/* TABConf 7–style neutrals: white page, #727272 body, #222 headings, gray chrome.
   Orange #FF9900 only for the primary Bitcoin CTA (matches 7’s sponsor accent). */

:root {
  --bg: #ffffff;
  --bg-subtle: #fafafa;
  --bg-panel: #f4f4f4;
  --bg-code: #f8f8f8;
  --text: #222222;
  --text-secondary: #393939;
  --text-muted: #727272;
  --text-soft: #494949;
  --link: #333333;
  --link-hover: #111111;
  --accent-orange: #ff9900;
  --accent-orange-dark: #e68a00;
  --border: #e5e5e5;
  --border-strong: #e0e0e0;
  --font-sans: "Instrument Sans", system-ui, -apple-system, "Noto Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, Monaco, Consolas, monospace;
  --max: 1180px;
  --sidebar-w: 220px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--text-muted);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  padding: 0.75rem 1rem;
  background: var(--text);
  color: #fff;
  font-weight: 600;
  z-index: 200;
}

.skip-link:focus {
  left: 1rem;
  top: 1rem;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}

.site-header__inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
}

.site-title {
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  color: var(--text);
  text-decoration: none;
}

.site-title:hover {
  color: var(--text-secondary);
}

/* Layout */
.layout {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.5rem 3rem;
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  gap: 2.5rem;
  align-items: start;
}

@media (max-width: 860px) {
  .layout {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    padding-bottom: 2rem;
  }
}

.sidebar {
  position: sticky;
  top: 0;
  padding: 1.25rem 1rem 1.25rem 0.75rem;
  margin-top: 1.5rem;
  background: var(--bg);
  border-radius: 8px;
  border: 1px solid var(--border);
}

@media (max-width: 860px) {
  .sidebar {
    position: static;
    margin-top: 0;
    padding: 1rem 1rem 1.1rem;
  }
}

.sidebar__heading {
  margin: 0 0 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--text-soft);
}

.sidebar__nav {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

@media (max-width: 860px) {
  .sidebar__nav {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.35rem 1rem;
  }
}

.sidebar__link {
  display: block;
  padding: 0.35rem 0.35rem 0.35rem 0.5rem;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: 4px;
  border-left: 2px solid transparent;
}

.sidebar__link:hover {
  color: var(--text);
  background: var(--bg-panel);
}

.sidebar__link.is-active {
  color: var(--text);
  font-weight: 600;
  border-left-color: var(--accent-orange);
  background: var(--bg-subtle);
}

.sidebar__rule {
  display: block;
  height: 1px;
  background: var(--border);
  margin: 0.65rem 0;
}

@media (max-width: 860px) {
  .sidebar__rule {
    width: 100%;
    flex-basis: 100%;
    margin: 0.35rem 0;
  }
}

.layout__main {
  min-width: 0;
  padding-top: 1.5rem;
}

/* Main typography (TABConf 7 weights) */
.site-main h1 {
  font-size: clamp(1.65rem, 4vw, 2.15rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin: 0 0 1.25rem;
  color: var(--text);
}

.site-main h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 2rem 0 0.85rem;
  color: var(--text-secondary);
  letter-spacing: -0.02em;
}

.site-main h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 1.5rem 0 0.6rem;
  color: var(--text-soft);
}

.site-main p {
  margin: 0 0 1.1rem;
  color: var(--text-muted);
  max-width: 58ch;
}

.site-main a {
  color: var(--link);
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.site-main a:hover {
  color: var(--link-hover);
}

.site-main hr {
  border: none;
  height: 1px;
  background: var(--border);
  margin: 2rem 0;
}

.site-main ul,
.site-main ol {
  margin: 0 0 1.25rem;
  padding-left: 1.35rem;
  color: var(--text-muted);
  max-width: 58ch;
}

.site-main li {
  margin-bottom: 0.4rem;
}

.site-main strong {
  color: var(--text);
  font-weight: 700;
}

.site-main table {
  width: 100%;
  max-width: 42rem;
  border-collapse: collapse;
  font-size: 0.98rem;
  margin: 1rem 0 1.5rem;
}

.site-main th,
.site-main td {
  border: 1px solid var(--border);
  padding: 0.65rem 0.85rem;
  text-align: left;
  color: var(--text-muted);
}

.site-main th {
  background: var(--bg-code);
  color: var(--text);
  font-weight: 700;
}

/* Home hero — white card, gray border only (no tinted panel) */
.home-hero {
  text-align: center;
  margin-bottom: 2.5rem;
  padding: 1.5rem 1rem 0.5rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.home-hero__dates {
  margin: 0 0 1.25rem;
  font-family: var(--font-mono);
  font-size: clamp(0.9rem, 2.2vw, 1rem);
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.06em;
}

.home-hero__logo {
  display: block;
  margin: 0 auto 1.75rem;
  max-width: min(380px, 88vw);
  width: 100%;
  height: auto;
}

.ticket-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  align-items: center;
  margin-top: 0.25rem;
  padding-bottom: 0.5rem;
}

.ticket-actions__btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 200px;
  padding: 0.85rem 1.45rem;
  border-radius: 6px;
  font-weight: 700;
  font-size: 0.98rem;
  text-decoration: none !important;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.12s ease;
}

.ticket-actions__btn:hover {
  transform: translateY(-1px);
}

.ticket-actions__btn:active {
  transform: translateY(0);
}

/* TABConf 7–style orange (title sponsor) for BTC */
.ticket-actions__btn--btc {
  background: var(--accent-orange);
  color: #fff;
  border: 2px solid var(--accent-orange);
  box-shadow: 0 1px 0 var(--accent-orange-dark);
}

.ticket-actions__btn--btc:hover {
  background: var(--accent-orange-dark);
  border-color: var(--accent-orange-dark);
  color: #fff;
}

/* Light bar like 7’s “downloads” strip for fiat */
.ticket-actions__btn--fiat {
  background: var(--bg-panel);
  color: #444;
  border: 1px solid var(--border-strong);
}

.ticket-actions__btn--fiat:hover {
  background: #eaeaea;
  border-color: #ccc;
  color: #222;
}

@media (max-width: 480px) {
  .ticket-actions__btn {
    width: 100%;
    min-width: unset;
  }
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.75rem 1.5rem 2.5rem;
  margin-top: 0;
  background: var(--bg);
}

.site-footer__inner {
  max-width: var(--max);
  margin: 0 auto;
}

.site-footer__tagline {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin: 0 0 0.75rem;
}

.site-footer__past {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0;
  line-height: 1.8;
}

.site-footer__past a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  margin-right: 0.55rem;
}

.site-footer__past a:hover {
  color: var(--text);
  text-decoration: underline;
}