/* responsive.css — mobile-first, progressively enhanced
   - Built to load after global.css
   - Uses rem/em units and min-width breakpoints only
   - Avoids assumptions about existing markup; enhances common classes/nodes
*/

/* 1) Root and scales */
:root {
  /* Fluid type scale using clamp for comfortable reading on phones */
  --fs-300: clamp(0.875rem, 0.84rem + 0.18vw, 0.95rem);  /* small */
  --fs-400: clamp(1rem, 0.96rem + 0.25vw, 1.125rem);     /* base */
  --fs-500: clamp(1.125rem, 1.06rem + 0.44vw, 1.25rem);  /* lead */
  --fs-600: clamp(1.25rem, 1.12rem + 0.75vw, 1.5rem);    /* h3 */
  --fs-700: clamp(1.5rem, 1.32rem + 1.1vw, 1.875rem);    /* h2 */
  --fs-800: clamp(1.875rem, 1.55rem + 1.6vw, 2.25rem);   /* h1 */

  /* Layout and rhythm */
  --container-max: 72rem; /* ~1152px */
  --container-pad: 1rem;  /* 16px default, fluid container uses inline padding */
  --radius: 0.75rem;

  /* Spacing scale (mobile-first) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;

  /* Color fallbacks (respect existing vars if defined) */
  --bg: var(--surface-default, #f8fafc);
  --surface: var(--surface-contrast, #ffffff);
  --text: var(--text-primary, #0f172a);
  --text-secondary: var(--text-secondary, #475569);
  --brand: var(--brand-primary, #1e40af);
  --border: var(--border-light, #e5e7eb);
}

/* 2) Base adjustments */
html { font-size: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-size: var(--fs-400);
  line-height: 1.55;
  -webkit-text-size-adjust: 100%;
  text-rendering: optimizeLegibility;
}

/* 3) Fluid container */
.container {
  /* Mobile-first: full-width minus inline padding */
  width: min(100% - 2rem, var(--container-max));
  margin-inline: auto;
}

/* 4) Sections stack naturally on small screens */
.section {
  padding-block: var(--space-6);
}
.section.tight { padding-block: var(--space-4); }
.section.alt { background: color-mix(in srgb, var(--bg) 92%, #ffffff 8%); }

/* 5) Typography (semantic elements) */
h1, h2, h3, h4 { line-height: 1.2; margin: 0 0 var(--space-3); color: var(--text); }
h1 { font-size: var(--fs-800); font-weight: 800; }
h2 { font-size: var(--fs-700); font-weight: 700; }
h3 { font-size: var(--fs-600); font-weight: 700; }
p { margin: 0 0 var(--space-3); color: var(--text-secondary); }
.small { font-size: var(--fs-300); }

/* 6) Media handling */
img, video, svg { max-width: 100%; height: auto; }
img { display: block; }

/* 7) Cards and surfaces */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--space-4);
  box-shadow: 0 1px 2px rgba(0,0,0,.04);
}

/* 8) Grid/Flex helpers (CSS Grid with auto-fit/minmax for natural wrapping) */
.grid { display: grid; gap: var(--space-4); }
.grid.cols-auto {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
}

/* 9) Forms and tap targets */
.field { margin-bottom: var(--space-4); }
.field label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.35rem;
  color: var(--text);
}
.field input,
.field select,
.field textarea {
  width: 100%;
  font: inherit;
  color: var(--text);
  background: #fff;
  border: 1px solid #d1d5db;
  border-radius: 0.5rem;
  padding: 0.625rem 0.75rem;
  min-height: 2.75rem; /* ~44px mobile tap target */
  transition: border-color .2s ease, box-shadow .2s ease, transform .2s ease;
}
.field textarea { resize: vertical; }
.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--brand);
  box-shadow: 0 0 0 0.1875rem color-mix(in srgb, var(--brand) 25%, transparent);
  transform: translateY(-1px);
}

.error-text {
  min-height: 1rem;
  font-size: var(--fs-300);
  color: #b91c1c;
  margin-top: 0.25rem;
}

/* 10) Buttons */
.cta, button, [role="button"] {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 700;
  line-height: 1;
  border-radius: 0.5rem;
  border: 1px solid transparent;
  background: var(--brand);
  color: #fff;
  padding: 0.75rem 1rem;
  min-height: 2.75rem; /* ~44px */
  text-decoration: none;
  cursor: pointer;
  touch-action: manipulation;
}
.cta.secondary {
  background: transparent;
  color: var(--brand);
  border-color: color-mix(in srgb, var(--brand) 45%, #ffffff 55%);
}

/* 11) Mobile-first Navigation
   - Hide nav by default on small screens
   - JS adds a .nav-toggle button and toggles .nav-open on body
   - Larger screens: show nav inline; hide toggle
*/
header { position: relative; background: var(--surface); }
header nav {
  display: none; /* collapsed by default on mobile */
}
.nav-toggle {
  /* Created by JS; accessible hamburger */
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem; height: 2.75rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
}
.nav-toggle .nav-toggle-box { position: relative; width: 1.25rem; height: 1rem; }
.nav-toggle .nav-toggle-bar,
.nav-toggle .nav-toggle-box::before,
.nav-toggle .nav-toggle-box::after {
  content: "";
  position: absolute;
  left: 0; right: 0;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform .2s ease, opacity .2s ease;
}
.nav-toggle .nav-toggle-bar { top: 50%; transform: translateY(-50%); }
.nav-toggle .nav-toggle-box::before { top: 0; }
.nav-toggle .nav-toggle-box::after { bottom: 0; }

body.nav-open .nav-toggle .nav-toggle-box::before { transform: translateY(8px) rotate(45deg); }
body.nav-open .nav-toggle .nav-toggle-box::after { transform: translateY(-8px) rotate(-45deg); }
body.nav-open .nav-toggle .nav-toggle-bar { opacity: 0; }

/* Fullscreen menu panel when open on mobile */
body.nav-open header nav {
  display: block;
  position: fixed;
  inset: 0;
  background: var(--surface);
  padding: var(--space-5);
  overflow: auto;
  z-index: 60;
}
body.nav-open { overflow: hidden; }
.nav-backdrop {
  display: none;
}
body.nav-open .nav-backdrop {
  display: block;
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.4);
  z-index: 50;
}

/* Make common nav items comfortable to tap on mobile */
header nav a {
  display: block;
  padding: 0.875rem 0.5rem;
  color: inherit;
  text-decoration: none;
}
header nav a:hover, header nav a:focus { color: var(--brand); }

/* 12) Breakpoints (min-width approach only) */
@media (min-width: 48em) {
  .section { padding-block: var(--space-7); }

  /* Desktop/tablet nav: show inline, hide toggle */
  .nav-toggle { display: none; }
  header nav {
    display: flex !important;
    position: static;
    inset: auto;
    background: transparent;
    padding: 0;
    overflow: visible;
  }
  header nav a { padding: 0.5rem; }
  body.nav-open { overflow: auto; }
  body.nav-open .nav-backdrop { display: none; }
}

@media (min-width: 64em) {
  .grid { gap: var(--space-5); }
}