diff --git a/theme/icons/heading1.svg b/theme/icons/heading1.svg
index 8906a9c..aa581f0 100644
--- a/theme/icons/heading1.svg
+++ b/theme/icons/heading1.svg
@@ -1 +1 @@
-<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><path d="M19 9v10h-2v-8h-2V9h4zM4 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1H10a1 1 0 0 1-1-1V11H4v4.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1H3a1 1 0 0 1 1 1v4.5z" fill="#2E2E2E" fill-rule="evenodd"/></svg>
\ No newline at end of file
+<svg viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M19 9v10h-2v-8h-2V9h4zM4 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1H10a1 1 0 0 1-1-1V11H4v4.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1H3a1 1 0 0 1 1 1v4.5z"/></svg>
\ No newline at end of file
diff --git a/theme/icons/heading2.svg b/theme/icons/heading2.svg
index a085964..9a0d965 100644
--- a/theme/icons/heading2.svg
+++ b/theme/icons/heading2.svg
@@ -1 +1 @@
-<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><path d="M3 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1H9a1 1 0 0 1-1-1V11H3v4.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1H2a1 1 0 0 1 1 1v4.5zm16.076 8.343V18.5h-6.252c.067-.626.27-1.22.61-1.78.338-.561 1.006-1.305 2.005-2.232.804-.749 1.297-1.257 1.479-1.523.245-.368.368-.732.368-1.092 0-.398-.107-.703-.32-.917-.214-.214-.51-.32-.886-.32-.372 0-.669.111-.889.336-.22.224-.347.596-.38 1.117l-1.778-.178c.106-.982.438-1.686.997-2.114.558-.427 1.257-.64 2.095-.64.918 0 1.64.247 2.164.742.525.495.787 1.11.787 1.847 0 .419-.075.818-.225 1.197-.15.378-.388.775-.714 1.19-.216.275-.605.67-1.168 1.187-.563.516-.92.859-1.07 1.028-.15.17-.272.334-.365.495h3.542z" fill="#2E2E2E" fill-rule="evenodd"/></svg>
\ No newline at end of file
+<svg viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M3 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1H9a1 1 0 0 1-1-1V11H3v4.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1H2a1 1 0 0 1 1 1v4.5zm16.076 8.343V18.5h-6.252c.067-.626.27-1.22.61-1.78.338-.561 1.006-1.305 2.005-2.232.804-.749 1.297-1.257 1.479-1.523.245-.368.368-.732.368-1.092 0-.398-.107-.703-.32-.917-.214-.214-.51-.32-.886-.32-.372 0-.669.111-.889.336-.22.224-.347.596-.38 1.117l-1.778-.178c.106-.982.438-1.686.997-2.114.558-.427 1.257-.64 2.095-.64.918 0 1.64.247 2.164.742.525.495.787 1.11.787 1.847 0 .419-.075.818-.225 1.197-.15.378-.388.775-.714 1.19-.216.275-.605.67-1.168 1.187-.563.516-.92.859-1.07 1.028a3.11 3.11 0 0 0-.365.495h3.542z"/></svg>
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diff --git a/theme/icons/heading3.svg b/theme/icons/heading3.svg
index 2701283..279c3c9 100644
--- a/theme/icons/heading3.svg
+++ b/theme/icons/heading3.svg
@@ -1 +1 @@
-<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><path d="M3 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1H9a1 1 0 0 1-1-1V11H3v4.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1H2a1 1 0 0 1 1 1v4.5zm9.989 7.53l1.726-.209c.055.44.203.777.445 1.01.24.232.533.349.876.349.368 0 .678-.14.93-.42.251-.279.377-.655.377-1.13 0-.448-.12-.803-.362-1.066a1.153 1.153 0 0 0-.882-.393c-.228 0-.501.044-.819.133l.197-1.453c.482.012.85-.092 1.105-.315.253-.222.38-.517.38-.885 0-.313-.093-.563-.279-.75-.186-.185-.434-.278-.743-.278-.304 0-.565.105-.78.317-.216.212-.347.52-.394.927l-1.644-.28c.114-.562.287-1.012.517-1.348.231-.337.553-.601.965-.794a3.24 3.24 0 0 1 1.387-.289c.876 0 1.579.28 2.108.838.436.457.653.973.653 1.549 0 .817-.446 1.468-1.339 1.955.533.114.96.37 1.28.768.319.398.478.878.478 1.441 0 .817-.298 1.513-.895 2.088-.596.576-1.339.864-2.228.864-.842 0-1.54-.243-2.094-.727-.555-.485-.876-1.118-.965-1.901z" fill="#2E2E2E" fill-rule="evenodd"/></svg>
\ No newline at end of file
+<svg viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M3 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1H9a1 1 0 0 1-1-1V11H3v4.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1H2a1 1 0 0 1 1 1v4.5zm9.989 7.53l1.726-.209c.055.44.203.777.445 1.01.24.232.533.349.876.349.368 0 .678-.14.93-.42.251-.279.377-.655.377-1.13 0-.448-.12-.803-.362-1.066a1.153 1.153 0 0 0-.882-.393c-.228 0-.501.044-.819.133l.197-1.453c.482.012.85-.092 1.105-.315.253-.222.38-.517.38-.885 0-.313-.093-.563-.279-.75-.186-.185-.434-.278-.743-.278a1.07 1.07 0 0 0-.78.317c-.216.212-.347.52-.394.927l-1.644-.28c.114-.562.287-1.012.517-1.348.231-.337.553-.601.965-.794a3.24 3.24 0 0 1 1.387-.289c.876 0 1.579.28 2.108.838.436.457.653.973.653 1.549 0 .817-.446 1.468-1.339 1.955.533.114.96.37 1.28.768.319.398.478.878.478 1.441 0 .817-.298 1.513-.895 2.088-.596.576-1.339.864-2.228.864-.842 0-1.54-.243-2.094-.727-.555-.485-.876-1.118-.965-1.901z"/></svg>
