/* ══════════════════════════════════════════════════════════════════════
   base.css — API Design System
   Shared tokens, nav, buttons, sections, grid, terminal, responsive.
   Every page links this first, then its page-specific CSS.
   ══════════════════════════════════════════════════════════════════════ */

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

/* ── Tokens ─────────────────────────────────────────────────────────── */
:root{
  --bg:#FAFAF9;--surface:#FFF;--surface-alt:#F4F4F5;
  --text:#09090B;--text-2:#52525B;--text-3:#71717A;
  --border:#E4E4E7;--ink:#09090B;
  --green:#15803D;--blue:#2563EB;--amber:#B45309;--red:#DC2626;
}
html.dark{
  --bg:#09090B;--surface:#18181B;--surface-alt:#18181B;
  --text:#FAFAF9;--text-2:#A1A1AA;--text-3:#71717A;
  --border:#27272A;--ink:#FAFAF9;
  --green:#4ADE80;--blue:#60A5FA;--amber:#FBBF24;--red:#F87171;
}

/* ── Base ───────────────────────────────────────────────────────────── */
html{scroll-behavior:smooth}
body{font-family:'Inter',system-ui,sans-serif;color:var(--text);background:var(--bg);
  -webkit-font-smoothing:antialiased;overflow-x:hidden}
a{color:inherit;text-decoration:none}
code{font-family:'JetBrains Mono',monospace;font-size:.85em;
  padding:2px 6px;border:1px solid var(--border);background:var(--surface-alt)}

/* ── Grid background (line grid, 48px) ──────────────────────────────── */
.grid-bg{position:fixed;inset:0;pointer-events:none;z-index:0;
  background-image:
    linear-gradient(var(--border) 1px,transparent 1px),
    linear-gradient(90deg,var(--border) 1px,transparent 1px);
  background-size:48px 48px;opacity:.22}
html.dark .grid-bg{opacity:.10}

/* ── Nav (full-width) ───────────────────────────────────────────────── */
nav{position:sticky;top:0;z-index:100;width:100%;
  background:color-mix(in srgb,var(--bg) 85%,transparent);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px)}
.nav-inner{width:100%;padding:0 48px;height:48px;
  display:flex;align-items:center;justify-content:space-between}
.logo{font-family:'JetBrains Mono',monospace;font-weight:500;font-size:14px;
  letter-spacing:-0.3px;display:flex;align-items:center;gap:8px;text-decoration:none}
.logo-dot{width:6px;height:6px;background:var(--text);display:inline-block}
.nav-links{display:flex;gap:28px}
.nav-links a{font-family:'JetBrains Mono',monospace;font-size:12px;color:var(--text-3);
  text-decoration:none;transition:color .15s;letter-spacing:0.5px}
.nav-links a:hover,.nav-links a.active{color:var(--text)}
.nav-right{display:flex;align-items:center;gap:12px}
.theme-toggle{background:none;border:none;padding:6px;cursor:pointer;
  color:var(--text-3);display:flex;align-items:center;transition:color .15s}
.theme-toggle:hover{color:var(--text)}
.theme-toggle .icon-sun{display:none}
.theme-toggle .icon-moon{display:block}
html.dark .theme-toggle .icon-sun{display:block}
html.dark .theme-toggle .icon-moon{display:none}
.mobile-toggle{display:none;background:none;border:none;color:var(--text-3);cursor:pointer;padding:4px}

/* ── Buttons ────────────────────────────────────────────────────────── */
.btn{font-size:13px;font-weight:500;padding:10px 24px;border:1px solid var(--border);
  display:inline-flex;align-items:center;gap:8px;transition:all .15s;
  color:var(--text-2);cursor:pointer;text-decoration:none}
.btn:hover{border-color:var(--text-3);color:var(--text)}
.btn--primary{background:var(--ink);border-color:var(--ink);color:var(--bg);font-weight:600}
.btn--primary:hover{opacity:.85;color:var(--bg)}
.btn--ghost{background:transparent}

/* ── Sections ───────────────────────────────────────────────────────── */
.sec{position:relative;z-index:1;width:100%;padding:96px 0;background:var(--bg);
  opacity:0;transform:translateY(20px);transition:opacity .7s ease,transform .7s ease}
.sec+.sec{margin-top:1px}
.sec.visible{opacity:1;transform:none}
.hero+.sec{margin-top:1px}
.inner{max-width:1104px;margin:0 auto;padding:0 48px}
.sec-label{font-family:'JetBrains Mono',monospace;font-size:10px;letter-spacing:2px;
  color:var(--text-3);font-weight:500;text-transform:uppercase;margin-bottom:12px}
.sec-h{font-size:28px;font-weight:700;letter-spacing:-0.8px;line-height:1.2;margin-bottom:12px}
.sec-sub{font-size:15px;color:var(--text-2);line-height:1.7;margin-bottom:48px;max-width:520px}

/* ── Terminal ───────────────────────────────────────────────────────── */
.term{border:1px solid var(--border);background:var(--surface);overflow:hidden}
.term-bar{display:flex;align-items:center;padding:10px 16px;
  border-bottom:1px solid var(--border);gap:10px;background:var(--surface-alt)}
.term-dots{display:flex;gap:5px}
.term-dots span,.term-dots i{width:8px;height:8px;background:var(--border);
  display:block;font-style:normal}
html.dark .term-dots span,html.dark .term-dots i{background:var(--text-3)}
.term-title{font-family:'JetBrains Mono',monospace;font-size:10px;color:var(--text-3);
  flex:1;text-align:center;letter-spacing:1px}
.term-body{padding:18px 20px;font-family:'JetBrains Mono',monospace;font-size:12px;
  line-height:1.8;white-space:pre;overflow-x:auto;color:var(--text-2);margin:0}

