:root{
  --t-display:clamp(2.25rem,1.5rem + 3.2vw,4rem);
  --t-title:clamp(1.75rem,1.3rem + 1.8vw,2.6rem);
  --t-lede:clamp(1.05rem,1rem + 0.45vw,1.3rem);
  --t-subtitle:clamp(1.3rem,1.15rem + 0.7vw,1.75rem);
  --t-heading:1.15rem;
  --t-body:1rem;
  --t-control:0.95rem;
  --t-small:0.875rem;
  --t-fine:0.8125rem;
  --t-micro:0.72rem;

  --bg:#f8fafc;
  --surface:#ffffff;
  --surface-alt:#f9fafb;
  --surface-sunken:#f3f4f6;

  --ink:#1e293b;
  --ink-deep:#0f172a;
  --text:#374151;
  --muted:#5b616b;

  --brand:#6366f1;
  --brand-dark:#4f46e5;
  --brand-deep:#4338ca;
  --brand-wash:#eef2ff;
  --brand-pale:#e0e7ff;
  --brand-mid:#c7d2fe;

  --border:#d1d5db;
  --border-input:#787e88;

  --success:#047857; --success-bg:#ecfdf5; --success-border:#a7f3d0; --success-dot:#10b981;
  --warning:#b45309; --warning-bg:#fffbeb; --warning-border:#fde68a;
  --danger:#b91c1c;  --danger-bg:#fef2f2;  --danger-border:#fecaca;

  --r-xs:4px; --r-sm:6px; --r-md:8px; --r-lg:12px; --r-xl:16px;
  --r-pill:999px; --r-circle:50%;
  --r-button:6px;

  --shadow-btn:0px 1px 2px rgba(16,32,52,0.06);
  --shadow-card:0px 4px 8px -1px rgba(0,0,0,0.10),0px 1px 2px -2px rgba(0,0,0,0.10);
  --shadow-lift:0px 10px 24px -6px rgba(15,23,42,0.14),0px 3px 8px -3px rgba(15,23,42,0.08);
  --shadow-brand:0px 4px 8px -1px rgba(99,102,241,0.20),0px 1px 2px -2px rgba(99,102,241,0.20);

  --sans:'Inter',ui-sans-serif,system-ui,-apple-system,'Segoe UI',sans-serif;
  --mono:'JetBrains Mono',ui-monospace,SFMono-Regular,Menlo,monospace;

  --measure:68ch;
}

*,*::before,*::after{box-sizing:border-box;}
*{margin:0;padding:0;}

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{
  font-family:var(--sans);
  font-size:var(--t-body);
  line-height:1.6;
  color:var(--text);
  background:var(--bg);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  font-variant-numeric:tabular-nums;
}

img,svg{display:block;max-width:100%;}
button,input,select,textarea{font:inherit;color:inherit;}

::selection{background:var(--brand-pale);color:var(--ink-deep);}
:root{accent-color:var(--brand-dark);caret-color:var(--brand-dark);}

*{scrollbar-width:thin;scrollbar-color:var(--border) transparent;}
::-webkit-scrollbar{width:10px;height:10px;}
::-webkit-scrollbar-track{background:transparent;}
::-webkit-scrollbar-thumb{background:var(--border);border-radius:var(--r-pill);border:3px solid var(--bg);}
::-webkit-scrollbar-thumb:hover{background:#9ca3af;}

:focus-visible{
  outline:2px solid var(--brand);
  outline-offset:2px;
  border-radius:var(--r-xs);
}
:focus:not(:focus-visible){outline:none;}

h1,h2,h3,h4{
  color:var(--ink-deep);
  line-height:1.15;
  letter-spacing:-0.025em;
  text-wrap:balance;
  font-weight:700;
}
h1{font-size:var(--t-display);letter-spacing:-0.035em;}
h2{font-size:var(--t-title);letter-spacing:-0.03em;}
h3{font-size:var(--t-heading);letter-spacing:-0.015em;}
h4{font-size:var(--t-control);letter-spacing:-0.01em;}

p{text-wrap:pretty;}
p + p{margin-top:1em;}

a{color:var(--brand-deep);text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px;}
a:hover{text-decoration-thickness:2px;}
a.plain{text-decoration:none;}
a.plain:hover{text-decoration:none;}

strong{font-weight:600;color:var(--ink);}
code,kbd,.mono{font-family:var(--mono);font-size:0.92em;}

.lede{font-size:var(--t-lede);color:var(--muted);max-width:var(--measure);line-height:1.55;}
.small{font-size:var(--t-small);}
.muted{color:var(--muted);}

.wrap{width:100%;max-width:1140px;margin:0 auto;padding:0 24px;}
.wrap-narrow{max-width:760px;}

section{padding:clamp(56px,7vw,104px) 0;}
.section-head{margin-bottom:44px;max-width:var(--measure);}
.section-head p{margin-top:14px;}

