/* Global CSS Variables & Design Tokens */
:root {
  --color-bg: #070708;
  --color-surface: rgba(13, 13, 18, 0.65);
  --color-border: rgba(52, 211, 153, 0.15);
  --color-border-hover: rgba(52, 211, 153, 0.6);
  --color-accent: #00ff9d;
  --color-accent-secondary: #00ccff;
  --color-accent-tertiary: #ff3366;
  --color-text: #f3f4f6;
  --font-sans: 'Outfit', ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

html {
  scroll-behavior: smooth;
  background-color: var(--color-bg);
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Glassmorphism Navigation Bar */
nav.fixed {
  margin: 1rem auto;
  left: 1rem;
  right: 1rem;
  width: calc(100% - 2rem);
  max-width: 80rem;
  border-radius: 1.25rem;
  border: 1px solid rgba(52, 211, 153, 0.2);
  background: rgba(7, 7, 8, 0.75);
  backdrop-filter: blur(20px);
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.7);
  transition: all 0.3s ease;
}

/* Custom Navigation Link Underline Animation */
.nav-link {
  position: relative;
  transition: color 0.3s ease;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-secondary));
  transition: width 0.3s ease;
}
.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

/* Typography Enhancements */
.neon-text {
  text-shadow: 0 0 10px rgba(0, 255, 157, 0.4), 0 0 25px rgba(0, 204, 255, 0.3);
}

.gradient-text {
  background: linear-gradient(135deg, #ffffff 30%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Premium Glass Cards with Glow on Hover */
.glass-card {
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  backdrop-filter: blur(16px);
  border-radius: 1.5rem;
  transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.glass-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-border-hover);
  box-shadow: 0 20px 40px -15px rgba(0, 255, 157, 0.15),
              0 0 20px -5px rgba(0, 255, 157, 0.1);
}

.card-glow {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  border-radius: 1.5rem;
  transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.card-glow::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(0, 255, 157, 0.05), rgba(0, 204, 255, 0.05));
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s ease;
}

.card-glow:hover {
  transform: translateY(-6px);
  border-color: var(--color-accent);
  box-shadow: 0 20px 45px -10px rgba(0, 255, 157, 0.2),
              0 0 30px -5px rgba(0, 204, 255, 0.15);
}

.card-glow:hover::before {
  opacity: 1;
}

/* Grayscale Sponsor Logos that Light Up on Hover */
.sponsor-card img {
  filter: grayscale(100%) brightness(0.85);
  transition: all 0.4s ease;
}

.sponsor-card:hover img {
  filter: grayscale(0%) brightness(1);
  transform: scale(1.05);
}

/* Cyberpunk-themed Countdown Boxes */
.countdown-box {
  border-radius: 1.25rem;
  border: 1px solid rgba(0, 255, 157, 0.25);
  background: rgba(10, 10, 15, 0.8);
  padding: 1.25rem;
  box-shadow: inset 0 0 15px rgba(0, 255, 157, 0.05);
  backdrop-filter: blur(10px);
  transition: border-color 0.3s ease;
}
.countdown-box:hover {
  border-color: var(--color-accent);
}

.countdown-number {
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  line-height: 1;
}

/* Premium Buttons with Glowing Micro-animations */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 1rem;
  padding: 0.875rem 1.75rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: #000000;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  background: linear-gradient(135deg, #00ff9d, #00ccff);
  cursor: pointer;
  border: none;
  box-shadow: 0 4px 15px rgba(0, 255, 157, 0.2);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 255, 157, 0.45),
              0 0 15px rgba(0, 204, 255, 0.3);
}

.btn-primary:active {
  transform: translateY(1px);
}

/* Dynamic Entrance / Scroll Reveal System (Pure JS / CSS) */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* Floating minimalist Scroll to Top button */
.scroll-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 50;
  display: none; /* JS toggles to flex */
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  border: 1px solid rgba(52, 211, 153, 0.35);
  background: rgba(10, 10, 15, 0.85);
  width: 3.5rem;
  height: 3.5rem;
  font-size: 1.125rem;
  color: #ffffff;
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(8px);
  transition: all 0.3s ease;
  cursor: pointer;
}

.scroll-top:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  transform: translateY(-3px);
  box-shadow: 0 15px 30px -5px rgba(0, 255, 157, 0.2);
}

/* Vertical Timeline Styling (Exhibition & Hackathon Schedules) */
.timeline-container {
  position: relative;
  padding-left: 2rem;
  border-left: 2px solid rgba(52, 211, 153, 0.25);
}
.timeline-dot {
  position: absolute;
  left: -6px;
  top: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 10px var(--color-accent);
}

/* Background Particles Layer */
.particles-bg {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100vh;
  z-index: 1;
  pointer-events: none;
}

.relative-z {
  position: relative;
  z-index: 2;
}

/* Fade-in animations for above fold hero elements */
.fade-in-up {
  animation: fadeInUp 1s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes fadeInUp {
  0% {
    opacity: 0;
    transform: translateY(30px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}