* {
  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;
  font-size: 36px;
  margin-bottom: 10px;
}

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

.section {
  background-color: #0f3460;
  border-radius: 16px;
  margin-bottom: 40px;
  padding: 25px;
}

.section-title {
  font-size: 22px;
  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;
}

/* ===================================
           DEMO CONTAINER
           =================================== */
.demo-container {
  position: relative;
  background-color: #0a0a1a;
  border-radius: 12px;
  padding: 40px;
  min-height: 350px;
  margin: 20px 0;
}

/* Base box style */
.box {
  width: 150px;
  height: 120px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  position: absolute;
  transition: all 0.3s ease;
}

.code {
  background-color: #0a0a1a;
  padding: 15px;
  border-radius: 8px;
  font-family: "Courier New", monospace;
  font-size: 13px;
  color: #82b1ff;
  overflow-x: auto;
  margin-top: 20px;
}

/* ===================================
           DEMO 1: BASIC Z-INDEX
           =================================== */
.demo1-container {
  position: relative;
  height: 250px;
}

.box1-1 {
  background-color: #e94560;
  top: 20px;
  left: 20px;
  z-index: 1;
}

.box1-2 {
  background-color: #4a90e2;
  top: 60px;
  left: 60px;
  z-index: 2;
}

.box1-3 {
  background-color: #2ecc71;
  top: 100px;
  left: 100px;
  z-index: 3;
}

/* ===================================
           DEMO 2: WITHOUT Z-INDEX (default order)
           =================================== */
.demo2-container {
  position: relative;
  height: 250px;
}

.box2-1 {
  background-color: #e94560;
  top: 20px;
  left: 20px;
}

.box2-2 {
  background-color: #4a90e2;
  top: 60px;
  left: 60px;
}

.box2-3 {
  background-color: #2ecc71;
  top: 100px;
  left: 100px;
}

/* ===================================
           DEMO 3: HIGHER Z-INDEX = ON TOP
           =================================== */
.demo3-container {
  position: relative;
  height: 250px;
}

.box3-1 {
  background-color: #e94560;
  top: 20px;
  left: 20px;
  z-index: 10;
}

.box3-2 {
  background-color: #4a90e2;
  top: 60px;
  left: 60px;
  z-index: 5;
}

.box3-3 {
  background-color: #2ecc71;
  top: 100px;
  left: 100px;
  z-index: 1;
}

/* ===================================
           DEMO 4: NEGATIVE Z-INDEX (goes behind parent)
           =================================== */
.demo4-container {
  position: relative;
  height: 300px;
}

.parent-box {
  position: relative;
  background-color: #4a90e2;
  width: 300px;
  height: 200px;
  border-radius: 12px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

.negative-child {
  position: absolute;
  background-color: #e94560;
  width: 200px;
  height: 100px;
  border-radius: 12px;
  top: 50px;
  left: 50px;
  z-index: -1;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===================================
           DEMO 5: STACKING CONTEXT (nested z-index)
           =================================== */
.demo5-wrapper {
  display: flex;
  gap: 40px;
  flex-wrap: wrap;
  justify-content: center;
}

.stacking-parent {
  position: relative;
  background-color: #2a3a5a;
  width: 280px;
  height: 280px;
  border-radius: 16px;
  padding: 20px;
}

.stacking-parent .title {
  text-align: center;
  margin-bottom: 15px;
  font-weight: bold;
}

.inner-box {
  position: absolute;
  width: 100px;
  height: 80px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.parent-a {
  background-color: rgba(233, 69, 96, 0.3);
  border: 2px solid #e94560;
}

.parent-b {
  background-color: rgba(46, 204, 113, 0.3);
  border: 2px solid #2ecc71;
}

.child-a1 {
  background-color: #e94560;
  top: 40px;
  left: 30px;
  z-index: 1;
}

.child-a2 {
  background-color: #ff6b6b;
  top: 80px;
  left: 60px;
  z-index: 2;
}

.child-b1 {
  background-color: #2ecc71;
  top: 40px;
  left: 30px;
  z-index: 2;
}

.child-b2 {
  background-color: #58d68d;
  top: 80px;
  left: 60px;
  z-index: 1;
}

/* ===================================
           DEMO 6: PRACTICAL USE - MODAL OVERLAY
           =================================== */
.modal-container {
  position: relative;
  height: 300px;
}

.page-content {
  background-color: #2a3a5a;
  padding: 30px;
  border-radius: 12px;
  text-align: center;
}

.modal-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.modal-card {
  background-color: white;
  color: #1a1a2e;
  padding: 25px;
  border-radius: 16px;
  width: 250px;
  text-align: center;
  z-index: 101;
}

.modal-card button {
  margin-top: 15px;
  padding: 8px 20px;
  background-color: #4a90e2;
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

/* ===================================
           DEMO 7: DROPDOWN MENU (z-index needed)
           =================================== */
.dropdown-demo {
  position: relative;
  display: inline-block;
}

.dropdown-button {
  background-color: #4a90e2;
  padding: 12px 25px;
  border-radius: 8px;
  cursor: pointer;
}

.dropdown-content {
  position: absolute;
  top: 50px;
  left: 0;
  background-color: white;
  color: #1a1a2e;
  min-width: 180px;
  border-radius: 8px;
  padding: 10px 0;
  z-index: 1000;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

.dropdown-content a {
  display: block;
  padding: 10px 20px;
  text-decoration: none;
  color: #333;
}

.dropdown-content a:hover {
  background-color: #f0f0f0;
}

/* Reference table */
.reference-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 20px;
}

.reference-table th,
.reference-table td {
  border: 1px solid #2a3a5a;
  padding: 12px;
  text-align: left;
}

.reference-table th {
  background-color: #0f3460;
  color: #4a90e2;
}

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