  background: var(--bg);
  box-shadow: var(--shadow-sm);
  cursor: default;
}


h1, h2, h3 {
  color: var(--fg);
  line-height: 1.25;
  letter-spacing: -0.012em;
  text-wrap: balance;
}

h1 {
  font-size: clamp(2rem, 1.4rem + 2.6vw, 3.3rem);
  font-weight: 700;
  letter-spacing: -0.022em;
  line-height: 1.12;
  margin: 0 0 18px;
}

h2 {
  font-size: clamp(1.4rem, 1.2rem + 0.8vw, 1.9rem);
  font-weight: 660;
  margin: 0 0 14px;
}

h3 {
  font-size: 1.1rem;
  font-weight: 640;
  margin: 32px 0 8px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 13px 5px 9px;
  margin: 0 0 22px;
  border-radius: var(--r-pill);
  background: var(--accent-wash);
  color: var(--accent);
  font-size: 0.84rem;
  font-weight: 600;
  letter-spacing: 0.005em;
}
.eyebrow::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: currentColor;
}

.section-kicker {
  display: block;
  margin: 0 0 10px;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.lede {
  font-size: clamp(1.05rem, 1rem + 0.35vw, 1.22rem);
  line-height: 1.65;
  color: var(--fg-2);
  margin: 0 0 26px;
  max-width: 46em;
}

.muted { color: var(--fg-2); }

.small { font-size: 0.92rem; }


section { scroll-margin-top: 88px; }

.band { padding: clamp(56px, 8vw, 96px) 0; }
.band--tint { background: var(--surface); }
.band--tight { padding: clamp(40px, 5vw, 64px) 0; }

.band + .band--tint,
.band--tint + .band { border-top: 1px solid var(--line); }


.hero {
  padding: clamp(48px, 7vw, 92px) 0 clamp(52px, 7vw, 96px);
}

.hero__grid {
  display: grid;
  gap: clamp(36px, 5vw, 64px);
  align-items: center;
}

@media (min-width: 900px) {
  .hero__grid { grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr); }
}

.hero__copy { min-width: 0; }

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 0 0 26px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 24px;
  border-radius: var(--r-pill);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform 0.12s ease, background-color 0.15s ease, border-color 0.15s ease;
}
.btn:active { transform: scale(0.985); }

.btn--primary {
  background: var(--accent);
  color: var(--accent-fg);
}
.btn--primary:hover { filter: brightness(1.08); }

.btn--ghost {
  background: transparent;
  color: var(--fg);
  border-color: var(--line-strong);
}
.btn--ghost:hover { background: var(--surface); border-color: var(--fg-3); }

.trust {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  margin: 0;
  padding: 0;
  list-style: none;
  color: var(--fg-2);
  font-size: 0.94rem;
}
.trust li {
  display: flex;
  align-items: center;
  gap: 7px;
}
.trust svg { width: 17px; height: 17px; flex: none; color: var(--accent); }


.hero__visual {
  display: flex;
  justify-content: center;
  min-width: 0;
}

.device {
  position: relative;
  width: min(310px, 82vw);
  aspect-ratio: 9 / 18.6;
  padding: 11px;
  border-radius: 46px;
  background: linear-gradient(160deg, #d8d8e2, #a8a8b6 40%, #d2d2dc);
  box-shadow: var(--shadow-lg);
  flex: none;
}

@media (prefers-color-scheme: dark) {
  .device { background: linear-gradient(160deg, #3a3f4e, #22262f 40%, #343948); }
}

.device__screen {
  position: relative;
  height: 100%;
  border-radius: 36px;
  overflow: hidden;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
}

.device__screen::before {
  content: "";
  position: absolute;
  top: 11px;
  left: 50%;
  transform: translateX(-50%);
  width: 78px;
  height: 22px;
  border-radius: var(--r-pill);
  background: #0b0c10;
  z-index: 3;
}

.stack {
  position: relative;
  width: 68%;
  aspect-ratio: 3 / 4;
}

.stack__card {
  position: absolute;
  inset: 0;
  border-radius: 15px;
  border: 5px solid #fff;
  background: var(--surface-2);
  box-shadow: 0 10px 30px -12px rgba(16, 18, 26, 0.5);
  overflow: hidden;
}