.skip{
  position:absolute;left:-9999px;top:0;z-index:100;
  background:var(--surface);color:var(--ink-deep);
  padding:12px 18px;border-radius:var(--r-md);box-shadow:var(--shadow-lift);
  text-decoration:none;font-weight:600;
}
.skip:focus{left:16px;top:16px;}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  font-family:var(--sans);font-size:var(--t-control);font-weight:600;line-height:1;
  padding:11px 20px;border-radius:var(--r-button);border:none;
  cursor:pointer;text-decoration:none;white-space:nowrap;
  transition:background 0.15s,box-shadow 0.15s,transform 0.15s,border-color 0.15s;
}
.btn:hover{text-decoration:none;}
.btn-lg{font-size:var(--t-body);padding:11px 22px;}
.btn-sm{font-size:var(--t-small);padding:9px 14px;}

.btn-primary{background:var(--brand-dark);color:#fff;box-shadow:var(--shadow-btn);}
.btn-primary:hover{background:var(--brand-deep);box-shadow:var(--shadow-brand);transform:translateY(-1px);}
.btn-primary:active{transform:translateY(0);}

.btn-secondary{background:var(--surface);color:var(--ink);border:1px solid var(--border);box-shadow:var(--shadow-btn);}
.btn-secondary:hover{background:var(--surface-alt);border-color:var(--border-input);transform:translateY(-1px);}

.btn-ghost{background:transparent;color:var(--muted);}
.btn-ghost:hover{background:var(--surface-sunken);color:var(--ink);}

.btn[disabled],.btn[aria-disabled="true"]{opacity:0.5;cursor:not-allowed;transform:none;box-shadow:var(--shadow-btn);}

.card{
  background:var(--surface);
  border-radius:var(--r-xl);
  box-shadow:var(--shadow-card);
  padding:28px;
}
.card-tight{padding:22px;}

.badge{
  display:inline-flex;align-items:center;gap:6px;
  font-size:var(--t-micro);font-weight:600;letter-spacing:0.01em;
  padding:4px 10px 4px 8px;border-radius:var(--r-pill);
  background:var(--brand-pale);color:var(--brand-deep);
}
.badge::before{
  content:'';width:6px;height:6px;border-radius:var(--r-circle);
  background:var(--brand);flex-shrink:0;
}
.badge-success{background:var(--success-bg);color:var(--success);}
.badge-success::before{background:var(--success-dot);}

.field{display:flex;flex-direction:column;gap:6px;}
.field label{font-size:var(--t-fine);font-weight:600;color:var(--ink);}
.field input,.field select,.field textarea{
  width:100%;
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:var(--r-md);
  padding:9px 12px;
  font-size:var(--t-control);
  line-height:1.3;
  color:var(--ink);
  box-shadow:var(--shadow-btn);
  transition:border-color 0.15s,box-shadow 0.15s;
}
.field input::placeholder,.field textarea::placeholder{color:var(--muted);}
.field input:focus,.field select:focus,.field textarea:focus{
  border-color:var(--brand);
  box-shadow:0 0 0 3px var(--brand-wash),var(--shadow-btn);
}
.field-row{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;}

.consent{
  display:grid;grid-template-columns:auto minmax(0,1fr);gap:10px;align-items:start;
  font-size:var(--t-fine);line-height:1.5;color:var(--muted);
}
.consent input{
  appearance:none;-webkit-appearance:none;
  width:18px;height:18px;margin-top:1px;flex-shrink:0;
  border:1px solid var(--border);border-radius:var(--r-xs);
  background:var(--surface);cursor:pointer;position:relative;
  transition:background 0.15s,border-color 0.15s;
}
.consent input:checked{background:var(--brand-dark);border-color:var(--brand-dark);}
.consent input:checked::after{
  content:'';position:absolute;left:5px;top:1px;width:5px;height:9px;
  border:solid #fff;border-width:0 2px 2px 0;transform:rotate(45deg);
}

.form-error{
  display:none;
  background:var(--danger-bg);border:1px solid var(--danger-border);
  color:var(--danger);border-radius:var(--r-md);
  padding:10px 12px;font-size:var(--t-small);font-weight:500;
}
.form-error.on{display:block;}

