:root {
  --bg: #0a0a0f;
  --surface: #12121a;
  --surface-2: #181823;
  --border: #1e1e2e;
  --border-2: #2a2a3e;
  --text: #e4e4ef;
  --text-dim: #8888a0;
  --text-faint: #565670;
  --accent: #6c5ce7;
  --accent-glow: #a29bfe;
  --green: #00b894;
  --amber: #fdcb6e;
  --red: #ff6b6b;
  --blue: #0984e3;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

code, pre, .mono {
  font-family: 'SF Mono', ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.9em;
}

pre {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
  overflow-x: auto;
  font-size: 0.85rem;
}

code {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  font-size: 0.9em;
}

pre code { background: none; border: none; padding: 0; }

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.container-narrow {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Nav */
nav.topnav {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: rgba(10, 10, 15, 0.9);
  backdrop-filter: blur(8px);
  z-index: 100;
}
nav.topnav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
}
.logo {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.5px;
  white-space: nowrap;
}
.logo span { color: var(--accent-glow); }
nav.topnav .nav-links {
  display: flex;
  gap: 24px;
  align-items: center;
  flex-wrap: wrap;
}
nav.topnav .nav-links a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}
nav.topnav .nav-links a:hover,
nav.topnav .nav-links a.active {
  color: var(--text);
}

/* Mode toggle */
.mode-pill {
  display: inline-flex;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px;
  gap: 2px;
}
.mode-pill button {
  border: none;
  background: transparent;
  color: var(--text-dim);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s;
  font-weight: 500;
}
.mode-pill button.active {
  background: var(--accent);
  color: #fff;
}

/* Sticky mode bar on content pages */
.mode-bar {
  position: sticky;
  top: 69px;
  background: rgba(10, 10, 15, 0.92);
  backdrop-filter: blur(8px);
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  z-index: 90;
  display: flex;
  justify-content: center;
}

/* Content sections — for humans / for math mode */
.for-humans { display: block; }
.for-math { display: none; }
body.mode-math .for-humans { display: none; }
body.mode-math .for-math { display: block; }

/* Hero */
.hero {
  padding: 80px 0 60px;
  text-align: center;
}
.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 20px;
  border: 1px solid var(--border);
  color: var(--accent-glow);
  font-size: 0.8rem;
  font-weight: 500;
  margin-bottom: 24px;
  letter-spacing: 0.5px;
}
.hero h1 {
  font-size: clamp(2.2rem, 5.5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 20px;
  letter-spacing: -1.2px;
}
.hero h1 em {
  font-style: normal;
  background: linear-gradient(135deg, var(--accent), var(--accent-glow));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero .lede {
  font-size: 1.15rem;
  color: var(--text-dim);
  max-width: 640px;
  margin: 0 auto 36px;
}
.hero-buttons {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 22px;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.15s;
  cursor: pointer;
  border: none;
  font-family: inherit;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-glow); }
.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-2);
}
.btn-secondary:hover { border-color: var(--accent-glow); color: var(--accent-glow); }
.btn-ghost {
  background: transparent;
  color: var(--text-dim);
  border: 1px dashed var(--border-2);
}
.btn-ghost:hover { color: var(--accent-glow); border-color: var(--accent-glow); border-style: solid; }
.btn-small { padding: 8px 14px; font-size: 0.85rem; }

/* Tier cards */
.tier-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin: 24px 0;
}
.tier-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
}
.tier-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 10px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.tier-card .pill {
  font-size: 0.72rem;
  padding: 2px 9px;
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: 999px;
  color: var(--text-dim);
  font-weight: 500;
}
.tier-card .big {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-glow);
  line-height: 1.1;
  margin: 8px 0;
}
.tier-card .sub {
  font-size: 0.85rem;
  color: var(--text-dim);
}
.tier-card .row {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-dim);
  padding: 4px 0;
}
.tier-card .row strong {
  color: var(--text);
  font-weight: 600;
}

/* Step cards */
.step-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  margin: 20px 0;
}
.step-card h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.3px;
}
.step-card .step-num {
  display: inline-block;
  font-size: 0.75rem;
  padding: 3px 10px;
  background: var(--accent);
  color: #fff;
  border-radius: 999px;
  margin-right: 10px;
  vertical-align: middle;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.step-card p { margin: 14px 0; color: var(--text); }
.step-card ul, .step-card ol {
  margin: 12px 0 12px 24px;
  color: var(--text);
}
.step-card li { margin: 6px 0; }
.step-card .katex-display { margin: 16px 0; }
.step-card blockquote {
  border-left: 3px solid var(--accent);
  padding: 4px 16px;
  margin: 16px 0;
  color: var(--text-dim);
  font-style: italic;
  background: var(--surface-2);
  border-radius: 0 8px 8px 0;
}

.step-card .override {
  display: flex;
  justify-content: flex-end;
  margin-top: 6px;
  font-size: 0.8rem;
}
.step-card .override a {
  color: var(--text-dim);
  text-decoration: none;
  border-bottom: 1px dotted var(--border-2);
}
.step-card .override a:hover { color: var(--accent-glow); }

