/* ============================================================
   Bridgewire — Components: header, nav, buttons, footer, cards
   ============================================================ */

/* — Buttons — */
.btn {
  --btn-bg: transparent;
  --btn-fg: var(--ink);
  --btn-bd: var(--line);
  display: inline-flex; align-items: center; gap: 0.7rem;
  font-family: var(--font-mono); font-size: 0.8rem; font-weight: 500;
  letter-spacing: 0.12em; text-transform: uppercase;
  padding: 0.95rem 1.5rem;
  color: var(--btn-fg); background: var(--btn-bg);
  border: 1px solid var(--btn-bd); border-radius: var(--radius-sm);
  cursor: pointer; white-space: nowrap;
  transition: transform var(--dur-fast) var(--ease), background var(--dur-fast) var(--ease),
              border-color var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}
.btn .arrow { transition: transform var(--dur) var(--ease); }
.btn:hover { transform: translateY(-2px); }
.btn:hover .arrow { transform: translateX(4px); }
.btn:active { transform: translateY(0); }

.btn--primary { --btn-bg: var(--accent); --btn-fg: var(--accent-ink); --btn-bd: var(--accent); }
.btn--primary:hover { background: var(--accent-strong); border-color: var(--accent-strong); }
.btn--ghost:hover { border-color: var(--ink); }

/* Text link with animated underline */
.link {
  display: inline-flex; align-items: center; gap: 0.5rem;
  font-family: var(--font-mono); font-size: 0.8rem; font-weight: 500;
  letter-spacing: 0.1em; text-transform: uppercase; color: var(--accent);
  position: relative;
}
.link::after {
  content: ""; position: absolute; left: 0; bottom: -3px; height: 1px; width: 100%;
  background: currentColor; transform: scaleX(0); transform-origin: right;
  transition: transform var(--dur) var(--ease);
}
.link:hover::after { transform: scaleX(1); transform-origin: left; }
.link .arrow { transition: transform var(--dur) var(--ease); }
.link:hover .arrow { transform: translateX(4px); }

/* — Site header — */
.site-header {
  position: sticky; top: 0; z-index: 100;
  backdrop-filter: blur(12px);
  background: color-mix(in oklab, var(--bg) 72%, transparent);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.site-header.is-stuck { border-bottom-color: var(--line-soft); }
.site-header__inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1.5rem; height: 78px;
}
.brand {
  font-family: var(--font-display); font-weight: 460; font-size: 1.4rem;
  letter-spacing: -0.01em; color: var(--ink); display: inline-flex; align-items: baseline; gap: 0.12em;
}
.brand::after { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); align-self: end; margin-bottom: 0.28em; }
.site-nav { display: flex; align-items: center; gap: 2rem; }
.site-nav__list { display: flex; gap: 2rem; list-style: none; }
.site-nav__link {
  font-family: var(--font-mono); font-size: 0.8rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--ink-dim); position: relative; padding-block: 0.4rem;
  transition: color var(--dur-fast) var(--ease);
}
.site-nav__link::after {
  content: ""; position: absolute; left: 0; bottom: 0; height: 1px; width: 100%;
  background: var(--accent); transform: scaleX(0); transform-origin: right;
  transition: transform var(--dur) var(--ease);
}
.site-nav__link:hover, .site-nav__link[aria-current="page"] { color: var(--ink); }
.site-nav__link:hover::after, .site-nav__link[aria-current="page"]::after { transform: scaleX(1); transform-origin: left; }

.menu-toggle { display: none; background: none; border: 0; width: 44px; height: 44px; cursor: pointer; position: relative; }
.menu-toggle span { position: absolute; left: 10px; right: 10px; height: 1.5px; background: var(--ink); transition: transform var(--dur) var(--ease), opacity var(--dur-fast) var(--ease); }
.menu-toggle span:nth-child(1) { top: 17px; }
.menu-toggle span:nth-child(2) { bottom: 17px; }

/* — Mobile overlay nav — */
.overlay {
  position: fixed; inset: 0; z-index: 90; background: var(--bg-inset);
  display: flex; flex-direction: column; justify-content: center;
  padding: var(--gutter); gap: 0.25rem;
  opacity: 0; visibility: hidden; transform: translateY(-8px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease), visibility var(--dur);
}
.overlay.is-open { opacity: 1; visibility: visible; transform: none; }
.overlay__link {
  font-family: var(--font-display); font-weight: 380; font-size: clamp(2.2rem, 12vw, 3.4rem);
  color: var(--ink); line-height: 1.3; letter-spacing: -0.01em;
  border-bottom: 1px solid var(--line-soft); padding-block: 0.55rem;
  transition: color var(--dur-fast) var(--ease), padding-left var(--dur) var(--ease);
}
.overlay__link:hover { color: var(--accent); padding-left: 0.5rem; }
.overlay__cta { margin-top: 2rem; align-self: flex-start; }

body.nav-open { overflow: hidden; }

/* — Footer — */
.site-footer { background: var(--bg-inset); border-top: 1px solid var(--line-soft); padding-block: clamp(3.5rem, 6vw, 6rem) 2.5rem; }
.site-footer__grid {
  display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 2.5rem;
  padding-bottom: 3.5rem; border-bottom: 1px solid var(--line-soft);
}
.site-footer__statement { font-family: var(--font-display); font-size: var(--fs-h3); color: var(--ink); line-height: 1.15; letter-spacing: -0.01em; max-width: 16ch; }
.footer-col__label { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-faint); margin-bottom: 1.1rem; }
.footer-col a { display: block; color: var(--ink-dim); padding-block: 0.35rem; transition: color var(--dur-fast) var(--ease); }
.footer-col a:hover { color: var(--ink); }
.site-footer__bottom { display: flex; justify-content: space-between; align-items: center; gap: 1rem; flex-wrap: wrap; padding-top: 2rem; }
.site-footer__copy { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.08em; color: var(--ink-faint); }
.to-top { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-dim); display: inline-flex; align-items: center; gap: 0.5rem; }
.to-top:hover { color: var(--ink); }
.to-top .arrow { transition: transform var(--dur) var(--ease); }
.to-top:hover .arrow { transform: translateY(-3px); }

/* — Responsive nav — */
@media (max-width: 820px) {
  .site-nav { display: none; }
  .menu-toggle { display: block; }
  .header-cta { display: none; }
  .site-footer__grid { grid-template-columns: 1fr 1fr; gap: 2rem 1.5rem; }
  .site-footer__statement { grid-column: 1 / -1; }
}