.nav{
  position:sticky;top:0;z-index:50;
  background:color-mix(in srgb,var(--bg) 88%,transparent);
  backdrop-filter:blur(12px);
  border-bottom:1px solid transparent;
  transition:border-color 0.2s,background 0.2s;
}
.nav.scrolled{border-bottom-color:var(--border);background:color-mix(in srgb,var(--bg) 96%,transparent);}
.nav-row{display:flex;align-items:center;gap:20px;height:68px;}
.nav-brand{
  display:inline-flex;align-items:center;gap:9px;white-space:nowrap;
  font-weight:700;font-size:var(--t-body);letter-spacing:-0.03em;
  color:var(--ink-deep);text-decoration:none;margin-right:auto;
}
.nav-brand:hover{text-decoration:none;}
.nav-mark{
  width:26px;height:26px;border-radius:var(--r-sm);
  background:var(--brand-dark);color:#fff;
  display:grid;place-items:center;
  font-size:var(--t-fine);font-weight:700;letter-spacing:0;
  box-shadow:var(--shadow-btn);
}
.nav-links{display:flex;align-items:center;gap:4px;}
.nav-links a{
  color:var(--text);text-decoration:none;
  font-size:var(--t-small);font-weight:500;
  padding:8px 12px;border-radius:var(--r-sm);
  transition:background 0.15s,color 0.15s;
}
.nav-links a:hover{background:var(--surface-sunken);color:var(--ink-deep);text-decoration:none;}
.nav-cta{display:flex;align-items:center;gap:10px;}
.nav-toggle{
  display:none;background:var(--surface);border:1px solid var(--border-input);
  border-radius:var(--r-sm);padding:8px;cursor:pointer;box-shadow:var(--shadow-btn);
}
.nav-signin-drawer{display:none;}

@media (max-width:900px){
  .nav-links{
    display:none;position:absolute;left:16px;right:16px;top:64px;
    flex-direction:column;align-items:stretch;gap:2px;
    background:var(--surface);border-radius:var(--r-lg);
    box-shadow:var(--shadow-lift);padding:10px;
  }
  .nav-links.open{display:flex;}
  .nav-links a{padding:11px 12px;font-size:var(--t-control);}
  .nav-toggle{display:block;}
  .nav-cta .btn-ghost{display:none;}
  .nav-signin-drawer{display:block;border-top:1px solid var(--border);margin-top:6px;padding-top:13px;}
}

.footer{
  background:var(--surface-sunken);
  border-top:1px solid var(--border);
  padding:56px 0 32px;
}
.footer-cols{
  display:grid;
  grid-template-columns:minmax(0,1.6fr) repeat(3,minmax(0,1fr));
  gap:40px 32px;
}
.footer h4{
  font-size:var(--t-micro);font-weight:700;letter-spacing:0.08em;text-transform:uppercase;
  color:var(--muted);margin-bottom:14px;
}
.footer ul{list-style:none;display:flex;flex-direction:column;gap:5px;}
.footer a{color:var(--text);text-decoration:none;font-size:var(--t-small);display:inline-block;padding:4px 0;}
.footer a.nav-brand{display:inline-flex;padding:0;font-size:var(--t-body);color:var(--ink-deep);}
.footer a:hover{color:var(--brand-deep);text-decoration:underline;text-underline-offset:3px;}
.footer a.nav-brand:hover{color:var(--ink-deep);text-decoration:none;}
.footer-base{
  margin-top:40px;padding-top:24px;border-top:1px solid var(--border);
  display:flex;flex-wrap:wrap;gap:12px 24px;align-items:center;
  font-size:var(--t-fine);color:var(--muted);
}
.footer-base .us{margin-left:auto;}

@media (max-width:820px){
  .footer-cols{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (max-width:520px){
  .footer-cols{grid-template-columns:minmax(0,1fr);gap:28px;}
  .footer-base .us{margin-left:0;}
}

.doc-head{border-bottom:1px solid var(--border);background:var(--surface);}
.doc-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;height:68px;}
.doc-nav{display:flex;gap:6px;}
.doc-nav a{color:var(--text);text-decoration:none;font-size:var(--t-small);font-weight:500;padding:7px 11px;border-radius:var(--r-sm);}
.doc-nav a:hover{background:var(--surface-sunken);color:var(--ink-deep);text-decoration:none;}

.doc{padding:56px 0 88px;}
.doc h1{font-size:var(--t-title);margin-bottom:10px;}
.doc .updated{font-size:var(--t-small);color:var(--muted);margin-bottom:40px;}
.doc h2{font-size:var(--t-heading);margin:44px 0 14px;letter-spacing:-0.02em;}
.doc h3{font-size:var(--t-body);margin:28px 0 10px;}
.doc p,.doc li{max-width:var(--measure);}
.doc ul,.doc ol{margin:12px 0 12px 22px;display:flex;flex-direction:column;gap:8px;}
.doc table{
  width:100%;border-collapse:collapse;margin:20px 0;font-size:var(--t-small);
  background:var(--surface);border-radius:var(--r-lg);overflow:hidden;
  box-shadow:var(--shadow-card);
}
.doc th,.doc td{padding:11px 14px;text-align:left;border-bottom:1px solid var(--border);vertical-align:top;}
.doc th{background:var(--surface-alt);font-weight:600;color:var(--ink);font-size:var(--t-fine);}
.doc tr:last-child td{border-bottom:none;}
.doc-note{
  background:var(--surface);border-radius:var(--r-lg);box-shadow:var(--shadow-card);
  padding:18px 20px;margin:24px 0;font-size:var(--t-small);
}

.scroll-x{overflow-x:auto;}