:root {
  /* AWS Palette */
  --color-squid-ink: #232F3E;
  --color-squid-ink-light: #3c4d63;
  --color-smile-orange: #FF9900;
  --color-smile-orange-hover: #e88b00;
  --color-white: #ffffff;
  --color-light-gray: #f2f3f3;
  --color-text-main: #232F3E;
  --color-text-light: #545b64;
  --color-border: #eaeded;

  /* Layout */
  --container-width: 1200px;
  --header-height: 80px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;

  /* Gradient Animation */
  --gradient-bg: linear-gradient(-45deg, #232F3E, #2f1c42, #161e2d, #521c42);
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-white: #161e2d;
    --color-light-gray: #0d1117;
    --color-text-main: #f2f3f3;
    --color-text-light: #d5dbdb;
    --color-border: #3c4d63;
    --color-squid-ink: #000000;
  }
}

/* Explicit light mode overrides when body has .light-mode class */
body.light-mode {
  --color-white: #ffffff;
  --color-light-gray: #f2f3f3;
  --color-text-main: #232F3E;
  --color-text-light: #545b64;
  --color-border: #eaeded;
  --color-squid-ink: #232F3E;
}

/* Explicit dark mode overrides when body has .dark-mode class */
body.dark-mode {
  --color-white: #161e2d;
  --color-light-gray: #0d1117;
  --color-text-main: #f2f3f3;
  --color-text-light: #d5dbdb;
  --color-border: #3c4d63;
  --color-squid-ink: #000000;
}


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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--color-light-gray);
  color: var(--color-text-main);
  line-height: 1.6;
}

/* Force vertical scrollbar to avoid layout shift */
html {
  overflow-y: scroll;
}

/* Animated Background Class */
.animated-bg {
  background: var(--gradient-bg);
  background-size: 400% 400%;
  animation: gradientBG 15s ease infinite;
  color: white;
  /* Ensure text is readable on dark animated bg */
}

@keyframes gradientBG {
  0% {
    background-position: 0% 50%;
  }

  50% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0% 50%;
  }
}

a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition-fast);
}

ul {
  list-style: none;
}

/* Utilities */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast);
  font-size: 1rem;
}

.btn-primary {
  background-color: var(--color-smile-orange);
  color: #232F3E;
  /* Orange on Dark Blue usually, but black text on orange is readable. Let's stick to brand guidelines or good contrast */
  color: #000;
}

.btn-primary:hover {
  background-color: var(--color-smile-orange-hover);
  transform: translateY(-1px);
}

.btn-outline {
  background-color: transparent;
  border: 2px solid var(--color-smile-orange);
  color: var(--color-smile-orange);
}

.btn-outline:hover {
  background-color: var(--color-smile-orange);
  color: #000;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 3rem;
  text-align: center;
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: var(--color-smile-orange);
  margin: 1rem auto 0;
  border-radius: 2px;
}

/* Header */
header {
  background-color: var(--color-squid-ink);
  color: white;
  height: var(--header-height);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-md);
}

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

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo span {
  color: var(--color-smile-orange);
}

nav ul {
  display: flex;
  gap: 2rem;
}

nav a {
  font-weight: 500;
  opacity: 0.9;
}

nav a:hover,
nav a.active {
  opacity: 1;
  color: var(--color-smile-orange);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 1.5rem;
  cursor: pointer;
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.theme-toggle,
.header-icon-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.2rem;
  color: white;
  padding: 0.5rem;
  border-radius: 50%;
  transition: background 0.2s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover,
.header-icon-btn:hover {
  background: rgba(255, 255, 255, 0.1);
}

.theme-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* Hero Section */
.hero {
  /* background: linear-gradient(135deg, var(--color-squid-ink) 0%, var(--color-squid-ink-light) 100%); REMOVED to prioritize animated class if present */
  color: white;
  padding: 6rem 0;
  position: relative;
  overflow: hidden;
  text-align: center;
}

.hero-content {
  position: relative;
  z-index: 10;
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: 1.5rem;
  line-height: 1.2;
}

.hero p {
  font-size: 1.25rem;
  margin-bottom: 2.5rem;
  opacity: 0.9;
}

.hero-meta {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 2.5rem;
  font-weight: 500;
  color: var(--color-smile-orange);
}

.countdown {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 3rem;
}

.countdown-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.countdown-number {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-smile-orange);
}

.countdown-label {
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* Sections */
section {
  padding: 5rem 0;
}

