:root {
  --bg: #0F172A;
  --text: #F8FAFC;
  --accent1: #6366F1;
  --accent2: #06B6D4;
  --card: rgba(30, 41, 59, 0.5);
  --border: rgba(100, 116, 139, 0.2);
  --hover: rgba(99, 102, 241, 0.1);
}

[data-theme="light"] {
  --bg: #F8FAFC;
  --text: #0F172A;
  --card: rgba(255, 255, 255, 0.8);
  --border: rgba(148, 163, 184, 0.3);
  --hover: rgba(99, 102, 241, 0.05);
}

/* Apply theme to body */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: all 0.3s ease;
  min-height: 100vh;
}

h1, h2 {
  background: linear-gradient(135deg, var(--accent1), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-weight: 600;
  font-size: 28px;
}

.header {
  background: var(--card);
  border-bottom: 2px solid var(--border);
  padding: 15px 20px;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  backdrop-filter: blur(10px);
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Theme Toggle Icon Button */
.theme-toggle {
  background: transparent;
  border: 2px solid var(--border);
  color: var(--text);
  width: 45px;
  height: 45px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 20px;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.theme-toggle:hover {
  background: var(--hover);
  border-color: var(--accent1);
  transform: rotate(180deg) scale(1.1);
}

.theme-toggle:active {
  transform: rotate(180deg) scale(0.95);
}

#themeIcon {
  font-size: 22px;
  transition: all 0.3s ease;
}

.content {
  margin-top: 80px;
  padding: 20px;
}



/* Cards */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  backdrop-filter: blur(10px);
  transition: all 0.3s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(99, 102, 241, 0.2);
  border-color: var(--accent1);
}

/* Card with normal solid background (no transparency) */
.card-solid {
  background: #1E293B;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  transition: all 0.3s ease;
}

[data-theme="light"] .card-solid {
  background: #FFFFFF;
}

.card-solid:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(99, 102, 241, 0.2);
  border-color: var(--accent1);
}

/* Primary Button */
.btn {
  background: linear-gradient(135deg, var(--accent1), var(--accent2));
  color: #FFFFFF;
  border: none;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(99, 102, 241, 0.4);
}

.btn:active {
  transform: translateY(0);
}

/* Outline Button */
.btn-outline {
  background: transparent;
  color: var(--accent1);
  border: 2px solid var(--accent1);
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.btn-outline:hover {
  background: var(--accent1);
  color: #FFFFFF;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(99, 102, 241, 0.4);
}

.btn-outline:active {
  transform: translateY(0);
}

/* Secondary Button */
.btn-secondary {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.btn-secondary:hover {
  background: var(--hover);
  border-color: var(--accent1);
  transform: translateY(-2px);
}

.btn-secondary:active {
  transform: translateY(0);
}

/* Small Button */
.btn-sm {
  padding: 8px 16px;
  font-size: 14px;
}

/* Large Button */
.btn-lg {
  padding: 16px 32px;
  font-size: 18px;
}

/* Full Width Button */
.btn-block {
  width: 100%;
  justify-content: center;
}

/* Disabled Button */
.btn:disabled,
.btn-outline:disabled,
.btn-secondary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.btn:disabled:hover,
.btn-outline:disabled:hover,
.btn-secondary:disabled:hover {
  transform: none;
  box-shadow: none;
}

/* Card Grid Layouts */
.card-grid {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.card-grid-2 {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
}

.card-grid-3 {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.card-grid-4 {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* Button Group */
.btn-group {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* Responsive */

@media (max-width: 480px) {
  .header h1 {
    font-size: 25px;
    font-weight: 600;
  }
  
  .theme-toggle {
    width: 40px;
    height: 40px;
    font-size: 18px;
  }
  
  #themeIcon {
    font-size: 18px;
  }
}

@media (max-width: 768px) {
  .card {
    padding: 16px;
  }
  
  .btn, .btn-outline, .btn-secondary {
    padding: 10px 20px;
    font-size: 14px;
  }
  
  .card-grid,
  .card-grid-2,
  .card-grid-3 {
    grid-template-columns: 1fr;
  }
  
  .card-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}