/* layout.css — the reusable SHELL: header, nav, footer, and shared layout
   utilities used on EVERY page. Mobile-first: base rules target small screens;
   @media (min-width: ...) rules add layout as the screen grows. */

/* Centered content column with consistent side gutters. */
.container {
  width: 100%;
  max-width: 72rem;
  margin-inline: auto;          /* center horizontally */
  padding-inline: var(--space-3);
}

/* Skip link: lets keyboard users jump past the nav straight to content.
   Hidden off-screen until it receives focus (Tab). */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -3rem;
  z-index: 100;
  background: var(--color-black);
  color: var(--color-white);
  padding: var(--space-1) var(--space-2);
  transition: top 0.15s ease;
}
.skip-link:focus { top: var(--space-2); }

/* --- Header --- */
.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid #eee;
}
.site-header__inner {
  display: flex;
  flex-wrap: wrap;              /* lets nav drop below the logo on tiny screens */
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding-block: var(--space-2);
}
.site-brand { display: inline-flex; align-items: center; }
.site-brand img { height: 44px; width: auto; }

/* Primary navigation */
.site-nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-3);
  margin: 0;
  padding: 0;
}
.site-nav a {
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--weight-medium);
  padding-block: var(--space-1);
  border-bottom: 2px solid transparent;   /* reserve space so hover doesn't shift layout */
}
.site-nav a:hover,
.site-nav a:focus-visible { border-bottom-color: var(--color-accent); }

/* --- Buttons (reusable component) --- */
.button {
  display: inline-block;
  font-family: var(--font-body);
  font-weight: var(--weight-semibold);
  text-decoration: none;
  padding: var(--space-2) var(--space-3);
  border: 2px solid var(--color-black);
  background: var(--color-black);
  color: var(--color-white);
  transition: background 0.15s ease, color 0.15s ease;
}
.button:hover,
.button:focus-visible { background: transparent; color: var(--color-black); }

/* Variant for dark backgrounds: white fill that hollows out on hover. */
.button--on-dark {
  border-color: var(--color-white);
  background: var(--color-white);
  color: var(--color-black);
}
.button--on-dark:hover,
.button--on-dark:focus-visible { background: transparent; color: var(--color-white); }

/* --- Footer --- */
.site-footer {
  background: var(--color-bg-invert);
  color: var(--color-text-invert);
  padding-block: var(--space-5);
  margin-top: var(--space-6);
}
.site-footer__mark { height: 56px; width: auto; margin-bottom: var(--space-2); }
.site-footer__tagline {
  font-family: var(--font-headline);
  font-size: var(--text-h2);
  margin-bottom: var(--space-1);
}
.site-footer__tagline .dot { color: var(--color-accent); }  /* gold accent on black = high contrast */
.site-footer__copy { font-size: var(--text-caption); color: #bbbbbb; }

/* Visible focus ring for keyboard users (refined in Phase 7's a11y pass). */
:focus-visible { outline: 3px solid var(--color-accent); outline-offset: 2px; }