:root {
  font-family: system-ui, Avenir, Helvetica, Arial, sans-serif;
  line-height: 1.5;
  font-weight: 400;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

* { box-sizing: border-box; }
div { position: relative; }
img { max-width: 100%; }
.white { color: rgba(255, 255, 255, 0.87); }
a {
  font-weight: 500;
  text-decoration: none;
}
a:hover {
  color: #535bf2;
}

body {
  margin: 0;
  min-height: 100vh;
}

#header { width: 100%; height: 400px; }

main { 
  width: 100%;
  max-width: 900px;
  padding: 30px; 
}

.hidden { display: none; }

#content {
  width: 100%; 
  padding: 10px;
  margin-top: 10px;
}