/* ── Card grid ──────────────────────────────────────────────────────── */
.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;
  background:var(--border);border:1px solid var(--border);overflow:hidden}
.card-grid>*{background:var(--bg);padding:24px;transition:background .15s}
.card-grid>*:hover{background:var(--surface-alt)}

/* ── Mode switch ────────────────────────────────────────────────────── */
.mode-switch{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);z-index:200;
  display:flex;background:color-mix(in srgb,var(--bg) 90%,transparent);
  border:1px solid var(--border);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px)}
.mode-switch button{font-family:'JetBrains Mono',monospace;font-size:11px;
  letter-spacing:1px;padding:10px 20px;border:none;background:none;
  color:var(--text-3);cursor:pointer;display:flex;align-items:center;gap:8px;transition:color .15s}
.mode-switch button.active{color:var(--text)}
.mode-switch button+button{border-left:1px solid var(--border)}
.dot{width:6px;height:6px;border:1px solid var(--text-3);display:inline-block}
.mode-switch button.active .dot{background:var(--text);border-color:var(--text)}

/* ── Machine view ───────────────────────────────────────────────────── */
.machine-view{display:none;position:relative;z-index:1;background:var(--bg);
  max-width:1104px;margin:0 auto;padding:48px 48px 120px}
.machine-view.active{display:block}
.human-view.hidden{display:none}
.md{background:var(--surface);padding:48px;border:1px solid var(--border);
  font-family:'JetBrains Mono',monospace;font-size:13px;line-height:1.4;
  color:var(--text-2);white-space:pre-wrap;word-break:break-word;position:relative}
.md .h1{color:var(--text);font-weight:700;font-size:16px;display:block;margin-top:20px}
.md .h1:first-child,.md button+.h1{margin-top:0}
.md .h2{color:var(--text);font-weight:600;font-size:14px;display:block;margin-top:16px}
.md .h3{color:var(--text-3);font-weight:500;display:block;margin-top:12px}
.md .dim{color:var(--text-3)}
.md .link,.md a.link{color:var(--text-2);text-decoration:underline;text-underline-offset:3px}
.md .bq{display:block;color:var(--text-3);padding-left:16px;border-left:1px solid var(--text-3)}
.md .li{display:block;line-height:1.5}
.md .ic{font-size:inherit;background:var(--surface-alt);padding:1px 5px;border:1px solid var(--border)}
.md strong{color:var(--text);font-weight:600}
.md .code-fence{display:block;background:var(--bg);border:1px solid var(--border);
  padding:12px 16px;margin:4px 0;font-size:12px;line-height:1.5;overflow-x:auto}
.md .code-lang{display:block;color:var(--text-3);font-size:10px;margin-bottom:4px;
  text-transform:uppercase;letter-spacing:0.5px}
.md .code-lang:empty{display:none}
.md .tbl{display:table;width:auto;margin:2px 0;font-size:12px;
  border-top:1px solid var(--text-3);border-left:1px solid var(--text-3)}
.md .tbl-h{display:table-row;font-weight:600;color:var(--text);
  border-bottom:1px solid var(--text-3)}
.md .tbl-r{display:table-row}
.md .tbl-c{display:table-cell;padding:3px 12px;white-space:nowrap;
  border-right:1px solid var(--text-3);border-bottom:1px solid var(--text-3)}
.md-copy{position:absolute;top:16px;right:16px;font-family:'JetBrains Mono',monospace;
  font-size:11px;padding:6px 14px;border:1px solid var(--border);background:var(--bg);
  color:var(--text-3);cursor:pointer;transition:all .15s}
.md-copy:hover{color:var(--text);border-color:var(--text-3)}

/* ── Animations ─────────────────────────────────────────────────────── */
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes fadeUp{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:none}}
@keyframes shimmer{0%{background-position:200% center}100%{background-position:-200% center}}
.shimmer{background:linear-gradient(90deg,var(--text) 20%,var(--text-3) 40%,var(--text-3) 60%,var(--text) 80%);
  background-size:200% auto;-webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;animation:shimmer 4s ease-in-out infinite}

/* ── Accessibility ──────────────────────────────────────────────────── */
:focus-visible{outline:2px solid var(--text-3);outline-offset:2px}
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.01ms !important;animation-iteration-count:1 !important;
    transition-duration:.01ms !important;scroll-behavior:auto !important;
  }
}

/* ── Responsive ─────────────────────────────────────────────────────── */
@media(max-width:1024px){
  .card-grid{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:768px){
  .card-grid{grid-template-columns:1fr}
  .inner{padding:0 24px}
  .sec{padding:64px 0}
  .term-body{font-size:11px;padding:14px 16px}
}
@media(max-width:640px){
  .nav-inner{padding:0 16px;height:48px}
  .nav-links{display:none;position:absolute;top:48px;left:0;right:0;
    flex-direction:column;padding:14px 20px;gap:14px;z-index:100;
    border-bottom:1px solid var(--border);
    background:color-mix(in srgb,var(--bg) 95%,transparent);
    backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px)}
  .nav-links.open{display:flex}
  .mobile-toggle{display:block}
  .inner{padding:0 20px}
  .sec{padding:48px 0}
  .mode-switch{bottom:16px}
  .mode-switch button{padding:8px 14px;font-size:10px}
  .nav-right{gap:8px}
  .machine-view{padding:32px 20px 80px}
  .md{padding:24px 20px;font-size:12px}
}
@supports(padding-bottom:env(safe-area-inset-bottom)){
  .mode-switch{bottom:max(16px,env(safe-area-inset-bottom))}
}