/* =========================================================
   ACTAG — Main Stylesheet
   Mobile-first, WCAG 2.1 AA, no CSS framework
   ========================================================= */

/* ── Google Fonts are loaded in each HTML <head> ── */

/* ─── CSS Custom Properties ─────────────────────────────── */
:root {
  /* Brand colors */
  --color-navy:       #1B3A6B;
  --color-navy-light: #2A5298;
  --color-sage:       #2D8A6E;
  --color-rose:       #9B2335;
  --color-amber:      #D4A843;

  /* Neutrals */
  --color-bg:         #F8F9FA;
  --color-white:      #FFFFFF;
  --color-border:     #E2E8F0;
  --color-gray-mid:   #64748B;
  --color-text:       #1E293B;
  --color-footer-bg:  #0F172A;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Spacing */
  --space-1:  8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --space-10: 80px;

  /* Layout */
  --max-width: 1200px;
  --section-padding-y: var(--space-6);

  /* Borders */
  --radius-card: 8px;
  --radius-btn:  6px;
}

/* ─── Reset / Base ──────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
}

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

a {
  color: var(--color-navy);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

ul {
  list-style: none;
}

/* ─── Skip to content ───────────────────────────────────── */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--color-navy);
  color: var(--color-white);
  padding: 12px 20px;
  font-size: 0.875rem;
  z-index: 9999;
  border-radius: 0 0 var(--radius-btn) 0;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
}

/* ─── Layout Utilities ──────────────────────────────────── */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-3);
}

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

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

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

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

/* ─── Typography ────────────────────────────────────────── */
h1, h2, h3, h4 {
  font-family: var(--font-family);
  color: var(--color-navy);
  line-height: 1.2;
}

h1 {
  font-size: 2rem; /* 32px mobile */
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

h2 {
  font-size: 1.75rem; /* 28px mobile */
  font-weight: 700;
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0;
  line-height: 1.3;
}

h4 {
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0;
  line-height: 1.4;
}

p {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  max-width: 720px;
}

.section--navy h1,
.section--navy h2,
.section--navy h3,
.section--navy h4,
.section--navy p {
  color: var(--color-white);
}

.text-center {
  text-align: center;
}

.text-gray {
  color: var(--color-gray-mid);
}

.section-title {
  margin-bottom: var(--space-3);
}

.section-intro {
  margin-bottom: var(--space-6);
  color: var(--color-gray-mid);
}

/* ─── Navigation ────────────────────────────────────────── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  background-color: var(--color-footer-bg);
  z-index: 1000;
  display: flex;
  align-items: center;
  transition: box-shadow 0.2s ease;
}

.nav.scrolled {
  box-shadow: 0 2px 16px rgba(0,0,0,0.25);
}

.nav__inner {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-3);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav__logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
}

.nav__logo svg {
  width: 120px;
  height: auto;
}

.nav__links {
  display: none;
  gap: var(--space-3);
  align-items: center;
}

.nav__links a {
  color: var(--color-bg);
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: color 0.2s ease;
  padding-block: 4px;
  border-bottom: 2px solid transparent;
}

.nav__links a:hover,
.nav__links a.active {
  color: var(--color-white);
  border-bottom-color: var(--color-amber);
}

/* Hamburger */
.nav__hamburger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 8px;
  z-index: 1100;
}

.nav__hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-bg);
  transition: all 0.2s ease;
  border-radius: 2px;
}

.nav__hamburger[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav__hamburger[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav__hamburger[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile menu overlay */
.nav__mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background-color: var(--color-footer-bg);
  z-index: 1050;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
}

.nav__mobile-overlay.open {
  display: flex;
}

.nav__mobile-overlay a {
  color: var(--color-bg);
  font-size: 1.5rem;
  font-weight: 500;
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: color 0.2s ease;
}

.nav__mobile-overlay a:hover {
  color: var(--color-amber);
  text-decoration: none;
}

.nav__mobile-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: none;
  border: none;
  color: var(--color-bg);
  font-size: 2rem;
  cursor: pointer;
  line-height: 1;
  padding: 8px;
}

