/* ═══════════════════════════════════════════════════
   Product Page Shared Design System
   Same tokens as homepage — consistent brand look
   ═══════════════════════════════════════════════════ */

/* ── Design Tokens (mirrors index.html) ── */
:root {
  --gray-0:   #ffffff;
  --gray-50:  #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --gray-900: #0f172a;
  --gray-950: #020617;

  --blue-500: #0f6ff0;
  --blue-600: #0a58ca;
  --blue-700: #0845a0;
  --indigo-500: #6356e5;
  --purple-500: #8b5cf6;
  --cyan-400:  #22d3ee;
  --green-500: #10b981;

  /* Semantic */
  --color-bg:            var(--gray-50);
  --color-surface:       var(--gray-0);
  --color-surface-alt:   var(--gray-100);
  --color-border:        var(--gray-200);
  --color-border-strong: var(--gray-300);
  --color-text:          var(--gray-900);
  --color-text-muted:    var(--gray-600);
  --color-text-subtle:   var(--gray-600);
  --color-primary:        var(--blue-500);
  --color-primary-hover:  var(--blue-600);
  --color-primary-active: var(--blue-700);
  --color-primary-soft:   rgba(15,111,240,0.08);
  --color-accent:         var(--indigo-500);

  /* Spacing — 8pt grid */
  --space-1: 4px;   --space-2: 8px;   --space-3: 12px;
  --space-4: 16px;  --space-5: 24px;  --space-6: 32px;
  --space-7: 48px;  --space-8: 64px;  --space-9: 96px;

  /* Type scale */
  --font-hero:    clamp(40px, 5.5vw, 64px);
  --font-h1:      clamp(32px, 4.5vw, 48px);
  --font-h2:      clamp(26px, 3.5vw, 36px);
  --font-h3:      22px;
  --font-body-lg: 18px;
  --font-body:    16px;
  --font-body-sm: 14px;
  --font-label:   13px;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Shadows */
  --shadow-sm:  0 1px 2px rgba(15,23,42,0.06);
  --shadow-md:  0 8px 24px rgba(15,23,42,0.08);
  --shadow-lg:  0 24px 48px rgba(15,23,42,0.12);

  /* Motion */
  --ease-out: cubic-bezier(0.2, 0.8, 0.2, 1);
  --duration-fast: 150ms;
  --duration-base: 200ms;
}

/* Dark mode */
[data-theme="dark"] {
  --color-bg:            var(--gray-950);
  --color-surface:       var(--gray-900);
  --color-surface-alt:   var(--gray-800);
  --color-border:        var(--gray-800);
  --color-border-strong: var(--gray-700);
  --color-text:          var(--gray-50);
  --color-text-muted:    var(--gray-300);
  --color-text-subtle:   var(--gray-400);
  --color-primary-soft:  rgba(15,111,240,0.18);
  --shadow-sm:  0 1px 2px rgba(0,0,0,0.4);
  --shadow-md:  0 6px 18px rgba(0,0,0,0.4);
  --shadow-lg:  0 24px 48px rgba(0,0,0,0.5);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 100%; scroll-behavior: smooth; }
body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
               "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  font-size: var(--font-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
ul { list-style: none; padding: 0; margin: 0; }
img { max-width: 100%; display: block; }

/* Focus */
:focus { outline: none; }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; border-radius: var(--radius-sm); }

/* ── Navigation (same as homepage) ── */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--color-bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--color-border);
}
.nav-inner {
  display: flex; align-items: center; justify-content: center;
  height: 64px; gap: var(--space-5); position: relative;
  max-width: 1200px; margin: 0 auto; padding: 0 var(--space-5);
}
.nav-logo-wrap { flex: 1; display: flex; align-items: center; }
.logo {
  display: inline-flex; align-items: center; gap: var(--space-2);
  font-weight: 700; font-size: 18px; letter-spacing: -0.01em;
  color: var(--color-text);
}
.logo-mark {
  width: 28px; height: 28px; border-radius: 8px;
  background: linear-gradient(135deg, var(--color-primary), var(--purple-500));
  display: inline-flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 800; font-size: 14px;
  box-shadow: var(--shadow-sm);
}

