* {
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

html {
  scroll-behavior: smooth;
}


body {
  margin: 0;
  background: linear-gradient(135deg, #00b4db, #0083b0);
  color: #111;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  transition: background 0.6s ease, color 0.6s ease;
}

body.dark {
  background: linear-gradient(135deg, #0f172a, #111827);
  color: #e5e7eb;
}

.container {
  width: 100%;
  max-width: 900px;
  padding: 20px;
}

.header {
  text-align: center;
  margin-bottom: 20px;
}

.header h1 {
  font-size: 2.4rem;
  margin: 0;
}

.header p {
  margin: 10px 0 0;
  font-size: 1.1rem;
}

.content,
.extra {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 15px;
  margin-bottom: 20px;
}

.card {
  background: rgba(255, 255, 255, 0.9);
  padding: 20px;
  border-radius: 15px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
  transition: transform 0.3s ease, background 0.6s ease;
}

body.dark .card {
  background: rgba(31, 41, 51, 0.85);
}

.card:hover {
  transform: translateY(-5px);
}

.footer {
  text-align: center;
  margin-top: 25px;
}

/* Theme Toggle Button */
.theme-toggle {
  position: fixed;
  top: 15px;
  right: 15px;
  padding: 12px 14px;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  font-size: 20px;
  background: #fff;
  box-shadow: 0 6px 15px rgba(0,0,0,0.2);
  transition: background 0.6s ease, color 0.6s ease;
}

body.dark .theme-toggle {
  background: #111;
  color: white;
}

/* Responsive */
@media (max-width: 900px) {
  .content,
  .extra {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 600px) {
  .content,
  .extra {
    grid-template-columns: 1fr;
  }

  .header h1 {
    font-size: 1.8rem;
  }
}