/* ─── Buttons ───────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 500;
  padding: 14px 28px;
  border-radius: var(--radius-btn);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
  white-space: nowrap;
}

.btn:hover {
  text-decoration: none;
}

.btn--primary {
  background-color: var(--color-navy);
  color: var(--color-white);
  border-color: var(--color-navy);
}

.btn--primary:hover {
  background-color: var(--color-navy-light);
  border-color: var(--color-navy-light);
  box-shadow: 0 4px 12px rgba(27, 58, 107, 0.3);
  color: var(--color-white);
}

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

.btn--secondary:hover {
  background-color: var(--color-navy);
  color: var(--color-white);
}

.btn--inverted {
  background-color: var(--color-white);
  color: var(--color-navy);
  border-color: var(--color-white);
}

.btn--inverted:hover {
  background-color: var(--color-bg);
  color: var(--color-navy);
}

/* Focus styles */
.btn:focus-visible,
a:focus-visible {
  outline: 3px solid var(--color-amber);
  outline-offset: 3px;
}

/* ─── Hero ──────────────────────────────────────────────── */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background-color: var(--color-bg);
  padding-top: 64px; /* nav height */
  position: relative;
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  opacity: 0.06;
  pointer-events: none;
  z-index: 0;
}

.hero__content {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  padding-block: var(--space-10);
}

.hero__wordmark {
  width: 180px;
  height: auto;
}

.hero__tagline {
  font-size: 1.125rem;
  font-weight: 300;
  letter-spacing: 0.15em;
  color: var(--color-gray-mid);
  text-transform: none;
}

.hero__description {
  font-size: 1.125rem;
  color: var(--color-gray-mid);
  max-width: 560px;
  margin-inline: auto;
}

.hero__buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  justify-content: center;
  margin-top: var(--space-1);
}

/* ─── Cards ─────────────────────────────────────────────── */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
}

.card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: var(--space-4);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  transition: box-shadow 0.2s ease;
  position: relative;
  overflow: hidden;
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.12);
}

.card--accent-sage  { border-top: 4px solid var(--color-sage); }
.card--accent-navy  { border-top: 4px solid var(--color-navy); }
.card--accent-amber { border-top: 4px solid var(--color-amber); }
.card--accent-rose  { border-top: 4px solid var(--color-rose); }

.card__icon {
  margin-bottom: var(--space-2);
  color: var(--color-navy);
}

.card__icon--sage  { color: var(--color-sage); }
.card__icon--navy  { color: var(--color-navy); }
.card__icon--amber { color: var(--color-amber); }

.card__title {
  margin-bottom: var(--space-1);
  color: var(--color-navy);
}

.card__body {
  color: var(--color-gray-mid);
  font-size: 0.9375rem;
  line-height: 1.6;
  max-width: 100%;
}

/* ─── Why Actag (icon blocks) ───────────────────────────── */
.icon-blocks {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.icon-block {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-2);
}

.icon-block__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background-color: var(--color-bg);
  color: var(--color-navy);
  flex-shrink: 0;
}

.icon-block__title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-navy);
}

.icon-block__body {
  color: var(--color-gray-mid);
  font-size: 0.9375rem;
  line-height: 1.6;
  max-width: 100%;
}

/* ─── Callout / Blockquote ──────────────────────────────── */
.callout {
  border-left: 4px solid var(--color-sage);
  padding: var(--space-3) var(--space-4);
  background-color: var(--color-white);
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
  margin-block: var(--space-4);
}

.callout p {
  color: var(--color-text);
  font-size: 1rem;
  font-style: italic;
}

/* ─── Service Sections ──────────────────────────────────── */
.service-section {
  padding: var(--space-4) var(--space-4);
  border-left: 4px solid var(--color-sage);
  margin-bottom: var(--space-6);
  background: var(--color-white);
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.service-section--sage  { border-left-color: var(--color-sage); }
.service-section--navy  { border-left-color: var(--color-navy); }
.service-section--amber { border-left-color: var(--color-amber); }