/* Nav links */
.nav-links { display: none; align-items: center; gap: var(--space-6); }
@media (min-width: 860px) { .nav-links { display: flex; } }
.nav-links a {
  font-size: var(--font-body-sm); color: var(--color-text-muted);
  font-weight: 500; padding: 6px 16px; border-radius: 8px;
  transition: all var(--duration-base) var(--ease-out); position: relative;
}
.nav-links a:hover { color: var(--color-text); background: rgba(15,111,240,.06); }
.nav-links a:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.nav-links a.active {
  color: var(--color-primary); background: rgba(15,111,240,.10);
  font-weight: 600; box-shadow: inset 0 1px 0 rgba(15,111,240,.08);
}
.nav-actions { flex: 1; display: flex; align-items: center; justify-content: flex-end; gap: var(--space-3); }

/* Theme toggle */
.theme-toggle {
  display: inline-flex; align-items: center;
  background: var(--color-surface-alt); border: 1px solid var(--color-border);
  border-radius: var(--radius-sm); padding: 4px;
}
.theme-toggle button {
  border: 0; background: transparent; color: var(--color-text-muted);
  width: 32px; height: 28px; border-radius: 4px;
  display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer;
  transition: background var(--duration-fast) var(--ease-out), color var(--duration-fast) var(--ease-out);
}
.theme-toggle button:hover { color: var(--color-text); }
.theme-toggle button:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.theme-toggle button[aria-pressed="true"] { background: var(--color-surface); color: var(--color-text); box-shadow: var(--shadow-sm); }
.theme-toggle svg { width: 16px; height: 16px; }

/* Mobile menu button */
.menu-btn {
  display: flex; align-items: center; justify-content: center;
  border: 0; background: none; cursor: pointer;
  width: 44px; height: 44px; border-radius: var(--radius-sm);
  color: var(--color-text-muted); transition: background var(--duration-fast);
}
.menu-btn:hover, .menu-btn:focus-visible { background: var(--color-surface-alt); }
@media (min-width: 860px) { .menu-btn { display: none; } }
.menu-btn svg { width: 22px; height: 22px; }

/* Mobile menu panel */
.mobile-menu {
  display: none; position: fixed; top: 65px; left: 16px; right: 16px;
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-4);
  box-shadow: var(--shadow-lg); z-index: 100;
  flex-direction: column; gap: var(--space-2);
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  display: block; padding: 12px 16px; border-radius: var(--radius-md);
  font-size: var(--font-body); font-weight: 500; color: var(--color-text);
  transition: background var(--duration-fast);
}
.mobile-menu a:hover, .mobile-menu a:focus-visible { background: var(--color-surface-alt); }
.mobile-menu .btn--primary { text-align: center; margin-top: var(--space-2); }

/* ── Breadcrumb ── */
.product-breadcrumb {
  max-width: 1200px; margin: 0 auto;
  padding: var(--space-3) var(--space-5);
  display: flex; align-items: center; gap: var(--space-2);
  font-size: var(--font-label);
}
.product-breadcrumb a {
  color: var(--color-text-muted); transition: color var(--duration-fast);
  display: inline-flex; align-items: center; gap: var(--space-1);
}
.product-breadcrumb a:hover { color: var(--color-primary); }
.product-breadcrumb .sep {
  color: var(--color-border-strong); font-size: 11px;
}
.product-breadcrumb .back-link {
  padding: 2px 10px; border: 1px solid var(--color-border);
  border-radius: var(--radius-sm); font-weight: 500;
  margin-right: var(--space-2);
}
.product-breadcrumb .back-link:hover {
  border-color: var(--color-primary); background: var(--color-primary-soft);
}
.product-breadcrumb .current { color: var(--color-text); font-weight: 600; }

/* ── Container ── */
.container-product {
  max-width: 1160px; margin: 0 auto; padding: 0 var(--space-5);
}

