/* ============================================================
   JKWeb — base.css
   Shared reset, layout, glass component, nav, footer, forms.
   Theme colors live in themes.css (per [data-theme]).
   ============================================================ */

/* ---- Reset ---- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { min-height: 100vh; line-height: 1.55; -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, input, textarea, select { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--focus, #79b8ff); outline-offset: 3px; border-radius: 4px; }

/* ---- Shared tokens ---- */
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;
  --font-serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Songti SC", "Noto Serif CJK SC", serif;

  --sp-1: 4px; --sp-2: 8px; --sp-3: 12px; --sp-4: 16px;
  --sp-5: 24px; --sp-6: 32px; --sp-7: 48px; --sp-8: 72px; --sp-9: 112px;

  --radius-card: 20px;
  --radius-control: 12px;
  --maxw: 1140px;
  --nav-h: 64px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

/* ---- Body base (theme paints the background) ---- */
body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg-base);
  position: relative;
  overflow-x: hidden;
}
/* Theme background layers (gradients / textures) attach to these. */
.bg-layer {
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
}
.bg-atmos {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
}

/* ---- Layout ---- */
.wrap { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: var(--sp-5); }
section { position: relative; }
.section-pad { padding-block: var(--sp-9); }
@media (max-width: 720px) { .section-pad { padding-block: var(--sp-8); } }

/* ---- Type scale ---- */
.eyebrow {
  font-size: 12px; letter-spacing: 0.28em; text-transform: uppercase;
  font-weight: 600; color: var(--accent); opacity: 0.9;
}
h1, h2, h3 { line-height: 1.08; letter-spacing: -0.02em; font-weight: 700; color: var(--text-strong); }
.display { font-size: clamp(44px, 8vw, 92px); line-height: 0.98; letter-spacing: -0.035em; }
h2.title { font-size: clamp(28px, 4.5vw, 46px); }
h3 { font-size: clamp(19px, 2.4vw, 23px); letter-spacing: -0.015em; }
.lede { font-size: clamp(17px, 2.1vw, 21px); color: var(--text-dim); max-width: 46ch; }
.muted { color: var(--text-dim); }
p { color: var(--text-dim); }

/* ---- Nav ---- */
.nav {
  position: sticky; top: 0; z-index: 50;
  height: var(--nav-h);
  display: flex; align-items: center;
  background: var(--nav-bg);
  backdrop-filter: blur(16px) saturate(1.3);
  -webkit-backdrop-filter: blur(16px) saturate(1.3);
  border-bottom: 1px solid var(--hairline);
}
.nav .wrap { display: flex; align-items: center; gap: var(--sp-4); width: 100%; }
.brand { font-weight: 700; letter-spacing: -0.02em; font-size: 17px; color: var(--text-strong); display: flex; align-items: center; gap: 8px; }
.brand .dot { width: 9px; height: 9px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 12px var(--accent); }
.nav-links { display: flex; gap: 2px; margin-left: auto; align-items: center; }
.nav-links a {
  font-size: 14px; font-weight: 500; color: var(--text-dim);
  padding: 8px 12px; border-radius: 10px; transition: color .2s var(--ease), background .2s var(--ease);
}
.nav-links a:hover { color: var(--text-strong); background: var(--surface-soft); }
.nav-links a.active { color: var(--text-strong); }
.nav-links a.active::after { content: ""; display: block; height: 2px; margin-top: 5px; border-radius: 2px; background: var(--accent); }
.lang-toggle {
  margin-left: 6px; font-size: 13px; font-weight: 600;
  padding: 7px 12px; border-radius: 999px;
  border: 1px solid var(--hairline); background: var(--surface-soft);
  color: var(--text); cursor: pointer; transition: border-color .2s var(--ease);
}
.lang-toggle:hover { border-color: var(--accent); }
@media (max-width: 640px) {
  .nav-links a:not(.nav-cta) { display: none; }
  .brand .brand-sub { display: none; }
}

/* ---- Glass card (the signature water-droplet frosted surface) ---- */
.glass {
  position: relative;
  background: var(--glass-bg);
  border: 1px solid var(--glass-stroke);
  border-radius: var(--radius-card);
  backdrop-filter: blur(22px) saturate(1.5);
  -webkit-backdrop-filter: blur(22px) saturate(1.5);
  box-shadow: var(--glass-shadow);
  overflow: hidden;
  isolation: isolate;
}
/* top droplet highlight + inner rim light */
.glass::before {
  content: ""; position: absolute; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(130% 90% at 30% -30%, var(--glass-highlight), transparent 55%),
    linear-gradient(180deg, var(--glass-sheen) 0%, transparent 22%);
  mix-blend-mode: var(--glass-blend, screen);
}
/* soft inner stroke to read like glass edge */
.glass::after {
  content: ""; position: absolute; inset: 0; pointer-events: none; border-radius: inherit;
  box-shadow: inset 0 1px 0 var(--glass-rim), inset 0 0 0 1px var(--glass-inner);
}
.glass-pad { padding: var(--sp-5); }
@media (min-width: 721px) { .glass-pad { padding: var(--sp-6); } }

/* Reduced transparency: honor accessibility, solid fallback */
@media (prefers-reduced-transparency: reduce) {
  .glass, .nav { backdrop-filter: none; -webkit-backdrop-filter: none; }
  .glass { background: var(--glass-solid); }
  .glass::before { display: none; }
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 13px 22px; border-radius: var(--radius-control);
  font-weight: 600; font-size: 15px; cursor: pointer;
  border: 1px solid transparent; transition: transform .18s var(--ease), box-shadow .2s var(--ease), background .2s var(--ease);
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: var(--on-accent); box-shadow: 0 8px 26px -10px var(--accent-glow); }
.btn-primary:hover { box-shadow: 0 12px 34px -10px var(--accent-glow); }
.btn-ghost { background: var(--surface-soft); color: var(--text-strong); border-color: var(--hairline); }
.btn-ghost:hover { border-color: var(--accent); }
.btn[disabled], .btn[aria-disabled="true"] { cursor: not-allowed; opacity: 0.62; box-shadow: none; }
.btn .badge-soon { font-size: 11px; font-weight: 700; letter-spacing: 0.06em; padding: 2px 7px; border-radius: 999px; background: var(--surface-soft); border: 1px solid var(--hairline); color: var(--text-dim); }

