/* ===================================================================
   ENTRAIN SPACE — Holding Page Stylesheet
   
   Design system: IBM Carbon–aligned (8px grid, type scale, spacing)
   Accessibility: WCAG AAA (7:1 body contrast, 4.5:1 large text)
   Heuristics:    Nielsen Norman 10 principles throughout
   
   Token reference:
     Primary (orange):  #f7931e — headings, brand marks
     Accent (green):    #8ebd3f — CTAs, interactive elements
     Body text:         #1a1a1a — near-black for AAA on white (12.6:1)
     Secondary text:    #4a4a4a — for supporting copy (9.7:1)
     Meta text:         #6d6f71 — labels on white (5.5:1, AA only)
     Surface:           #ffffff — page background
     Surface alt:       #f5f5f5 — banded sections
     Surface dark:      #2b2b2b — footer, credibility band
   =================================================================== */

/* -------------------------
   0. CUSTOM PROPERTIES
   ------------------------- */
:root {
  /* Colours */
  --color-primary: #f7931e;
  --color-primary-dark: #d47a0f;
  --color-accent: #8ebd3f;
  --color-accent-dark: #6d9a2b;
  --color-accent-light: #a8d45f;
  --color-text: #1a1a1a;
  --color-text-secondary: #4a4a4a;
  --color-text-meta: #6d6f71;
  --color-text-inverse: #ffffff;
  --color-border: #d1d3d4;
  --color-border-light: #e8e8e8;
  --color-surface: #ffffff;
  --color-surface-alt: #f5f5f5;
  --color-surface-dark: #2b2b2b;
  --color-focus: #0f62fe;
  --color-error: #da1e28;
  --color-success: #198038;

  /* Typography */
  --font-family: 'Montserrat', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-3xl: 2.5rem;
  --font-size-4xl: 3rem;
  --line-height-tight: 1.25;
  --line-height-body: 1.6;
  --font-weight-light: 300;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;

  /* Spacing — 8px base grid */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 2.5rem;
  --space-8: 3rem;
  --space-9: 4rem;
  --space-10: 5rem;
  --space-11: 6rem;
  --space-12: 8rem;

  /* Layout */
  --max-width: 72rem;
  --max-width-narrow: 40rem;
  --header-height: 4rem;

  /* Transitions */
  --transition-fast: 120ms ease;
  --transition-base: 200ms ease;

  /* Borders */
  --radius-sm: 2px;
  --radius-md: 4px;
  --radius-lg: 8px;
}

/* -------------------------
   1. RESET & BASE
   ------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 100%;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-light);
  line-height: var(--line-height-body);
  color: var(--color-text);
  background-color: var(--color-surface);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-accent);
}

/* -------------------------
   2. FOCUS STYLES (AAA)
   ------------------------- */
:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

/* -------------------------
   3. SKIP LINK
   ------------------------- */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  z-index: 1000;
  padding: var(--space-2) var(--space-4);
  background: var(--color-focus);
  color: var(--color-text-inverse);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  border-radius: var(--radius-md);
}

.skip-link:focus {
  top: var(--space-2);
}

/* -------------------------
   4. LAYOUT UTILITIES
   ------------------------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.container--narrow {
  max-width: var(--max-width-narrow);
}

.section {
  padding-block: var(--space-8);
}

@media (min-width: 48rem) {
  .section {
    padding-block: var(--space-10);
  }
}

.section--alt {
  background-color: var(--color-surface-alt);
}

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

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

/* -------------------------
   5. TYPOGRAPHY
   ------------------------- */
h1, h2, h3, h4 {
  font-weight: var(--font-weight-regular);
  line-height: var(--line-height-tight);
  color: var(--color-primary);
}

h1 {
  font-size: var(--font-size-2xl);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-5);
}

h3 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-3);
}

p + p {
  margin-top: var(--space-4);
}

@media (min-width: 48rem) {
  h1 { font-size: var(--font-size-3xl); }
  h2 { font-size: var(--font-size-2xl); }
}

@media (min-width: 64rem) {
  h1 { font-size: var(--font-size-4xl); }
}

/* -------------------------
   6. HEADER
   ------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border-light);
  height: var(--header-height);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.site-logo {
  display: block;
  height: 2.25rem;
  width: auto;
}

.site-logo img {
  height: 100%;
  width: auto;
  object-fit: contain;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.header-nav a {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  color: var(--color-text-secondary);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.header-nav a:hover {
  color: var(--color-text);
}

/* Hide text-only nav links on small screens, keep CTA button */
.header-nav a:not(.btn) {
  display: none;
}

@media (min-width: 36rem) {
  .header-nav a:not(.btn) {
    display: inline-flex;
  }
  .header-nav {
    gap: var(--space-4);
  }
}

/* -------------------------
   7. BUTTONS
   ------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
  min-height: 2.75rem;
  min-width: 2.75rem;
}

.btn--primary {
  background-color: var(--color-accent);
  color: var(--color-text-inverse);
  border-color: var(--color-accent);
}