/* ── Product Hero ── */
.product-hero {
  padding: 120px var(--space-5) var(--space-8);
  position: relative; overflow: hidden;
  background:
    radial-gradient(55% 45% at 50% 0%, var(--color-primary-soft), transparent 70%),
    radial-gradient(35% 35% at 75% 25%, rgba(139,92,246,0.08), transparent 70%),
    radial-gradient(35% 35% at 15% 15%, rgba(34,211,238,0.06), transparent 70%),
    linear-gradient(180deg, var(--color-surface) 0%, var(--color-bg) 100%);
  text-align: center;
}
.product-hero-dark {
  color: #fff;
  background:
    radial-gradient(55% 45% at 50% 0%, rgba(255,255,255,0.06), transparent 70%),
    linear-gradient(160deg, var(--color-primary) 0%, #1a38a8 50%, var(--color-accent) 100%);
}
.product-hero-dark .product-hero-tag {
  background: rgba(255,255,255,0.12); border-color: rgba(255,255,255,0.2); color: rgba(255,255,255,0.85);
}
.product-hero-dark .product-hero-desc { color: rgba(255,255,255,0.75); }
.product-hero-inner { max-width: 900px; margin: 0 auto; position: relative; z-index: 1; }
.product-hero-tag {
  display: inline-flex; align-items: center; gap: var(--space-2);
  padding: 6px var(--space-4); background: var(--color-surface);
  border: 1px solid var(--color-border); border-radius: 999px;
  font-size: var(--font-body-sm); color: var(--color-text-muted);
  box-shadow: var(--shadow-sm); margin-bottom: var(--space-5);
}
.product-hero-tag .dot {
  width: 8px; height: 8px; border-radius: 50%; background: var(--green-500);
  box-shadow: 0 0 0 4px rgba(16,185,129,0.18);
}
.product-hero h1 {
  font-size: var(--font-hero); font-weight: 800; line-height: 1.08;
  letter-spacing: -0.025em; margin-bottom: var(--space-5);
}
.product-hero-dark h1 { color: #fff; }
.product-hero-desc {
  font-size: var(--font-body-lg); color: var(--color-text-muted);
  max-width: 56ch; margin: 0 auto var(--space-6); line-height: 1.7;
}

/* ── Buttons ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: var(--space-2); min-height: 44px; padding: 0 var(--space-5);
  border: 1px solid transparent; border-radius: var(--radius-sm);
  font: inherit; font-size: var(--font-body-sm); font-weight: 600;
  cursor: pointer; white-space: nowrap;
  transition: all var(--duration-fast) var(--ease-out);
}
.btn:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.btn--primary {
  background: var(--color-primary); color: #fff;
  box-shadow: 0 1px 0 rgba(255,255,255,0.15) inset, 0 1px 2px rgba(15,23,42,0.15);
}
.btn--primary:hover { background: var(--color-primary-hover); box-shadow: var(--shadow-md); transform: translateY(-1px); }
.btn--primary:active { background: var(--color-primary-active); transform: translateY(0); }
.btn--outline {
  background: #fff; color: var(--color-text); border-color: var(--color-border);
}
.btn--outline:hover { background: var(--color-primary-soft); color: var(--color-primary); border-color: var(--color-primary); }
.btn:disabled,
.btn[aria-disabled="true"] { opacity: 0.5; cursor: not-allowed; pointer-events: none; }
.btn--lg { min-height: 48px; padding: 0 var(--space-6); font-size: var(--font-body); }

/* ── Section primitives ── */
.product-section { padding: var(--space-8) 0; }
.product-section-alt { background: var(--color-surface); border-top: 1px solid var(--color-border); border-bottom: 1px solid var(--color-border); }
.section-head {
  text-align: center; max-width: 720px; margin: 0 auto var(--space-7);
}
.section-eyebrow {
  font-size: var(--font-label); text-transform: uppercase;
  letter-spacing: 0.1em; font-weight: 700; color: var(--color-primary);
  margin-bottom: var(--space-3);
}
.section-head h2 {
  font-size: var(--font-h1); font-weight: 700; letter-spacing: -0.02em;
  line-height: 1.15; margin-bottom: var(--space-4);
}
.section-desc {
  font-size: var(--font-body-lg); color: var(--color-text-muted);
}

/* ── Card grids ── */
.card-grid-4 {
  display: grid; grid-template-columns: 1fr; gap: var(--space-4);
}
@media (min-width: 600px) { .card-grid-4 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 900px) { .card-grid-4 { grid-template-columns: repeat(4, 1fr); } }

.card-grid-3 {
  display: grid; grid-template-columns: 1fr; gap: var(--space-5);
}
@media (min-width: 760px) { .card-grid-3 { grid-template-columns: repeat(3, 1fr); } }

