html, body, 
header, footer {
  min-width: 320px;
  max-width: 1920px;
}

html, body {
  background-color: var(--color-negative);
  margin: 0 auto;
}

body, 
input, textarea {
  font-family: "San Francisco", sans-serif;
  font-weight: 400;
  letter-spacing: +0.025em;
  line-height: 1.25;
}

body {
  border-left: 1px solid rgba(255, 255, 255, 0.05);
  border-right: 1px solid rgba(255, 255, 255, 0.05);
  color: var(--color-positive);
  font-size: var(--font-medium);
  overflow-x: hidden;
  position: relative;
}

header, 
section, 
footer {
  box-sizing: border-box;
  display: flex;
  padding: var(--margin-vertical) var(--margin-horizontal);
}

header, 
footer {
  align-items: center;
  justify-content: space-between;
}

header {
  opacity: 0.0;
  pointer-events: none;
  position: fixed;
  top: 0;
  transition: opacity var(--animation-duration) var(--animation-function);
  width: 100vw;
  z-index: 2;
}

header.active {
  opacity: 1.0;
  pointer-events: all;
}

header img, 
footer img {
  height: 44px;
  padding-top: 10px;
}

nav {
  display: flex;
}

a:not(a.inline) {
  color: inherit;
  cursor: pointer;
  font-size: var(--font-small);
  font-weight: 600;
  padding: 1.5em 2.0em;
  text-decoration: none;
  transition: all var(--animation-duration) var(--animation-function);
}

a:not(a.button, a.inline) {
  opacity: var(--animation-opacity);
  text-shadow: 0 0 0 rgba(255, 255, 255, 0.0);
}

a:not(a.button, a.inline):hover, 
a:not(a.button, a.inline).active {
  opacity: 1.0;
  text-shadow: 0 0 12px rgba(255, 255, 255, 0.1);
}

a.button, 
input, textarea {
  backdrop-filter: 
    blur(12px) 
    brightness(1.5) 
    saturate(1.5);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.05);
  box-shadow:
    inset +1px +1px 0 rgba(255, 255, 255, 0.3),
    inset -1px -1px 0 rgba(255, 255, 255, 0.2),
    inset 0 0 12px rgba(255, 255, 255, 0.1),
    0 1px 2px rgba(0, 0, 0, 0.2);
}

a.button {
  border-radius: calc(var(--font-small) + 3.0em);
  display: inline-block;
  transform: scale(1.0);
}

a.button:hover {
  backdrop-filter: 
    blur(18px) 
    brightness(1.25) 
    saturate(1.25);
  box-shadow:
    inset -1px +1px 0 rgba(255, 255, 255, 0.6),
    inset +1px -1px 0 rgba(255, 255, 255, 0.4),
    inset 0 0 12px rgba(255, 255, 255, 0.2),
    0 2px 4px rgba(0, 0, 0, 0.1);
  transform: scale(1.05);
}

mark {
  background-color: transparent;
  color: var(--color-accent);
}

a.inline {
  color: var(--color-accent);
}

section {
  height: 100vh;
  position: relative;
}

section#about {
  padding-top: calc(var(--margin-vertical) + 54px + var(--margin-vertical));
}

section#contact {
  height: auto;
  min-height: 100vh;
  padding-bottom: calc(var(--margin-vertical) + 54px + var(--margin-vertical));
}

section div,
article {
  opacity: 0.1;
  transition: opacity var(--animation-duration) var(--animation-function);
}

section.active div,
article.active {
  opacity: 1.0;
}

div.foreground {
  z-index: 1;
}

div.background, 
section img, section video {
  position: absolute;
}

div.background, section video {
  height: 100%;
  left: 0;
  top: 0;
  width: 100%;
}

div.background {
  background-color: var(--color-negative);
  z-index: 0;
}

h1, h2, h3, 
p, 
form {
  max-width: 512px;
}

h1, h2, h3 {
  font-size: var(--font-large);
  font-weight: 400;
  line-height: 1.0;
  margin: 0;
}

h2:first-child, h3 {
  color: var(--color-accent);
}

p {
  margin: var(--font-large) 0;
}

input, textarea {
  box-sizing: border-box;
  color: var(--color-positive);
  border-radius: var(--font-medium);
  font-size: var(--font-small);
  margin-bottom: var(--font-small);
  padding: 1.5em 2.0em;
  width: 100%;
}

  input:focus, textarea:focus {
    outline: none;
  }

  textarea {
    resize: none;
  }

section video {
  object-fit: cover;
}

section picture + video {
  mix-blend-mode: screen;
}

footer {
  position: absolute;
  bottom: 0;
  width: 100vw;
  z-index: 2;
}

footer a.busy {
  pointer-events: none;
}