/* ===== Tokens ===== */
:root {
  color-scheme: dark;
  --bg: #0b0f1e;
  --bg-alt: #0f1426;
  --bg-deep: #080c18;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-strong: rgba(255, 255, 255, 0.07);
  --border: rgba(255, 255, 255, 0.12);
  --text: #eaf0fb;
  --text-muted: #9aa7c0;
  --text-dim: #6f7c99;
  --primary-a: #7c5cff;
  --primary-b: #4f8cff;
  --accent: #ffd24f;
  --danger: #ff6b7a;
  --ok: #3fd6a0;
  --grad: linear-gradient(135deg, var(--primary-a), var(--primary-b));
  --font-body: "PingFang SC", "Microsoft YaHei", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
  --content-width: 74rem;
  /* 契约必需 Token（映射到语义 Token） */
  --color-primary: #4f8cff;
  --color-background: #0b0f1e;
  --color-surface: #141a2f;
  --color-text: #eaf0fb;
  --color-muted-text: #9aa7c0;
  --color-border: rgba(255, 255, 255, 0.12);
  --color-focus: #6ea8ff;
  --font-display: "PingFang SC", "Microsoft YaHei", ui-sans-serif, system-ui, sans-serif;
  --space-unit: 0.25rem;
}

* { box-sizing: border-box; }

html {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body { margin: 0; min-height: 100dvh; }

button, input, select, textarea { font: inherit; }

:focus-visible { outline: 3px solid #6ea8ff; outline-offset: 3px; }
::selection { background: rgba(124, 92, 255, 0.4); }

.skip-link {
  left: 1rem; position: fixed; top: 1rem;
  transform: translateY(-200%); z-index: 100;
  background: var(--bg-alt); color: var(--text);
  padding: 0.6rem 1rem; border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}
.skip-link:focus { transform: translateY(0); }

/* ===== Shared header ===== */
.site-header {
  position: sticky; top: 0; z-index: 80;
  background: rgba(8, 12, 24, 0.82);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--content-width); margin: 0 auto;
  display: flex; align-items: center; gap: 1rem;
  padding: 0.7rem 1.5rem;
}
.brand { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; color: var(--text); }
.brand-logo { width: 2.1rem; height: 2.1rem; object-fit: contain; }
.brand-name { font-weight: 700; font-size: 1.08rem; letter-spacing: 0.02em; }
.brand-name .sub { color: var(--text-dim); font-weight: 400; font-size: 0.78rem; margin-left: 0.35rem; }
.nav-links { display: flex; align-items: center; gap: 1.1rem; margin-left: auto; }
.nav-links a { color: var(--text-muted); text-decoration: none; font-size: 0.92rem; transition: color 0.15s; }
.nav-links a:hover { color: var(--text); }
.nav-cta { display: inline-block; }

/* mobile menu */
.nav-toggle {
  display: none; margin-left: auto; background: none; border: 1px solid var(--border);
  color: var(--text); border-radius: var(--radius-sm); padding: 0.4rem 0.6rem; cursor: pointer;
  line-height: 1;
}
.nav-toggle:hover { background: var(--surface); }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 0.45rem;
  padding: 0.68rem 1.35rem; border-radius: 999px; font-weight: 600; font-size: 0.95rem;
  text-decoration: none; cursor: pointer; border: 1px solid transparent;
  transition: transform 0.15s, box-shadow 0.2s, background 0.2s;
}
.btn-primary { background: var(--grad); color: #0a0f1c; box-shadow: 0 8px 24px rgba(99, 108, 255, 0.35); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 30px rgba(99, 108, 255, 0.45); }
.btn-ghost { background: transparent; color: var(--text); border-color: var(--border); }
.btn-ghost:hover { background: var(--surface); border-color: rgba(255, 255, 255, 0.25); }
.btn-accent { background: var(--accent); color: #17110a; }
.btn-accent:hover { transform: translateY(-2px); }

/* ===== Layout ===== */
main { max-width: 100%; overflow: clip; }
.container { max-width: var(--content-width); margin: 0 auto; padding: 0 1.5rem; }
section.block { padding: 5.5rem 0; }
.section-title { margin: 0; font-size: 2rem; line-height: 1.25; letter-spacing: -0.01em; }
.section-sub { margin: 0.8rem 0 0; color: var(--text-muted); font-size: 1.02rem; line-height: 1.7; }
.sec-head { max-width: 46rem; }
.sec-head.center { margin-inline: auto; text-align: center; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 0.4rem;
  color: var(--primary-b); font-size: 0.82rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; margin-bottom: 0.8rem;
}

