/* ============================================
   TECH LEADERSHIP — styles.css
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400&display=swap');

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --black:    #000000;
  --white:    #ffffff;
  --gray-50:  #fafafa;
  --gray-100: #f4f4f4;
  --gray-200: #e4e4e4;
  --gray-400: #a0a0a0;
  --gray-600: #666666;
  --gray-800: #2a2a2a;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --max-w: 1080px;
  --pad: clamp(20px, 5vw, 48px);
}

html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--gray-800);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }

/* ── NAVIGATION ───────────────────────────── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 16px var(--pad);
}
.nav-logo { display: flex; align-items: center; }
.nav-logo img { height: 44px; width: auto; }
.nav-logo:hover { opacity: 0.75; }

.nav-links {
  display: none;
  list-style: none;
  gap: 32px;
}
.nav-links a {
  font-size: 13px;
  font-weight: 500;
  color: var(--gray-600);
  letter-spacing: 0.03em;
  transition: color 0.15s;
}
.nav-links a:hover { color: var(--black); }

.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--black);
  transition: transform 0.25s, opacity 0.25s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-mobile {
  display: none;
  flex-direction: column;
  background: var(--white);
  border-top: 1px solid var(--gray-200);
  padding: 24px var(--pad) 32px;
  gap: 0;
}
.nav-mobile.open { display: flex; }
.nav-mobile a {
  font-size: 20px;
  font-weight: 400;
  color: var(--black);
  padding: 16px 0;
  border-bottom: 1px solid var(--gray-100);
  display: block;
  transition: color 0.15s;
}
.nav-mobile a:hover { color: var(--gray-600); }

@media (min-width: 768px) {
  .nav-links { display: flex; }
  .nav-toggle { display: none; }
}

/* ── HERO ─────────────────────────────────── */
.hero {
  background: var(--black);
  color: var(--white);
  text-align: center;
  padding: clamp(72px, 12vw, 120px) var(--pad);
}
.hero-inner { max-width: 620px; margin: 0 auto; }

.hero h1 {
  font-size: clamp(38px, 6vw, 64px);
  font-weight: 300;
  letter-spacing: -0.03em;
  line-height: 1.08;
  margin-bottom: 24px;
}
.hero h1 strong { font-weight: 700; }

.hero p {
  font-size: clamp(15px, 2vw, 17px);
  line-height: 1.75;
  color: rgba(255,255,255,0.72);
  margin-bottom: 40px;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

/* ── BUTTONS ──────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 30px;
  font-family: var(--font);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border: 2px solid;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  text-decoration: none;
}
.btn:hover { text-decoration: none; }

.btn-white { color: var(--black); background: var(--white); border-color: var(--white); }
.btn-white:hover { background: transparent; color: var(--white); }

.btn-black { color: var(--white); background: var(--black); border-color: var(--black); }
.btn-black:hover { background: transparent; color: var(--black); }

.btn-outline { color: var(--black); background: transparent; border-color: var(--black); }
.btn-outline:hover { background: var(--black); color: var(--white); }

/* ── SECTION LABELS ───────────────────────── */
.label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gray-400);
  margin-bottom: 14px;
}
.text-center { text-align: center; }

