style.css

@import url('https://fonts.googleapis.com/css2?family=Open+Sans:ital,wght@0,300;0,400;0,500;0,600;0,700;0,800;1,300;1,400;1,500;1,600;1,700;1,800&display=swap');

:root {
  --text-color: #1bdd86;
  --background-color: #0e2018;
  --fonts: 'Open Sans', Helvetica, Arial, sans-serif;
  --border-color: #327b77;
  --text-bg-color: #264a43;
}

* {
  font-family: var(--fonts);
  font-size: 1em;
  text-align: center;
  color: var(--text-color);
}

html {
  color-scheme: dark;
}

body {
  background-color: var(--background-color);
}

main {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: min(128ch, calc(100% - 4rem));
  margin-inline: auto;
  padding: 1.5rem;
}

footer {
  background-color: #3145437f;
  padding: 1.5rem;
  font-size: 0.875em;
}

button {
  background-color: #4e7469;
  border: none;
  padding: 0.625em 1.25em;
  cursor: pointer;
  border-radius: 1em;
  margin-top: 1rem;
  margin-bottom: 1rem;
}

strong {
  font-weight: 500;
}

label {
  font-size: 1em;
  display: block;
  margin-bottom: 0.5rem;
}

input {
  background-color: #2b3432;
  border-color: var(--border-color);
  width: 15em;
  height: 1.875em;
  margin-bottom: 1rem;
  border-radius: 0.5em;
}

a {
  color: var(--text-color);
  text-align: center;
  text-decoration: underline;
  transition: all 0.25s ease-in-out;
}

a:hover {
  color: #738c73;
  text-decoration: underline;
}

mark {
  background-color: #27ac7e7f;
}

h1, h2, h3 {
  text-wrap: balance;
}

h1 {
  font-weight: 800;
  font-size: 2em;
}

h2 {
  font-weight: 700;
  font-size: 1.5625em;
}

h3 {
  font-weight: 600;
  font-size: 1.325em;
}

textarea {
  background-color: var(--text-bg-color);
  border-color: var(--border-color);
  border-radius: 1em;
  margin-bottom: 0.5rem;
  margin-top: 0.5rem;
  font-weight: 400;
  font-size: 0.85em;
}

p {
  font-weight: 300;
  text-align: justify;
}

code {
  font-size: 0.875em;
  font-weight: 400;
  font-family: 'Inconsolata', 'Menlo', 'Courier New', Courier, monospace;
}

::selection {
  background-color: #27ac63ce;
}