diff --git a/styles.css b/styles.css
index f291da8..0c32490 100644
--- a/styles.css
+++ b/styles.css
@@ -174,6 +174,15 @@ table.matrix td:first-child { font-weight: 600; }
 .dl-card h3 { font-size: 20px; }
 .dl-card .ver { font-size: 12.5px; color: var(--ink-500); }
 .dl-card .btn { width: 100%; margin-top: 18px; }
+.dl-card .btn + .btn { margin-top: 10px; }
+.dev-toggle { margin-top: 22px; border-top: 1px solid var(--line); padding-top: 18px; }
+.dev-toggle summary { cursor: pointer; font-size: 13px; color: var(--ink-600); user-select: none; list-style: none; display: flex; align-items: center; gap: 6px; }
+.dev-toggle summary::-webkit-details-marker { display: none; }
+.dev-toggle summary::before { content: "▸"; font-size: 10px; transition: transform .15s; color: var(--ink-500); }
+.dev-toggle[open] summary::before { transform: rotate(90deg); }
+.dev-toggle summary:hover { color: var(--ink-800); }
+.dev-toggle .steps { margin-top: 16px; }
+.dev-note { font-size: 12.5px; color: var(--ink-500); margin-top: 14px; font-style: italic; }
 .steps { margin-top: 22px; counter-reset: s; display: grid; gap: 14px; }
 .steps li { list-style: none; display: flex; gap: 13px; font-size: 14px; color: var(--ink-700); }
 .steps li::before { counter-increment: s; content: counter(s); flex: none; width: 24px; height: 24px; border-radius: 99px; background: var(--accent); color: var(--accent-contrast); font-size: 12px; font-weight: 700; display: grid; place-items: center; }