.btn-row { display: flex; flex-wrap: wrap; gap: var(--sp-3); align-items: center; }

/* Store badge (Apple) rendered inline as glyph + text */
.store-badge { display: inline-flex; align-items: center; gap: 10px; }
.store-badge .apple { width: 22px; height: 22px; fill: currentColor; }

/* ---- Feature grid ---- */
.grid { display: grid; gap: var(--sp-4); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 900px) { .grid-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .grid-3, .grid-2 { grid-template-columns: 1fr; } }

.feature h3 { margin-bottom: 8px; }
.feature .kicker { font-size: 12px; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent); margin-bottom: 14px; display: block; }
.feature p { font-size: 15px; line-height: 1.6; }

/* ---- Hero ---- */
.hero { padding-top: var(--sp-8); padding-bottom: var(--sp-8); }
.hero .eyebrow { margin-bottom: var(--sp-4); }
.hero .lede { margin-top: var(--sp-5); }
.hero .btn-row { margin-top: var(--sp-6); }

/* ---- Section heading block ---- */
.head-block { max-width: 40ch; margin-bottom: var(--sp-6); }
.head-block .eyebrow { margin-bottom: var(--sp-3); }
.head-block p { margin-top: var(--sp-3); }

/* ---- Footer ---- */
.footer { border-top: 1px solid var(--hairline); padding-block: var(--sp-7); margin-top: var(--sp-8); }
.footer .wrap { display: flex; flex-wrap: wrap; gap: var(--sp-5); justify-content: space-between; align-items: flex-start; }
.footer .col h4 { font-size: 13px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-dim); margin-bottom: 12px; font-weight: 700; }
.footer .col a { display: block; font-size: 14px; color: var(--text-dim); padding: 4px 0; }
.footer .col a:hover { color: var(--text-strong); }
.footer .legal { width: 100%; margin-top: var(--sp-5); padding-top: var(--sp-5); border-top: 1px solid var(--hairline); font-size: 13px; color: var(--text-dim); display: flex; flex-wrap: wrap; gap: 6px 16px; align-items: center; }
.footer .legal a:hover { color: var(--text-strong); text-decoration: underline; }
.beian { display: inline-flex; align-items: center; gap: 6px; }

/* ---- Forms (support page) ---- */
.form-grid { display: grid; gap: var(--sp-4); grid-template-columns: 1fr 1fr; }
.form-grid .full { grid-column: 1 / -1; }
@media (max-width: 620px) { .form-grid { grid-template-columns: 1fr; } }
.field label { display: block; font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 7px; }
.field label .req { color: var(--accent); }
.field input, .field textarea {
  width: 100%; padding: 12px 14px; border-radius: var(--radius-control);
  background: var(--input-bg); border: 1px solid var(--hairline); color: var(--text-strong);
  transition: border-color .18s var(--ease), background .18s var(--ease);
}
.field input::placeholder, .field textarea::placeholder { color: var(--text-faint); }
.field input:focus, .field textarea:focus { outline: none; border-color: var(--accent); background: var(--input-bg-focus); }
.field textarea { resize: vertical; min-height: 130px; }
.field .err { display: none; color: var(--danger); font-size: 12.5px; margin-top: 6px; }
.field.invalid .err { display: block; }
.field.invalid input, .field.invalid textarea { border-color: var(--danger); }
.form-note { font-size: 13px; color: var(--text-dim); margin-top: var(--sp-4); line-height: 1.6; }
.contact-line { font-family: var(--font-mono); font-size: 15px; color: var(--text-strong); }

/* ---- Home app cards ---- */
.app-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--sp-5); }
@media (max-width: 860px) { .app-cards { grid-template-columns: 1fr; } }
.app-card { display: flex; flex-direction: column; min-height: 340px; text-decoration: none; transition: transform .25s var(--ease), box-shadow .25s var(--ease); }
.app-card:hover { transform: translateY(-6px); }
.app-card .card-art { height: 156px; position: relative; overflow: hidden; }
.app-card .card-body { padding: var(--sp-5); display: flex; flex-direction: column; gap: 10px; flex: 1; }
.app-card .card-body h3 { color: var(--text-strong); }
.app-card .card-body p { font-size: 14.5px; flex: 1; }
.app-card .go { font-size: 14px; font-weight: 600; color: var(--accent); display: inline-flex; align-items: center; gap: 6px; }

/* ---- i18n visibility (JS sets html lang; default paints ZH) ---- */
/* Elements carry data-zh / data-en; i18n.js swaps text. Long blocks use .only-* classes. */
html:not(.lang-en) .only-en { display: none !important; }
html.lang-en .only-zh { display: none !important; }

/* ---- Utility ---- */
.stack > * + * { margin-top: var(--sp-4); }
.center { text-align: center; }
.pill { display: inline-flex; align-items: center; gap: 7px; font-size: 12.5px; font-weight: 600; padding: 6px 12px; border-radius: 999px; background: var(--surface-soft); border: 1px solid var(--hairline); color: var(--text-dim); }
.divider { height: 1px; background: var(--hairline); border: 0; margin-block: var(--sp-6); }

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
}