/* --------------------------------------------------
   BASE RESET
-------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", system-ui, sans-serif;
  background: #f3f4f6;
  color: #1f2937;
  line-height: 1.6;
}

/* Layout container width */
:root {
  --max-width: 1100px;
  --radius: 6px;
  --radius-lg: 10px;

  --space-sm: 0.75rem;
  --space-md: 1.25rem;
  --space-lg: 2rem;

  --accent: #6C757D;
}

/* --------------------------------------------------
   HEADER — Modern Engineering Style
-------------------------------------------------- */
header {
  background: #ffffff;
  border-bottom: 1px solid #e5e7eb;

  display: flex;
  justify-content: space-between;
  align-items: center;

  padding: var(--space-md) var(--space-lg);
  position: sticky;
  top: 0;
  z-index: 1000;

  transition: box-shadow 0.25s ease;
}

body.scrolled header {
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.4rem;
  font-weight: 600;
  color: #1f2937;
  text-decoration: none;
}

.logo img {
  width: 48px;
  height: 48px;
  border-radius: var(--radius);
}

/* --------------------------------------------------
   APP STORE BUTTONS — Engineering UI Style
-------------------------------------------------- */
.app-buttons {
  display: flex;
  gap: var(--space-sm);
}

.appstore-btn {
  padding: 8px 14px;
  background: #2563eb;
  color: white;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s ease;
}

.appstore-btn:hover {
  background: #1e4fc7;
}

/* --------------------------------------------------
   SECTION BLOCKS
-------------------------------------------------- */
.section {
  max-width: var(--max-width);
  margin: var(--space-lg) auto;
  padding: var(--space-lg);
  background: white;
  border-radius: var(--radius-lg);
  border: 1px solid #e5e7eb;
}

.section h2 {
  font-size: 1.9rem;
  margin-bottom: var(--space-md);
  color: #1f2937;
}

/* --------------------------------------------------
   HERO SECTION
-------------------------------------------------- */
.hero {
  text-align: left;
   border-left: 4px solid #ccd5e9;
  padding-left: 1rem;
}

.hero h2 {
  font-size: 2rem;
  font-weight: 600;
  color: #1f2937;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.1rem;
  color: #374151;
  max-width: 650px;
  line-height: 1.7;
}

/* --------------------------------------------------
   VIDEO DEMO PANEL
-------------------------------------------------- */
.app-demo-container {
  display: flex;
  gap: var(--space-lg);
  align-items: stretch;
}

.app-demo-video,
.app-demo-description {
  flex: 0 0 420px;
}


.app-demo-video {
  width: 420px;
}

.app-demo-video video {
  width: 100%;
  height: 100%;
  aspect-ratio: 16 / 9;
  display: block;
  border-radius: var(--radius-lg);
  border: 1px solid #e5e7eb;
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}


/* Cue text fade */
#demoText {
  opacity: 0;
  transition: opacity 0.4s ease;
}

#demoText.show {
  opacity: 1;
}

/* --------------------------------------------------
   VIDEO LIST (Selector Buttons)
-------------------------------------------------- */
.video-list {
  
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.video-item {
  padding: 10px 16px;
  background: #e5e7eb;
  border: 1px solid #d1d5db;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.95rem;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.video-item:hover {
  background: #dbe1e8;
  border-color: #2563eb;
}

/* --------------------------------------------------
   FOOTER
-------------------------------------------------- */
footer {
  text-align: center;
  padding: var(--space-lg);
  color: #6b7280;
  font-size: 0.85rem;
}

.column {
  float: left;
  width: 50%;
}

/* Clear floats after the columns */
.row:after {
  content: "";
  display: table;
  clear: both;
}

/* --------------------------------------------------
   MOBILE
-------------------------------------------------- */
@media (max-width: 800px) {
  .app-demo-container {
    flex-direction: column;
  }

  .app-demo-video {
    width: 100%;
  }

  .video-list {
    flex-direction: column;
  }

  .column {
    width: 100%;
  }
  
}