diff --git a/web/src/styles.css b/web/src/styles.css
index 12e043a..a98642b 100644
--- a/web/src/styles.css
+++ b/web/src/styles.css
@@ -18,6 +18,23 @@
 }
 
 * { box-sizing: border-box; }
+
+/* The table is a control surface, not a document. Dragging across it should never
+   paint a card's number blue or pop a long-press copy menu on mobile. Selection is
+   off everywhere and turned back on only for text you would actually want to copy
+   or edit -- in practice the seed field. user-select does not touch click or focus,
+   so every button still works. */
+.app-shell {
+  user-select: none;
+  -webkit-user-select: none;
+  -webkit-touch-callout: none;
+}
+
+.app-shell input,
+.app-shell textarea {
+  user-select: text;
+  -webkit-user-select: text;
+}
 html, body, #root { min-width: 1024px; min-height: 100%; margin: 0; }
 /* Below the supported minimum width/height the board no longer shrinks
    (app-shell keeps a 1024x720 floor), so allow scrolling instead of clipping