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

body {
  font-family: Arial, sans-serif;
  background: #fff;
}

section {
  height: 100vh;
  padding: 40px;
  display: flex;
  flex-direction: column;
}

section h2 {
  margin-bottom: 20px;
  font-size: 28px;
  color: #333;
}

[class^="grid"] {
  display: grid;
  gap: 10px;
  flex: 1;
}

[class^="grid"] div {
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 32px;
  font-weight: bold;
}

/* 1. Basic Grid */
.grid1 {
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(2, 1fr);
}
.grid1 div:nth-child(1) { background: #e74c3c; }
.grid1 div:nth-child(2) { background: #3498db; }
.grid1 div:nth-child(3) { background: #2ecc71; }
.grid1 div:nth-child(4) { background: #f39c12; }
.grid1 div:nth-child(5) { background: #9b59b6; }
.grid1 div:nth-child(6) { background: #1abc9c; }

/* 2. Column Span */
.grid2 {
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(2, 1fr);
}
.grid2 div:nth-child(1) { background: #e74c3c; grid-column: span 2; }
.grid2 div:nth-child(2) { background: #3498db; }
.grid2 div:nth-child(3) { background: #2ecc71; }
.grid2 div:nth-child(4) { background: #f39c12; }
.grid2 div:nth-child(5) { background: #9b59b6; }

/* 3. Row Span */
.grid3 {
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(2, 1fr);
}
.grid3 div:nth-child(1) { background: #e74c3c; grid-row: span 2; }
.grid3 div:nth-child(2) { background: #3498db; }
.grid3 div:nth-child(3) { background: #2ecc71; }
.grid3 div:nth-child(4) { background: #f39c12; }
.grid3 div:nth-child(5) { background: #9b59b6; }

/* 4. Complex Spans */
.grid4 {
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(3, 1fr);
}
.grid4 div:nth-child(1) { background: #e74c3c; grid-column: span 2; }
.grid4 div:nth-child(2) { background: #3498db; grid-column: span 2; }
.grid4 div:nth-child(3) { background: #2ecc71; grid-row: span 2; }
.grid4 div:nth-child(4) { background: #f39c12; grid-column: span 2; }
.grid4 div:nth-child(5) { background: #9b59b6; grid-row: span 2; }
.grid4 div:nth-child(6) { background: #1abc9c; }
.grid4 div:nth-child(7) { background: #e67e22; }

/* 5. Asymmetric */
.grid5 {
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(2, 1fr);
}
.grid5 div:nth-child(1) { background: #e74c3c; grid-column: span 3; }
.grid5 div:nth-child(2) { background: #3498db; }
.grid5 div:nth-child(3) { background: #2ecc71; }
.grid5 div:nth-child(4) { background: #f39c12; grid-column: span 2; }
.grid5 div:nth-child(5) { background: #9b59b6; }

/* 6. Large Item */
.grid6 {
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(2, 1fr);
}
.grid6 div:nth-child(1) { background: #e74c3c; grid-column: span 2; grid-row: span 2; }
.grid6 div:nth-child(2) { background: #3498db; }
.grid6 div:nth-child(3) { background: #2ecc71; }
.grid6 div:nth-child(4) { background: #f39c12; }
.grid6 div:nth-child(5) { background: #9b59b6; }

/* 7. Mixed Layout */
.grid7 {
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
}
.grid7 div:nth-child(1) { background: #e74c3c; grid-column: span 2; }
.grid7 div:nth-child(2) { background: #3498db; grid-row: span 2; }
.grid7 div:nth-child(3) { background: #2ecc71; }
.grid7 div:nth-child(4) { background: #f39c12; }
.grid7 div:nth-child(5) { background: #9b59b6; }
.grid7 div:nth-child(6) { background: #1abc9c; }

/* 8. Sidebar Layout */
.grid8 {
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
}
.grid8 div:nth-child(1) { background: #e74c3c; grid-row: span 3; }
.grid8 div:nth-child(2) { background: #3498db; grid-column: span 2; }
.grid8 div:nth-child(3) { background: #2ecc71; }
.grid8 div:nth-child(4) { background: #f39c12; }
.grid8 div:nth-child(5) { background: #9b59b6; grid-column: span 2; }

/* 9. Full Complex */
.grid9 {
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(3, 1fr);
}
.grid9 div:nth-child(1) { background: #e74c3c; grid-column: span 2; grid-row: span 2; }
.grid9 div:nth-child(2) { background: #3498db; }
.grid9 div:nth-child(3) { background: #2ecc71; }
.grid9 div:nth-child(4) { background: #f39c12; }
.grid9 div:nth-child(5) { background: #9b59b6; }
.grid9 div:nth-child(6) { background: #1abc9c; grid-column: span 2; }
.grid9 div:nth-child(7) { background: #e67e22; }
.grid9 div:nth-child(8) { background: #34495e; }