.stack__card img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 10px;
}

@media (prefers-color-scheme: dark) {
  .stack__card { border-color: #f2f2f4; }
}

.stack__card--3 { transform: rotate(-13deg) translate(-27px, 12px) scale(0.92); }
.stack__card--2 { transform: rotate(10deg) translate(26px, 5px) scale(0.945); }
.stack__card--1 { transform: rotate(-1.5deg); }

.verdict {
  position: absolute;
  top: 30%;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  color: #fff;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1;
  box-shadow: 0 8px 20px -8px rgba(16, 18, 26, 0.6);
  z-index: 2;
}
.verdict--keep { right: 13%; background: #0b7c94; }
.verdict--del  { left: 13%;  background: #c1493f; }

.island {
  position: absolute;
  bottom: 26px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 12px;
  padding: 11px 15px;
  border-radius: var(--r-pill);
  background: rgba(255, 255, 255, 0.62);
  border: 1px solid rgba(255, 255, 255, 0.5);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: 0 8px 24px -12px rgba(16, 18, 26, 0.45);
  z-index: 2;
}
.island i {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--fg-3);
}
.island i:nth-child(2) { background: var(--coral); }
.island i:nth-child(4) { background: var(--accent); }

@media (prefers-color-scheme: dark) {
  .island {
    background: rgba(40, 44, 56, 0.6);
    border-color: rgba(255, 255, 255, 0.14);
  }
}


.cards {
  display: grid;
  gap: 16px;
  grid-template-columns: 1fr;
  margin-top: 36px;
}
@media (min-width: 620px) { .cards { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (min-width: 1000px) { .cards { grid-template-columns: repeat(4, minmax(0, 1fr)); } }

.card {
  padding: 26px 24px 28px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-sm);
}
.card h3 { margin: 16px 0 6px; font-size: 1.05rem; }
.card p { margin: 0; color: var(--fg-2); font-size: 0.97rem; line-height: 1.62; }

.card__icon {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: var(--r-sm);
  background: var(--accent-wash);
  color: var(--accent);
}
.card__icon svg { width: 22px; height: 22px; }


.panel {
  display: grid;
  gap: clamp(28px, 4vw, 52px);
  padding: clamp(28px, 4vw, 46px);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
}
@media (min-width: 860px) {
  .panel { grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr); align-items: start; }
}
.panel p:last-child { margin-bottom: 0; }

.factlist {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}
.factlist li {
  display: flex;
  gap: 13px;
  align-items: baseline;
  padding: 13px 0;
  border-top: 1px solid var(--line);
  font-size: 0.97rem;
}
.factlist li:first-child { border-top: 0; padding-top: 0; }
.factlist b {
  flex: none;
  min-width: 6.4em;
  font-weight: 600;
  color: var(--fg);
}
.factlist span { color: var(--fg-2); }

.badge-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: var(--r-pill);
  background: var(--accent);
  color: var(--accent-fg);
  font-size: 0.92rem;
  font-weight: 650;
}


.doclinks {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  margin: 0;
  padding: 0;
  list-style: none;
}
.doclinks a {
  display: block;
  height: 100%;
  padding: 22px 24px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  text-decoration: none;
  color: var(--fg);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.doclinks a:hover { border-color: var(--accent); transform: translateY(-2px); }
.doclinks strong { display: block; font-size: 1.02rem; font-weight: 640; margin-bottom: 4px; }
.doclinks span { display: block; color: var(--fg-2); font-size: 0.92rem; line-height: 1.55; }


.pagehead {
  padding: clamp(38px, 5.5vw, 64px) 0 clamp(24px, 3vw, 34px);
  border-bottom: 1px solid var(--line);
  margin-bottom: clamp(32px, 4vw, 48px);
}
.pagehead h1 { font-size: clamp(1.85rem, 1.4rem + 1.6vw, 2.6rem); margin-bottom: 10px; }
.pagehead .lede { margin-bottom: 0; }

.back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 22px;
  color: var(--fg-2);
  font-size: 0.92rem;
  text-decoration: none;
}
.back:hover { color: var(--fg); }