/* ── EVENTS SECTION ───────────────────────── */
.events {
  padding: clamp(60px, 8vw, 96px) var(--pad);
  text-align: center;
  border-bottom: 1px solid var(--gray-200);
}
.events h2 {
  font-size: clamp(26px, 4vw, 40px);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 8px;
}
.events .sub {
  font-size: 17px;
  color: var(--gray-600);
  margin-bottom: 36px;
  font-style: italic;
}
.events-btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ── GALLERY SECTION ──────────────────────── */
.gallery {
  padding: clamp(60px, 8vw, 96px) var(--pad);
  background: var(--gray-50);
  border-bottom: 1px solid var(--gray-200);
}
.gallery-header {
  text-align: center;
  max-width: 560px;
  margin: 0 auto 48px;
}
.gallery-header h2 {
  font-size: clamp(24px, 3.5vw, 36px);
  font-weight: 400;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}
.gallery-header p {
  font-size: 15px;
  color: var(--gray-600);
  line-height: 1.65;
}
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 4px;
  max-width: var(--max-w);
  margin: 0 auto;
}
/* Photo placeholder tiles */
.gallery-tile {
  aspect-ratio: 4/3;
  background: var(--gray-200);
  overflow: hidden;
  position: relative;
}
.gallery-tile img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
.gallery-tile:hover img { transform: scale(1.04); }
/* Placeholder style when no image yet */
.gallery-tile.placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--gray-400);
}
.gallery-tile.placeholder span {
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.gallery-tile.placeholder svg { opacity: 0.4; }

/* ── SPONSORS SECTION ─────────────────────── */
.sponsors {
  padding: clamp(60px, 8vw, 96px) var(--pad);
  border-bottom: 1px solid var(--gray-200);
}
.sponsors-inner { max-width: var(--max-w); margin: 0 auto; }
.sponsors-header { text-align: center; margin-bottom: 56px; }
.sponsors-header h2 {
  font-size: clamp(24px, 3.5vw, 36px);
  font-weight: 400;
  letter-spacing: -0.02em;
}

.sponsor-card {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: start;
  padding: 40px;
  border: 1px solid var(--gray-200);
  background: var(--white);
}
.sponsor-logo img {
  height: 48px;
  width: auto;
}
.sponsor-body h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 14px;
}
.sponsor-body p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--gray-600);
  margin-bottom: 14px;
}

/* YouTube embed */
.video-wrap {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  background: var(--gray-200);
  margin-top: 32px;
}
.video-wrap iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: none;
}

@media (min-width: 768px) {
  .sponsor-card { grid-template-columns: 200px 1fr; gap: 56px; }
}

/* ── PAGE HERO (inner pages) ──────────────── */
.page-hero {
  background: var(--black);
  color: var(--white);
  padding: clamp(56px, 8vw, 96px) var(--pad);
  text-align: center;
}
.page-hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 300;
  letter-spacing: -0.02em;
}

/* ── ABOUT PAGE ───────────────────────────── */
.about-quote {
  max-width: 680px;
  margin: 0 auto;
  padding: clamp(48px, 7vw, 80px) var(--pad);
  text-align: center;
  border-bottom: 1px solid var(--gray-200);
}
.about-quote p {
  font-size: clamp(20px, 2.8vw, 28px);
  font-weight: 300;
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--gray-800);
}
.about-body {
  max-width: 680px;
  margin: 0 auto;
  padding: clamp(48px, 7vw, 80px) var(--pad);
}
.about-body p {
  font-size: 16px;
  line-height: 1.85;
  color: var(--gray-600);
  margin-bottom: 24px;
}
.about-body p:last-child { margin-bottom: 0; }

/* ── CODE OF CONDUCT PAGE ─────────────────── */
.coc-body {
  max-width: 720px;
  margin: 0 auto;
  padding: clamp(48px, 7vw, 80px) var(--pad);
}
.coc-section {
  margin-bottom: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--gray-200);
}
.coc-section:last-child {
  border-bottom: none;
  margin-bottom: 0;
}
.coc-section h2 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--black);
}
.coc-section p {
  font-size: 15px;
  line-height: 1.85;
  color: var(--gray-600);
  margin-bottom: 14px;
}
.coc-section p:last-child { margin-bottom: 0; }
.coc-section p.muted { font-size: 13px; color: var(--gray-400); }
.coc-section a { color: var(--black); text-decoration: underline; }
.coc-section a:hover { color: var(--gray-600); }

/* ── BOOKS PAGE ───────────────────────────── */
.books-intro {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  padding: clamp(48px, 7vw, 72px) var(--pad) 40px;
}
.books-intro h2 {
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 400;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}
.books-intro p { font-size: 15px; line-height: 1.75; color: var(--gray-600); }

