use padding rather than margin to avoid margin collapse; drop overflow clear approach

src/components/join-flow/join-flow-step.scss

@@ -9,6 +9,8 @@
 .join-flow-inner-content {
     box-shadow: none;
     width: calc(100% - 5.875rem);
-    margin: 2.3125rem auto 2.5rem;
+    /* must use padding for top, rather than margin, because margins will collapse */
+    margin: 0 auto;
+    padding: 2.3125rem 0 2.5rem;
     font-size: .875rem;
 }

src/components/modal/base/modal-inner-content.jsx

@@ -8,7 +8,6 @@ const ModalInnerContent = ({
     children,
     className
 }) => (
-    <div className="modal-inner-clear">
     <div
         className={classNames(
             'modal-inner-content',
@@ -17,7 +16,6 @@ const ModalInnerContent = ({
     >
         {children}
     </div>
-    </div>
 );
 
 ModalInnerContent.propTypes = {

src/components/modal/base/modal-inner-content.scss

@@ -1,15 +1,6 @@
 @import "../../../colors";
 @import "../../../frameless";
 
-/*
-necessary to prevent modal-inner-content's margins from
-unexpectedly collapsing with a parent
-*/
-.modal-inner-clear {
-    overflow: auto;
-    height: 100%;
-}
-
 .modal-inner-content {
     box-sizing: border-box;
     display: flex;