/* ============================================================
   Smart Dark Toggle — site styles
   Dark-first aesthetic (the product is a dark-mode tool).
   Zero framework, zero external dependency.
   ============================================================ */

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

:root {
  --bg: #0b0d10;
  --bg-elev: #14171c;
  --bg-elev-2: #1b1f26;
  --fg: #e9ecf1;
  --fg-dim: #9aa3b0;
  --fg-faint: #6b7280;
  --accent: #8ab4ff;
  --accent-soft: color-mix(in srgb, var(--accent) 16%, transparent);
  --hairline: color-mix(in srgb, #ffffff 9%, transparent);
  --hairline-strong: color-mix(in srgb, #ffffff 16%, transparent);
  --radius: 14px;
  --radius-sm: 9px;
  --maxw: 860px;
  --space: 20px;
  --shadow: 0 1px 0 color-mix(in srgb, #ffffff 6%, transparent) inset,
            0 20px 60px -30px rgba(0, 0, 0, 0.9);
}

html {
  height: 100%;
}

body {
  margin: 0;
  min-height: 100%;
  background:
    radial-gradient(1200px 600px at 50% -10%, color-mix(in srgb, var(--accent) 8%, transparent), transparent 60%),
    var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ── language switching (JS toggles .lang-zh / .lang-en on <body>) ── */
/* Before JS runs (no lang class yet) hide both to avoid a flash of both. */
body:not(.lang-zh, .lang-en) :is(.l-zh, .l-en) {
  display: none;
}
body.lang-zh .l-en,
body.lang-en .l-zh {
  display: none;
}
/* block-level dual elements (paragraphs / list items) that carry the class directly */
body.lang-zh p.l-en,
body.lang-en p.l-zh,
body.lang-zh li.l-en,
body.lang-en li.l-zh,
body.lang-zh div.l-en,
body.lang-en div.l-zh {
  display: none;
}

a {
  color: var(--accent);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ── top bar ── */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  background: color-mix(in srgb, var(--bg) 72%, transparent);
  border-bottom: 1px solid var(--hairline);
}
.topbar-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 650;
  font-size: 0.98rem;
  color: var(--fg);
}
.brand svg {
  width: 26px;
  height: 26px;
  color: var(--accent);
  flex: none;
}
.spacer {
  flex: 1;
}
.navlink {
  color: var(--fg-dim);
  font-size: 0.92rem;
}
.navlink:hover {
  color: var(--fg);
  text-decoration: none;
}
.lang-toggle {
  min-width: 40px;
  padding: 5px 11px;
  font: inherit;
  font-size: 0.85rem;
  color: var(--fg-dim);
  background: color-mix(in srgb, #ffffff 6%, transparent);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  cursor: pointer;
}
.lang-toggle:hover {
  color: var(--fg);
  border-color: var(--hairline-strong);
}

/* ── hero ── */
.hero {
  text-align: center;
  padding: 84px 24px 56px;
}
.hero .app-icon {
  width: 96px;
  height: 96px;
  color: var(--accent);
  filter: drop-shadow(0 10px 30px color-mix(in srgb, var(--accent) 35%, transparent));
}
.hero h1 {
  margin: 22px 0 10px;
  font-size: 2.6rem;
  line-height: 1.15;
  font-weight: 720;
  letter-spacing: -0.02em;
}
.hero .subtitle {
  margin: 0 auto;
  max-width: 620px;
  font-size: 1.18rem;
  color: var(--fg-dim);
}

/* ── App Store button (disabled placeholder) ── */
.cta {
  margin-top: 30px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}
.appstore-btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 12px 22px;
  border-radius: 12px;
  border: 1px solid var(--hairline-strong);
  background: linear-gradient(180deg, var(--bg-elev-2), var(--bg-elev));
  color: var(--fg-faint);
  font-weight: 600;
  cursor: not-allowed;
  opacity: 0.72;
  user-select: none;
}
.appstore-btn svg {
  width: 26px;
  height: 26px;
  flex: none;
}
.appstore-btn .btn-label {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  line-height: 1.2;
  text-align: left;
}
.appstore-btn .btn-small {
  font-size: 0.7rem;
  color: var(--fg-faint);
}
.appstore-btn .btn-big {
  font-size: 1.05rem;
  color: var(--fg-dim);
}
.coming-soon {
  font-size: 0.85rem;
  color: var(--fg-faint);
}