.books-list {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--pad) clamp(60px, 8vw, 96px);
}
.book-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 24px;
  padding: 32px 0;
  border-bottom: 1px solid var(--gray-200);
  align-items: start;
}
.book-item:first-child { border-top: 1px solid var(--gray-200); }
.book-cover-link { display: block; flex-shrink: 0; }
.book-cover {
  width: 90px;
  height: auto;
  display: block;
  box-shadow: 0 2px 12px rgba(0,0,0,0.15);
  transition: opacity 0.2s, transform 0.2s;
}
.book-cover-link:hover .book-cover { opacity: 0.85; transform: translateY(-2px); }
.book-cover-placeholder {
  width: 90px;
  height: 130px;
  background: var(--gray-100);
  border: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  color: var(--gray-400);
  text-align: center;
}
.book-info h3 {
  font-size: 15px;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 6px;
}
.book-info h3 a { color: var(--black); }
.book-info h3 a:hover { text-decoration: underline; }
.book-author { font-size: 13px; color: var(--gray-400); font-style: italic; margin-bottom: 10px; }
.book-blurb { font-size: 14px; line-height: 1.7; color: var(--gray-600); }

/* ── ORGANISERS PAGE ──────────────────────── */
.organisers {
  padding: clamp(48px, 7vw, 80px) var(--pad);
}
.organisers-header {
  text-align: center;
  max-width: 560px;
  margin: 0 auto 56px;
}
.organisers-header h2 {
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 400;
  letter-spacing: -0.02em;
}
.organisers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 300px));
  gap: 48px;
  max-width: var(--max-w);
  margin: 0 auto;
  justify-content: center;
}
.organiser-card { text-align: center; }
.organiser-card > a:first-child { display: block; }
.organiser-photo {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  object-position: center top;
  margin-bottom: 16px;
  transition: opacity 0.2s;
}
.organiser-card > a:first-child:hover .organiser-photo { opacity: 0.85; }
.organiser-photo-placeholder {
  width: 100%;
  aspect-ratio: 1;
  background: var(--gray-100);
  border: 1px solid var(--gray-200);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--gray-400);
  font-size: 13px;
}
.organiser-name {
  display: block;
  font-size: 16px;
  font-weight: 500;
  color: var(--black);
  text-decoration: underline;
  margin-bottom: 4px;
}
.organiser-name:hover { color: var(--gray-600); text-decoration: underline; }
.organiser-role { font-size: 13px; color: var(--gray-400); }

/* ── FOOTER ───────────────────────────────── */
.footer {
  background: var(--black);
  color: var(--white);
  padding: clamp(48px, 7vw, 80px) var(--pad) 32px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  max-width: var(--max-w);
  margin: 0 auto 48px;
}
.footer-logo img { height: 48px; width: auto; filter: invert(1); margin-bottom: 12px; }
.footer-tagline { font-size: 13px; color: rgba(255,255,255,0.5); line-height: 1.6; max-width: 220px; }

.footer-col h4 {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.4);
  margin-bottom: 16px;
}
.footer-col a, .footer-col p {
  display: block;
  font-size: 14px;
  color: rgba(255,255,255,0.75);
  margin-bottom: 10px;
  line-height: 1.5;
  transition: color 0.15s;
}
.footer-col a:hover { color: var(--white); text-decoration: none; }

.footer-bottom {
  max-width: var(--max-w);
  margin: 0 auto;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-bottom p { font-size: 12px; color: rgba(255,255,255,0.35); letter-spacing: 0.04em; }
.footer-bottom a { font-size: 12px; color: rgba(255,255,255,0.35); transition: color 0.15s; }
.footer-bottom a:hover { color: rgba(255,255,255,0.8); }

@media (min-width: 640px) {
  .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; }
}