.btn--primary:hover {
  background-color: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  color: var(--color-text-inverse);
}

.btn--secondary {
  background-color: transparent;
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.btn--secondary:hover {
  background-color: var(--color-accent);
  color: var(--color-text-inverse);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text-secondary);
  border-color: var(--color-border);
}

.btn--ghost:hover {
  border-color: var(--color-text);
  color: var(--color-text);
}

.btn--inverse {
  background-color: var(--color-text-inverse);
  color: var(--color-accent-dark);
  border-color: var(--color-text-inverse);
}

.btn--inverse:hover {
  background-color: var(--color-accent-light);
  color: var(--color-surface-dark);
}

/* -------------------------
   8. HERO
   ------------------------- */
.hero {
  padding-block: var(--space-6) var(--space-8);
  text-align: center;
}

@media (min-width: 48rem) {
  .hero {
    padding-block: var(--space-9) var(--space-10);
  }
}

.hero__heading {
  max-width: 48rem;
  margin-inline: auto;
  margin-bottom: var(--space-3);
}

.hero__sub {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 36rem;
  margin-inline: auto;
  margin-bottom: var(--space-8);
}

.hero__video {
  max-width: 56rem;
  margin-inline: auto;
  margin-bottom: var(--space-6);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-3);
}

.hero__actions .btn {
  width: 100%;
}

@media (min-width: 30rem) {
  .hero__actions .btn {
    width: auto;
  }
  .hero__actions {
    gap: var(--space-4);
  }
}

/* -------------------------
   9. LITE YOUTUBE EMBED
   ------------------------- */
.lite-yt {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  background-color: #000;
  background-size: cover;
  background-position: center;
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  contain: content;
}

.lite-yt::before {
  content: '';
  display: block;
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, rgba(0,0,0,0.15) 0%, transparent 35%, transparent 65%, rgba(0,0,0,0.2) 100%);
  z-index: 1;
  transition: background var(--transition-base);
}

.lite-yt:hover::before {
  background: rgba(0,0,0,0.08);
}

.lite-yt__play {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 2;
  width: 4.5rem;
  height: 4.5rem;
  background: rgba(0,0,0,0.7);
  border-radius: 50%;
  border: 3px solid rgba(255,255,255,0.9);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.lite-yt:hover .lite-yt__play {
  background: rgba(247, 147, 30, 0.9);
  transform: translate(-50%, -50%) scale(1.08);
}

.lite-yt__play::after {
  content: '';
  display: block;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0.75rem 0 0.75rem 1.25rem;
  border-color: transparent transparent transparent #fff;
  margin-left: 0.2rem;
}

.lite-yt--activated {
  cursor: default;
}

.lite-yt--activated::before,
.lite-yt--activated .lite-yt__play {
  display: none;
}

.lite-yt iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.lite-yt__a11y {
  display: block;
  text-align: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-meta);
  margin-top: var(--space-2);
}

/* -------------------------
   10. TILES (What We Offer)
   ------------------------- */
.tiles {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-5);
}

@media (min-width: 48rem) {
  .tiles {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-6);
  }
  .tile {
    padding: var(--space-6);
  }
}

.tile {
  padding: var(--space-5);
  background: var(--color-surface);
  border-left: 3px solid var(--color-primary);
  border-radius: var(--radius-sm);
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
  transition: box-shadow var(--transition-base);
}

.tile:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.tile__icon {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-3);
  line-height: 1;
}

.tile__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.tile__text {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-body);
}

/* -------------------------
   11. PHOTO GALLERY (scroll-snap)
   ------------------------- */
.gallery {
  padding-block: var(--space-8);
  overflow: hidden;
}

.gallery__track {
  display: flex;
  gap: var(--space-4);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-padding-inline: var(--space-5);
  padding-inline: var(--space-5);
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}

.gallery__track::-webkit-scrollbar {
  height: 6px;
}

.gallery__track::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

.gallery__item {
  flex: 0 0 min(80vw, 28rem);
  scroll-snap-align: start;
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 16 / 10;
}

.gallery__item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

@media (min-width: 48rem) {
  .gallery__item {
    flex: 0 0 min(45vw, 28rem);
  }
}

@media (min-width: 64rem) {
  .gallery__item {
    flex: 0 0 min(32vw, 28rem);
  }
}

/* -------------------------
   12. APPLY SECTION
   ------------------------- */
.apply-section .eligibility-list {
  list-style: none;
  padding: 0;
  margin-bottom: var(--space-6);
}

.apply-section .eligibility-list li {
  position: relative;
  padding-left: var(--space-6);
  margin-bottom: var(--space-3);
  color: var(--color-text-secondary);
}

.apply-section .eligibility-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  line-height: 1.4;
}

.apply-section__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  align-items: start;
}

@media (min-width: 48rem) {
  .apply-section__layout {
    grid-template-columns: 1fr 1fr;
  }
}

.apply-section__privacy {
  font-size: var(--font-size-sm);
  color: var(--color-text-meta);
  margin-top: var(--space-4);
}