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diff --git a/theme/icons/heading4.svg b/theme/icons/heading4.svg
index a2c71a6..c6891fe 100644
--- a/theme/icons/heading4.svg
+++ b/theme/icons/heading4.svg
@@ -1 +1 @@
-<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><path d="M3.5 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V11h-5v4.5a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v4.5zM17.05 18.5v-1.873H13.24v-1.561l4.037-5.91h1.498v5.904h1.156v1.567h-1.156V18.5H17.05zm0-3.44v-3.18l-2.14 3.18h2.14z"/></svg>
+<svg viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M3.5 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V11h-5v4.5a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v4.5zm13.55 10v-1.873h-3.81v-1.561l4.037-5.91h1.498v5.904h1.156v1.567h-1.156V18.5H17.05zm0-3.44v-3.18l-2.14 3.18h2.14z"/></svg>
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diff --git a/theme/icons/heading5.svg b/theme/icons/heading5.svg
index adff14b..c3aed18 100644
--- a/theme/icons/heading5.svg
+++ b/theme/icons/heading5.svg
@@ -1 +1 @@
-<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><path d="M3.5 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V11h-5v4.5a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v4.5zM13.078 16.107l1.777-.184c.05.402.201.72.45.955a1.223 1.223 0 0 0 1.81-.101c.258-.303.387-.759.387-1.368 0-.572-.128-1-.384-1.286-.256-.285-.59-.428-1-.428-.512 0-.971.226-1.377.679l-1.448-.21.915-4.843h4.716v1.67H15.56l-.28 1.58a2.697 2.697 0 0 1 1.219-.298c.791 0 1.462.288 2.012.863.55.576.825 1.323.825 2.241a3.36 3.36 0 0 1-.666 2.05c-.605.821-1.445 1.232-2.52 1.232-.86 0-1.56-.23-2.101-.692-.542-.461-.866-1.081-.971-1.86z"/></svg>
+<svg viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M3.5 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V11h-5v4.5a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v4.5zm9.578 7.607l1.777-.184c.05.402.201.72.45.955a1.223 1.223 0 0 0 1.81-.101c.258-.303.387-.759.387-1.368 0-.572-.128-1-.384-1.286-.256-.285-.59-.428-1-.428-.512 0-.971.226-1.377.679l-1.448-.21.915-4.843h4.716v1.67H15.56l-.28 1.58a2.697 2.697 0 0 1 1.219-.298 2.68 2.68 0 0 1 2.012.863c.55.576.825 1.323.825 2.241a3.36 3.36 0 0 1-.666 2.05c-.605.821-1.445 1.232-2.52 1.232-.86 0-1.56-.23-2.101-.692-.542-.461-.866-1.081-.971-1.86z"/></svg>
\ No newline at end of file
diff --git a/theme/icons/heading6.svg b/theme/icons/heading6.svg
index 48d24e2..1054809 100644
--- a/theme/icons/heading6.svg
+++ b/theme/icons/heading6.svg
@@ -1 +1 @@
-<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><path d="M3.5 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V11h-5v4.5a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v4.5zM19.095 11.473l-1.726.19c-.043-.355-.153-.617-.33-.787-.178-.169-.409-.253-.692-.253-.377 0-.695.169-.956.507-.26.339-.424 1.043-.492 2.114.445-.525.997-.787 1.657-.787.745 0 1.383.284 1.914.85.531.568.797 1.3.797 2.197 0 .952-.28 1.716-.838 2.291-.559.576-1.276.864-2.152.864-.94 0-1.712-.365-2.317-1.095-.605-.73-.908-1.927-.908-3.59 0-1.705.316-2.935.946-3.688.63-.753 1.45-1.13 2.457-1.13.706 0 1.291.198 1.755.594.463.395.758.97.885 1.723zm-4.043 3.891c0 .58.133 1.028.4 1.343.266.315.57.473.914.473.33 0 .605-.13.825-.388.22-.258.33-.68.33-1.27 0-.604-.118-1.047-.355-1.329a1.115 1.115 0 0 0-.89-.422c-.342 0-.632.134-.869.403s-.355.666-.355 1.19z"/></svg>
+<svg viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M3.5 8.5h5V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v11.5a1 1 0 0 1-1 1h-.5a1 1 0 0 1-1-1V11h-5v4.5a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h.5a1 1 0 0 1 1 1v4.5zm15.595 2.973l-1.726.19c-.043-.355-.153-.617-.33-.787-.178-.169-.409-.253-.692-.253-.377 0-.695.169-.956.507-.26.339-.424 1.043-.492 2.114.445-.525.997-.787 1.657-.787.745 0 1.383.284 1.914.85.531.568.797 1.3.797 2.197 0 .952-.28 1.716-.838 2.291-.559.576-1.276.864-2.152.864-.94 0-1.712-.365-2.317-1.095-.605-.73-.908-1.927-.908-3.59 0-1.705.316-2.935.946-3.688.63-.753 1.45-1.13 2.457-1.13.706 0 1.291.198 1.755.594.463.395.758.97.885 1.723zm-4.043 3.891c0 .58.133 1.028.4 1.343.266.315.57.473.914.473.33 0 .605-.13.825-.388.22-.258.33-.68.33-1.27 0-.604-.118-1.047-.355-1.329a1.115 1.115 0 0 0-.89-.422c-.342 0-.632.134-.869.403s-.355.666-.355 1.19z"/></svg>
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