/* Ensure canvas overscroll background matches dark mode default */
html {
  background-color: #0d0f12;
  min-height: 100%;
}

/* DARK MODE (New Default) */
:root {
  --bg-image: url('assets/darkmode.png');
  --bg-overlay: rgba(13, 15, 18, 0);
  --card-bg: rgba(22, 25, 32, 0.8);
  --card-hover-bg: rgba(30, 35, 45, 0.95);
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --text: #f8fafc;
  --muted: #94a3b8;
  --border: rgba(255, 255, 255, 0.1);
  --footer-text: #94a3b8;
  --card-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
}

/* LIGHT MODE OVERRIDES */
[data-theme="light"] {
  --bg-image: url('assets/lightmode.png');
  --bg-overlay: rgba(255, 255, 255, 0);
  --card-bg: rgba(255, 255, 255, 0.75);
  --card-hover-bg: rgba(255, 255, 255, 0.9);
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --text: #0f172a;
  --muted: #475569;
  --border: rgba(226, 232, 240, 0.8);
  --footer-text: #334155;
  --card-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}

[data-theme="light"],
[data-theme="light"] body {
  background-color: #f8fafc;
}

/* Default (Dark Mode): Show Dark Logo, Hide Light Logo */
.logo-dark {
  display: block;
}
.logo-light {
  display: none;
}

/* Light Mode Overrides: Hide Dark Logo, Show Light Logo */
[data-theme="light"] .logo-light {
  display: block;
}
[data-theme="light"] .logo-dark {
  display: none;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background-color: #0d0f12;
  background-image: linear-gradient(var(--bg-overlay), var(--bg-overlay)), var(--bg-image);
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  background-repeat: no-repeat;
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
  transition: background-image 0.3s ease, color 0.3s ease, background-color 0.3s ease;
}

/* Theme Toggle Button */
.theme-toggle-btn {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.6rem 1rem;
  color: var(--text);
  font-weight: 600;
  font-size: 0.875rem;
  cursor: pointer;
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
  box-shadow: var(--card-shadow);
}

.theme-toggle-btn:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

/* Header Styling */
header {
  text-align: center;
  margin-bottom: 3rem;
  max-width: 600px;
}

header h1 {
  font-size: 2.75rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-bottom: 0.75rem;
}

header p {
  color: var(--muted);
  font-size: 1.1rem;
  line-height: 1.5;
}

/* Navigation / Back Button */
nav.top-nav {
  width: 100%;
  max-width: 800px;
  margin-bottom: 2rem;
}

.back-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  transition: color 0.2s ease;
}

.back-link:hover {
  color: var(--accent);
}

/* Grid Layout for Hub Cards */
.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  width: 100%;
  max-width: 800px;
}

.hub-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.75rem;
  text-decoration: none;
  color: var(--text);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  backdrop-filter: blur(12px);
  transition: all 0.25s ease;
  min-height: 160px;
  box-shadow: var(--card-shadow);
}

.hub-card:hover {
  background: var(--card-hover-bg);
  border-color: var(--accent);
  transform: translateY(-4px);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.5rem;
}

.card-title span.arrow {
  color: var(--accent);
  transition: transform 0.2s ease;
}

.hub-card:hover .card-title span.arrow {
  transform: translateX(4px);
}

.card-desc {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.4;
}

/* Dynamic Logo Styling */
.logo-card {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

.logo-card img {
  max-width: 100%;
  height: auto;
  max-height: 80px;
  object-fit: contain;
  transition: opacity 0.2s ease;
}

/* Home Button (Top Left) */
.home-btn {
  position: absolute;
  top: 1.5rem;
  left: 1.5rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.6rem 1rem;
  color: var(--text);
  font-weight: 600;
  font-size: 0.875rem;
  text-decoration: none;
  cursor: pointer;
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
  box-shadow: var(--card-shadow);
}

.home-btn:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

/* Default (Light Mode): Show Light Logo, Hide Dark Logo */
.logo-dark {
  display: none;
}
.logo-light {
  display: block;
}

/* Dark Mode Overrides: Hide Light Logo, Show Dark Logo */
[data-theme="dark"] .logo-light {
  display: none;
}
[data-theme="dark"] .logo-dark {
  display: block;
}

/* Footer Styling */
footer {
  margin-top: 4rem;
  color: var(--footer-text);
  font-size: 0.85rem;
  text-align: center;
}