/* ============================================================
   layout.css — Structural Layout Utilities
   Container, grid system, flexbox helpers, section spacing.
   Mobile-first: base styles target mobile, min-width queries
   in responsive.css expand to tablet/desktop.
   ============================================================ */

/* ============================
   Container
   ============================ */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-md);
  padding-right: var(--spacing-md);
}

.container-wide {
  max-width: var(--container-wide);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-md);
  padding-right: var(--spacing-md);
}

.container-narrow {
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-md);
  padding-right: var(--spacing-md);
}


/* ============================
   Grid System
   ============================ */

/*
  Base grid: single column on mobile.
  Responsive breakpoints in responsive.css expand columns.
*/

.grid {
  display: grid;
  gap: var(--spacing-xl);
  grid-template-columns: 1fr;
}

.grid-2 {
  display: grid;
  gap: var(--spacing-xl);
  grid-template-columns: 1fr;
}

.grid-3 {
  display: grid;
  gap: var(--spacing-xl);
  grid-template-columns: 1fr;
}

.grid-4 {
  display: grid;
  gap: var(--spacing-xl);
  grid-template-columns: 1fr;
}

/* Auto-fit grid (self-adapting, use sparingly) */
.grid-auto {
  display: grid;
  gap: var(--spacing-xl);
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

/* Gap variants */
.gap-sm  { gap: var(--spacing-sm); }
.gap-md  { gap: var(--spacing-md); }
.gap-lg  { gap: var(--spacing-lg); }
.gap-xl  { gap: var(--spacing-xl); }
.gap-2xl { gap: var(--spacing-2xl); }


/* ============================
   Flexbox Utilities
   ============================ */

.flex         { display: flex; }
.flex-col     { flex-direction: column; }
.flex-wrap    { flex-wrap: wrap; }
.flex-nowrap  { flex-wrap: nowrap; }

.items-center  { align-items: center; }
.items-start   { align-items: flex-start; }
.items-end     { align-items: flex-end; }
.items-stretch { align-items: stretch; }

.justify-center  { justify-content: center; }
.justify-start   { justify-content: flex-start; }
.justify-end     { justify-content: flex-end; }
.justify-between { justify-content: space-between; }
.justify-around  { justify-content: space-around; }

.flex-1    { flex: 1; }
.flex-none { flex: none; }

.self-center { align-self: center; }
.self-start  { align-self: flex-start; }
.self-end    { align-self: flex-end; }


/* ============================
   Sections
   ============================ */

.section {
  padding-top: var(--spacing-2xl);
  padding-bottom: var(--spacing-2xl);
}

.section-sm {
  padding-top: var(--spacing-2xl);
  padding-bottom: var(--spacing-2xl);
}

.section-lg {
  padding-top: var(--spacing-5xl);
  padding-bottom: var(--spacing-5xl);
}

/* Alternating background sections */
.section-alt {
  background-color: var(--color-light-gray);
}

.section-dark {
  background-color: var(--color-navy);
  color: var(--color-text-inverse);
}

.section-primary {
  background-color: var(--color-primary);
  color: var(--color-white);
}


/* ============================
   Page Layout
   ============================ */

/* Ensure footer sticks to bottom of short pages */
.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-wrapper main {
  flex: 1;
}

/* Offset for sticky nav */
.has-sticky-nav {
  padding-top: var(--nav-height);
}


/* ============================
   Two-Column Content Layout
   ============================ */

/* Text + Image / Sidebar layouts */
.layout-split {
  display: grid;
  gap: var(--spacing-3xl);
  grid-template-columns: 1fr;
  align-items: center;
}

.layout-split-content {}
.layout-split-media {}


/* ============================
   Spacing Utilities
   ============================ */

.mt-xs  { margin-top: var(--spacing-xs); }
.mt-sm  { margin-top: var(--spacing-sm); }
.mt-md  { margin-top: var(--spacing-md); }
.mt-lg  { margin-top: var(--spacing-lg); }
.mt-xl  { margin-top: var(--spacing-xl); }
.mt-2xl { margin-top: var(--spacing-2xl); }
.mt-3xl { margin-top: var(--spacing-3xl); }

.mb-xs  { margin-bottom: var(--spacing-xs); }
.mb-sm  { margin-bottom: var(--spacing-sm); }
.mb-md  { margin-bottom: var(--spacing-md); }
.mb-lg  { margin-bottom: var(--spacing-lg); }
.mb-xl  { margin-bottom: var(--spacing-xl); }
.mb-2xl { margin-bottom: var(--spacing-2xl); }
.mb-3xl { margin-bottom: var(--spacing-3xl); }

.pt-0   { padding-top: 0; }
.pb-0   { padding-bottom: 0; }


/* ============================
   Visibility Utilities
   ============================ */

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

.hide-mobile  { display: none; }   /* hidden on mobile by default */
.hide-desktop {}                    /* show on mobile, hidden via responsive.css */