switch to sass and split global styles, rework heading css

src/styles/main.scss

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+@import 'reset';
+
+
+@font-face {
+    font-family: 'Tajawal';
+    font-style: normal;
+    font-weight: 400;
+    src: url(/Tajawal-Regular.woff2) format('woff2');
+    font-display: block;
+}
+
+@font-face {
+    font-family: 'Baskerville';
+    font-style: normal;
+    font-weight: 400;
+    src: url(/Baskerville-Regular.woff2) format('woff2');
+    font-display: block;
+}
+
+:root {
+    --content-size: 1.25rem;
+    --content-line-height: 1.3;
+    --content-width: 52.5rem;
+    --content-color: #1e1e1e;
+    --content-color-faded: #555;
+    --accent-color: hsl(0deg, 92%, 29%);
+}
+
+body {
+    font-family: 'Tajawal', sans-serif;
+    font-size: var(--content-size);
+    line-height: var(--content-line-height);
+    letter-spacing: -0.005em;
+    color: var(--content-color);
+}

src/styles/prose.scss

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+h1, h2, h3, h4, h5, h6 {
+    font-family: -apple-system, system-ui, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Ubuntu, Arial, sans-serif;
+    font-weight: 600;
+    color: #464646;
+}
+
+h1 {
+    margin-top: 0.5em;
+    font-size: 2em;
+    font-variant:  petite-caps;
+}
+
+h2 {
+    font-size: 1.5em;
+}
+
+h3 {
+    font-size: 1.2em;
+}
+
+h4 {
+    font-size: 1.1em;
+}
+
+h1, h2, h3, h4 {
+    margin-bottom: 0.5em;
+}
+
+p {
+    margin-bottom: 0.8em;
+}
+
+code {
+    background: #eee;
+    border-radius: 0.2rem;
+    font-family: Consolas, monospace;
+    font-size: 0.75em;
+    padding: 0.05rem 0.2rem 0.1rem;
+}
+
+pre > code[class*="language-"] {
+    font-size: 1rem;
+    font-family: 'Consolas', monospace;
+}

src/styles/reset.scss

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+// This reset lifted largely from Josh Comeau's "CSS for JS Devs" course
+
+// Use a more-intuitive box-sizing model.
+*, *::before, *::after {
+  box-sizing: border-box;
+}
+
+// Remove default margin
+* {
+  margin: 0;
+}
+
+// Allow percentage-based heights in the application
+html, body {
+  height: 100%;
+}
+
+// Improve media defaults
+img, picture, video, canvas, svg {
+  display: block;
+  max-width: 100%;
+}