.service-section__header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}

.service-section__icon {
  flex-shrink: 0;
  color: var(--color-navy);
}

.service-section--sage .service-section__icon  { color: var(--color-sage); }
.service-section--amber .service-section__icon { color: var(--color-amber); }

.service-section__title {
  color: var(--color-navy);
}

.service-section p {
  color: var(--color-gray-mid);
  margin-bottom: var(--space-2);
  max-width: 100%;
}

.service-section ul {
  list-style: disc;
  padding-left: var(--space-3);
  color: var(--color-gray-mid);
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: var(--space-2);
}

.service-section ul li {
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* ─── Team Cards ────────────────────────────────────────── */
.team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.team-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: var(--space-4);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-2);
}

.team-card__photo {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background-color: var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--color-gray-mid);
  margin-bottom: var(--space-1);
}

.team-card__name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-navy);
}

.team-card__title-role {
  font-size: 0.9375rem;
  color: var(--color-sage);
  font-weight: 500;
}

.team-card__bio {
  font-size: 0.9375rem;
  color: var(--color-gray-mid);
  line-height: 1.6;
  max-width: 480px;
}

/* ─── Research / Publications ───────────────────────────── */
.pub-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.pub-item {
  padding: var(--space-3);
  border-left: 3px solid var(--color-navy);
  background: var(--color-white);
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
}

.pub-item__title {
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-navy);
  display: block;
  margin-bottom: 4px;
}

.pub-item__title:hover {
  text-decoration: underline;
  color: var(--color-navy-light);
}

.pub-item__meta {
  font-size: 0.875rem;
  color: var(--color-gray-mid);
  margin-bottom: 4px;
}

.pub-item__desc {
  font-size: 0.9375rem;
  color: var(--color-text);
  max-width: 100%;
}

/* Research stat cards */
.stat-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.stat-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-top: 4px solid var(--color-amber);
  border-radius: var(--radius-card);
  padding: var(--space-3);
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.stat-card__number {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-amber);
  display: block;
  margin-bottom: 4px;
}

.stat-card__label {
  font-size: 0.9375rem;
  color: var(--color-gray-mid);
  line-height: 1.5;
}

/* ─── Blog ──────────────────────────────────────────────── */
.blog-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.blog-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: var(--space-4);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  transition: box-shadow 0.2s ease;
}

.blog-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.12);
}

.blog-card__date {
  font-size: 0.875rem;
  color: var(--color-gray-mid);
  letter-spacing: 0.01em;
  margin-bottom: var(--space-1);
}

.blog-card__title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-navy);
  margin-bottom: var(--space-2);
}

.blog-card__excerpt {
  color: var(--color-gray-mid);
  font-size: 0.9375rem;
  line-height: 1.6;
  margin-bottom: var(--space-3);
  max-width: 100%;
}

.blog-card__link {
  color: var(--color-navy);
  font-weight: 500;
  font-size: 0.9375rem;
  text-decoration: none;
  border-bottom: 1px solid var(--color-navy);
  padding-bottom: 2px;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.blog-card__link:hover {
  color: var(--color-navy-light);
  border-color: var(--color-navy-light);
  text-decoration: none;
}

/* ─── Contact Form ──────────────────────────────────────── */
.contact-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: var(--space-3);
}

.form-group label {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text);
}

.form-group input,
.form-group textarea {
  font-family: var(--font-family);
  font-size: 1rem;
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-btn);
  background: var(--color-white);
  color: var(--color-text);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  width: 100%;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-navy);
  box-shadow: 0 0 0 3px rgba(27, 58, 107, 0.15);
}

.form-group textarea {
  resize: vertical;
  min-height: 140px;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.contact-info__item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-2);
}

.contact-info__icon {
  flex-shrink: 0;
  color: var(--color-navy);
  margin-top: 2px;
}

.contact-info__text {
  font-size: 0.9375rem;
  color: var(--color-gray-mid);
  line-height: 1.6;
}

.contact-info__text a {
  color: var(--color-navy);
}

.contact-info__text a:hover {
  color: var(--color-navy-light);
}

/* ─── CTA Section ───────────────────────────────────────── */
.cta-section {
  background-color: var(--color-navy);
  padding-block: var(--space-10);
  text-align: center;
}

