Add SCSS files.

source/scss/colors.scss

@@ -0,0 +1,25 @@
+@use "sass:color";
+
+body {
+  $accents: (
+    "red" #dc322f,
+    "orange" #cb4b16,
+    "yellow" #b58900,
+    "green" #859900,
+    "cyan" #2aa198,
+    "blue" #268bd2,
+    "violet" #6c71c4,
+    "magenta" #d33682,
+  );
+
+  --background-primary: #{color.adjust(#002b36, $lightness: -5%)};
+  --background-secondary: #002b36;
+  --background-tertiary: #000;
+  --foreground: #fdf6e3;
+
+  @each $name, $color in $accents {
+    --#{$name}: #{$color};
+    --light-#{$name}: #{color.adjust($color, $lightness: 10%)};
+    --dark-#{$name}: #{color.adjust($color, $lightness: -10%)};
+  }
+}

source/scss/common.scss

@@ -0,0 +1,18 @@
+@use "modern-normalize/modern-normalize.css";
+@use "reset";
+@use "colors";
+
+html {
+  font-size: 62.5%;
+}
+
+body {
+  --spacing-small: 4px;
+  --spacing-medium: 8px;
+  --spacing-large: 16px;
+  --spacing-extra-large: 32px;
+
+  background-color: var(--background-primary);
+  color: var(--foreground);
+  font-size: 1.6rem;
+}

source/scss/reset.scss

@@ -0,0 +1,14 @@
+h1,
+h2,
+h3,
+h4,
+h5,
+ol,
+ul,
+li,
+p,
+button,
+input {
+  margin: 0;
+  padding: 0;
+}