/* ===== Hero ===== */
.hero {
  position: relative; padding: 6rem 0 5rem;
  background:
    radial-gradient(900px 460px at 15% 0%, rgba(124, 92, 255, 0.28), transparent 60%),
    radial-gradient(760px 420px at 85% 10%, rgba(79, 140, 255, 0.22), transparent 60%),
    var(--bg-deep);
  border-bottom: 1px solid var(--border);
}
.hero-inner { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 3rem; align-items: center; }
.hero h1 { margin: 0 0 1.1rem; font-size: clamp(1.9rem, 3.6vw, 3.1rem); line-height: 1.18; letter-spacing: -0.02em; }
.hero h1 .hl {
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p.lead { margin: 0 0 2rem; color: var(--text-muted); font-size: 1.08rem; line-height: 1.8; max-width: 34rem; }
.hero-cta { display: flex; gap: 0.9rem; flex-wrap: wrap; }
.hero-note { margin-top: 1.1rem; color: var(--text-dim); font-size: 0.85rem; }

/* hero visual */
.hero-visual { position: relative; }
.fx-card {
  position: relative; background: linear-gradient(160deg, rgba(124, 92, 255, 0.16), rgba(79, 140, 255, 0.08));
  border: 1px solid rgba(255, 255, 255, 0.14); border-radius: var(--radius-lg);
  padding: 1.4rem; backdrop-filter: blur(8px); box-shadow: var(--shadow);
}
.fx-flow { display: flex; align-items: stretch; gap: 0.5rem; }
.fx-step { flex: 1 1 auto; background: rgba(8, 12, 24, 0.6); border: 1px solid var(--border); border-radius: var(--radius-md); padding: 0.75rem 0.7rem; min-width: 4.2rem; }
.fx-step .ico { font-size: 1.25rem; }
.fx-step .t { font-size: 0.82rem; color: var(--text-muted); margin-top: 0.35rem; }
.fx-step b { font-size: 0.88rem; display: block; white-space: nowrap; }
.fx-arrow { align-self: center; color: var(--primary-b); font-size: 1.1rem; font-weight: 700; }
.fx-chip {
  margin-top: 0.8rem; display: inline-block; font-size: 0.76rem; color: var(--accent);
  background: rgba(255, 210, 79, 0.1); border: 1px solid rgba(255, 210, 79, 0.3);
  border-radius: 999px; padding: 0.28rem 0.7rem;
}
.fx-mask { margin-top: 1rem; background: rgba(8, 12, 24, 0.6); border: 1px solid var(--border); border-radius: var(--radius-md); padding: 0.8rem 0.9rem; font-size: 0.86rem; line-height: 1.7; }
.fx-mask .ph { color: var(--primary-b); font-weight: 600; }
.fx-mask .clear { color: var(--text-muted); }

/* ===== Trust bar ===== */
.trust-bar { border-bottom: 1px solid var(--border); background: var(--bg-alt); }
.trust-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; padding: 1.6rem 0; }
.trust-item { display: flex; align-items: center; gap: 0.7rem; }
.trust-item .dot { width: 0.55rem; height: 0.55rem; border-radius: 50%; background: var(--grad); box-shadow: 0 0 10px rgba(124, 92, 255, 0.8); flex: none; }
.trust-item span { font-size: 0.92rem; color: var(--text); }

/* ===== Pain ===== */
.pain-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.2rem; margin-top: 2.4rem; }
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 1.5rem 1.4rem;
}
.card h3 { margin: 0 0 0.5rem; font-size: 1.05rem; }
.card p { margin: 0; color: var(--text-muted); line-height: 1.7; font-size: 0.94rem; }
.card .ico { font-size: 1.5rem; margin-bottom: 0.8rem; display: block; }

/* ===== Steps ===== */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.2rem; margin-top: 2.4rem; counter-reset: step; }
.step-card { position: relative; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 1.6rem 1.4rem 1.4rem; }
.step-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 2rem; height: 2rem; border-radius: 50%; background: var(--grad); color: #0a0f1c;
  font-weight: 700; margin-bottom: 0.9rem;
}
.step-card h3 { margin: 0 0 0.5rem; font-size: 1.08rem; }
.step-card p { margin: 0; color: var(--text-muted); line-height: 1.7; font-size: 0.94rem; }

