@import url(https://fonts.googleapis.com/css?family=Roboto:100);

html,
body {
  height: 100%;
  min-height: 100%;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: Roboto, sans-serif;
  background: linear-gradient(#8b9da9, #fff6e4);
}

.calculator {
  max-width: 320px;
  box-shadow: 0 0 75px 30px rgba(205, 205, 205, 0.7);
}

.calculator__display {
  padding: 10px;
  color: rgba(255, 255, 255, 0.7);
  font-size: 4em;
  text-align: right;
}

.calculator__functions {
  display: flex;
  flex-wrap: wrap;
  border: 1px solid rgba(255, 255, 255, 0.4);
  mix-blend-mode: overlay;
}
.calculator__functions button {
  flex: 0 1 25%;
  height: 70px;
  color: #111;
  font-size: 2em;
  mix-blend-mode: overlay;
  background: rgba(255, 255, 255, 0.4);
  border: 1px solid rgba(255, 255, 255, 0.4);
}
.calculator__functions button.btn--large {
  flex: 0 1 50%;
}
.calculator__functions button.btn--opaque {
  background: rgba(255, 255, 255, 0.2);
}

header {
  width: 100%;
  height: 300px;
  /*background-color: #3498db;*/
  text-align: center;
  position: relative;
  position: fixed;
  top: 0;
  overflow: hidden;
}
h1{
  font-size: 42px;
  color: #fff;
  line-height: 230px;
  text-transform: uppercase;
  font-weight: 100;
}
nav{
  margin: -13.33em 0;
  text-align: left;
  font-size: 20px;
  color: #fff;
  line-height: 20px;
  font-weight: 100;
}