/* -------------------------
   13. CREDIBILITY BAND
   ------------------------- */
.credibility {
  padding-block: var(--space-6);
  background-color: var(--color-surface-dark);
  color: rgba(255, 255, 255, 0.8);
  font-size: var(--font-size-sm);
  text-align: center;
}

.credibility p {
  max-width: 48rem;
  margin-inline: auto;
  margin-bottom: var(--space-3);
}

.credibility a {
  color: rgba(255, 255, 255, 0.9);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.credibility a:hover {
  color: var(--color-text-inverse);
}

.credibility__links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-4);
  margin-top: var(--space-3);
  list-style: none;
}

.credibility__links li {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.credibility__links li::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: rgba(255,255,255,0.4);
}

.credibility__links li:first-child::before {
  display: none;
}

/* -------------------------
   14. FOOTER
   ------------------------- */
.site-footer {
  background-color: var(--color-surface-dark);
  color: rgba(255, 255, 255, 0.75);
  padding-block: var(--space-8) var(--space-6);
  font-size: var(--font-size-sm);
  border-top: 1px solid rgba(255,255,255,0.08);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-8);
}

@media (min-width: 48rem) {
  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.footer__heading {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-inverse);
  margin-bottom: var(--space-3);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.site-footer a {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-footer a:hover {
  color: var(--color-text-inverse);
}

.footer__contact-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer__contact-list a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.footer__links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer__social {
  list-style: none;
  display: flex;
  gap: var(--space-4);
  margin-top: var(--space-3);
}

.footer__social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  background: rgba(255,255,255,0.1);
  transition: background var(--transition-fast);
}

.footer__social a:hover {
  background: rgba(255,255,255,0.2);
}

.footer__social svg {
  width: 1.125rem;
  height: 1.125rem;
  fill: rgba(255,255,255,0.8);
}

.footer__legal {
  padding-top: var(--space-6);
  border-top: 1px solid rgba(255,255,255,0.08);
  text-align: center;
  font-size: var(--font-size-xs);
  color: rgba(255,255,255,0.5);
}

/* -------------------------
   15. FORM STYLES (apply.html)
   ------------------------- */
.form-section {
  padding-block: var(--space-9);
}

.form-intro {
  max-width: var(--max-width-narrow);
  margin-bottom: var(--space-8);
}

.form-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-5);
  max-width: var(--max-width-narrow);
}

@media (min-width: 36rem) {
  .form-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-field--full {
  grid-column: 1 / -1;
}

.form-field label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
}

.form-field .required-mark {
  color: var(--color-error);
}

.form-field input,
.form-field textarea,
.form-field select {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-light);
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  width: 100%;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  min-height: 2.75rem;
}

.form-field textarea {
  resize: vertical;
  min-height: 6rem;
}

.form-field input:focus,
.form-field textarea:focus,
.form-field select:focus {
  border-color: var(--color-focus);
  box-shadow: 0 0 0 1px var(--color-focus);
  outline: none;
}

.form-field input:invalid:not(:placeholder-shown),
.form-field textarea:invalid:not(:placeholder-shown) {
  border-color: var(--color-error);
}

.radio-group {
  display: flex;
  gap: var(--space-5);
  padding-top: var(--space-1);
}

.radio-option {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  cursor: pointer;
}

.radio-option input[type="radio"] {
  width: 1.25rem;
  height: 1.25rem;
  min-height: auto;
  accent-color: var(--color-accent);
  cursor: pointer;
}

.radio-option span {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-light);
  color: var(--color-text);
}

.form-submit {
  grid-column: 1 / -1;
  padding-top: var(--space-4);
}

.form-submit .btn {
  width: 100%;
}

@media (min-width: 36rem) {
  .form-submit .btn {
    width: auto;
  }
}

.form-privacy {
  grid-column: 1 / -1;
  padding: var(--space-5);
  background: var(--color-surface-alt);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-body);
}

.form-privacy strong {
  display: block;
  margin-bottom: var(--space-2);
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
}

.form-success {
  display: none;
  text-align: center;
  padding: var(--space-9);
}

.form-success.is-visible {
  display: block;
}

.form-success__icon {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-4);
}

/* -------------------------
   16. PAGE-LEVEL VARIANTS
   ------------------------- */
.page-apply .hero {
  padding-block: var(--space-5) var(--space-6);
  text-align: left;
}

@media (min-width: 48rem) {
  .page-apply .hero {
    padding-block: var(--space-8);
  }
}

.page-apply .hero__heading {
  margin-inline: 0;
  max-width: none;
}

.page-apply .hero__sub {
  margin-inline: 0;
  max-width: 36rem;
}

/* -------------------------
   17. PRINT STYLES
   ------------------------- */
@media print {
  .site-header,
  .lite-yt,
  .gallery,
  .footer__social {
    display: none;
  }

  body {
    font-size: 12pt;
    color: #000;
    background: #fff;
  }

  a {
    color: #000;
    text-decoration: underline;
  }

  .section, .section--alt, .section--dark {
    background: #fff !important;
    color: #000 !important;
    padding-block: 1rem;
  }
}