/* Shared by every page: buttons, the site header and the site footer.
   Colour and font tokens (--ink, --paper, --display, ...) are defined in each page's :root. */

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: 10px; justify-content: center;
  font: 600 15px/1 var(--sans); letter-spacing: 0.02em; text-decoration: none;
  padding: 17px 26px; border: 1px solid var(--ink); background: var(--ink); color: var(--paper);
  transition: background .2s, color .2s, border-color .2s; cursor: pointer;
}
.btn:hover { background: transparent; color: var(--ink); }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--rule); }
.btn.ghost:hover { border-color: var(--ink); }
.btn .arrow { display: inline-block; transition: transform .2s; }
.btn:hover .arrow { transform: translateX(3px); }

/* Header */
.site-header {
  position: sticky; top: env(safe-area-inset-top, 0px); z-index: 20;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(12px); -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid var(--rule);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 24px; min-height: 72px; }
.brand { text-decoration: none; display: grid; gap: 6px; line-height: 1.05; }
.brand-name { font-family: var(--display); font-size: 1.55rem; font-weight: 600; letter-spacing: 0.01em; }
.brand-sub { font-size: 10.5px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--muted); font-weight: 600; }
.nav { display: flex; align-items: center; gap: clamp(16px, 2.4vw, 32px); }
.nav a.link { font-size: 14.5px; font-weight: 500; text-decoration: none; color: var(--muted); transition: color .2s; }
.nav a.link:hover { color: var(--ink); }
.nav .btn { padding: 13px 20px; font-size: 14px; }
.nav .short { display: none; }
.brand-sub, .nav .btn { white-space: nowrap; }
@media (max-width: 1080px) { .nav a.link { display: none; } }
@media (max-width: 520px) { .brand-name { font-size: 1.35rem; } }

/* Mobile menu: below 1080px the links fold into a panel under the header; below 640px the button joins them. */
.menu-toggle {
  display: none; width: 44px; height: 44px; flex: none; padding: 0; cursor: pointer;
  align-items: center; justify-content: center; background: transparent; color: var(--ink);
  border: 1px solid var(--rule); transition: border-color .2s;
}
.menu-toggle:hover { border-color: var(--ink); }
.menu-toggle .bars, .menu-toggle .bars::before, .menu-toggle .bars::after {
  display: block; width: 18px; height: 1.5px; background: currentColor; transition: transform .2s, background-color .2s;
}
.menu-toggle .bars { position: relative; }
.menu-toggle .bars::before, .menu-toggle .bars::after { content: ""; position: absolute; left: 0; }
.menu-toggle .bars::before { top: -6px; }
.menu-toggle .bars::after { top: 6px; }
.site-header.open .menu-toggle .bars { background-color: transparent; }
.site-header.open .menu-toggle .bars::before { transform: translateY(6px) rotate(45deg); }
.site-header.open .menu-toggle .bars::after { transform: translateY(-6px) rotate(-45deg); }
@media (max-width: 1080px) {
  .site-header .wrap { gap: 12px; }
  .brand { margin-right: auto; }
  .menu-toggle { display: inline-flex; }
  .site-header.open .nav {
    position: absolute; top: 100%; left: 0; right: 0; display: flex; flex-direction: column; align-items: stretch; gap: 0;
    padding: 4px var(--gutter-r, 16px) 24px var(--gutter, 16px);
    background: var(--paper); border-bottom: 1px solid var(--rule); box-shadow: 0 18px 30px -24px rgba(0, 0, 0, .35);
  }
  .site-header.open .nav a.link { display: block; padding: 15px 0; border-bottom: 1px solid var(--rule); font-size: 17px; color: var(--ink); }
  .site-header.open .nav .btn { margin-top: 22px; }
}
@media (max-width: 640px) { .nav { display: none; } }

/* Footer */
.site-footer { background: var(--band); color: var(--band-muted); border-top: 1px solid var(--band-rule); }
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 18px 32px; padding-block: 32px; font-size: 14px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 10px 26px; }
.site-footer a { color: var(--band-fg); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; text-decoration-color: var(--band-brass); }