.card-grid-2 {
  display: grid; grid-template-columns: 1fr; gap: var(--space-4);
}
@media (min-width: 720px) { .card-grid-2 { grid-template-columns: repeat(2, 1fr); } }

.card {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-6);
  transition: transform var(--duration-base) var(--ease-out),
              box-shadow var(--duration-base) var(--ease-out),
              border-color var(--duration-base) var(--ease-out);
}
.card:hover {
  transform: translateY(-4px); box-shadow: var(--shadow-lg);
  border-color: var(--color-border-strong);
}
.card .card-icon {
  width: 44px; height: 44px; border-radius: var(--radius-md);
  background: var(--color-primary-soft); color: var(--color-primary);
  display: inline-flex; align-items: center; justify-content: center;
  margin-bottom: var(--space-4); font-size: 20px;
}
.card .card-icon svg { width: 22px; height: 22px; }
.card h3 { font-size: var(--font-h3); font-weight: 600; margin-bottom: var(--space-2); letter-spacing: -0.01em; }
.card h4 { font-size: 18px; font-weight: 600; margin-bottom: var(--space-2); letter-spacing: -0.01em; }
.card p { color: var(--color-text-muted); font-size: var(--font-body-sm); line-height: 1.7; }

/* ── Flow steps ── */
.flow-row {
  display: grid; grid-template-columns: 1fr; gap: var(--space-4);
}
@media (min-width: 600px) { .flow-row { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 900px) { .flow-row { grid-template-columns: repeat(4, 1fr); } }

.flow-item {
  text-align: center; padding: var(--space-5); background: var(--color-surface);
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
  position: relative; transition: all var(--duration-base) var(--ease-out);
}
.flow-item:hover {
  transform: translateY(-3px); border-color: var(--color-primary); box-shadow: var(--shadow-md);
}
.flow-num {
  width: 40px; height: 40px; background: var(--color-primary); color: #fff;
  border-radius: 50%; display: inline-flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 15px; margin-bottom: var(--space-3);
  box-shadow: 0 6px 16px rgba(15,111,240,0.25);
}
.flow-item h4 { font-size: 17px; font-weight: 600; margin-bottom: var(--space-2); }
.flow-item p { font-size: var(--font-body-sm); color: var(--color-text-muted); line-height: 1.65; }

/* ── CTA ── */
.product-cta {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: #fff; text-align: center; padding: var(--space-8) var(--space-5);
  position: relative; overflow: hidden;
}
.product-cta::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(30% 30% at 20% 90%, rgba(34,211,238,0.25), transparent 70%),
              radial-gradient(30% 30% at 85% 20%, rgba(139,92,246,0.3), transparent 70%);
  pointer-events: none;
}
.product-cta-inner { position: relative; z-index: 1; }
.product-cta h2 {
  font-size: clamp(28px, 4vw, 40px); font-weight: 800;
  letter-spacing: -0.02em; margin-bottom: var(--space-4);
}
.product-cta p {
  opacity: 0.9; max-width: 56ch; margin: 0 auto var(--space-5);
  font-size: var(--font-body-lg);
}
.product-cta .btn--primary { background: #fff; color: var(--color-primary); }
.product-cta .btn--primary:hover { background: #f1f5f9; }

/* ── Footer ── */
.product-footer {
  border-top: 1px solid var(--color-border); background: var(--color-surface);
  padding: var(--space-6) var(--space-5); text-align: center;
  font-size: var(--font-body-sm); color: var(--color-text-subtle);
}

/* ── Stats row ── */
.stats-row {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-4);
}
@media (min-width: 720px) { .stats-row { grid-template-columns: repeat(4, 1fr); } }
.stat-card {
  text-align: center; padding: var(--space-6); background: var(--color-surface);
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
}
.stat-card .stat-value {
  font-size: clamp(28px, 3.5vw, 42px); font-weight: 800; letter-spacing: -0.02em;
  background: linear-gradient(120deg, var(--color-primary), var(--purple-500));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat-card .stat-label {
  font-size: var(--font-body-sm); color: var(--color-text-muted); margin-top: var(--space-2);
}

/* ── Responsive ── */
@media (max-width: 600px) {
  .product-hero { padding: 100px var(--space-4) var(--space-7); }
  .product-section { padding: var(--space-7) 0; }
  .product-hero h1 { font-size: clamp(32px, 10vw, 44px); }
}