.doc h2 {
  font-size: 1.28rem;
  margin: 48px 0 12px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}
.doc > :first-child { margin-top: 0; }
.doc h2:first-of-type { margin-top: 0; }
.doc p { margin: 0 0 16px; }
.doc ul, .doc ol { padding-left: 1.35em; margin: 0 0 16px; }
.doc li { margin-bottom: 9px; }
.doc li::marker { color: var(--fg-3); }

.meta {
  display: grid;
  gap: 7px;
  padding: 20px 22px;
  margin: 0 0 30px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  color: var(--fg-2);
  font-size: 0.93rem;
  line-height: 1.55;
}
.meta div { display: flex; gap: 10px 14px; flex-wrap: wrap; }
.meta dt {
  flex: none;
  min-width: 7.5em;
  margin: 0;
  color: var(--fg-3);
  font-weight: 500;
}
.meta dd {
  flex: 1 1 16em;
  margin: 0;
  min-width: 0;
  color: var(--fg-2);
}
.meta a { color: var(--accent); }

.callout {
  padding: 20px 22px;
  margin: 0 0 26px;
  background: var(--accent-wash);
  border: 1px solid color-mix(in srgb, var(--accent) 28%, transparent);
  border-radius: var(--r-md);
}
.callout > :last-child { margin-bottom: 0; }
.callout--warn {
  background: color-mix(in srgb, var(--coral) 9%, transparent);
  border-color: color-mix(in srgb, var(--coral) 30%, transparent);
}

@supports not (color: color-mix(in srgb, red 10%, transparent)) {
  .callout { border-color: var(--line-strong); }
  .callout--warn { background: var(--surface-2); border-color: var(--line-strong); }
}

details {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  padding: 4px 20px;
  margin-bottom: 10px;
  background: var(--bg);
}
details[open] { background: var(--surface); }
details > summary {
  cursor: pointer;
  font-weight: 600;
  padding: 14px 0;
  list-style: none;
  display: flex;
  align-items: baseline;
  gap: 10px;
}
details > summary::-webkit-details-marker { display: none; }
details > summary::before {
  content: "";
  flex: none;
  width: 7px;
  height: 7px;
  border-right: 2px solid var(--fg-3);
  border-bottom: 2px solid var(--fg-3);
  transform: rotate(-45deg) translateY(-2px);
  transition: transform 0.18s ease;
}
details[open] > summary::before { transform: rotate(45deg) translateY(-1px); }
details > summary + * { margin-top: 0; }
details > :last-child { margin-bottom: 16px; }

.faq-group { margin-bottom: 34px; }

.table-scroll {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  margin: 0 0 22px;
  -webkit-overflow-scrolling: touch;
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.93rem;
  min-width: 520px;
}
th, td {
  padding: 12px 15px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}
tr:last-child td { border-bottom: 0; }
th {
  background: var(--surface);
  font-weight: 620;
  color: var(--fg);
  white-space: nowrap;
}
th:nth-child(1) { width: 24%; }
th:nth-child(2) { width: 26%; }


footer {
  border-top: 1px solid var(--line);
  background: var(--surface);
  padding: clamp(36px, 5vw, 56px) 0 clamp(30px, 4vw, 44px);
  font-size: 0.92rem;
  color: var(--fg-2);
}

main > .prose { padding-bottom: clamp(48px, 7vw, 88px); }

.footer__top {
  display: flex;
  flex-wrap: wrap;
  gap: 22px 40px;
  align-items: flex-start;
  justify-content: space-between;
  padding-bottom: 26px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 650;
  font-size: 1.02rem;
  color: var(--fg);
}
.footer__brand img { width: 30px; height: 30px; border-radius: 8px; }

.footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.footer__nav a { color: var(--fg-2); text-decoration: none; }
.footer__nav a:hover { color: var(--accent); text-decoration: underline; }

.footer__legal p { margin: 0 0 6px; line-height: 1.6; }
.footer__legal p:last-child { margin-bottom: 0; }
.footer__legal .muted a { color: var(--fg-2); }

@media (max-width: 560px) {
  body { font-size: 16px; }
  .btn { width: 100%; }
  .cta-row { flex-direction: column; align-items: stretch; }
  .device { width: min(250px, 66vw); }
}