/* ── sections ── */
section.block {
  padding: 46px 0;
  border-top: 1px solid var(--hairline);
}
section.block h2 {
  margin: 0 0 8px;
  font-size: 1.6rem;
  font-weight: 680;
  letter-spacing: -0.01em;
}
section.block .lede {
  margin: 0 0 28px;
  color: var(--fg-dim);
  font-size: 1.05rem;
}

/* three-state cards */
.modes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.mode-card {
  padding: 20px 18px;
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  background: var(--bg-elev);
  box-shadow: var(--shadow);
}
.mode-card .mode-name {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 660;
  font-size: 1.12rem;
  margin-bottom: 6px;
}
.mode-card .mode-name .dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex: none;
}
.mode-card.on .dot   { background: #5bd08a; }
.mode-card.auto .dot { background: var(--accent); }
.mode-card.off .dot  { background: var(--fg-faint); }
.mode-card p {
  margin: 0;
  color: var(--fg-dim);
  font-size: 0.98rem;
}
.per-site-note {
  margin: 18px 0 0;
  color: var(--fg-faint);
  font-size: 0.95rem;
}

/* engine feature grid */
.features {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.feature {
  padding: 22px 20px;
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  background: var(--bg-elev);
}
.feature .ficon {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-soft);
  color: var(--accent);
  margin-bottom: 12px;
}
.feature .ficon svg {
  width: 20px;
  height: 20px;
}
.feature h3 {
  margin: 0 0 6px;
  font-size: 1.08rem;
  font-weight: 640;
}
.feature p {
  margin: 0;
  color: var(--fg-dim);
  font-size: 0.98rem;
}

/* privacy block */
.privacy-block {
  padding: 30px 26px;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--radius);
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--accent) 6%, transparent), transparent),
    var(--bg-elev);
}
.privacy-block .shield {
  width: 40px;
  height: 40px;
  color: var(--accent);
  margin-bottom: 12px;
}
.privacy-block h2 {
  margin: 0 0 12px;
}
.privacy-block ul {
  margin: 0;
  padding-left: 1.25em;
}
.privacy-block li {
  margin-bottom: 8px;
  color: var(--fg-dim);
}
.privacy-block li strong {
  color: var(--fg);
}

/* ── footer ── */
footer {
  border-top: 1px solid var(--hairline);
  padding: 34px 0 48px;
  color: var(--fg-faint);
  font-size: 0.92rem;
}
footer .foot-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  align-items: center;
}
footer a {
  color: var(--fg-dim);
}
footer .dev {
  width: 100%;
  margin-top: 4px;
  color: var(--fg-faint);
}

/* ── privacy policy document page ── */
.doc {
  padding: 40px 0 60px;
}
.doc h1 {
  font-size: 2rem;
  margin: 0 0 6px;
  letter-spacing: -0.015em;
}
.doc .effective {
  color: var(--fg-faint);
  font-size: 0.95rem;
  margin: 0 0 32px;
}
.doc h2 {
  font-size: 1.2rem;
  font-weight: 660;
  margin: 34px 0 8px;
}
.doc p,
.doc li {
  color: var(--fg-dim);
}
.doc ul {
  padding-left: 1.3em;
}
.doc li {
  margin-bottom: 6px;
}
.doc .meta-row {
  margin: 2px 0;
}
.doc strong {
  color: var(--fg);
  font-weight: 620;
}

/* ── responsive ── */
@media (max-width: 720px) {
  body { font-size: 16px; }
  .hero { padding: 60px 20px 44px; }
  .hero h1 { font-size: 2.1rem; }
  .modes { grid-template-columns: 1fr; }
  .features { grid-template-columns: 1fr; }
}