/* ===== Features ===== */
.feat-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.2rem; margin-top: 2.4rem; }
.feat-card { display: flex; gap: 1rem; align-items: flex-start; }
.feat-ico { flex: none; width: 2.7rem; height: 2.7rem; border-radius: var(--radius-md); background: var(--grad); display: flex; align-items: center; justify-content: center; font-size: 1.35rem; }
.feat-card h3 { margin: 0 0 0.35rem; font-size: 1.05rem; }
.feat-card p { margin: 0; color: var(--text-muted); line-height: 1.7; font-size: 0.93rem; }

/* ===== Security ===== */
.security {
  background:
    radial-gradient(700px 380px at 80% 20%, rgba(124, 92, 255, 0.14), transparent 60%),
    var(--bg-alt);
  border-block: 1px solid var(--border);
}
.sec-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.2rem; margin-top: 2.4rem; }
.sec-big {
  text-align: center; padding: 1.8rem 1.2rem;
}
.sec-big .num { font-size: 2.2rem; font-weight: 800; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.sec-big .lbl { margin-top: 0.5rem; color: var(--text-muted); font-size: 0.9rem; }

/* ===== Scenarios / versions ===== */
.pill-grid { display: flex; flex-wrap: wrap; gap: 0.7rem; margin-top: 1.6rem; }
.pill {
  padding: 0.5rem 1rem; border-radius: 999px; background: var(--surface); border: 1px solid var(--border);
  color: var(--text); font-size: 0.92rem;
}
.version-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.2rem; margin-top: 2.4rem; }
.version-card { display: flex; flex-direction: column; }
.version-card .name { font-size: 1.15rem; font-weight: 700; }
.version-card .price { margin: 0.4rem 0 1rem; color: var(--text-muted); font-size: 0.95rem; }
.version-card .price b { color: var(--text); font-size: 1.6rem; }
.version-card ul { margin: 0 0 1.4rem; padding: 0; list-style: none; }
.version-card li { color: var(--text-muted); font-size: 0.93rem; padding: 0.35rem 0; padding-left: 1.3rem; position: relative; }
.version-card li::before { content: "✓"; position: absolute; left: 0; color: var(--ok); font-weight: 700; }
.version-card .btn { margin-top: auto; align-self: flex-start; }
.version-highlight { border-color: rgba(124, 92, 255, 0.5); background: linear-gradient(170deg, rgba(124, 92, 255, 0.1), var(--surface)); }

/* ===== FAQ ===== */
.faq-list { max-width: 46rem; margin: 2.2rem auto 0; }
.faq-item { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-md); margin-bottom: 0.7rem; overflow: hidden; }
.faq-item summary { cursor: pointer; padding: 1rem 1.2rem; font-weight: 600; font-size: 0.98rem; list-style: none; display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 1.3rem; color: var(--primary-b); transition: transform 0.2s; }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item .a { padding: 0 1.2rem 1.1rem; color: var(--text-muted); line-height: 1.75; font-size: 0.94rem; }

/* ===== Footer ===== */
.site-footer { border-top: 1px solid var(--border); background: var(--bg-deep); padding: 3rem 0 2.2rem; }
.footer-inner { display: flex; justify-content: space-between; gap: 2rem; flex-wrap: wrap; }
.footer-brand .brand-name { font-size: 1rem; }
.footer-sub { margin-top: 0.4rem; color: var(--text-dim); font-size: 0.85rem; line-height: 1.6; }
.footer-contact { text-align: right; }
.footer-contact a { color: var(--text-muted); text-decoration: none; display: block; margin: 0.25rem 0; font-size: 0.92rem; }
.footer-contact a:hover { color: var(--text); }
.footer-copy { margin-top: 2rem; padding-top: 1.2rem; border-top: 1px solid var(--border); color: var(--text-dim); font-size: 0.8rem; display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-visual { order: -1; }
  .trust-grid, .sec-grid { grid-template-columns: repeat(2, 1fr); }
  .pain-grid, .steps, .feat-grid { grid-template-columns: 1fr; }
  .version-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .nav-links { display: none; flex-direction: column; align-items: flex-start; gap: 0.8rem; padding: 0.8rem 1.5rem 1.1rem; }
  .nav-links.open { display: flex; }
  .nav-toggle { display: inline-flex; }
  .nav-links { position: absolute; top: 100%; left: 0; right: 0; background: rgba(8, 12, 24, 0.97); border-bottom: 1px solid var(--border); }
  section.block { padding: 3.5rem 0; }
  .hero { padding: 3.5rem 0 3rem; }
  .trust-item span { font-size: 0.85rem; }
  .fx-flow { flex-direction: column; }
  .fx-arrow { transform: rotate(90deg); align-self: center; }
}

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