:root {
  --primary-color: #495057;
}

* {
  box-sizing: border-box;
}

body {
  width: 100vw;
  height: 100vh;
  margin: 0;

  display: flex;
  flex-direction: column;
  align-items: center;

  color: var(--primary-color);
}

h1 {
  font-family: cursive;
  font-size: 4em;
}

.gallery {
  display: flex;
  flex-wrap: wrap;
}

.gallery > img {
  flex: 1;
  object-fit: cover;
}

.gallery > img:nth-child(3n) {
  flex: 2;
}

.loader {
  display: flex;
  margin: 50px;

  visibility: hidden;
}

.loader.visible {
  visibility: visible;
}

.dot-loader {
  height: 20px;
  width: 20px;

  border-radius: 50%;
  margin: 0 20px;

  background-color: var(--primary-color);
  position: relative;
  animation: 1.2s scale ease-in-out infinite;
}

.dot-loader:nth-child(2) {
  animation: 1.2s scale ease-in-out infinite 0.15s;
}

.dot-loader:nth-child(3) {
  animation: 1.2s scale ease-in-out infinite 0.3s;
}

@keyframes scale {
  0%,
  40%,
  100% {
    transform: scale(0);
  }
  50% {
    transform: scale(1);
  }
}