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

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

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

h1 {
  font-size: clamp(1.75rem, 2rem + 2vw, 2.5rem);
  text-align: center;
  margin-bottom: 0.5rem;
}

.subtitle {
  text-align: center;
  color: #aaa;
  margin-bottom: 2rem;
}

/* ===================================
           THEORY SECTION
           =================================== */
.theory {
  background-color: #0a0a1a;
  border-radius: 1rem;
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.theory h2 {
  color: #4a90e2;
  margin-bottom: 1rem;
}

.theory h3 {
  color: #e94560;
  margin: 1.5rem 0 0.75rem;
}

.theory p {
  color: #ccc;
  line-height: 1.6;
  margin-bottom: 1rem;
}

.theory ul {
  margin-left: 1.5rem;
  color: #ccc;
  line-height: 1.8;
}

.theory code {
  background-color: #1a1a2e;
  padding: 0.125rem 0.375rem;
  border-radius: 0.25rem;
  color: #82b1ff;
}

/* ===================================
           DEMO BUTTONS
           =================================== */
.demo-section {
  background-color: #0f3460;
  border-radius: 1rem;
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.demo-section h3 {
  color: #4a90e2;
  margin-bottom: 1rem;
}

.button-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 1.5rem 0;
  align-items: center;
}

/* Base button styles */
.btn {
  border: none;
  font-family: inherit;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

/* ===================================
           DEMO 1: TOO SMALL (Bad for touch)
           =================================== */
.btn-too-small {
  background-color: #e94560;
  color: white;
  padding: 4px 8px;
  border-radius: 0.5rem;
  font-size: 0.75rem;
}

/* ===================================
           DEMO 2: GOOD SIZE (44px min)
           =================================== */
.btn-good-size {
  background-color: #4a90e2;
  color: white;
  padding: 12px 20px;
  border-radius: 0.5rem;
  font-size: 1rem;
  min-width: 44px;
  min-height: 44px;
}

/* ===================================
           DEMO 3: HOVER (works on mouse only)
           =================================== */
.btn-hover {
  background-color: #2ecc71;
  color: white;
  padding: 12px 24px;
  border-radius: 0.5rem;
}

/* This hover style ONLY applies on devices that support hover (mouse) */
@media (hover: hover) {
  .btn-hover:hover {
    background-color: #27ae60;
    transform: scale(1.05);
  }
}

/* Active state for touch (tap feedback) */
.btn-hover:active {
  background-color: #1e8449;
  transform: scale(0.98);
}

/* ===================================
           DEMO 4: :active for touch feedback
           =================================== */
.btn-active {
  background-color: #f39c12;
  color: white;
  padding: 12px 24px;
  border-radius: 0.5rem;
  transition: all 0.05s ease;
}

/* Instant feedback on tap */
.btn-active:active {
  background-color: #e67e22;
  transform: scale(0.97);
}

/* ===================================
           DEMO 5: Menu items (touch-friendly)
           =================================== */
.menu {
  list-style: none;
  margin: 1rem 0;
}

.menu-item {
  margin-bottom: 0.5rem;
}

.menu-link {
  display: block;
  padding: 12px 16px;
  background-color: #1a1a2e;
  color: white;
  text-decoration: none;
  border-radius: 0.5rem;
  transition: all 0.2s ease;
  /* Minimum touch target: 44px tall */
  min-height: 44px;
}

/* Hover only on mouse devices */
@media (hover: hover) {
  .menu-link:hover {
    background-color: #4a90e2;
    padding-left: 24px;
  }
}

/* Tap feedback (works on all devices) */
.menu-link:active {
  background-color: #e94560;
  transform: scale(0.99);
}

/* ===================================
           DEMO 6: Detect touch devices
           =================================== */
.device-info {
  background-color: #1a1a2e;
  border-radius: 0.75rem;
  padding: 1rem;
  margin: 1rem 0;
}

.code-block {
  background-color: #0a0a1a;
  padding: 1rem;
  border-radius: 0.75rem;
  font-family: "Courier New", monospace;
  font-size: 0.8rem;
  color: #82b1ff;
  overflow-x: auto;
  margin: 1rem 0;
}

.note {
  background-color: #1a1a2e;
  border-left: 4px solid #e94560;
  padding: 1rem;
  border-radius: 0.5rem;
  margin: 1rem 0;
}

footer {
  text-align: center;
  padding: 2rem;
  color: #666;
  font-size: 0.875rem;
}

/* Responsive */
@media (min-width: 768px) {
  body {
    padding: 40px;
  }
}