* {
  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;
}

/* Grid Demo Container */
.grid-demo {
  background-color: #1a1a2e;
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
}

.grid-item {
  background-color: #4a90e2;
  padding: 20px;
  text-align: center;
  border-radius: 8px;
  font-weight: bold;
}

.grid-item:nth-child(even) {
  background-color: #e94560;
}

hr {
  border-color: #2a3a5a;
  margin: 30px 0;
}

/* ===================================
           DEMO 1: BASIC GRID
           =================================== */
.grid-1 {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 20px;
}

/* ===================================
           DEMO 2: DIFFERENT COLUMN SIZES
           =================================== */
.grid-2 {
  display: grid;
  grid-template-columns: 100px 200px 1fr;
  gap: 15px;
}

/* ===================================
           DEMO 3: REPEAT FUNCTION
           =================================== */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 15px;
}

/* ===================================
           DEMO 4: GRID WITH ROWS
           =================================== */
.grid-4 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 100px 150px 100px;
  gap: 15px;
}

/* ===================================
           DEMO 5: GRID GAP (row-gap + column-gap)
           =================================== */
.grid-5 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  row-gap: 30px;
  column-gap: 10px;
}

/* ===================================
           DEMO 6: AUTO FIT / MINMAX (Responsive)
           =================================== */
.grid-6 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 15px;
}

/* ===================================
           DEMO 7: GRID TEMPLATE AREAS
           =================================== */
.grid-7 {
  display: grid;
  grid-template-areas:
    "header header header"
    "sidebar main main"
    "footer footer footer";
  gap: 15px;
}

.header {
  grid-area: header;
  background-color: #2ecc71;
}
.sidebar {
  grid-area: sidebar;
  background-color: #e94560;
}
.main {
  grid-area: main;
  background-color: #4a90e2;
}
.footer {
  grid-area: footer;
  background-color: #f39c12;
}

.area-item {
  padding: 20px;
  text-align: center;
  border-radius: 8px;
  font-weight: bold;
}

/* ===================================
           DEMO 8: SPANNING COLUMNS
           =================================== */
.grid-8 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 15px;
}

.span-2 {
  grid-column: span 2;
  background-color: #e94560;
}

.span-3 {
  grid-column: span 3;
  background-color: #2ecc71;
}

.span-all {
  grid-column: 1 / -1;
  background-color: #f39c12;
}

/* ===================================
           DEMO 9: NESTED GRID
           =================================== */
.grid-9 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
}

.nested-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  background-color: #2a3a5a;
  padding: 10px;
  border-radius: 8px;
}

.nested-item {
  background-color: #e94560;
  padding: 10px;
  text-align: center;
  border-radius: 4px;
}

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