/* ═══════════════════════════════════════════
   AI in the Enterprise — Design System
   Cornell Tech Strategy & Consulting Club
   ═══════════════════════════════════════════ */

:root {
  --bg-deep: #0c0618;
  --bg-mid: #271248;
  --bg-warm: #5e2a64;
  --accent-rose: #b85868;
  --accent-soft: #a84d5e;
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.75);
  --text-muted: rgba(255, 255, 255, 0.55);
  --text-faint: rgba(255, 255, 255, 0.35);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-light: rgba(255, 255, 255, 0.15);
  --surface-glass: rgba(255, 255, 255, 0.04);
  --gradient-main: linear-gradient(140deg, #0c0618 0%, #160b30 15%, #271248 30%, #432060 45%, #5e2a64 55%, #7a3460 65%, #96405c 78%, #a84d5e 90%, #b85868 100%);
  --gradient-header: linear-gradient(140deg, #0c0618 0%, #1e0e42 40%, #3d1a5c 70%, #5e2a64 100%);
  --font-display: 'Sora', sans-serif;
  --font-body: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --page-px: 64px;
  --page-max: 1120px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  color: var(--text-primary);
  background: var(--bg-deep);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ═══════════════════════════════════════════
   NAV BAR
   ═══════════════════════════════════════════ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 0 var(--page-px);
  background: rgba(12, 6, 24, 0.75);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
}

.nav-inner {
  max-width: var(--page-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  height: 32px;
  overflow: hidden;
  display: flex;
  align-items: center;
}

.nav-logo img {
  width: 150px;
  height: auto;
  filter: brightness(0) invert(1);
  margin-top: -58px;
  margin-bottom: -58px;
  opacity: 0.85;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.3px;
  transition: color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
}

.nav-register {
  display: inline-flex;
  align-items: center;
  padding: 8px 20px;
  background: var(--accent-rose);
  border-radius: 6px;
  font-size: 13px;
  font-weight: 600;
  color: #fff;
  letter-spacing: 0.3px;
  transition: background 0.2s, transform 0.2s;
}

.nav-register:hover {
  background: #c96474;
  transform: translateY(-1px);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-secondary);
  margin: 5px 0;
  border-radius: 1px;
  transition: 0.3s;
}

/* ═══════════════════════════════════════════
   PAGE HEADER (for inner pages)
   ═══════════════════════════════════════════ */

.page-header {
  padding: 140px var(--page-px) 60px;
  background: var(--gradient-header);
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 80% at 75% 20%, rgba(168, 77, 94, 0.2) 0%, transparent 60%),
    radial-gradient(ellipse 60% 60% at 10% 80%, rgba(12, 6, 24, 0.6) 0%, transparent 50%);
  pointer-events: none;
}

.page-header-inner {
  max-width: var(--page-max);
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.page-header h1 {
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 800;
  letter-spacing: -1.5px;
  line-height: 1.1;
  margin-bottom: 12px;
}

.page-header p {
  font-size: clamp(15px, 1.3vw, 18px);
  color: var(--text-muted);
  max-width: 520px;
  line-height: 1.6;
}

/* ═══════════════════════════════════════════
   SECTIONS (inner pages)
   ═══════════════════════════════════════════ */

.section {
  padding: 80px var(--page-px);
  background: var(--bg-deep);
}

.section-inner {
  max-width: var(--page-max);
  margin: 0 auto;
}

.section-label {
  font-family: var(--font-display);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 4px;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-bottom: 40px;
}

/* ═══════════════════════════════════════════
   CTA BANNER
   ═══════════════════════════════════════════ */

.cta-banner {
  padding: 64px var(--page-px);
  background: linear-gradient(135deg, #271248 0%, #5e2a64 50%, #96405c 100%);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 50%, rgba(184, 88, 104, 0.2) 0%, transparent 60%);
  pointer-events: none;
}

.cta-inner {
  position: relative;
  z-index: 1;
  max-width: 560px;
  margin: 0 auto;
}

.cta-banner h2 {
  font-family: var(--font-display);
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 12px;
}

.cta-banner p {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 28px;
}

.cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 36px;
  background: #fff;
  color: var(--bg-mid);
  border-radius: 8px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.3px;
  transition: transform 0.2s, box-shadow 0.2s;
}

.cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}

.cta-btn .arrow-icon {
  font-size: 18px;
  transition: transform 0.2s;
}

.cta-btn:hover .arrow-icon {
  transform: translateX(3px);
}

/* ═══════════════════════════════════════════
   FOOTER
   ═══════════════════════════════════════════ */

.footer {
  padding: 40px var(--page-px);
  background: var(--bg-deep);
  border-top: 1px solid var(--border-subtle);
}

.footer-inner {
  max-width: var(--page-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-left {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.footer-name {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
}

.footer-copy {
  font-size: 12px;
  color: var(--text-faint);
}

.footer-links {
  display: flex;
  gap: 24px;
  list-style: none;
}

.footer-links a {
  font-size: 12px;
  color: var(--text-faint);
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--text-secondary);
}

/* ═══════════════════════════════════════════
   SPEAKER CARDS (shared)
   ═══════════════════════════════════════════ */

.speaker-photo {
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
  border: 2px solid var(--border-light);
  background: var(--surface-glass);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.35), 0 0 40px rgba(107, 36, 98, 0.15);
  position: relative;
}

.speaker-photo::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: linear-gradient(135deg, rgba(30, 14, 66, 0.15) 0%, rgba(176, 74, 94, 0.1) 100%);
  mix-blend-mode: color;
  pointer-events: none;
}

.speaker-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  filter: contrast(1.05) brightness(1.02);
}

/* ═══════════════════════════════════════════
   PILL / TAG
   ═══════════════════════════════════════════ */

.pill {
  display: inline-block;
  padding: 6px 15px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 100px;
  font-size: 12px;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.7);
  background: var(--surface-glass);
}

/* ═══════════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════════ */

@media (max-width: 768px) {
  :root {
    --page-px: 24px;
  }

  .nav-links { display: none; }
  .nav-toggle { display: block; }

  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(12, 6, 24, 0.95);
    backdrop-filter: blur(20px);
    padding: 24px var(--page-px);
    gap: 20px;
    border-bottom: 1px solid var(--border-subtle);
  }

  .footer-inner {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
}