/* Status panels */
.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
  margin: 16px 0;
}
.panel h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.panel .row {
  display: flex;
  justify-content: space-between;
  padding: 6px 0;
  border-bottom: 1px dashed var(--border);
  font-size: 0.9rem;
}
.panel .row:last-child { border-bottom: none; }
.panel .row span:first-child { color: var(--text-dim); }
.panel .row code {
  font-size: 0.8rem;
  max-width: 60%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Badges & indicators */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.3px;
}
.badge-green { background: rgba(0, 184, 148, 0.15); color: var(--green); border: 1px solid rgba(0, 184, 148, 0.3); }
.badge-amber { background: rgba(253, 203, 110, 0.15); color: var(--amber); border: 1px solid rgba(253, 203, 110, 0.3); }
.badge-red   { background: rgba(255, 107, 107, 0.15); color: var(--red); border: 1px solid rgba(255, 107, 107, 0.3); }
.badge-dim   { background: var(--surface-2); color: var(--text-dim); border: 1px solid var(--border-2); }

.dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-faint);
  margin-right: 6px;
}
.dot-green { background: var(--green); box-shadow: 0 0 8px rgba(0, 184, 148, 0.6); }
.dot-amber { background: var(--amber); box-shadow: 0 0 8px rgba(253, 203, 110, 0.5); }
.dot-red   { background: var(--red); }

/* Forms */
.form-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 12px 0;
}
.form-field label {
  font-size: 0.85rem;
  color: var(--text-dim);
  font-weight: 500;
}
.form-field input[type="text"],
.form-field input[type="email"],
.form-field textarea,
.form-field select {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  color: var(--text);
  padding: 10px 14px;
  border-radius: 8px;
  font-family: inherit;
  font-size: 0.95rem;
}
.form-field textarea { min-height: 100px; font-family: 'SF Mono', ui-monospace, Menlo, monospace; font-size: 0.85rem; }
.form-field input:focus,
.form-field textarea:focus,
.form-field select:focus {
  outline: none;
  border-color: var(--accent);
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  margin-top: 80px;
  color: var(--text-dim);
  font-size: 0.85rem;
  text-align: center;
}
footer a { color: var(--text-dim); text-decoration: none; border-bottom: 1px dotted var(--border-2); }
footer a:hover { color: var(--accent-glow); }

/* Utilities */
.text-dim { color: var(--text-dim); }
.text-faint { color: var(--text-faint); }
.text-accent { color: var(--accent-glow); }
.text-green { color: var(--green); }
.text-red { color: var(--red); }
.text-center { text-align: center; }
.mt-2 { margin-top: 12px; }
.mt-4 { margin-top: 24px; }
.mt-6 { margin-top: 40px; }
.mt-8 { margin-top: 60px; }
.mb-2 { margin-bottom: 12px; }
.mb-4 { margin-bottom: 24px; }
.flex { display: flex; }
.flex-gap { gap: 10px; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }

/* Responsive */
@media (max-width: 640px) {
  .hero { padding: 50px 0 40px; }
  nav.topnav .nav-links { gap: 14px; font-size: 0.85rem; }
  .step-card { padding: 20px; }
}

/* SVG visualizations */
.viz {
  width: 100%;
  height: auto;
  max-width: 640px;
  margin: 20px auto;
  display: block;
}

/* Hash / long strings */
.hash {
  font-family: 'SF Mono', ui-monospace, Menlo, monospace;
  font-size: 0.8rem;
  color: var(--text-dim);
  word-break: break-all;
}

/* Alerts */
.alert {
  padding: 14px 18px;
  border-radius: 10px;
  margin: 16px 0;
  border: 1px solid;
  font-size: 0.9rem;
}
.alert-info { background: rgba(9, 132, 227, 0.08); border-color: rgba(9, 132, 227, 0.3); }
.alert-warn { background: rgba(253, 203, 110, 0.08); border-color: rgba(253, 203, 110, 0.3); }
.alert-error { background: rgba(255, 107, 107, 0.08); border-color: rgba(255, 107, 107, 0.3); }
.alert-ok { background: rgba(0, 184, 148, 0.08); border-color: rgba(0, 184, 148, 0.3); }

/* Disclosure (native <details>/<summary>) */
.step-card details {
  margin: 12px 0;
  border: 1px solid var(--border-2);
  border-radius: 8px;
  background: var(--surface);
}
.step-card details > summary {
  padding: 10px 14px;
  cursor: pointer;
  color: var(--accent-glow);
  font-size: 0.92rem;
  list-style: none;
}
.step-card details > summary::-webkit-details-marker { display: none; }
.step-card details > summary::before {
  content: '▸ ';
  color: var(--text-faint);
  font-size: 0.8em;
}
.step-card details[open] > summary::before { content: '▾ '; }
.step-card details[open] > summary { border-bottom: 1px solid var(--border); }
.step-card details > div { padding: 4px 14px 14px; }
.step-card details p { margin: 10px 0; font-size: 0.92rem; }

/* Signer grid on the sign-in card */
.signer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 10px;
  margin-top: 12px;
}
.signer {
  display: block;
  border: 1px solid var(--border-2);
  border-radius: 8px;
  padding: 12px 14px;
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
}
.signer:hover { border-color: var(--accent-glow); }
.signer strong { color: var(--accent-glow); font-size: 0.95rem; }
.signer .sub {
  display: block;
  color: var(--text-dim);
  font-size: 0.85rem;
  margin-top: 4px;
  line-height: 1.5;
}
.signer .tag {
  display: inline-block;
  font-size: 0.7rem;
  color: var(--amber);
  border: 1px solid rgba(253, 203, 110, 0.3);
  background: rgba(253, 203, 110, 0.06);
  border-radius: 999px;
  padding: 1px 8px;
  margin-left: 6px;
  vertical-align: middle;
}