/* GitHub-inspired Dark Theme */
:root {
  --gh-bg-primary: #0d1117;
  --gh-bg-secondary: #161b22;
  --gh-bg-tertiary: #21262d;
  --gh-border: #30363d;
  --gh-text-primary: #c9d1d9;
  --gh-text-secondary: #8b949e;
  --gh-accent-blue: #58a6ff;
  --gh-accent-green: #3fb950;
  --gh-accent-purple: #bc8cff;
  --gh-accent-pink: #f778ba;
  --gh-gradient-blue: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --gh-gradient-purple: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gh-gradient-pink: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --gh-gradient-green: linear-gradient(135deg, #4ade80 0%, #3b82f6 100%);
}

html {
  font-size: 14px;
  position: relative;
  min-height: 100%;
}

@media (min-width: 768px) {
  html {
    font-size: 16px;
  }
}

body {
  background-color: var(--gh-bg-primary);
  color: var(--gh-text-primary);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  flex: 1;
  padding-bottom: 200px;
}

footer {
  position: sticky;
  bottom: 0;
  flex-shrink: 0;
}

.btn-sponsor-gradient {
  background: var(--gh-bg-secondary);
  border: 2px solid transparent;
  background-image: linear-gradient(var(--gh-bg-secondary), var(--gh-bg-secondary)), var(--gh-gradient-pink);
  background-origin: border-box;
  background-clip: padding-box, border-box;
  color: #f5576c;
  font-weight: 700;
  padding: 0.75rem 2rem;
  border-radius: 8px;
  transition: all 0.3s;
}

.btn-sponsor-gradient:hover {
  color: #ffffff;
  box-shadow: 0 6px 20px rgba(240, 147, 251, 0.35);
  transform: translateY(-1px);
}

/* Gradient Hero Section */
.gradient-hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
  background-size: 200% 200%;
  animation: gradientShift 15s ease infinite;
  padding: 3rem 0;
  border-radius: 12px;
  margin-bottom: 2rem;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.gradient-hero h1 {
  color: #ffffff;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.gradient-hero .lead {
  color: rgba(255, 255, 255, 0.9);
}

/* Cards */
.card {
  background-color: var(--gh-bg-secondary);
  border: 1px solid var(--gh-border);
  border-radius: 12px;
  transition: transform 0.2s, box-shadow 0.2s;
}

/* Hover effect only for nested/inner cards */
.card .card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

/* Hover effect for tier selection cards on index page */
.tier-bronze:hover,
.tier-silver:hover,
.tier-gold:hover,
.tier-organization:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

.card-body {
  color: var(--gh-text-primary);
}

.card-header {
  border-bottom: 1px solid var(--gh-border);
  background: transparent;
}

/* Tier Cards with Gradients */
.tier-bronze {
  border: 2px solid transparent;
  background: var(--gh-bg-secondary) padding-box,
              linear-gradient(135deg, #cd7f32 0%, #b87333 100%) border-box;
  position: relative;
  overflow: hidden;
}

.tier-bronze::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #cd7f32 0%, #b87333 100%);
}

.tier-silver {
  border: 2px solid transparent;
  background: var(--gh-bg-secondary) padding-box,
              linear-gradient(135deg, #4ade80 0%, #3b82f6 100%) border-box;
  position: relative;
  overflow: hidden;
}

.tier-silver::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #4ade80 0%, #3b82f6 100%);
}

.tier-gold {
  border: 2px solid transparent;
  background: var(--gh-bg-secondary) padding-box,
              linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%) border-box;
  position: relative;
  overflow: hidden;
}

.tier-gold::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #fbbf24 0%, #f59e0b 100%);
}

.tier-organization {
  border: 2px solid transparent;
  background: var(--gh-bg-secondary) padding-box,
              linear-gradient(135deg, #f5576c 0%, #f778ba 100%) border-box;
  position: relative;
  overflow: hidden;
}

.tier-organization::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #f5576c 0%, #f778ba 100%);
}

.tier-card-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 1rem;
}

.tier-price {
  background: linear-gradient(135deg, var(--gh-accent-blue), var(--gh-accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Buttons */
.btn-primary {
  background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  border: none;
  color: #ffffff;
  font-weight: 600;
  padding: 0.75rem 2rem;
  border-radius: 8px;
  transition: all 0.3s;
}

.btn-primary:hover {
  background: linear-gradient(135deg, #3b9bfe 0%, #00d8e4 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(79, 172, 254, 0.4);
}

.btn-outline-secondary {
  border: 2px solid var(--gh-border);
  color: var(--gh-text-primary);
  font-weight: 600;
  padding: 0.75rem 2rem;
  border-radius: 8px;
  background: transparent;
  transition: all 0.3s;
}

.btn-outline-secondary:hover {
  background: var(--gh-bg-tertiary);
  border-color: var(--gh-accent-blue);
  color: var(--gh-accent-blue);
  transform: translateY(-2px);
}

.btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
  box-shadow: 0 0 0 0.1rem var(--gh-bg-primary), 0 0 0 0.25rem var(--gh-accent-blue);
}

/* Alert */
.alert-info {
  background: linear-gradient(135deg, rgba(88, 166, 255, 0.1) 0%, rgba(188, 140, 255, 0.1) 100%);
  border: 1px solid rgba(88, 166, 255, 0.3);
  color: var(--gh-accent-blue);
  border-radius: 8px;
}

/* Text Colors */
.text-muted {
  color: var(--gh-text-secondary) !important;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--gh-text-primary);
}

strong {
  color: #ffffff;
}

/* Lists */
ol li, ul li {
  color: var(--gh-text-primary);
}

/* Links */
a {
  color: var(--gh-accent-blue);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--gh-accent-purple);
}

/* Shadows */
.shadow-sm {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3) !important;
}

/* Icon styling */
.bi {
  display: inline-block;
}