.cta-section h2 {
  color: var(--color-white);
  margin-bottom: var(--space-2);
}

.cta-section p {
  color: rgba(248, 249, 250, 0.85);
  max-width: 540px;
  margin-inline: auto;
  margin-bottom: var(--space-4);
}

/* ─── Footer ────────────────────────────────────────────── */
.footer {
  background-color: var(--color-footer-bg);
  padding-block: var(--space-10) var(--space-4);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer__brand svg {
  width: 100px;
  height: auto;
  margin-bottom: var(--space-2);
}

.footer__tagline {
  font-size: 0.875rem;
  color: rgba(248, 249, 250, 0.7);
  letter-spacing: 0.08em;
  margin-bottom: var(--space-2);
  font-weight: 300;
}

.footer__copy {
  font-size: 0.8125rem;
  color: rgba(248, 249, 250, 0.5);
}

.footer__col-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-bg);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--space-2);
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer__links a {
  font-size: 0.9375rem;
  color: rgba(248, 249, 250, 0.7);
  text-decoration: none;
  transition: color 0.2s ease;
}

.footer__links a:hover {
  color: var(--color-white);
  text-decoration: none;
}

.footer__contact-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 12px;
}

.footer__contact-item svg {
  flex-shrink: 0;
  margin-top: 2px;
  color: rgba(248, 249, 250, 0.6);
}

.footer__contact-item a,
.footer__contact-item span {
  font-size: 0.9375rem;
  color: rgba(248, 249, 250, 0.7);
  text-decoration: none;
}

.footer__contact-item a:hover {
  color: var(--color-white);
  text-decoration: none;
}

.footer__social {
  display: flex;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.footer__social a {
  color: rgba(248, 249, 250, 0.6);
  transition: color 0.2s ease;
}

.footer__social a:hover {
  color: var(--color-white);
}

.footer__fine-print {
  margin-top: var(--space-4);
  font-size: 0.8125rem;
  color: rgba(248, 249, 250, 0.4);
  text-align: center;
}

/* ─── Fade-in animation ─────────────────────────────────── */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ─── Page header ───────────────────────────────────────── */
.page-header {
  background-color: var(--color-navy);
  padding-top: calc(64px + var(--space-8));
  padding-bottom: var(--space-8);
}

.page-header h1 {
  color: var(--color-white);
}

.page-header p {
  color: rgba(248, 249, 250, 0.8);
  margin-top: var(--space-2);
}

/* ─── Inline link ───────────────────────────────────────── */
.inline-link {
  color: var(--color-navy);
  font-weight: 500;
  border-bottom: 1px solid var(--color-navy);
  padding-bottom: 1px;
}

.inline-link:hover {
  color: var(--color-navy-light);
  border-color: var(--color-navy-light);
  text-decoration: none;
}

/* ─── Responsive — 768px ────────────────────────────────── */
@media (min-width: 768px) {
  :root {
    --section-padding-y: var(--space-10);
  }

  body {
    font-size: 1.125rem;
  }

  h1 {
    font-size: 3rem;
  }

  h2 {
    font-size: 2.25rem;
  }

  h3 {
    font-size: 1.5rem;
  }

  h4 {
    font-size: 1.25rem;
  }

  p {
    font-size: 1.125rem;
  }

  .nav__links {
    display: flex;
  }

  .nav__hamburger {
    display: none;
  }

  .hero__wordmark {
    width: 200px;
  }

  .hero__tagline {
    font-size: 1.25rem;
  }

  .hero__description {
    font-size: 1.125rem;
  }

  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .icon-blocks {
    grid-template-columns: repeat(3, 1fr);
  }

  .team-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .stat-cards {
    grid-template-columns: repeat(3, 1fr);
  }

  .blog-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact-layout {
    grid-template-columns: 1fr 1fr;
  }

  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

/* ─── Responsive — 1024px ───────────────────────────────── */
@media (min-width: 1024px) {
  .card-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .icon-blocks {
    grid-template-columns: repeat(3, 1fr);
  }
}
