diff --git a/edit/edit.css b/edit/edit.css
index 21f27057..5489a7ad 100644
--- a/edit/edit.css
+++ b/edit/edit.css
@@ -263,14 +263,20 @@ input:invalid {
 #lint:not([open]) + #footer {
   margin-top: 4em;
 }
-/************ content ***********/
-#sections > * {
+/************ section editor ***********/
+.section-editor .section {
   margin: 0 0.7rem;
   padding: 1rem;
 }
-#sections > :not(:first-child) {
+.section-editor .section:not(:first-child) {
   border-top: 2px solid hsl(0, 0%, 80%);
 }
+.section-editor:not(.section-editor-ready) .section {
+  visibility: hidden;
+}
+.section-editor:not(.section-editor-ready) .CodeMirror {
+  height: 0;
+}
 .add-section:after {
   content: attr(short-text);
 }
@@ -311,6 +317,7 @@ input:invalid {
 }
 .section .CodeMirror {
   margin-bottom: .875rem;
+  box-sizing: border-box;
 }
 /* deleted section */
 .deleted-section {
@@ -950,12 +957,8 @@ html:not(.usercss) .usercss-only,
     flex: 1;
   }
   #sections > * {
-    margin: 0 .5rem .5rem;
-    padding: .5rem 0 0;
-  }
-  #sections > *:first-child {
-    margin: .5rem;
-    padding: 0;
+    margin: 0 .5rem;
+    padding: .5rem 0;
   }
   .usercss .CodeMirror-scroll {
     max-height: calc(100vh - var(--header-narrow-min-height));
diff --git a/edit/refresh-on-view.js b/edit/refresh-on-view.js
index 0fa123d6..ffbc0589 100644
--- a/edit/refresh-on-view.js
+++ b/edit/refresh-on-view.js
@@ -10,6 +10,7 @@ CodeMirror.defineExtension('refreshOnView', function () {
   const cm = this;
   if (typeof IntersectionObserver === 'undefined') {
     // uh
+    cm.isRefreshed = true;
     cm.refresh();
     return;
   }
@@ -18,6 +19,7 @@ CodeMirror.defineExtension('refreshOnView', function () {
     for (const entry of entries) {
       if (entry.isIntersecting) {
         // wrapper.style.visibility = 'visible';
+        cm.isRefreshed = true;
         cm.refresh();
         observer.disconnect();
       }
diff --git a/edit/sections-editor-section.js b/edit/sections-editor-section.js
index 74540e79..67880a35 100644
--- a/edit/sections-editor-section.js
+++ b/edit/sections-editor-section.js
@@ -9,7 +9,11 @@ function createResizeGrip(cm) {
   const resizeGrip = template.resizeGrip.cloneNode(true);
   wrapper.appendChild(resizeGrip);
   let lastClickTime = 0;
+  let initHeight;
+  let initY;
   resizeGrip.onmousedown = event => {
+    initHeight = wrapper.offsetHeight;
+    initY = event.pageY;
     if (event.button !== 0) {
       return;
     }
@@ -31,9 +35,8 @@ function createResizeGrip(cm) {
     document.addEventListener('mouseup', resizeStop);
 
     function resize(e) {
-      const cmPageY = wrapper.getBoundingClientRect().top + window.scrollY;
-      const height = Math.max(minHeight, e.pageY - cmPageY);
-      if (height !== wrapper.clientHeight) {
+      const height = Math.max(minHeight, initHeight + e.pageY - initY);
+      if (height !== wrapper.offsetHeight) {
         cm.setSize(null, height);
       }
     }
diff --git a/edit/sections-editor.js b/edit/sections-editor.js
index 99772f2b..c4b7cab3 100644
--- a/edit/sections-editor.js
+++ b/edit/sections-editor.js
@@ -13,6 +13,8 @@ function createSectionsEditor({style, onTitleChanged}) {
   const container = $('#sections');
   const sections = [];
 
+  container.classList.add('section-editor');
+
   const nameEl = $('#name');
   nameEl.addEventListener('input', () => {
     dirty.modify('name', style.name, nameEl.value);
@@ -48,12 +50,11 @@ function createSectionsEditor({style, onTitleChanged}) {
   const initializing = new Promise(resolve => initSection({
     sections: style.sections.slice(),
     done:() => {
-      // FIXME: implement this with CSS?
-      // https://github.com/openstyles/stylus/commit/2895ce11e271788df0e4f7314b3b981fde086574
       dirty.clear();
       rerouteHotkeys(true);
       resolve();
       updateHeader();
+      sections.forEach(fitToContent);
     }
   }));
 
@@ -80,6 +81,45 @@ function createSectionsEditor({style, onTitleChanged}) {
     getSearchableInputs,
   };
 
+  function fitToContent(section) {
+    if (section.cm.isRefreshed) {
+      resize();
+    } else {
+      section.cm.on('update', resize);
+    }
+
+    function resize() {
+      let contentHeight = section.el.querySelector('.CodeMirror-sizer').offsetHeight;
+      if (contentHeight < section.cm.defaultTextHeight()) {
+        return;
+      }
+      contentHeight += 9; // border & resize grip
+      section.cm.off('update', resize);
+      const cmHeight = section.cm.getWrapperElement().offsetHeight;
+      const maxHeight = cmHeight + window.innerHeight - section.el.offsetHeight;
+      section.cm.setSize(null, Math.min(contentHeight, maxHeight));
+      if (sections.every(s => s.cm.isRefreshed)) {
+        fitToAvailableSpace();
+      }
+      setTimeout(() => {
+        container.classList.add('section-editor-ready');
+      }, 50);
+    }
+  }
+
+  function fitToAvailableSpace() {
+    const available =
+      Math.floor(container.offsetHeight - sections.reduce((h, s) => h + s.el.offsetHeight, 0)) ||
+      window.innerHeight - container.offsetHeight;
+    if (available <= 0) {
+      return;
+    }
+    const cmHeights = sections.map(s => s.cm.getWrapperElement().offsetHeight);
+    sections.forEach((section, i) => {
+      section.cm.setSize(null, cmHeights[i] + Math.floor(available / sections.length));
+    });
+  }
+
   function genId() {
     return INC_ID++;
   }