diff --git a/styles.css b/styles.css
index cb5ce9b..093b898 100644
--- a/styles.css
+++ b/styles.css
@@ -1,4 +1,10 @@
 /* tugtile — markdown kanban (prototype, read-only renderer) */
+/* Squircle corners: continuous-curvature corners layered on top of the existing
+   border-radius. corner-shape is Chromium-only as of mid-2026 (Safari/WebKit & Firefox
+   ignore it and keep the plain border-radius arc), so this is pure progressive
+   enhancement with zero visual regression. corner-shape needs a non-zero radius to do
+   anything and is not inherited — but the custom property is, so we route through a token. */
+:root { --corner: squircle; }
 .tugtile {
   height: 100%;
   padding: 0;
@@ -44,7 +50,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
 .tugtile-brand {
   display: inline-flex; align-items: center; gap: 5px;
   color: var(--text-faint); font-weight: var(--font-normal);
-  cursor: pointer; border-radius: var(--radius-s); padding: 2px 6px;
+  cursor: pointer; border-radius: var(--radius-s); corner-shape: var(--corner); padding: 2px 6px;
 }
 .tugtile-brand:hover { background: var(--background-modifier-hover); color: var(--text-muted); }
 .tugtile-lock-icon { display: inline-flex; }
@@ -77,7 +83,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
   display: flex;
   flex-direction: column;
   background: var(--background-secondary);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   padding: 8px;
   overflow: hidden;         /* Cleanly clips content into the changing lane width during collapse/expand (dragging uses a clone on body and is unaffected) */
   --tg-d1: 0.26s;           /* Stage 1: lane narrows + horizontal title tucks into the chevron (collapse) / widens + title grows back (expand) */
@@ -127,7 +133,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
   position: relative;
   background: var(--background-primary);
   border: 1px solid var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   padding: 8px;
   cursor: grab;
 }
@@ -167,7 +173,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
   padding: 0 0.4em;
   background: var(--interactive-accent);
   color: var(--text-on-accent);
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
   font-weight: 700;
   line-height: 1.25;
 }
@@ -212,7 +218,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
   z-index: 9999;
   background: var(--background-primary);
   border: 1px solid var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   box-shadow: var(--shadow-l);
   padding: 8px;
   user-select: none;
@@ -241,7 +247,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
 .tugtile__popup-w { opacity: 0.5; font-size: 0.8em; }
 .tugtile__popup-d {
   cursor: pointer;
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
   padding: 3px 0;
   line-height: 1.4;
 }
@@ -255,7 +261,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
 .tugtile__popup-t {
   cursor: pointer;
   padding: 4px 16px;
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
 }
 .tugtile__popup-t:hover { background: var(--background-modifier-hover); }
 /* Tag chips at the bottom of the card (when move-tags-to-card-footer is enabled) */
@@ -305,7 +311,7 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
   text-align: left;
   background: transparent;
   border: 1px dashed var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   color: var(--text-muted);
   padding: 8px;              /* Match card padding and the add-lane button (consistent 8px rhythm); left-aligned "+" lines up with the card number chip */
   cursor: pointer;
@@ -318,13 +324,13 @@ body.is-phone .workspace-leaf-content[data-type="tugtile-board"] .view-content {
   width: 100%;
   min-height: 4em;
   resize: vertical;
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
 }
 .tugtile__add-ok {
   background: var(--interactive-accent);
   color: var(--text-on-accent);
   border: none;
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
   padding: 4px 12px;
   cursor: pointer;
 }
@@ -438,7 +444,7 @@ body.is-phone .tugtile-prompt-modal { margin-top: calc(env(safe-area-inset-top)
   box-sizing: border-box; height: 40px; padding: 0 12px;
   background: var(--background-modifier-form-field);
   border: 1px solid var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   overflow: hidden;   /* Clip the input to the rounded box so it can never poke out of the corners */
 }
 .tugtile-prompt-field:focus-within { border-color: var(--interactive-accent); }
@@ -497,7 +503,7 @@ input.tugtile-prompt-input:active {
