body {
  background: #eef4ff;
  color: #1a1a1a;
  font-family: "DotGothic16", monospace;
  margin: auto auto;
  max-width: 800px;
  padding: 20px;
}

h1 {
  text-align: center;
  color: #004ea8;
  border-bottom: 2px solid #004ea8;
  padding-bottom: 8px;
  margin-bottom: 20px;
}

p {
  line-height: 1.5;
}

a {
  color: green;
  text-decoration: none;
}

input[type="text"] {
  width: 100%;
  box-sizing: border-box;
  padding: 8px;
  font-size: 1rem;
  font-family: inherit;
  background: #ffffff;
  border: 2px solid #004ea8;
  border-radius: 0;
  box-shadow: 2px 2px 0 #89aee9;
}

input[type="text"]:focus {
  border-color: #1a6fff;
  outline: none;
}

#result {
  margin-top: 10px;
  padding: 6px 10px;
  background: #dfeaff;
  border-left: 4px solid #004ea8;
}

.thumbnails-gallery {
  margin-top: 20px;
  display: none;
  gap: 20px;
}

.thumbnails-gallery div {
  padding: 10px;
  background: #ffffff;
  border: 2px solid #6fa8ff;
  box-shadow: 2px 2px 0 #bcd4ff;
}

.thumbnails-gallery p {
  margin: 0 0 6px;
  color: #004ea8;
  font-weight: bold;
}

.thumbnails-gallery img {
  width: 100%;
  border: 2px solid #004ea8;
}

#result.false {
  background-color:#FFD3D3;
  border-left: 4px solid #ff4343;
}
#result.false::before {
  content: '✘ Invalid URL!';
}

#result.true {
  background-color:#e5ffdf;
  border-left: 4px solid #61fe3d;
}

#result.true::before {
  content: '✔ Valid YouTube URL!';
}

#result::before {
  content: 'Waiting for input...';
}