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

body {
  font-family: "Segoe UI", Arial, sans-serif;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  color: #eee;
  padding: 40px 20px;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
}

h1 {
  text-align: center;
  margin-bottom: 10px;
}

.subtitle {
  text-align: center;
  color: #aaa;
  margin-bottom: 40px;
}

.section {
  background-color: #0f3460;
  border-radius: 16px;
  padding: 25px;
  margin-bottom: 30px;
}

.section-title {
  font-size: 24px;
  font-weight: bold;
  margin-bottom: 15px;
  color: #4a90e2;
  border-left: 4px solid #4a90e2;
  padding-left: 15px;
}

.section-description {
  color: #aaa;
  margin-bottom: 25px;
  font-size: 14px;
  padding-left: 19px;
}

.code {
  background-color: #0a0a1a;
  padding: 15px;
  border-radius: 8px;
  font-family: "Courier New", monospace;
  font-size: 13px;
  color: #82b1ff;
  overflow-x: auto;
  margin-top: 15px;
}

.note {
  background-color: #1a1a2e;
  border-left: 4px solid #f39c12;
  padding: 15px;
  border-radius: 8px;
  margin: 15px 0;
}

.card {
  background: linear-gradient(135deg, #4a90e2, #357abd);
  padding: 30px 20px;
  text-align: center;
  border-radius: 12px;
  transition: transform 0.3s ease;
}

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

.card-number {
  font-size: 32px;
  font-weight: bold;
  margin-bottom: 10px;
}

/* ===================================
           DEMO 1: MEDIA QUERIES WITH GRID
           =================================== */
.responsive-grid-1 {
  display: grid;
  gap: 20px;
}

/* Default: 1 column (mobile) */
.responsive-grid-1 {
  grid-template-columns: 1fr;
}

/* Tablet: 2 columns */
@media (min-width: 768px) {
  .responsive-grid-1 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Desktop: 3 columns */
@media (min-width: 1024px) {
  .responsive-grid-1 {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Large Desktop: 4 columns */
@media (min-width: 1200px) {
  .responsive-grid-1 {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ===================================
           DEMO 2: ASYMMETRIC GRID (changes layout)
           =================================== */
.responsive-grid-2 {
  display: grid;
  gap: 20px;
}

/* Mobile: 1 column */
.responsive-grid-2 {
  grid-template-columns: 1fr;
}

/* Tablet: 2 columns (featured spans both) */
@media (min-width: 768px) {
  .responsive-grid-2 {
    grid-template-columns: 1fr 1fr;
  }

  .featured {
    grid-column: span 2;
  }
}

/* Desktop: 3 columns (featured spans all) */
@media (min-width: 1024px) {
  .responsive-grid-2 {
    grid-template-columns: repeat(3, 1fr);
  }

  .featured {
    grid-column: span 3;
  }
}

/* ===================================
           DEMO 3: BEST OF BOTH (auto-fit + media query)
           =================================== */
.responsive-grid-3 {
  display: grid;
  gap: 20px;
  /* auto-fit for flexibility, but with limits */
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* But on large screens, limit to 4 columns max */
@media (min-width: 1200px) {
  .responsive-grid-3 {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ===================================
           DEMO 4: DASHBOARD LAYOUT (changes entirely)
           =================================== */
.dashboard {
  display: grid;
  gap: 20px;
}

/* Mobile: stacked */
.dashboard {
  grid-template-areas:
    "header"
    "stats"
    "chart1"
    "chart2"
    "table";
  grid-template-columns: 1fr;
}

/* Tablet: 2 columns */
@media (min-width: 768px) {
  .dashboard {
    grid-template-areas:
      "header header"
      "stats stats"
      "chart1 chart2"
      "table table";
    grid-template-columns: 1fr 1fr;
  }
}

/* Desktop: full dashboard */
@media (min-width: 1024px) {
  .dashboard {
    grid-template-areas:
      "header header header"
      "stats stats stats"
      "chart1 chart2 table"
      "chart1 chart2 table";
    grid-template-columns: 1fr 1fr 1fr;
  }
}

.dash-header {
  grid-area: header;
  background-color: #4a90e2;
  padding: 20px;
  border-radius: 8px;
  text-align: center;
}
.dash-stats {
  grid-area: stats;
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}
.stat-card {
  flex: 1;
  background-color: #2ecc71;
  padding: 15px;
  border-radius: 8px;
  text-align: center;
  min-width: 120px;
}
.dash-chart1 {
  grid-area: chart1;
  background-color: #e94560;
  padding: 20px;
  border-radius: 8px;
  text-align: center;
  min-height: 200px;
}
.dash-chart2 {
  grid-area: chart2;
  background-color: #f39c12;
  padding: 20px;
  border-radius: 8px;
  text-align: center;
  min-height: 200px;
}
.dash-table {
  grid-area: table;
  background-color: #1a1a2e;
  padding: 20px;
  border-radius: 8px;
  border: 1px solid #4a90e2;
}

footer {
  text-align: center;
  padding: 40px;
  color: #666;
}