   -webkit-appearance: none; appearance: none;
   position: relative;
   width: 40px; height: 40px;
-  border: none; border-radius: var(--radius-m);
+  border: none; border-radius: var(--radius-m); corner-shape: var(--corner);
   background: transparent; color: var(--text-muted);
   cursor: pointer;
 }
@@ -542,7 +548,7 @@ body.is-phone .tugtile-ed-bar { padding-top: 6px; padding-bottom: 4px; }
 }
 .tugtile-ed-find-i {
   flex: 1; min-width: 80px;
-  font-size: 16px; padding: 5px 8px; border-radius: var(--radius-s);   /* 16px avoids iOS focus-zoom */
+  font-size: 16px; padding: 5px 8px; border-radius: var(--radius-s); corner-shape: var(--corner);   /* 16px avoids iOS focus-zoom */
 }
 .tugtile-ed-find-n { flex: 0 0 auto; color: var(--text-muted); font-size: 0.85em; min-width: 1.6em; text-align: center; }
 /* .tugtile-ed-find-b inherits everything from .tugtile-iconbtn */
@@ -609,7 +615,7 @@ body.is-phone .tugtile-ed-bar { padding-top: 6px; padding-bottom: 4px; }
 .marktile-toc-item--ghost { opacity: 0.4; background: var(--background-modifier-hover); }   /* the gap left behind */
 .marktile-toc-item--chosen { box-shadow: inset 0 0 0 2px var(--interactive-accent); }        /* the picked row */
 .marktile-toc-item--drag {   /* the row following the finger (re-parented to <body> by fallbackOnBody) */
-  opacity: 0.97; background: var(--background-secondary); border-radius: 6px;
+  opacity: 0.97; background: var(--background-secondary); border-radius: 6px; corner-shape: var(--corner);
   box-shadow: 0 10px 24px rgba(0, 0, 0, 0.4); cursor: grabbing;
   rotate: 3deg; scale: 1.03;   /* "picked up" tilt — standalone props (NOT transform) so Sortable's drag translation isn't overwritten */
 }
@@ -658,7 +664,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
   width: 100%;
   min-height: 4em;
   resize: vertical;
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
 }
 /* Lane header container */
 .tugtile__lane-title {
@@ -679,7 +685,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
 .tugtile__lane-rename {
   flex: 1;
   font-weight: 700;
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
 }
 /* Responsive board (opt-in, default off): on a narrow pane the horizontal lanes reflow into a single full-width vertical stack — the behaviour of the retired List view, now automatic via a container query. Drag-and-drop/editing logic is shared with the board view. */
 .tugtile--rwd { container-type: inline-size; container-name: tugtileboard; }
@@ -698,7 +704,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
 /* Centered header view-cycle control: "<icon> <name>" — click cycles board → table → markdown. Same padding as the lock button so the "·" separator sits symmetrically between them. */
 .tugtile-viewcycle {
   display: inline-flex; align-items: center; gap: 5px;
-  cursor: pointer; border-radius: var(--radius-s);
+  cursor: pointer; border-radius: var(--radius-s); corner-shape: var(--corner);
   padding: 2px 6px;
 }
 .tugtile-viewcycle:hover { background: var(--background-modifier-hover); }
@@ -749,7 +755,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
   margin: 0 12px 8px;
   padding: 12px;
   border: 2px dashed var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   background: var(--background-secondary);
   color: var(--text-muted);
   font-weight: 600;
@@ -762,7 +768,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
   flex: 0 0 auto;
   width: 1.6em;
   height: 1.6em;
-  border-radius: var(--radius-s);
+  border-radius: var(--radius-s); corner-shape: var(--corner);
   /* Opaque (translucent hover tint composited over the lane bg) so the vertical title retracting INTO the
      chevron during collapse/expand is fully masked — a see-through button would leak that text. */
   background: linear-gradient(var(--background-modifier-hover), var(--background-modifier-hover)), var(--background-secondary);
@@ -862,7 +868,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
   gap: 8px;
   padding: 8px;
   border: 1px solid var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
 }
 .tugtile-archive-body {
   flex: 1;
@@ -886,7 +892,7 @@ body.is-phone .tugtile-ed-rich { padding-bottom: 55vh; }
   text-align: left;          /* Match the add-card button (consistent left-aligned "+ label") */
   background: transparent;
   border: 1px dashed var(--background-modifier-border);
-  border-radius: var(--radius-m);
+  border-radius: var(--radius-m); corner-shape: var(--corner);
   color: var(--text-muted);
   padding: 8px;
   cursor: pointer;