/* Sponsors */
.sponsors-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 3rem;
  align-items: center;
}

.sponsor-card {
  background: white;
  padding: 2rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  height: 120px;
  width: 250px;
}

@media (prefers-color-scheme: dark) {
  .sponsor-card {
    background: #1e2a3b;
  }
}

.sponsor-card img {
  max-width: 100%;
  max-height: 100%;
  filter: grayscale(0%);
  transition: all var(--transition-fast);
  opacity: 1;
  transform: scale(1);
}

.sponsor-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}

.sponsor-card:hover img {
  filter: brightness(1.2) saturate(1.2);
  transform: scale(1.1);
  opacity: 1;
}

/* Registration Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
  backdrop-filter: blur(5px);
}

.modal-overlay.open {
  opacity: 1;
  pointer-events: all;
}

.modal {
  background: var(--color-white);
  padding: 2.5rem;
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 500px;
  position: relative;
  transform: translateY(20px);
  transition: transform var(--transition-normal);
  box-shadow: var(--shadow-lg);
}

.modal.modal-wide {
  max-width: 760px;
  max-height: 85vh;
  overflow-y: auto;
}

.modal-overlay.open .modal {
  transform: translateY(0);
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1.5rem;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-text-light);
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  /* Ensure contrast */
  color: var(--color-text-main);
  font-size: 1rem;
}

.modal .coc-list {
  list-style: disc;
  padding-left: 1.25rem;
  color: var(--color-text-main);
}

.modal .coc-list li {
  margin-bottom: 0.75rem;
}

/* Schedule Contrast Fix */
.session-card {
  background: var(--color-white);
  /* Force dark text in card even if global is weird, but rely on vars mostly */
  color: var(--color-text-main);
}

/* Organizers Section */
.organizers-grid {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 2rem;
  margin-top: 2rem;
}

.organizer-card {
  text-align: center;
  width: 200px;
}

.organizer-img {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  margin-bottom: 1rem;
  border: 3px solid var(--color-smile-orange);
}

/* Social Buttons */
.social-buttons {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
}

.social-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  transition: all 0.2s;
}

/* Default brand colors */
.social-btn .fa-linkedin,
.social-btn .fa-linkedin-in {
  color: #0077b5;
}

.social-btn .fa-github {
  color: white;
}

.social-btn .fa-youtube {
  color: #ff0000;
}

.social-btn .fa-twitch {
  color: #9146ff;
}

.social-btn .fa-meetup {
  color: #f64060;
}

.social-btn .fa-twitter {
  color: #1da1f2;
}

.social-btn .fa-facebook {
  color: #1877f2;
}

.social-btn .fa-discord {
  color: #5865f2;
}

/* Hover highlight effect */
.social-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.social-btn:hover .fa-linkedin,
.social-btn:hover .fa-linkedin-in {
  color: #00a0dc;
  filter: brightness(1.2);
}

.social-btn:hover .fa-github {
  color: white;
  filter: brightness(1.2);
}

.social-btn:hover .fa-discord {
  color: #7289da;
  filter: brightness(1.2);
}

.social-btn:hover .fa-youtube {
  color: #ff0000;
  filter: brightness(1.2);
}

.social-btn:hover .fa-twitch {
  color: #a970ff;
  filter: brightness(1.2);
}

.social-btn:hover .fa-meetup {
  color: #ff5a60;
  filter: brightness(1.2);
}

.social-btn:hover .fa-twitter {
  color: #1da1f2;
  filter: brightness(1.2);
}

.social-btn:hover .fa-facebook {
  color: #42a5f5;
  filter: brightness(1.2);
}

.calendar-options {
  display: none;
  /* Hidden by default */
  flex-direction: column;
  gap: 1rem;
  margin-top: 2rem;
  text-align: center;
}

.calendar-options.visible {
  display: flex;
}

/* Footer */
footer {
  background-color: var(--color-squid-ink);
  color: var(--color-text-light);
  padding: 4rem 0;
  text-align: center;
}

.footer-content h3 {
  color: white;
  margin-bottom: 1rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 1rem;
  }

  .section-title {
    font-size: 1rem;
  }

  .hero p {
    font-size: 0rem;
  }

  .mobile-menu-btn {
    display: block;
  }

  nav ul {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-squid-ink);
    flex-direction: column;
    padding: 2rem;
    gap: 1.5rem;
    transform: translateY(-150%);
    transition: transform var(--transition-normal);
    z-index: 999;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  }

  nav ul.is-open {
    transform: translateY(0);
  }
}